TY  - JOUR
AU  - Filipić, Brankica
AU  - Ušjak, Dušan
AU  - Hrast Rambaher, Martina
AU  - Oljačić, Slavica
AU  - Milenković, Marina
PY  - 2024
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/5574
AB  - Antimicrobial resistance is a global threat, leading to an alarming increase in the prevalence of bacterial infections that can no longer be treated with available antibiotics. The World Health Organization estimates that by 2050 up to 10 million deaths per year could be associated with antimicrobial resistance, which would equal the annual number of cancer deaths worldwide. To overcome this emerging crisis, novel anti-bacterial compounds are urgently needed. There are two possible approaches in the fight against bacterial infections: a) targeting structures within bacterial cells, similar to existing antibiotics; and/or b) targeting virulence factors rather than bacterial growth. Here, for the first time, we provide a comprehensive overview of the key steps in the evaluation of potential new anti-bacterial and/or anti-virulence compounds. The methods described in this review include: a) in silico methods for the evaluation of novel compounds; b) anti-bacterial assays (MIC, MBC, Time-kill); b) anti-virulence assays (anti-biofilm, anti-quorum sensing, anti-adhesion); and c) evaluation of safety aspects (cytotoxicity assay and Ames test). Overall, we provide a detailed description of the methods that are an essential tool for chemists, computational chemists, microbiologists, and toxicologists in the evaluation of potential novel antimicrobial compounds. These methods are cost-effective and have high predictive value. They are widely used in preclinical studies to identify new molecular candidates, for further investigation in animal and human trials.
PB  - Frontiers Media SA
T2  - Frontiers in Cellular and Infection Microbiology
T1  - Evaluation of novel compounds as anti-bacterial or anti-virulence agents
VL  - 14
DO  - 10.3389/fcimb.2024.1370062
ER  - 

@article{
author = "Filipić, Brankica and Ušjak, Dušan and Hrast Rambaher, Martina and Oljačić, Slavica and Milenković, Marina",
year = "2024",
abstract = "Antimicrobial resistance is a global threat, leading to an alarming increase in the prevalence of bacterial infections that can no longer be treated with available antibiotics. The World Health Organization estimates that by 2050 up to 10 million deaths per year could be associated with antimicrobial resistance, which would equal the annual number of cancer deaths worldwide. To overcome this emerging crisis, novel anti-bacterial compounds are urgently needed. There are two possible approaches in the fight against bacterial infections: a) targeting structures within bacterial cells, similar to existing antibiotics; and/or b) targeting virulence factors rather than bacterial growth. Here, for the first time, we provide a comprehensive overview of the key steps in the evaluation of potential new anti-bacterial and/or anti-virulence compounds. The methods described in this review include: a) in silico methods for the evaluation of novel compounds; b) anti-bacterial assays (MIC, MBC, Time-kill); b) anti-virulence assays (anti-biofilm, anti-quorum sensing, anti-adhesion); and c) evaluation of safety aspects (cytotoxicity assay and Ames test). Overall, we provide a detailed description of the methods that are an essential tool for chemists, computational chemists, microbiologists, and toxicologists in the evaluation of potential novel antimicrobial compounds. These methods are cost-effective and have high predictive value. They are widely used in preclinical studies to identify new molecular candidates, for further investigation in animal and human trials.",
publisher = "Frontiers Media SA",
journal = "Frontiers in Cellular and Infection Microbiology",
title = "Evaluation of novel compounds as anti-bacterial or anti-virulence agents",
volume = "14",
doi = "10.3389/fcimb.2024.1370062"
}

Filipić, B., Ušjak, D., Hrast Rambaher, M., Oljačić, S.,& Milenković, M.. (2024). Evaluation of novel compounds as anti-bacterial or anti-virulence agents. in Frontiers in Cellular and Infection Microbiology
Frontiers Media SA., 14.
https://doi.org/10.3389/fcimb.2024.1370062

Filipić B, Ušjak D, Hrast Rambaher M, Oljačić S, Milenković M. Evaluation of novel compounds as anti-bacterial or anti-virulence agents. in Frontiers in Cellular and Infection Microbiology. 2024;14.
doi:10.3389/fcimb.2024.1370062 .

Filipić, Brankica, Ušjak, Dušan, Hrast Rambaher, Martina, Oljačić, Slavica, Milenković, Marina, "Evaluation of novel compounds as anti-bacterial or anti-virulence agents" in Frontiers in Cellular and Infection Microbiology, 14 (2024),
https://doi.org/10.3389/fcimb.2024.1370062 . .

TY  - JOUR
AU  - Mićović, Tijana
AU  - Ušjak, Dušan
AU  - Milenković, Marina
AU  - Samardžić, Stevan
AU  - Maksimović, Zoran
PY  - 2023
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/5463
AB  - In this study, antimicrobial activity of essential oils extracted from the aerial flowering parts (herbs) of Hyssopus officinalis subsp. aristatus (Godr.) Nyman (Lamiaceae) collected from five different locations in Montenegro, or purchased in Serbia, were investigated. In addition, their antibacterial activity in combination with antibiotics was studied. The antimicrobial activity against selected standard bacterial and yeast strains was investigated using the broth microdilution method. Two standard antibiotics were used for comparison: the aminoglycoside antibiotic amikacin and the cephalosporin antibiotic ceftriaxone. The antimicrobial activity of the essential oil-amikacin combination was investigated using the checkerboard assay. The main components of the essential oils were 1,8-cineole, cis-pinocamphone, β-pinene and limonene in varying quantities. Most of the tested essential oils showed no significant antimicrobial activity. However, an essential oil rich in cis-pinocamphone showed moderate activity against both Staphylococcus aureus and Escherichia coli (MIC = 400 µg/mL). The overall effect of the essential oils and antibiotic combinations against E. coli or S. aureus ranged from additive (FICI = 0.625) to indifferent (FICI = 1.5), depending on the source of the essential oil.
PB  - Institut za proučavanje lekovitog bilja Dr Josif Pančić, Beograd
T2  - Lekovite sirovine
T1  - Antimicrobial activity of Hyssopus officinalis L. subsp. aristatus (Godr.) Nyman (Lamiaceae) essential oils from Montenegro and Serbia
VL  - 43
DO  - 10.61652/leksir2343e173M
ER  - 

@article{
author = "Mićović, Tijana and Ušjak, Dušan and Milenković, Marina and Samardžić, Stevan and Maksimović, Zoran",
year = "2023",
abstract = "In this study, antimicrobial activity of essential oils extracted from the aerial flowering parts (herbs) of Hyssopus officinalis subsp. aristatus (Godr.) Nyman (Lamiaceae) collected from five different locations in Montenegro, or purchased in Serbia, were investigated. In addition, their antibacterial activity in combination with antibiotics was studied. The antimicrobial activity against selected standard bacterial and yeast strains was investigated using the broth microdilution method. Two standard antibiotics were used for comparison: the aminoglycoside antibiotic amikacin and the cephalosporin antibiotic ceftriaxone. The antimicrobial activity of the essential oil-amikacin combination was investigated using the checkerboard assay. The main components of the essential oils were 1,8-cineole, cis-pinocamphone, β-pinene and limonene in varying quantities. Most of the tested essential oils showed no significant antimicrobial activity. However, an essential oil rich in cis-pinocamphone showed moderate activity against both Staphylococcus aureus and Escherichia coli (MIC = 400 µg/mL). The overall effect of the essential oils and antibiotic combinations against E. coli or S. aureus ranged from additive (FICI = 0.625) to indifferent (FICI = 1.5), depending on the source of the essential oil.",
publisher = "Institut za proučavanje lekovitog bilja Dr Josif Pančić, Beograd",
journal = "Lekovite sirovine",
title = "Antimicrobial activity of Hyssopus officinalis L. subsp. aristatus (Godr.) Nyman (Lamiaceae) essential oils from Montenegro and Serbia",
volume = "43",
doi = "10.61652/leksir2343e173M"
}

Mićović, T., Ušjak, D., Milenković, M., Samardžić, S.,& Maksimović, Z.. (2023). Antimicrobial activity of Hyssopus officinalis L. subsp. aristatus (Godr.) Nyman (Lamiaceae) essential oils from Montenegro and Serbia. in Lekovite sirovine
Institut za proučavanje lekovitog bilja Dr Josif Pančić, Beograd., 43.
https://doi.org/10.61652/leksir2343e173M

Mićović T, Ušjak D, Milenković M, Samardžić S, Maksimović Z. Antimicrobial activity of Hyssopus officinalis L. subsp. aristatus (Godr.) Nyman (Lamiaceae) essential oils from Montenegro and Serbia. in Lekovite sirovine. 2023;43.
doi:10.61652/leksir2343e173M .

Mićović, Tijana, Ušjak, Dušan, Milenković, Marina, Samardžić, Stevan, Maksimović, Zoran, "Antimicrobial activity of Hyssopus officinalis L. subsp. aristatus (Godr.) Nyman (Lamiaceae) essential oils from Montenegro and Serbia" in Lekovite sirovine, 43 (2023),
https://doi.org/10.61652/leksir2343e173M . .

