Antimikrobna aktivnost halkona i in vitro uticaj na fiziološko-biohemijske karakteristike i ekspresiju faktora virulencije meticilin-rezistentnih sojeva Staphylococcus aureus

Abstract

Uvod: Meticilin-rezistentan S. aureus (MRSA) je jedan od glavnih izazivačaintrahospitalnih infekcija sa čestim letalnim ishodom i infekcija kod mladih i zdravihljudi koji dolaze iz vanbolničke sredine. Brz razvoj rezistencije stafilokoka na noveantimikrobne agense i interhumano širenje rezistentnih sojeva su glavni terapijskiproblemi današnjice. Iz tog razloga je neophodno razviti nove agense koji bi imaliprimenu u prevenciji ili lečenju stafilokoknih infekcija. Halkoni spadaju u grupuflavonoida, jedinjenja koja se mogu izolovati iz prirodnih izvora kao što su biljke, voćei povrće ili se dobiti metodama klasične i kombinatorne sinteze. Hemijska strukturahalkona se sastoji od dva aril prstena koja su povezana α,β-nezasićenim ketonom.Dosadašnja istraživanja su pokazala da različiti halkoni ispoljavaju širok spektarbioloških aktivnosti, kao što su antibakterijska, antivirusna, antigljivična, antiangiogena,antitumorska, antiproliferativna i antiinflamatorna aktivnost.Ciljevi istraživanja: Osnovni cilj istraživanja je bilo ispitivanje osetljivosti genotipski ifenotipski heterogenih MRSA sojeva na tri sintetisana halkona: Bis-(2-hydroxyphenyl)-propenona (u daljem tekstu O-OH), 3-(3-Hydroxy-phenyl)-1-(2-hydroxyphenyl)-propenona (u daljem tekstu M-OH) i 3-(4-Hydroxy-phenyl)-1-(2-hydroxyphenyl)-propenona (u daljem tekstu P-OH) i ispitivanje in vitro uticaja halkona nabiohemijsko-fiziološke osobine MRSA sojeva, ekspresiju faktora virulencije(produkciju glikokaliksa, produkciju biofilma i vezivanje za humani fibronektin) iprodukciju stafilokoknih hemolizina. Takoñe je izvršeno i ispitivanje efektakombinovane primene halkona i antibiotika sa različitim mehanizmima delovanja narast izolovanih MRSA sojeva.Materijal i metode: Izolovani sojevi S. aureus su identifikovani kao MRSA pomoćukonvencionalnih metoda, komercijalnim automatizovanim sistemom (VITEK 2 IDkarticama) i molekularnim metodama (PCR metod - detekcija nuc i mecA gena).Genotipizacija izolovanih MRSA sojeva je izvršena različitim PCR protokolima naosnovu čega su MRSA sojevi klasifikovani u različite SCCmec tipove, agr tipove, spatipove i grupisani u spa klonske komplekse...

Introduction: Staphylococcus aureus is potentially pathogenic bacterium that causes abroad spectrum of diseases, ranging from minor infections of the skin and soft tissue inthe community, to severe nosocomial infections like endocarditis, bacteremia andsepsis. Multiresistance of methicillin-resistant S.aureus (MRSA) is one of the mostserious therapeutical problems nowadays, and requires urgent development of newantibacterial compounds. Chalcones belong to a group of naturally occurring flavonoidswith chemical structure made of two aryl rings linked by a α,β-unsaturated ketone.Although these compounds are usually isolated from various plant species, they can alsobe obtained by the methods of classical and combinatorial synthesis. Chalcones arecompounds with potent biological activities, amongst which are antibacterial, antiviral,antifungal, antiproliferative and antiinflammatory.The aim of the study: The goal of this study was to evaluate the antibacterial effect ofthree newly-synthesized chalcones: 1,3- Bis-(2-hydroxy-phenyl)-propenone (furtherreferred as O-OH), 3-(3-hydroxy-phenyl)-1-(2-hydroxy-phenyl)-propenone (furtherreferred as M-OH) and 3-(4-hydroxy-phenyl)-1-(2-hydroxy-phenyl)-propenone (furtherreferred as P-OH) against genetically diverse clinical isolates of MRSA, and the effecton physiological and biochemical characteristics and expression of virulence factors(production of glycocalyx, biofilm and adherence to human fibronectin) and productionof α-hemolysin of these bacteria. One of the aims of this study was also to investigatethe synergism of chalcones with various β-lactam and non- β-lactam antibiotics.Methods:Clinical isolates of S. aureus were identified as MRSA with classical methods,commercial automated microbiological identification system (VITEK 2 ID test cards)and molecular methods (PCR method for detection of nuc and mecA gene). Genotypingof MRSA was performed with adequate PCR protocols for the detection of SCCmectype, agr type, Panton-Valentin leucocidin (PVL) gene and spa type. Different spatypes were clustered into spa clonal complexes (CC)...