TY  - CONF
AU  - Radović-Selgrad, Jelena
AU  - Ušjak, Dušan
AU  - Milenković, Marina
AU  - Kundaković-Vasović, Tatjana
PY  - 2022
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/4580
AB  - Dry methanol extract (DER 3.95:1) of aerial flowering parts of Alchemilla viridiflora
Rothm., Rosaceae, obtained after successive extraction with cyclohexane and
dichloromethane, predominantly contains polyphenols, tannins (3.74%), mostly ellagic, and
flavonoids (0.30%), hexosides of quercetin and kaempferol. It shows ACE inhibitory and
anti-Helicobacter pylori activity in vitro (1). Based on the traditional use of the common A.
vulgaris in the treatment of diabetes (2), the effect of this A. viridiflora extract on α-amylase
activity in vitro and lowering blood glucose in rats were investigated. α-Amylase inhibitory
activity was assessed using the 3,5-dinitrosalicylic acid method. Extract in doses of 50, 100
and 200 mg/kg, p.o., was administered to streptozotocin-induced diabetic rats for 20 days,
and blood glucose level and weight of rats were monitored during treatment. Extract
inhibited α-amylase activity at IC 50 5.47 ± 0.30 mg/mL. A dose of 200 mg/kg significantly
decreased blood glucose level after 10 (32.2%) and 20 days of treatment (38.3%). The effect
of this dose was similar to the effect of the reference drug, glibenclamide. A dose of 100
mg/kg significantly increased glucose level by day 10 (50.5%) and a reduction in blood sugar
level of 51.2% was observed only after 10 days. Body weight was correlated with changes in
blood sugar levels. A dose of 50 mg/kg had no statistically significant effect. Results indicate
a significant potential of A. viridiflora aerial parts in the treatment of diabetes, which must be
confirmed by additional studies, and active ingredients need to be identified.
AB  - Suvi metanolni ekstrakt (DER 3,95:1) nadzemnih delova u cvetu Alchemilla viridiflora
Rothm., Rosaceae, dobijen nakon sukcesivne ekstrakcije cikloheksanom i dihlormetanom,
sadrži visok nivo polifenola, tanina (3,74%), uglavnom elagnih, i flavonoida (0,30%),
heksozida kvercetina i kemferola. Pokazuje ACE inhibitornu i anti-Helicobacter pylori
aktivnost in vitro (1). Na osnovu podataka o tradicionalnoj upotrebi herbe A. vulgaris,
najčešće korišćene Alchemilla vrste, u lečenju dijabetesa (2), ispitivan je uticaj navedenog
ekstrakta A. viridiflora na aktivnost α-amilaze in vitro i na snižavanje nivoa glukoze u krvi
kod pacova. Uticaj na aktivnost α-amilaze procenjen je primenom metode sa 3,5-
dinitrosalicilnom kiselinom. Ekstrakt A. viridiflora u dozama od 50, 100 i 200 mg/kg, p.o.,
aplikovan je pacovima sa dijabetesom izazvanim streptozotocinom tokom 20 dana, a nivoi
glukoze u krvi i težina pacova su praćeni u određenim vremenskim intervalima tokom
trajanja tretmana. Ekstrakt je inhibirao aktivnost α-amilaze, a vrednost IC 50 iznosila je
5,47±0,30 mg/mL. Doza od 200 mg/kg značajno je smanjila nivo glukoze u krvi nakon 10
(32,2%) i 20 dana tretmana (38,3%). Efekat ove doze bio je sličan efektu referentnog leka,
glibenklamida. S druge strane, doza od 100 mg/kg značajno je povećala nivo glukoze do 10.
dana (50,5%) a do značajnog poboljšanja, tj. sniženja nivoa šećera od 51,2% dovela je tek
nakon 10 dana. Telesna težina bila je u korelaciji sa promenama nivoa šećera u krvi. Doza od
50 mg/kg nije imala statistički značajan efekat. Rezultati ukazuju na značajan potencijal
herbe A. viridiflora u lečenju dijabetesa, što mora biti potvrđeno dodatnim studijama, a
aktivni sastojci identifikovani.
PB  - Savez farmaceutskih udruženja Srbije (SFUS)
C3  - Arhiv za farmaciju
T1  - Inhibition of A-amylase in vitro and in vivo hypoglycemic effect of methanol extract of Alchemilla viridiflora Rothm
T1  - Inhibicija Α‐amilaze in vitro i in vivo hipoglikemijski efekat metanolnog ekstrakta herbe Alchemilla viridiflora Rothm
VL  - 72
IS  - 4 suplement
SP  - S461
EP  - S462
UR  - https://hdl.handle.net/21.15107/rcub_farfar_4580
ER  - 

@conference{
author = "Radović-Selgrad, Jelena and Ušjak, Dušan and Milenković, Marina and Kundaković-Vasović, Tatjana",
year = "2022",
abstract = "Dry methanol extract (DER 3.95:1) of aerial flowering parts of Alchemilla viridiflora
Rothm., Rosaceae, obtained after successive extraction with cyclohexane and
dichloromethane, predominantly contains polyphenols, tannins (3.74%), mostly ellagic, and
flavonoids (0.30%), hexosides of quercetin and kaempferol. It shows ACE inhibitory and
anti-Helicobacter pylori activity in vitro (1). Based on the traditional use of the common A.
vulgaris in the treatment of diabetes (2), the effect of this A. viridiflora extract on α-amylase
activity in vitro and lowering blood glucose in rats were investigated. α-Amylase inhibitory
activity was assessed using the 3,5-dinitrosalicylic acid method. Extract in doses of 50, 100
and 200 mg/kg, p.o., was administered to streptozotocin-induced diabetic rats for 20 days,
and blood glucose level and weight of rats were monitored during treatment. Extract
inhibited α-amylase activity at IC 50 5.47 ± 0.30 mg/mL. A dose of 200 mg/kg significantly
decreased blood glucose level after 10 (32.2%) and 20 days of treatment (38.3%). The effect
of this dose was similar to the effect of the reference drug, glibenclamide. A dose of 100
mg/kg significantly increased glucose level by day 10 (50.5%) and a reduction in blood sugar
level of 51.2% was observed only after 10 days. Body weight was correlated with changes in
blood sugar levels. A dose of 50 mg/kg had no statistically significant effect. Results indicate
a significant potential of A. viridiflora aerial parts in the treatment of diabetes, which must be
confirmed by additional studies, and active ingredients need to be identified., Suvi metanolni ekstrakt (DER 3,95:1) nadzemnih delova u cvetu Alchemilla viridiflora
Rothm., Rosaceae, dobijen nakon sukcesivne ekstrakcije cikloheksanom i dihlormetanom,
sadrži visok nivo polifenola, tanina (3,74%), uglavnom elagnih, i flavonoida (0,30%),
heksozida kvercetina i kemferola. Pokazuje ACE inhibitornu i anti-Helicobacter pylori
aktivnost in vitro (1). Na osnovu podataka o tradicionalnoj upotrebi herbe A. vulgaris,
najčešće korišćene Alchemilla vrste, u lečenju dijabetesa (2), ispitivan je uticaj navedenog
ekstrakta A. viridiflora na aktivnost α-amilaze in vitro i na snižavanje nivoa glukoze u krvi
kod pacova. Uticaj na aktivnost α-amilaze procenjen je primenom metode sa 3,5-
dinitrosalicilnom kiselinom. Ekstrakt A. viridiflora u dozama od 50, 100 i 200 mg/kg, p.o.,
aplikovan je pacovima sa dijabetesom izazvanim streptozotocinom tokom 20 dana, a nivoi
glukoze u krvi i težina pacova su praćeni u određenim vremenskim intervalima tokom
trajanja tretmana. Ekstrakt je inhibirao aktivnost α-amilaze, a vrednost IC 50 iznosila je
5,47±0,30 mg/mL. Doza od 200 mg/kg značajno je smanjila nivo glukoze u krvi nakon 10
(32,2%) i 20 dana tretmana (38,3%). Efekat ove doze bio je sličan efektu referentnog leka,
glibenklamida. S druge strane, doza od 100 mg/kg značajno je povećala nivo glukoze do 10.
dana (50,5%) a do značajnog poboljšanja, tj. sniženja nivoa šećera od 51,2% dovela je tek
nakon 10 dana. Telesna težina bila je u korelaciji sa promenama nivoa šećera u krvi. Doza od
50 mg/kg nije imala statistički značajan efekat. Rezultati ukazuju na značajan potencijal
herbe A. viridiflora u lečenju dijabetesa, što mora biti potvrđeno dodatnim studijama, a
aktivni sastojci identifikovani.",
publisher = "Savez farmaceutskih udruženja Srbije (SFUS)",
journal = "Arhiv za farmaciju",
title = "Inhibition of A-amylase in vitro and in vivo hypoglycemic effect of methanol extract of Alchemilla viridiflora Rothm, Inhibicija Α‐amilaze in vitro i in vivo hipoglikemijski efekat metanolnog ekstrakta herbe Alchemilla viridiflora Rothm",
volume = "72",
number = "4 suplement",
pages = "S461-S462",
url = "https://hdl.handle.net/21.15107/rcub_farfar_4580"
}

Radović-Selgrad, J., Ušjak, D., Milenković, M.,& Kundaković-Vasović, T.. (2022). Inhibition of A-amylase in vitro and in vivo hypoglycemic effect of methanol extract of Alchemilla viridiflora Rothm. in Arhiv za farmaciju
Savez farmaceutskih udruženja Srbije (SFUS)., 72(4 suplement), S461-S462.
https://hdl.handle.net/21.15107/rcub_farfar_4580

Radović-Selgrad J, Ušjak D, Milenković M, Kundaković-Vasović T. Inhibition of A-amylase in vitro and in vivo hypoglycemic effect of methanol extract of Alchemilla viridiflora Rothm. in Arhiv za farmaciju. 2022;72(4 suplement):S461-S462.
https://hdl.handle.net/21.15107/rcub_farfar_4580 .

Radović-Selgrad, Jelena, Ušjak, Dušan, Milenković, Marina, Kundaković-Vasović, Tatjana, "Inhibition of A-amylase in vitro and in vivo hypoglycemic effect of methanol extract of Alchemilla viridiflora Rothm" in Arhiv za farmaciju, 72, no. 4 suplement (2022):S461-S462,
https://hdl.handle.net/21.15107/rcub_farfar_4580 .

TY  - JOUR
AU  - Stojanović, Danilo
AU  - Marčetić, Mirjana
AU  - Ušjak, Dušan
AU  - Milenković, Marina
PY  - 2022
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/4061
AB  - Background/Aim. Plant essential oils (EOs) can have a significant antibacterial effect especially through additive or synergistic action as antibiotic adjuvants. We investi-gated the composition and activity of EOs of two species of genus Salvia (S) from Greece with the aim to deter-mine their antimicrobial activity as well as the activity in combination with selected antibiotics. Methods. The aerial parts of wild-growing S. fruticosa and S. ringens were subjected to a steam distillation and the obtained EOs were analyzed by gas chromatography and gas chroma-tography/mass spectrometry. The broth-microdilution method was used in order to determine the minimum in-hibitory concentrations (MICs) of EOs on seven strains of bacteria and one yeast. Antimicrobial activity of the combination of EO and antibiotics was investigated by checkerboard method and estimated by calculating frac-tional inhibitory concentration (FIC) of each component and fractional inhibitory concentration index (FICI). Re-sults. Dominant component of S. fruticosa EO was trans-thujone (54.2%) and for S. ringens EO it was α-pinene (28.1%). The MICs of EOs of both species were in the range from 200 μg/mL to > 500 μg/mL. The strongest antimicrobial effect was achieved against Bacillus subtilis and Candida albicans. According to FICI values, EO of S. fruticosa had additive effect with ciprofloxacin against most of bacterial strains but not with amikacin. Conclu-sion. The essential oils of S. ringens and S. fruticosa showed modest antimicrobial activity. However, the es-sential oil of S. fruticosa showed a promising additive ef-fect in combination with ciprofloxacin.
AB  - Uvod/Cilj. Etarska ulja različitih biljaka mogu imati značajna antibakterijska svojstva, posebno kao adjuvanti antibiotika sa kojima ostvaruju aditivno ili sinergistično dejstvo. Ispitivali smo sastav i aktivnost etarskih ulja dve vrste roda Salvia (S) iz Grčke sa ciljem da odredimo njihovu antimkrobnu aktivnost, kao i dejstvo u kombi-naciji sa odabranim antibioticima. Metode. Nadzemni delovi samoniklih S. fruticosa i S. ringens su destilovani vodenom parom i dobijena etarska ulja su analizirana gasnom hromatografijom i gasnom hromatografijom sa masenom spektrometrijom. Radi određivanja minimalnih inhibitornih koncentracija (MICs) etarskog ulja na sedam sojeva bakterija i na jednoj patogenoj gljivici korišćena je mikrodiluciona metoda. Antimikrobna aktivnost kombi-nacije etarskog ulja i antibiotika ispitana je checkerboard metodom i procenjena je na osnovu frakcione inhibi-torne koncentracije (FIC) svake komponente i indeksa frakcione inhibitorne koncentracije (FICI). Resultati. Dominantna komponenta etarskog ulja S. fruticosa je bio trans-tujon (54,2%), a etarskog ulja S. ringens α-pinen (28,1%). MICs etarskog ulja obe vrste su bile u opsegu od 200 μg/mL do > 500 μg/mL. Najsnažnija anti-mikrobna aktivnost ostvarena je protiv Bacillus subtilis i Candida albicans. Na osnovu FICI vrednosti, etarsko ulje S. fruticosa je sa ciprofloksacinom, ali ne i sa amikacinom imalo aditivni efekat protiv većine bakterijskih sojeva. Zaključak. Etarska ulja S. ringens i S. fruticosa su pokazala skromnu antimikrobnu aktivnost, ali je etarsko ulje S. fru-ticosa u kombinaciji sa ciprofloksacinom ispoljilo značajan aditivni efekat.
PB  - Belgrade : Military Medical Academy, INI
T2  - Vojnosanitetski pregled
T1  - Composition and antimicrobial activity of essential oils of Salvia fruticosa and Salvia ringens (Lamiaceae)
T1  - Sastav i antimikrobna aktivnost etarskih ulja Salvia fruticosa i Salvia ringens (Lamiaceae)
VL  - 79
IS  - 1
SP  - 62
EP  - 68
DO  - 10.2298/VSP200508083S
ER  - 

@article{
author = "Stojanović, Danilo and Marčetić, Mirjana and Ušjak, Dušan and Milenković, Marina",
year = "2022",
abstract = "Background/Aim. Plant essential oils (EOs) can have a significant antibacterial effect especially through additive or synergistic action as antibiotic adjuvants. We investi-gated the composition and activity of EOs of two species of genus Salvia (S) from Greece with the aim to deter-mine their antimicrobial activity as well as the activity in combination with selected antibiotics. Methods. The aerial parts of wild-growing S. fruticosa and S. ringens were subjected to a steam distillation and the obtained EOs were analyzed by gas chromatography and gas chroma-tography/mass spectrometry. The broth-microdilution method was used in order to determine the minimum in-hibitory concentrations (MICs) of EOs on seven strains of bacteria and one yeast. Antimicrobial activity of the combination of EO and antibiotics was investigated by checkerboard method and estimated by calculating frac-tional inhibitory concentration (FIC) of each component and fractional inhibitory concentration index (FICI). Re-sults. Dominant component of S. fruticosa EO was trans-thujone (54.2%) and for S. ringens EO it was α-pinene (28.1%). The MICs of EOs of both species were in the range from 200 μg/mL to > 500 μg/mL. The strongest antimicrobial effect was achieved against Bacillus subtilis and Candida albicans. According to FICI values, EO of S. fruticosa had additive effect with ciprofloxacin against most of bacterial strains but not with amikacin. Conclu-sion. The essential oils of S. ringens and S. fruticosa showed modest antimicrobial activity. However, the es-sential oil of S. fruticosa showed a promising additive ef-fect in combination with ciprofloxacin., Uvod/Cilj. Etarska ulja različitih biljaka mogu imati značajna antibakterijska svojstva, posebno kao adjuvanti antibiotika sa kojima ostvaruju aditivno ili sinergistično dejstvo. Ispitivali smo sastav i aktivnost etarskih ulja dve vrste roda Salvia (S) iz Grčke sa ciljem da odredimo njihovu antimkrobnu aktivnost, kao i dejstvo u kombi-naciji sa odabranim antibioticima. Metode. Nadzemni delovi samoniklih S. fruticosa i S. ringens su destilovani vodenom parom i dobijena etarska ulja su analizirana gasnom hromatografijom i gasnom hromatografijom sa masenom spektrometrijom. Radi određivanja minimalnih inhibitornih koncentracija (MICs) etarskog ulja na sedam sojeva bakterija i na jednoj patogenoj gljivici korišćena je mikrodiluciona metoda. Antimikrobna aktivnost kombi-nacije etarskog ulja i antibiotika ispitana je checkerboard metodom i procenjena je na osnovu frakcione inhibi-torne koncentracije (FIC) svake komponente i indeksa frakcione inhibitorne koncentracije (FICI). Resultati. Dominantna komponenta etarskog ulja S. fruticosa je bio trans-tujon (54,2%), a etarskog ulja S. ringens α-pinen (28,1%). MICs etarskog ulja obe vrste su bile u opsegu od 200 μg/mL do > 500 μg/mL. Najsnažnija anti-mikrobna aktivnost ostvarena je protiv Bacillus subtilis i Candida albicans. Na osnovu FICI vrednosti, etarsko ulje S. fruticosa je sa ciprofloksacinom, ali ne i sa amikacinom imalo aditivni efekat protiv većine bakterijskih sojeva. Zaključak. Etarska ulja S. ringens i S. fruticosa su pokazala skromnu antimikrobnu aktivnost, ali je etarsko ulje S. fru-ticosa u kombinaciji sa ciprofloksacinom ispoljilo značajan aditivni efekat.",
publisher = "Belgrade : Military Medical Academy, INI",
journal = "Vojnosanitetski pregled",
title = "Composition and antimicrobial activity of essential oils of Salvia fruticosa and Salvia ringens (Lamiaceae), Sastav i antimikrobna aktivnost etarskih ulja Salvia fruticosa i Salvia ringens (Lamiaceae)",
volume = "79",
number = "1",
pages = "62-68",
doi = "10.2298/VSP200508083S"
}

Stojanović, D., Marčetić, M., Ušjak, D.,& Milenković, M.. (2022). Composition and antimicrobial activity of essential oils of Salvia fruticosa and Salvia ringens (Lamiaceae). in Vojnosanitetski pregled
Belgrade : Military Medical Academy, INI., 79(1), 62-68.
https://doi.org/10.2298/VSP200508083S

Stojanović D, Marčetić M, Ušjak D, Milenković M. Composition and antimicrobial activity of essential oils of Salvia fruticosa and Salvia ringens (Lamiaceae). in Vojnosanitetski pregled. 2022;79(1):62-68.
doi:10.2298/VSP200508083S .

Stojanović, Danilo, Marčetić, Mirjana, Ušjak, Dušan, Milenković, Marina, "Composition and antimicrobial activity of essential oils of Salvia fruticosa and Salvia ringens (Lamiaceae)" in Vojnosanitetski pregled, 79, no. 1 (2022):62-68,
https://doi.org/10.2298/VSP200508083S . .

TY  - CONF
AU  - Ušjak, Dušan
AU  - Novović, Katarina
AU  - Filipić, Brankica
AU  - Kojić, Milan
AU  - Filipović, Nenad
AU  - Stevanović, Magdalena M.
AU  - Arsenović-Ranin, Nevena
AU  - Milenković, Marina
PY  - 2022
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/5133
AB  - Colistin is used as a “last resort” drug in the treatment
of carbapenem-resistant Acinetobacter baumannii
infections. Though not the most convenient option due to
the serious side effects, this antibiotic can be very efficient
if administered properly (Garnacho-Montero and Timsit,
2019). However, for several years now, we are witnessing
a steady emergence of colistin-resistant (ColR) strains, with
the constant threat of a sudden burst worldwide (Nowak et
al., 2017). Having in mind that these strains are usually
non-susceptible to any of the existing treatments, i.e.
pandrug-resistant (PDR), the development of new
therapeutic strategies is desperately needed.
In the present study, we showed that colistin
susceptibility of ColR A. baumannii strains can be fully
restored in the presence of very low amounts of selenium
nanoparticles (SeNPs). To demonstrate potent synergistic
interactions between colistin and SeNPs, we performed
checkerboard and time-kill analyses.
PB  - Macedonian Pharmaceutical Association
C3  - Macedonian Pharmaceutical Bulletin
T1  - Selenium nanoparticles render pandrug-resistant Acinetobacter  baumannii susceptible to colistin
VL  - 68
IS  - Suppl. 1
SP  - 295
EP  - 296
DO  - 10.33320/maced.pharm.bull.2022.68.03.142
ER  - 

@conference{
author = "Ušjak, Dušan and Novović, Katarina and Filipić, Brankica and Kojić, Milan and Filipović, Nenad and Stevanović, Magdalena M. and Arsenović-Ranin, Nevena and Milenković, Marina",
year = "2022",
abstract = "Colistin is used as a “last resort” drug in the treatment
of carbapenem-resistant Acinetobacter baumannii
infections. Though not the most convenient option due to
the serious side effects, this antibiotic can be very efficient
if administered properly (Garnacho-Montero and Timsit,
2019). However, for several years now, we are witnessing
a steady emergence of colistin-resistant (ColR) strains, with
the constant threat of a sudden burst worldwide (Nowak et
al., 2017). Having in mind that these strains are usually
non-susceptible to any of the existing treatments, i.e.
pandrug-resistant (PDR), the development of new
therapeutic strategies is desperately needed.
In the present study, we showed that colistin
susceptibility of ColR A. baumannii strains can be fully
restored in the presence of very low amounts of selenium
nanoparticles (SeNPs). To demonstrate potent synergistic
interactions between colistin and SeNPs, we performed
checkerboard and time-kill analyses.",
publisher = "Macedonian Pharmaceutical Association",
journal = "Macedonian Pharmaceutical Bulletin",
title = "Selenium nanoparticles render pandrug-resistant Acinetobacter  baumannii susceptible to colistin",
volume = "68",
number = "Suppl. 1",
pages = "295-296",
doi = "10.33320/maced.pharm.bull.2022.68.03.142"
}

Ušjak, D., Novović, K., Filipić, B., Kojić, M., Filipović, N., Stevanović, M. M., Arsenović-Ranin, N.,& Milenković, M.. (2022). Selenium nanoparticles render pandrug-resistant Acinetobacter  baumannii susceptible to colistin. in Macedonian Pharmaceutical Bulletin
Macedonian Pharmaceutical Association., 68(Suppl. 1), 295-296.
https://doi.org/10.33320/maced.pharm.bull.2022.68.03.142

Ušjak D, Novović K, Filipić B, Kojić M, Filipović N, Stevanović MM, Arsenović-Ranin N, Milenković M. Selenium nanoparticles render pandrug-resistant Acinetobacter  baumannii susceptible to colistin. in Macedonian Pharmaceutical Bulletin. 2022;68(Suppl. 1):295-296.
doi:10.33320/maced.pharm.bull.2022.68.03.142 .

Ušjak, Dušan, Novović, Katarina, Filipić, Brankica, Kojić, Milan, Filipović, Nenad, Stevanović, Magdalena M., Arsenović-Ranin, Nevena, Milenković, Marina, "Selenium nanoparticles render pandrug-resistant Acinetobacter  baumannii susceptible to colistin" in Macedonian Pharmaceutical Bulletin, 68, no. Suppl. 1 (2022):295-296,
https://doi.org/10.33320/maced.pharm.bull.2022.68.03.142 . .

TY  - JOUR
AU  - Stevanović, Magdalena M.
AU  - Filipović, Nenad
AU  - Kuzmanović, Maja
AU  - Tomić, Nina
AU  - Ušjak, Dušan
AU  - Milenković, Marina
AU  - Zheng, Kai
AU  - Stampfl, Juergen
AU  - Boccaccini, Aldo R.
PY  - 2022
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/4357
AB  - Multidrug-resistant bacterial strains represent an emerging global health threat and a great obstacle for bone tissue engineering. One of the major components of the extracellular matrix of the bone is a collagen protein, while selenium is an element that has antimicrobial potential, and is also important for bone metabolism and bone health. Here we represent the incorporation of selenium nanoparticles (SeNPs) synthesized by the green chemical reduction method into collagen gels to produce a composite material, collagen/SeNPs, with antimicrobial properties. The samples were comprehensively characterized by zeta potential measurements, dynamic light scattering inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), optical microscopy, field-emission scanning electron microscopy (FE-SEM), and differential scanning calorimetry The cytotoxicity of the SeNPS, as well as collagen/SeNPs, was tested on the MRC-5 cells. It was revealed that collagen/SeNPS expressed a lower cytotoxic effect. Collagen/SeNPs showed significant antibacterial activity against all tested Gram-positive strains, the major causative agents of orthopedic infections as well as Candida albicans. Furthermore, three-dimensional β-tricalcium phosphate (3D-TCP) scaffolds were fabricated by a well-established 3D printing (lithography) method, and afterward preliminary coated by newly-synthesized SeNPs or collagen/SeNPs. In addition, uncoated 3D-TCP scaffolds as well as coated by collagen/SeNPs were subjected to biofilm formation. The production of Staphylococcus aureus biofilm on coated scaffolds by collagen/SeNPs was significantly reduced compared to the uncoated ones.
PB  - SAGE Publications Ltd
T2  - Journal of Biomaterials Applications
T1  - Synthesis and characterization of a collagen-based composite material containing selenium nanoparticles
VL  - 36
IS  - 10
SP  - 1800
EP  - 1811
DO  - 10.1177/08853282211073731
ER  - 

@article{
author = "Stevanović, Magdalena M. and Filipović, Nenad and Kuzmanović, Maja and Tomić, Nina and Ušjak, Dušan and Milenković, Marina and Zheng, Kai and Stampfl, Juergen and Boccaccini, Aldo R.",
year = "2022",
abstract = "Multidrug-resistant bacterial strains represent an emerging global health threat and a great obstacle for bone tissue engineering. One of the major components of the extracellular matrix of the bone is a collagen protein, while selenium is an element that has antimicrobial potential, and is also important for bone metabolism and bone health. Here we represent the incorporation of selenium nanoparticles (SeNPs) synthesized by the green chemical reduction method into collagen gels to produce a composite material, collagen/SeNPs, with antimicrobial properties. The samples were comprehensively characterized by zeta potential measurements, dynamic light scattering inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), optical microscopy, field-emission scanning electron microscopy (FE-SEM), and differential scanning calorimetry The cytotoxicity of the SeNPS, as well as collagen/SeNPs, was tested on the MRC-5 cells. It was revealed that collagen/SeNPS expressed a lower cytotoxic effect. Collagen/SeNPs showed significant antibacterial activity against all tested Gram-positive strains, the major causative agents of orthopedic infections as well as Candida albicans. Furthermore, three-dimensional β-tricalcium phosphate (3D-TCP) scaffolds were fabricated by a well-established 3D printing (lithography) method, and afterward preliminary coated by newly-synthesized SeNPs or collagen/SeNPs. In addition, uncoated 3D-TCP scaffolds as well as coated by collagen/SeNPs were subjected to biofilm formation. The production of Staphylococcus aureus biofilm on coated scaffolds by collagen/SeNPs was significantly reduced compared to the uncoated ones.",
publisher = "SAGE Publications Ltd",
journal = "Journal of Biomaterials Applications",
title = "Synthesis and characterization of a collagen-based composite material containing selenium nanoparticles",
volume = "36",
number = "10",
pages = "1800-1811",
doi = "10.1177/08853282211073731"
}

Stevanović, M. M., Filipović, N., Kuzmanović, M., Tomić, N., Ušjak, D., Milenković, M., Zheng, K., Stampfl, J.,& Boccaccini, A. R.. (2022). Synthesis and characterization of a collagen-based composite material containing selenium nanoparticles. in Journal of Biomaterials Applications
SAGE Publications Ltd., 36(10), 1800-1811.
https://doi.org/10.1177/08853282211073731

Stevanović MM, Filipović N, Kuzmanović M, Tomić N, Ušjak D, Milenković M, Zheng K, Stampfl J, Boccaccini AR. Synthesis and characterization of a collagen-based composite material containing selenium nanoparticles. in Journal of Biomaterials Applications. 2022;36(10):1800-1811.
doi:10.1177/08853282211073731 .

Stevanović, Magdalena M., Filipović, Nenad, Kuzmanović, Maja, Tomić, Nina, Ušjak, Dušan, Milenković, Marina, Zheng, Kai, Stampfl, Juergen, Boccaccini, Aldo R., "Synthesis and characterization of a collagen-based composite material containing selenium nanoparticles" in Journal of Biomaterials Applications, 36, no. 10 (2022):1800-1811,
https://doi.org/10.1177/08853282211073731 . .

TY  - JOUR
AU  - Ušjak, Dušan
AU  - Novović, Katarina
AU  - Filipić, Brankica
AU  - Kojić, Milan
AU  - Filipović, Nenad
AU  - Stevanović, Magdalena
AU  - Milenković, Marina
PY  - 2022
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/4177
AB  - Aims: To investigate the synergistic activity of colistin and selenium nanoparticles (SeNPs) against pandrug-resistant (PDR) Ac. baumannii. Methods and Results: Chequerboard and time-kill assays were employed to ex- plore the potential synergistic interactions between colistin and SeNPs against Ac. baumannii isolates (8), previously determined as colistin-resistant (MIC range 16– 256 μg ml−1 ). Also, whole-genome sequencing (WGS) and gene expression analyses were used to elucidate the mechanisms of colistin resistance. Exceptionally strong synergistic activity (FICI range 0.004–0.035) of colistin and SeNPs against colistin- resistant isolates was revealed. Colistin (0.5 or 1 μg ml −1 ) used in combination with SeNPs (0.5 μg ml−1 ) was able to reduce initial inoculum during the first 4 h of incuba- tion, in contrast to colistin (0.5, 1 or 2 μg ml−1 ) alone. Conclusions: These findings propose colistin/SeNPs combination as a new option to fight PDR Ac. baumannii, the therapeutic possibilities of which should be proved in future in vivo studies. Significance and Impact of Study: Here we present the first evidence of synergy between colistin and selenium compounds against bacteria in general. Also, WGS and gene expression analyses provide some new insights into Ac. baumannii colistin resistance mechanisms.
PB  - John Wiley and Sons Inc
T2  - Journal of Applied Microbiology
T1  - In vitro colistin susceptibility of pandrug-resistant Ac. baumannii is restored in the presence of selenium nanoparticles
VL  - 133
IS  - 3
SP  - 1197
SP  - 1197
EP  - 1206
DO  - 10.1111/jam.15638
ER  - 

@article{
author = "Ušjak, Dušan and Novović, Katarina and Filipić, Brankica and Kojić, Milan and Filipović, Nenad and Stevanović, Magdalena and Milenković, Marina",
year = "2022",
abstract = "Aims: To investigate the synergistic activity of colistin and selenium nanoparticles (SeNPs) against pandrug-resistant (PDR) Ac. baumannii. Methods and Results: Chequerboard and time-kill assays were employed to ex- plore the potential synergistic interactions between colistin and SeNPs against Ac. baumannii isolates (8), previously determined as colistin-resistant (MIC range 16– 256 μg ml−1 ). Also, whole-genome sequencing (WGS) and gene expression analyses were used to elucidate the mechanisms of colistin resistance. Exceptionally strong synergistic activity (FICI range 0.004–0.035) of colistin and SeNPs against colistin- resistant isolates was revealed. Colistin (0.5 or 1 μg ml −1 ) used in combination with SeNPs (0.5 μg ml−1 ) was able to reduce initial inoculum during the first 4 h of incuba- tion, in contrast to colistin (0.5, 1 or 2 μg ml−1 ) alone. Conclusions: These findings propose colistin/SeNPs combination as a new option to fight PDR Ac. baumannii, the therapeutic possibilities of which should be proved in future in vivo studies. Significance and Impact of Study: Here we present the first evidence of synergy between colistin and selenium compounds against bacteria in general. Also, WGS and gene expression analyses provide some new insights into Ac. baumannii colistin resistance mechanisms.",
publisher = "John Wiley and Sons Inc",
journal = "Journal of Applied Microbiology",
title = "In vitro colistin susceptibility of pandrug-resistant Ac. baumannii is restored in the presence of selenium nanoparticles",
volume = "133",
number = "3",
pages = "1197-1197-1206",
doi = "10.1111/jam.15638"
}

Ušjak, D., Novović, K., Filipić, B., Kojić, M., Filipović, N., Stevanović, M.,& Milenković, M.. (2022). In vitro colistin susceptibility of pandrug-resistant Ac. baumannii is restored in the presence of selenium nanoparticles. in Journal of Applied Microbiology
John Wiley and Sons Inc., 133(3), 1197-1206.
https://doi.org/10.1111/jam.15638

Ušjak D, Novović K, Filipić B, Kojić M, Filipović N, Stevanović M, Milenković M. In vitro colistin susceptibility of pandrug-resistant Ac. baumannii is restored in the presence of selenium nanoparticles. in Journal of Applied Microbiology. 2022;133(3):1197-1206.
doi:10.1111/jam.15638 .

Ušjak, Dušan, Novović, Katarina, Filipić, Brankica, Kojić, Milan, Filipović, Nenad, Stevanović, Magdalena, Milenković, Marina, "In vitro colistin susceptibility of pandrug-resistant Ac. baumannii is restored in the presence of selenium nanoparticles" in Journal of Applied Microbiology, 133, no. 3 (2022):1197-1206,
https://doi.org/10.1111/jam.15638 . .

TY  - THES
AU  - Ušjak, Dušan
PY  - 2022
UR  - https://eteze.bg.ac.rs/application/showtheses?thesesId=9037
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:28480/bdef:Content/download
UR  - https://plus.cobiss.net/cobiss/sr/sr/bib/77543689
UR  - https://nardus.mpn.gov.rs/handle/123456789/21379
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/4836
AB  - Acinetobacter baumannii je nozokomijalni, multirezistentni patogen, koga karakterišesposobnost perzistencije na neživim površinama i mogućnost veoma brzog sticanja rezistencije naantibiotike. Danas su u svetu rasprostranjeni izrazito rezistentni sojevi protiv kojih u mnogimzdravstvenim ustanovama ne postoji efikasna terapija, a pronalazak alternativnih terapijskihpristupa je od izuzetne važnosti. Halkoni su jedinjenja sa potvrđenim antimikrobnim svojstvima ipokazanim različitim antivirulentnim aktivnostima. Ciljevi istraživanja ovog rada bili suodređivanje profila rezistencije, ispitivanje mogućnosti kontaminacije antiseptika i ispitivanjeprodukcije biofilma identifikovanih kliničkih izolata A. baumannii, kao i sinteza derivatahidroksihalkona i ispitivanje njihovih antimikrobnih i antivirulentnih aktivnosti protiv ovih izolata.Osetljivost izolata na antibiotike ispitana je kombinacijom difuzionih, dilucionih iautomatizovanih metoda, a identifikovani kolistin-rezistentni izolati dodatno su podvrgnutisekvenciranju celog genoma (WGS) i genetički su okarakterisani. Takođe, mehanizmi rezistencijena kolistin ispitani su primenom komparativne analize genoma i Real-Time kvantitativne lančanereakcije polimeraze (RT-qPCR). Time-kill test je primenjen za ispitivanje perzistencije uantisepticima, a nivo produkcije biofilma ispitan je pod različitim uslovima kultivacije in vitrostatičkom metodom uz bojenje safraninom. Derivati hidroksihalkona sintetisani su pomoću Claisen-Schmidt kondenzacije i njihove antimikrobne aktivnosti, samih i u kombinaciji sa antibioticima,ispitane su bujon-mikrodilucionom, Time-kill i Checkerboard analizom. Antivirulentne aktivnostiodabranih halkona procenjene su posredstvom uticaja na produkciju biofilma (monomikrobnog ipolimikrobnog), vijabilnost biofilmskih ćelija, ekspresiju motiliteta, gensku ekspresiju faktoravirulencije (OmpA, Bap i AbaI), adheziju A. baumannii na komponente ekstracelularnog matriksa(ECM), kao što su fibronektin i kolagen, i aktivnost sistema međućelijske komunikacije (Quorum-Sensing, QS).Klinički izolati A. baumannii gotovo uniformno bili su rezistentni na karbapeneme, a čakskoro 19% izolata bilo je rezistentno na kolistin, pripadajući tako ekstenzivno rezistentnom ilipanrezistentnom fenotipu. Izolati su pokazali sposobnost kontaminacije antiseptika i produkcijevelikih količina biofilma. Nutritivni sastav hranljivih medijuma značajno je uticao na nivoprodukcije biofilma, dok se visok nivo produkcije održao pri širokom opsegu različitih temperaturainkubacije i u prisustvu subinhibitornih koncentracija antibiotika. Sintetisani halkoni ispoljili suumerenu antimikrobnu aktivnost, pri čemu su metoksi-supstituisani derivati u proseku najjačeinhibirali rast. Takođe, zabeleženo je nekoliko sinergističkih interakcija halkona sa meropenemom,a inhibicija efluksnih pumpi predložena je kao potencijalni mehanizam. Halkoni su pokazalisposobnost značajne inhibicije motiliteta i produkcije biofilma, a metoksi-supstituisani derivat (o-OCH3) ispoljio je značajnu antivirulentnu aktivnost posredstvom nishodne regulacije ekspresijeompA, bap i abaI gena i inhibicije adhezije na komponente ECM. Na osnovu ovih rezultata, o-OCH3 halkon je identifikovan kao potentni antivirulentni agens protiv A. baumannii.
AB  - Acinetobacter baumannii is a nosocomial, multiresistant pathogen, able to persist on abioticsurfaces and to rapidly acquire antibiotic resistance. Nowadays, highly resistant strains are widelydisseminated throughout the world, and the discovery of alternative therapeutic strategies is of utterimportance. Chalcones are compounds whose antimicrobial properties are well-known and forwhich different antivirulence activities have been demonstrated. The aims of this research were todetermine resistance profiles, to evaluate the possibility of antiseptic contamination, and to analyzethe biofilm production of identified A. baumannii clinical isolates, as well as to synthesizehydroxychalcone derivatives and to investigate their antimicrobial and antivirulence activitiesagainst these isolates.Antibiotic susceptibility of the isolates was tested by combination of diffusion, dilution, andautomated methods, and additionally, identified colistin-resistant isolates were subjected to wholegenome sequencing (WGS) and were genetically characterized. Also, colistin resistancemechanisms were explored by using comparative genome analysis and Real-Time quantitativepolymerase chain reaction (RT-qPCR). Time-kill test was used for the measurement of bacterialsurvival in antiseptics, whereas the level of biofilm production under different cultivationconditions was quantified by in vitro static method using safranin stain. Hydroxychalconederivatives were synthesized by Claisen-Schmidt condensation, and their antimicrobial activities,alone and in combination with antibiotics, were investigated using broth-microdilution, Time-kill,and Checkerboard analyses. Antivirulence activities of selected chalcones were evaluated based onthe impact on biofilm production (monomicrobial and polymicrobial), biofilm cell viability,motility, virulence factors (OmpA, Bap, and AbaI) gene expression, fibronectin- and collagen-mediated adhesion, and quorum-sensing (QS) activity.A. baumannii clinical isolates expressed extensive drug-resistant or pan-drug resistantphenotypes, being nearly uniformly resistant to carbapenems. Almost 19% of isolates were resistantto colistin as well. The isolates proved to be able to contaminate the antiseptic solutions and toproduce large quantities of biofilms. Nutritional composition of growth media significantly affectedthe level of biofilm production. In contrast, wide range of different incubation temperatures and thepresence of antibiotics at subinhibitory concentrations had little effect, and the bacteria managed tomaintain high level of biofilm production. Moderate antimicrobial activity was displayed bysynthesized chalcones, among which methoxy-substituted derivatives achieved greatest growthinhibition in average. Also, synergistic activity of chalcones and meropenem was present in severalcases, for which efflux pump inhibition was proposed as the potential mechanism. The chalconessignificantly inhibited motility and biofilm production, whereas methoxy-substituted derivative (o-OCH3) also displayed significant antivirulence activity, by downregulating the ompA, bap, and abaIgene expression and by inhibiting fibronectin- and collagen-mediated adhesion. It can be concludedthat o-OCH3 has been identified as a potent antivirulence agent against A. baumannii.
PB  - Универзитет у Београду, Фармацеутски факултет
T2  - Универзитет у Београду
T1  - Uticaj novosintetisanih derivata halkona na rast, produkciju biofilma i faktore virulencije multirezistentnih sojeva Acinetobacter baumannii
UR  - https://hdl.handle.net/21.15107/rcub_nardus_21379
ER  - 

@phdthesis{
author = "Ušjak, Dušan",
year = "2022",
abstract = "Acinetobacter baumannii je nozokomijalni, multirezistentni patogen, koga karakterišesposobnost perzistencije na neživim površinama i mogućnost veoma brzog sticanja rezistencije naantibiotike. Danas su u svetu rasprostranjeni izrazito rezistentni sojevi protiv kojih u mnogimzdravstvenim ustanovama ne postoji efikasna terapija, a pronalazak alternativnih terapijskihpristupa je od izuzetne važnosti. Halkoni su jedinjenja sa potvrđenim antimikrobnim svojstvima ipokazanim različitim antivirulentnim aktivnostima. Ciljevi istraživanja ovog rada bili suodređivanje profila rezistencije, ispitivanje mogućnosti kontaminacije antiseptika i ispitivanjeprodukcije biofilma identifikovanih kliničkih izolata A. baumannii, kao i sinteza derivatahidroksihalkona i ispitivanje njihovih antimikrobnih i antivirulentnih aktivnosti protiv ovih izolata.Osetljivost izolata na antibiotike ispitana je kombinacijom difuzionih, dilucionih iautomatizovanih metoda, a identifikovani kolistin-rezistentni izolati dodatno su podvrgnutisekvenciranju celog genoma (WGS) i genetički su okarakterisani. Takođe, mehanizmi rezistencijena kolistin ispitani su primenom komparativne analize genoma i Real-Time kvantitativne lančanereakcije polimeraze (RT-qPCR). Time-kill test je primenjen za ispitivanje perzistencije uantisepticima, a nivo produkcije biofilma ispitan je pod različitim uslovima kultivacije in vitrostatičkom metodom uz bojenje safraninom. Derivati hidroksihalkona sintetisani su pomoću Claisen-Schmidt kondenzacije i njihove antimikrobne aktivnosti, samih i u kombinaciji sa antibioticima,ispitane su bujon-mikrodilucionom, Time-kill i Checkerboard analizom. Antivirulentne aktivnostiodabranih halkona procenjene su posredstvom uticaja na produkciju biofilma (monomikrobnog ipolimikrobnog), vijabilnost biofilmskih ćelija, ekspresiju motiliteta, gensku ekspresiju faktoravirulencije (OmpA, Bap i AbaI), adheziju A. baumannii na komponente ekstracelularnog matriksa(ECM), kao što su fibronektin i kolagen, i aktivnost sistema međućelijske komunikacije (Quorum-Sensing, QS).Klinički izolati A. baumannii gotovo uniformno bili su rezistentni na karbapeneme, a čakskoro 19% izolata bilo je rezistentno na kolistin, pripadajući tako ekstenzivno rezistentnom ilipanrezistentnom fenotipu. Izolati su pokazali sposobnost kontaminacije antiseptika i produkcijevelikih količina biofilma. Nutritivni sastav hranljivih medijuma značajno je uticao na nivoprodukcije biofilma, dok se visok nivo produkcije održao pri širokom opsegu različitih temperaturainkubacije i u prisustvu subinhibitornih koncentracija antibiotika. Sintetisani halkoni ispoljili suumerenu antimikrobnu aktivnost, pri čemu su metoksi-supstituisani derivati u proseku najjačeinhibirali rast. Takođe, zabeleženo je nekoliko sinergističkih interakcija halkona sa meropenemom,a inhibicija efluksnih pumpi predložena je kao potencijalni mehanizam. Halkoni su pokazalisposobnost značajne inhibicije motiliteta i produkcije biofilma, a metoksi-supstituisani derivat (o-OCH3) ispoljio je značajnu antivirulentnu aktivnost posredstvom nishodne regulacije ekspresijeompA, bap i abaI gena i inhibicije adhezije na komponente ECM. Na osnovu ovih rezultata, o-OCH3 halkon je identifikovan kao potentni antivirulentni agens protiv A. baumannii., Acinetobacter baumannii is a nosocomial, multiresistant pathogen, able to persist on abioticsurfaces and to rapidly acquire antibiotic resistance. Nowadays, highly resistant strains are widelydisseminated throughout the world, and the discovery of alternative therapeutic strategies is of utterimportance. Chalcones are compounds whose antimicrobial properties are well-known and forwhich different antivirulence activities have been demonstrated. The aims of this research were todetermine resistance profiles, to evaluate the possibility of antiseptic contamination, and to analyzethe biofilm production of identified A. baumannii clinical isolates, as well as to synthesizehydroxychalcone derivatives and to investigate their antimicrobial and antivirulence activitiesagainst these isolates.Antibiotic susceptibility of the isolates was tested by combination of diffusion, dilution, andautomated methods, and additionally, identified colistin-resistant isolates were subjected to wholegenome sequencing (WGS) and were genetically characterized. Also, colistin resistancemechanisms were explored by using comparative genome analysis and Real-Time quantitativepolymerase chain reaction (RT-qPCR). Time-kill test was used for the measurement of bacterialsurvival in antiseptics, whereas the level of biofilm production under different cultivationconditions was quantified by in vitro static method using safranin stain. Hydroxychalconederivatives were synthesized by Claisen-Schmidt condensation, and their antimicrobial activities,alone and in combination with antibiotics, were investigated using broth-microdilution, Time-kill,and Checkerboard analyses. Antivirulence activities of selected chalcones were evaluated based onthe impact on biofilm production (monomicrobial and polymicrobial), biofilm cell viability,motility, virulence factors (OmpA, Bap, and AbaI) gene expression, fibronectin- and collagen-mediated adhesion, and quorum-sensing (QS) activity.A. baumannii clinical isolates expressed extensive drug-resistant or pan-drug resistantphenotypes, being nearly uniformly resistant to carbapenems. Almost 19% of isolates were resistantto colistin as well. The isolates proved to be able to contaminate the antiseptic solutions and toproduce large quantities of biofilms. Nutritional composition of growth media significantly affectedthe level of biofilm production. In contrast, wide range of different incubation temperatures and thepresence of antibiotics at subinhibitory concentrations had little effect, and the bacteria managed tomaintain high level of biofilm production. Moderate antimicrobial activity was displayed bysynthesized chalcones, among which methoxy-substituted derivatives achieved greatest growthinhibition in average. Also, synergistic activity of chalcones and meropenem was present in severalcases, for which efflux pump inhibition was proposed as the potential mechanism. The chalconessignificantly inhibited motility and biofilm production, whereas methoxy-substituted derivative (o-OCH3) also displayed significant antivirulence activity, by downregulating the ompA, bap, and abaIgene expression and by inhibiting fibronectin- and collagen-mediated adhesion. It can be concludedthat o-OCH3 has been identified as a potent antivirulence agent against A. baumannii.",
publisher = "Универзитет у Београду, Фармацеутски факултет",
journal = "Универзитет у Београду",
title = "Uticaj novosintetisanih derivata halkona na rast, produkciju biofilma i faktore virulencije multirezistentnih sojeva Acinetobacter baumannii",
url = "https://hdl.handle.net/21.15107/rcub_nardus_21379"
}

Ušjak, D.. (2022). Uticaj novosintetisanih derivata halkona na rast, produkciju biofilma i faktore virulencije multirezistentnih sojeva Acinetobacter baumannii. in Универзитет у Београду
Универзитет у Београду, Фармацеутски факултет..
https://hdl.handle.net/21.15107/rcub_nardus_21379

Ušjak D. Uticaj novosintetisanih derivata halkona na rast, produkciju biofilma i faktore virulencije multirezistentnih sojeva Acinetobacter baumannii. in Универзитет у Београду. 2022;.
https://hdl.handle.net/21.15107/rcub_nardus_21379 .

Ušjak, Dušan, "Uticaj novosintetisanih derivata halkona na rast, produkciju biofilma i faktore virulencije multirezistentnih sojeva Acinetobacter baumannii" in Универзитет у Београду (2022),
https://hdl.handle.net/21.15107/rcub_nardus_21379 .

TY  - JOUR
AU  - Pavun, Leposava
AU  - Janošević-Ležaić, Aleksandra
AU  - Tanasković, Slađana
AU  - Ušjak, Dušan
AU  - Milenković, Marina
AU  - Uskoković-Marković, Snežana
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/4055
AB  - The presence of residual cardiovascular disease (CVD) risk is a current dilemma in clinical practice; indeed, despite optimal management and treatment, a considerable proportion of patients still undergo major CV events. Novel lipoprotein biomarkers are suggested as possible targets for improving the outcomes of patients at higher risk for CVD, and their impact on major CV events and mortality have previously been investigated. Innovative antidiabetic therapies have recently shown a significant reduction in atherogenic lipoproteins, beyond their effects on glucose parameters; it has also been suggested that such anti-atherogenic effect may represent a valuable mechanistic explanation for the cardiovascular benefit of, at least, some of the novel antidiabetic agents, such as glucagon-like peptide-1 receptor agonists. This emphasizes the need for further research in the field in order to clearly assess the effects of innovative treatments on different novel biomarkers, including atherogenic lipoproteins, such as small dense low-density lipoprotein (LDL), lipoprotein(a) (Lp(a)) and dysfunctional high-density lipoprotein (HDL). The current article discusses the clinical importance of novel lipid biomarkers for better management of patients in order to overcome residual cardiovascular risk.
AB  - Постои постојана потреба од ефикасни лекови, комбинации на лекови и методи за спречување на бактериски и вирусни инфекции, вклучувајќи го и коронавирусот. Познато е дека улогата на елементи во траги во зајакнување на човековиот имун систем е значајна. Витамините, микроелементите, вклучувајќи цинк, железо, селен, магнезиум и бакар, масните киселини омега-3 играат значајна физиолошка улога во унапредување на имуниот систем. Цинкот е неопходен микроелемент за основните ензимски физиолошки процеси. Тој игра важна улога во делбата на клетките и е вклучен во развојот на клетки одговорни за неспецифичен имунитет. Познато е дека недостигот на цинк ги предиспонира пациентите на вирусни инфекции поради намалениот антивирусен имунитет. Од друга страна, флавоноидите како метаболити на растенијата играат важна улога во спречување на оксидативен стрес. Овој труд има за цел да ја дискутира in vitro улогата на цинкот, флавонидите и нивните комплекси, како и нивните антиоксидативни и антимикорбни активности. Разгледана е и оправданоста за истовремена употреба на цинк и флавоноиди.
PB  - Macedonian Journal of Chemistry and Chemical Engineering
T2  - Macedonian Journal of Chemistry and Chemical Engineering
T1  - Antioxidant capacity and antimicrobial effects of zinc complexes of flavonoids – does synergism exist?
T1  - Aнтиоксидативен капацитет и антимикробни ефекти на комплекси
на цинк со флавоноиди – дали постои синергизам?
VL  - 40
IS  - 2
SP  - 231
EP  - 239
DO  - 10.20450/mjcce.2021.2401
ER  - 

@article{
author = "Pavun, Leposava and Janošević-Ležaić, Aleksandra and Tanasković, Slađana and Ušjak, Dušan and Milenković, Marina and Uskoković-Marković, Snežana",
year = "2021",
abstract = "The presence of residual cardiovascular disease (CVD) risk is a current dilemma in clinical practice; indeed, despite optimal management and treatment, a considerable proportion of patients still undergo major CV events. Novel lipoprotein biomarkers are suggested as possible targets for improving the outcomes of patients at higher risk for CVD, and their impact on major CV events and mortality have previously been investigated. Innovative antidiabetic therapies have recently shown a significant reduction in atherogenic lipoproteins, beyond their effects on glucose parameters; it has also been suggested that such anti-atherogenic effect may represent a valuable mechanistic explanation for the cardiovascular benefit of, at least, some of the novel antidiabetic agents, such as glucagon-like peptide-1 receptor agonists. This emphasizes the need for further research in the field in order to clearly assess the effects of innovative treatments on different novel biomarkers, including atherogenic lipoproteins, such as small dense low-density lipoprotein (LDL), lipoprotein(a) (Lp(a)) and dysfunctional high-density lipoprotein (HDL). The current article discusses the clinical importance of novel lipid biomarkers for better management of patients in order to overcome residual cardiovascular risk., Постои постојана потреба од ефикасни лекови, комбинации на лекови и методи за спречување на бактериски и вирусни инфекции, вклучувајќи го и коронавирусот. Познато е дека улогата на елементи во траги во зајакнување на човековиот имун систем е значајна. Витамините, микроелементите, вклучувајќи цинк, железо, селен, магнезиум и бакар, масните киселини омега-3 играат значајна физиолошка улога во унапредување на имуниот систем. Цинкот е неопходен микроелемент за основните ензимски физиолошки процеси. Тој игра важна улога во делбата на клетките и е вклучен во развојот на клетки одговорни за неспецифичен имунитет. Познато е дека недостигот на цинк ги предиспонира пациентите на вирусни инфекции поради намалениот антивирусен имунитет. Од друга страна, флавоноидите како метаболити на растенијата играат важна улога во спречување на оксидативен стрес. Овој труд има за цел да ја дискутира in vitro улогата на цинкот, флавонидите и нивните комплекси, како и нивните антиоксидативни и антимикорбни активности. Разгледана е и оправданоста за истовремена употреба на цинк и флавоноиди.",
publisher = "Macedonian Journal of Chemistry and Chemical Engineering",
journal = "Macedonian Journal of Chemistry and Chemical Engineering",
title = "Antioxidant capacity and antimicrobial effects of zinc complexes of flavonoids – does synergism exist?, Aнтиоксидативен капацитет и антимикробни ефекти на комплекси
на цинк со флавоноиди – дали постои синергизам?",
volume = "40",
number = "2",
pages = "231-239",
doi = "10.20450/mjcce.2021.2401"
}

Pavun, L., Janošević-Ležaić, A., Tanasković, S., Ušjak, D., Milenković, M.,& Uskoković-Marković, S.. (2021). Antioxidant capacity and antimicrobial effects of zinc complexes of flavonoids – does synergism exist?. in Macedonian Journal of Chemistry and Chemical Engineering
Macedonian Journal of Chemistry and Chemical Engineering., 40(2), 231-239.
https://doi.org/10.20450/mjcce.2021.2401

Pavun L, Janošević-Ležaić A, Tanasković S, Ušjak D, Milenković M, Uskoković-Marković S. Antioxidant capacity and antimicrobial effects of zinc complexes of flavonoids – does synergism exist?. in Macedonian Journal of Chemistry and Chemical Engineering. 2021;40(2):231-239.
doi:10.20450/mjcce.2021.2401 .

Pavun, Leposava, Janošević-Ležaić, Aleksandra, Tanasković, Slađana, Ušjak, Dušan, Milenković, Marina, Uskoković-Marković, Snežana, "Antioxidant capacity and antimicrobial effects of zinc complexes of flavonoids – does synergism exist?" in Macedonian Journal of Chemistry and Chemical Engineering, 40, no. 2 (2021):231-239,
https://doi.org/10.20450/mjcce.2021.2401 . .

TY  - JOUR
AU  - Ilić, Milan
AU  - Samardžić, Stevan
AU  - Kotur-Stevuljević, Jelena
AU  - Ušjak, Dušan
AU  - Milenković, Marina
AU  - Kovačević, Nada
AU  - Drobac, Milica
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3995
AB  - Plants and plant extracts are of great scientific interest due to the chemical diversity and pharmacological properties of present bioactive molecules. The Geranium L . species are widely used in ethnomedicine. In the current study, the total phenolic and tannin content, antioxidant and antimicrobial activity of methanol extracts of eight Geranium species were investigated.
PB  - Verduci Editore s.r.l
T2  - European Review for Medical and Pharmacological Sciences
T1  - Polyphenol rich extracts of Geranium L. species as potential natural antioxidant and antimicrobial agents
VL  - 25
IS  - 20
SP  - 6283
EP  - 6294
DO  - 10.26355/eurrev_202110_26998
ER  - 

@article{
author = "Ilić, Milan and Samardžić, Stevan and Kotur-Stevuljević, Jelena and Ušjak, Dušan and Milenković, Marina and Kovačević, Nada and Drobac, Milica",
year = "2021",
abstract = "Plants and plant extracts are of great scientific interest due to the chemical diversity and pharmacological properties of present bioactive molecules. The Geranium L . species are widely used in ethnomedicine. In the current study, the total phenolic and tannin content, antioxidant and antimicrobial activity of methanol extracts of eight Geranium species were investigated.",
publisher = "Verduci Editore s.r.l",
journal = "European Review for Medical and Pharmacological Sciences",
title = "Polyphenol rich extracts of Geranium L. species as potential natural antioxidant and antimicrobial agents",
volume = "25",
number = "20",
pages = "6283-6294",
doi = "10.26355/eurrev_202110_26998"
}

Ilić, M., Samardžić, S., Kotur-Stevuljević, J., Ušjak, D., Milenković, M., Kovačević, N.,& Drobac, M.. (2021). Polyphenol rich extracts of Geranium L. species as potential natural antioxidant and antimicrobial agents. in European Review for Medical and Pharmacological Sciences
Verduci Editore s.r.l., 25(20), 6283-6294.
https://doi.org/10.26355/eurrev_202110_26998

Ilić M, Samardžić S, Kotur-Stevuljević J, Ušjak D, Milenković M, Kovačević N, Drobac M. Polyphenol rich extracts of Geranium L. species as potential natural antioxidant and antimicrobial agents. in European Review for Medical and Pharmacological Sciences. 2021;25(20):6283-6294.
doi:10.26355/eurrev_202110_26998 .

Ilić, Milan, Samardžić, Stevan, Kotur-Stevuljević, Jelena, Ušjak, Dušan, Milenković, Marina, Kovačević, Nada, Drobac, Milica, "Polyphenol rich extracts of Geranium L. species as potential natural antioxidant and antimicrobial agents" in European Review for Medical and Pharmacological Sciences, 25, no. 20 (2021):6283-6294,
https://doi.org/10.26355/eurrev_202110_26998 . .

TY  - JOUR
AU  - Filipović, Nenad
AU  - Ušjak, Dušan
AU  - Milenković, Marina
AU  - Zheng, Kai
AU  - Liverani, Liliana
AU  - Boccaccini, Aldo R.
AU  - Stevanović, Magdalena
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3787
AB  - Although selenium nanoparticles (SeNPs) have gained attention in the scientific community mostly through investigation of their anticancer activity, a great potential of this nanomaterial was recognized recently regarding its antimicrobial activity. The particle form, size, and surface chemistry have been recognized as crucial parameters determining the interaction of nanomaterials with biological entities. Furthermore, considering a narrow boundary between beneficial and toxic effects for selenium per se, it is clear that investigations of biomedical applications of SeNPs are very demanding and must be done with great precautions. The goal of this work is to evaluate the effects of SeNPs surface chemistry and structure on antimicrobial activity against several common bacterial strains, including Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212), Bacillus subtilis (ATCC 6633), and Kocuria rhizophila (ATCC 9341), as well as Escherichia coli (ATCC 8739), Salmonella Abony (NCTC 6017), Klebsiella pneumoniae (NCIMB 9111) and Pseudomonas aeruginosa (ATCC 9027), and the standard yeast strain Candida albicans (ATCC 10231). Three types of SeNPs were synthesized by chemical reduction approach using different stabilizers and reducing agents: (i) bovine serum albumin (BSA) + ascorbic acid, (ii) chitosan + ascorbic acid, and (iii) with glucose. A thorough physicochemical characterization of the obtained SeNPs was performed to determine the effects of varying synthesis parameters on their morphology, size, structure, and surface chemistry. All SeNPs were amorphous, with spherical morphology and size in the range 70–300 nm. However, the SeNPs obtained under different synthesis conditions, i.e. by using different stabilizers as well as reducing agents, exhibited different antimicrobial activity as well as cytotoxicity which are crucial for their applications. In this paper, the antimicrobial screening of the selected systems is presented, which was determined by the broth microdilution method, and inhibitory influence on the production of monomicrobial and dual-species biofilm was evaluated. The potential mechanism of action of different systems is proposed. Additionally, the cytotoxicity of SeNPs was examined on the MRC-5 cell line, in the same concentration interval as for antimicrobial testing. It was shown that formulation SeNPs-BSA expressed a significantly lower cytotoxic effect than the other two formulations.
PB  - Frontiers Media S.A.
T2  - Frontiers in Bioengineering and Biotechnology
T1  - Comparative Study of the Antimicrobial Activity of Selenium Nanoparticles With Different Surface Chemistry and Structure
VL  - 8
DO  - 10.3389/fbioe.2020.624621
ER  - 

@article{
author = "Filipović, Nenad and Ušjak, Dušan and Milenković, Marina and Zheng, Kai and Liverani, Liliana and Boccaccini, Aldo R. and Stevanović, Magdalena",
year = "2021",
abstract = "Although selenium nanoparticles (SeNPs) have gained attention in the scientific community mostly through investigation of their anticancer activity, a great potential of this nanomaterial was recognized recently regarding its antimicrobial activity. The particle form, size, and surface chemistry have been recognized as crucial parameters determining the interaction of nanomaterials with biological entities. Furthermore, considering a narrow boundary between beneficial and toxic effects for selenium per se, it is clear that investigations of biomedical applications of SeNPs are very demanding and must be done with great precautions. The goal of this work is to evaluate the effects of SeNPs surface chemistry and structure on antimicrobial activity against several common bacterial strains, including Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212), Bacillus subtilis (ATCC 6633), and Kocuria rhizophila (ATCC 9341), as well as Escherichia coli (ATCC 8739), Salmonella Abony (NCTC 6017), Klebsiella pneumoniae (NCIMB 9111) and Pseudomonas aeruginosa (ATCC 9027), and the standard yeast strain Candida albicans (ATCC 10231). Three types of SeNPs were synthesized by chemical reduction approach using different stabilizers and reducing agents: (i) bovine serum albumin (BSA) + ascorbic acid, (ii) chitosan + ascorbic acid, and (iii) with glucose. A thorough physicochemical characterization of the obtained SeNPs was performed to determine the effects of varying synthesis parameters on their morphology, size, structure, and surface chemistry. All SeNPs were amorphous, with spherical morphology and size in the range 70–300 nm. However, the SeNPs obtained under different synthesis conditions, i.e. by using different stabilizers as well as reducing agents, exhibited different antimicrobial activity as well as cytotoxicity which are crucial for their applications. In this paper, the antimicrobial screening of the selected systems is presented, which was determined by the broth microdilution method, and inhibitory influence on the production of monomicrobial and dual-species biofilm was evaluated. The potential mechanism of action of different systems is proposed. Additionally, the cytotoxicity of SeNPs was examined on the MRC-5 cell line, in the same concentration interval as for antimicrobial testing. It was shown that formulation SeNPs-BSA expressed a significantly lower cytotoxic effect than the other two formulations.",
publisher = "Frontiers Media S.A.",
journal = "Frontiers in Bioengineering and Biotechnology",
title = "Comparative Study of the Antimicrobial Activity of Selenium Nanoparticles With Different Surface Chemistry and Structure",
volume = "8",
doi = "10.3389/fbioe.2020.624621"
}

Filipović, N., Ušjak, D., Milenković, M., Zheng, K., Liverani, L., Boccaccini, A. R.,& Stevanović, M.. (2021). Comparative Study of the Antimicrobial Activity of Selenium Nanoparticles With Different Surface Chemistry and Structure. in Frontiers in Bioengineering and Biotechnology
Frontiers Media S.A.., 8.
https://doi.org/10.3389/fbioe.2020.624621

Filipović N, Ušjak D, Milenković M, Zheng K, Liverani L, Boccaccini AR, Stevanović M. Comparative Study of the Antimicrobial Activity of Selenium Nanoparticles With Different Surface Chemistry and Structure. in Frontiers in Bioengineering and Biotechnology. 2021;8.
doi:10.3389/fbioe.2020.624621 .

Filipović, Nenad, Ušjak, Dušan, Milenković, Marina, Zheng, Kai, Liverani, Liliana, Boccaccini, Aldo R., Stevanović, Magdalena, "Comparative Study of the Antimicrobial Activity of Selenium Nanoparticles With Different Surface Chemistry and Structure" in Frontiers in Bioengineering and Biotechnology, 8 (2021),
https://doi.org/10.3389/fbioe.2020.624621 . .

TY  - JOUR
AU  - Ušjak, Dušan
AU  - Dinić, Miroslav
AU  - Novović, Katarina
AU  - Ivković, Branka
AU  - Filipović, Nenad
AU  - Stevanović, Magdalena
AU  - Milenković, Marina
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3752
AB  - An increasing lack of available therapeutic options against Acinetobacter baumannii urged researchers to seek alternative ways to fight this extremely resistant nosocomial pathogen. Targeting its virulence appears to be a promising strategy, as it offers considerably reduced selection of resistant mutants. In this study, we tested antibiofilm potential of four synthetic chalcone derivatives against A. baumannii. Compound that showed the greatest activity was selected for further evaluation of its antivirulence properties. Real-time PCR was used to evaluate mRNA expression of biofilm-associated virulence factor genes (ompA, bap, abaI) in treated A. baumannii strains. Also, we examined virulence properties related to the expression of these genes, such as fibronectin- and collagen-mediated adhesion, surface motility, and quorum-sensing activity. The results revealed that the expression of all tested genes is downregulated together with the reduction of adhesion and motility. The conclusion is that 2′-hydroxy-2-methoxychalcone exhibits antivirulence activity against A. baumannii by inhibiting the expression of ompA and bap genes, which is reflected in reduced biofilm formation, adhesion, and surface motility.
PB  - Wiley-VCH Verlag
T2  - Chemistry and Biodiversity
T1  - Methoxy-Substituted Hydroxychalcone Reduces Biofilm Production,
Adhesion and Surface Motility of Acinetobacter baumannii by
Inhibiting ompA Gene Expression
VL  - 18
IS  - 1
DO  - 10.1002/cbdv.202000786
ER  - 

@article{
author = "Ušjak, Dušan and Dinić, Miroslav and Novović, Katarina and Ivković, Branka and Filipović, Nenad and Stevanović, Magdalena and Milenković, Marina",
year = "2021",
abstract = "An increasing lack of available therapeutic options against Acinetobacter baumannii urged researchers to seek alternative ways to fight this extremely resistant nosocomial pathogen. Targeting its virulence appears to be a promising strategy, as it offers considerably reduced selection of resistant mutants. In this study, we tested antibiofilm potential of four synthetic chalcone derivatives against A. baumannii. Compound that showed the greatest activity was selected for further evaluation of its antivirulence properties. Real-time PCR was used to evaluate mRNA expression of biofilm-associated virulence factor genes (ompA, bap, abaI) in treated A. baumannii strains. Also, we examined virulence properties related to the expression of these genes, such as fibronectin- and collagen-mediated adhesion, surface motility, and quorum-sensing activity. The results revealed that the expression of all tested genes is downregulated together with the reduction of adhesion and motility. The conclusion is that 2′-hydroxy-2-methoxychalcone exhibits antivirulence activity against A. baumannii by inhibiting the expression of ompA and bap genes, which is reflected in reduced biofilm formation, adhesion, and surface motility.",
publisher = "Wiley-VCH Verlag",
journal = "Chemistry and Biodiversity",
title = "Methoxy-Substituted Hydroxychalcone Reduces Biofilm Production,
Adhesion and Surface Motility of Acinetobacter baumannii by
Inhibiting ompA Gene Expression",
volume = "18",
number = "1",
doi = "10.1002/cbdv.202000786"
}

Ušjak, D., Dinić, M., Novović, K., Ivković, B., Filipović, N., Stevanović, M.,& Milenković, M.. (2021). Methoxy-Substituted Hydroxychalcone Reduces Biofilm Production,
Adhesion and Surface Motility of Acinetobacter baumannii by
Inhibiting ompA Gene Expression. in Chemistry and Biodiversity
Wiley-VCH Verlag., 18(1).
https://doi.org/10.1002/cbdv.202000786

Ušjak D, Dinić M, Novović K, Ivković B, Filipović N, Stevanović M, Milenković M. Methoxy-Substituted Hydroxychalcone Reduces Biofilm Production,
Adhesion and Surface Motility of Acinetobacter baumannii by
Inhibiting ompA Gene Expression. in Chemistry and Biodiversity. 2021;18(1).
doi:10.1002/cbdv.202000786 .

Ušjak, Dušan, Dinić, Miroslav, Novović, Katarina, Ivković, Branka, Filipović, Nenad, Stevanović, Magdalena, Milenković, Marina, "Methoxy-Substituted Hydroxychalcone Reduces Biofilm Production,
Adhesion and Surface Motility of Acinetobacter baumannii by
Inhibiting ompA Gene Expression" in Chemistry and Biodiversity, 18, no. 1 (2021),
https://doi.org/10.1002/cbdv.202000786 . .

TY  - CONF
AU  - Ušjak, Dušan
AU  - Dinić, Miroslav
AU  - Novović, Katarina
AU  - Ivković, Branka
AU  - Filipović, Nenad
AU  - Stevanović, Magdalena
AU  - Milenković, Marina
PY  - 2020
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3758
AB  - Uvod: Acinetobacter baumannii je globalno rasprostranjen nozokomijalni patogen koji se odlikuje izuzetnom sposobnošću ekstremno brzog sticanja rezistencije na antibiotike, kao i adaptacije na preživljavanje u suvim uslovima bolničke sredine [1]. Zbog velike zastupljenosti rezistentnih sojeva protiv kojih ne postoji delotvorna terapija, Svetska zdravstvena organizacija (WHO, 2017) i Centri za kontrolu i prevenciju bolesti (CDC, 2019), označili su A. baumannii kao patogen od kritične važnosti za otkriće novih antimikrobnih agenasa ili novih terapijskih strategija [2]. Targetiranje virulencije je oblik alternativnog terapijskog pristupa koji pruža mogućnost prevencije teže kliničke slike kod inficiranih pacijenata posredstvom inhibicije ekspresije ključnih faktora virulencije, uz istovremenu redukovanu selekciju rezistentnih mutanata [3].
Rezultati i Diskusija: Od četiri različito supstituisana hidroksihalkona, sintetisanih u postupku bazno-katalizovane Claisen-Schmidt kondenzacije, selektiran je metkosi-supstituisani derivat kao najpotentniji inhibitor produkcije biofilma kod A. baumannii. Primenom Real-Time kvantitativne PCR metode sa reverznom transkriptazom ispitan je uticaj subinhibitornih koncentracija selektiranog jedinjenja (70, 35 i 10 μg/mL) na ekspresiju gena faktora virulencije povezanih sa produkcijom biofilma kod A. baumannii: ompA, bap i abaI. Pokazana je značajna dozno-zavisna nishodna ekspresija ompA gena, koji kodira OmpA protein spoljašnje membrane ćelijskog zida, koji učestvuje u brojnim virulentnim osobinama A. baumannii, kao što su adhezija, citotoksičnost, motilitet i rezistencija na imunski odgovor i antibiotike [4]. Takođe, zabeležena je značajna inhibicija ekspresije bap gena, koja je neophodna za adheziju na humane epitelne ćelije, i abaI gena, integralnog dela bakterijskog kvorum-sensing sistema, koji kodira sintazu autoinduktorskih molekula. Sposobnost antivirulentnog delovanja metoksi-supstituisanog derivata hidroksihalkona potvrđena je demonstracijom inhibicije fenotipske ekspresije faktora virulencije povezanih sa ekspresijom ompA, bap i abaI gena, kao što su adhezija za komponente ekstracelularnog matriksa (fibronektin i kolagen), površinski motilitet i produkcija autoinduktorskih molekula.
Zaključak: Metoksi-supstituisani hidroksihalkon ispoljava antivirulentno dejstvo protiv A. baumannii, pre svega posredstvom nishodne regulacije ompA gena, što se reflektuje u inhibiciji produkcije biofilma, sposobnosti adhezije i površinskog motiliteta ovog patogena.
AB  - Over the last two decades, Acinetobacter baumannii has emerged as one of the most troublesome pathogens, rapidly acquiring resistance to virtually all available antibiotics. This has urged researchers to seek alternative ways to fight this pathogen. Targeting its virulence appears to be a promising strategy, as it offers considerably reduced selection of resistant mutants. In this study, we tested antibiofilm activity of four synthetic chalcone derivatives against A. baumannii. Compound that showed the greatest activity was selected for further evaluation of its antivirulence properties. We used quantitative Real-Time PCR to evaluate mRNA expression of virulence-associated genes (ompA, bap, abaI) in extensively drug-resistant (XDR) A. baumannii wound isolate and A. baumannii ATCC 19606 strain, treated with selected compound. Also, we tested biofilm production, fibronectin- and collagen-mediated adhesion, surface motility and quorum-sensing activity of treated strains. The results revealed downregulation of the expression of all tested virulence genes together with the reduction of biofilm production, adhesion and motility. The most notable finding is significant reduction of ompA gene expression, whose encoded protein product is associated with numerous virulence traits of A. baumannii. Therefore, we conclude that selected methoxy-substituted hydroxychalcone exhibits antivirulence activity against A. baumannii by inhibiting the expression of the bacterial adhesins, most importantly OmpA, which is reflected in reduced biofilm formation, adhesion and surface motility.
C3  - FEMS Online Conference on Microbiology
T1  - Methoxy-substituted hydroxychalcone reduces biofilm production, adhesion, and surface motility of Acinetobacter baumannii by inhibiting ompA gene expression
UR  - https://hdl.handle.net/21.15107/rcub_farfar_3758
ER  - 

@conference{
author = "Ušjak, Dušan and Dinić, Miroslav and Novović, Katarina and Ivković, Branka and Filipović, Nenad and Stevanović, Magdalena and Milenković, Marina",
year = "2020",
abstract = "Uvod: Acinetobacter baumannii je globalno rasprostranjen nozokomijalni patogen koji se odlikuje izuzetnom sposobnošću ekstremno brzog sticanja rezistencije na antibiotike, kao i adaptacije na preživljavanje u suvim uslovima bolničke sredine [1]. Zbog velike zastupljenosti rezistentnih sojeva protiv kojih ne postoji delotvorna terapija, Svetska zdravstvena organizacija (WHO, 2017) i Centri za kontrolu i prevenciju bolesti (CDC, 2019), označili su A. baumannii kao patogen od kritične važnosti za otkriće novih antimikrobnih agenasa ili novih terapijskih strategija [2]. Targetiranje virulencije je oblik alternativnog terapijskog pristupa koji pruža mogućnost prevencije teže kliničke slike kod inficiranih pacijenata posredstvom inhibicije ekspresije ključnih faktora virulencije, uz istovremenu redukovanu selekciju rezistentnih mutanata [3].
Rezultati i Diskusija: Od četiri različito supstituisana hidroksihalkona, sintetisanih u postupku bazno-katalizovane Claisen-Schmidt kondenzacije, selektiran je metkosi-supstituisani derivat kao najpotentniji inhibitor produkcije biofilma kod A. baumannii. Primenom Real-Time kvantitativne PCR metode sa reverznom transkriptazom ispitan je uticaj subinhibitornih koncentracija selektiranog jedinjenja (70, 35 i 10 μg/mL) na ekspresiju gena faktora virulencije povezanih sa produkcijom biofilma kod A. baumannii: ompA, bap i abaI. Pokazana je značajna dozno-zavisna nishodna ekspresija ompA gena, koji kodira OmpA protein spoljašnje membrane ćelijskog zida, koji učestvuje u brojnim virulentnim osobinama A. baumannii, kao što su adhezija, citotoksičnost, motilitet i rezistencija na imunski odgovor i antibiotike [4]. Takođe, zabeležena je značajna inhibicija ekspresije bap gena, koja je neophodna za adheziju na humane epitelne ćelije, i abaI gena, integralnog dela bakterijskog kvorum-sensing sistema, koji kodira sintazu autoinduktorskih molekula. Sposobnost antivirulentnog delovanja metoksi-supstituisanog derivata hidroksihalkona potvrđena je demonstracijom inhibicije fenotipske ekspresije faktora virulencije povezanih sa ekspresijom ompA, bap i abaI gena, kao što su adhezija za komponente ekstracelularnog matriksa (fibronektin i kolagen), površinski motilitet i produkcija autoinduktorskih molekula.
Zaključak: Metoksi-supstituisani hidroksihalkon ispoljava antivirulentno dejstvo protiv A. baumannii, pre svega posredstvom nishodne regulacije ompA gena, što se reflektuje u inhibiciji produkcije biofilma, sposobnosti adhezije i površinskog motiliteta ovog patogena., Over the last two decades, Acinetobacter baumannii has emerged as one of the most troublesome pathogens, rapidly acquiring resistance to virtually all available antibiotics. This has urged researchers to seek alternative ways to fight this pathogen. Targeting its virulence appears to be a promising strategy, as it offers considerably reduced selection of resistant mutants. In this study, we tested antibiofilm activity of four synthetic chalcone derivatives against A. baumannii. Compound that showed the greatest activity was selected for further evaluation of its antivirulence properties. We used quantitative Real-Time PCR to evaluate mRNA expression of virulence-associated genes (ompA, bap, abaI) in extensively drug-resistant (XDR) A. baumannii wound isolate and A. baumannii ATCC 19606 strain, treated with selected compound. Also, we tested biofilm production, fibronectin- and collagen-mediated adhesion, surface motility and quorum-sensing activity of treated strains. The results revealed downregulation of the expression of all tested virulence genes together with the reduction of biofilm production, adhesion and motility. The most notable finding is significant reduction of ompA gene expression, whose encoded protein product is associated with numerous virulence traits of A. baumannii. Therefore, we conclude that selected methoxy-substituted hydroxychalcone exhibits antivirulence activity against A. baumannii by inhibiting the expression of the bacterial adhesins, most importantly OmpA, which is reflected in reduced biofilm formation, adhesion and surface motility.",
journal = "FEMS Online Conference on Microbiology",
title = "Methoxy-substituted hydroxychalcone reduces biofilm production, adhesion, and surface motility of Acinetobacter baumannii by inhibiting ompA gene expression",
url = "https://hdl.handle.net/21.15107/rcub_farfar_3758"
}

Ušjak, D., Dinić, M., Novović, K., Ivković, B., Filipović, N., Stevanović, M.,& Milenković, M.. (2020). Methoxy-substituted hydroxychalcone reduces biofilm production, adhesion, and surface motility of Acinetobacter baumannii by inhibiting ompA gene expression. in FEMS Online Conference on Microbiology.
https://hdl.handle.net/21.15107/rcub_farfar_3758

Ušjak D, Dinić M, Novović K, Ivković B, Filipović N, Stevanović M, Milenković M. Methoxy-substituted hydroxychalcone reduces biofilm production, adhesion, and surface motility of Acinetobacter baumannii by inhibiting ompA gene expression. in FEMS Online Conference on Microbiology. 2020;.
https://hdl.handle.net/21.15107/rcub_farfar_3758 .

Ušjak, Dušan, Dinić, Miroslav, Novović, Katarina, Ivković, Branka, Filipović, Nenad, Stevanović, Magdalena, Milenković, Marina, "Methoxy-substituted hydroxychalcone reduces biofilm production, adhesion, and surface motility of Acinetobacter baumannii by inhibiting ompA gene expression" in FEMS Online Conference on Microbiology (2020),
https://hdl.handle.net/21.15107/rcub_farfar_3758 .