Phenotypic characterization and antimicrobial profile of uropathogenic enterococci

Cilj: Istražiti odabrane čimbenike virulencije te antimikrobnu osjetljivost/rezistenciju uropatogenih bakterija Enterococcus faecalis i Enterococcus faecium. Materijali i metode: Ukupno 96 urinarnih izolata enterokoka identificirano je standardnim i automatiziranim biokemijskim postupcima. Fenotipskim metodama dokazana je prisutnost kazeinaze i želatinaze te lipaze. Metodom agar dilucije određena je rezistencija prema lizozimu. Disk difuzijskom i mikrodilucijskom metodom ispitana je osjetljivost/rezistencija izolata prema odabranim antibioticima. Rezultati: Od ukupnog broja uropatogenih enterokoka, E. faecalis je identificiran u 79,2%, a E. faecium u 20,8% slučajeva. Većina sojeva uropatogenih enterokoka pokazivala je lipolitičku aktivnost, dok je produkcija želatinaze i kazeinaze dominantna karakteristika E. faecalis, a izostaje u E. faecium. Rezistencija prema nižim koncentracijama lizozima uočena je u 97% od ukupnog broja testiranih uropatogenih enterokoka. Visoki stupanj rezistencije na lizozim, zabilježen je u 72% svih ispitanih sojeva. Svi izolati E. faecalis bili su osjetljivi prema glikopeptidima i imipenemu. Vankomicin (VanA fenotip) rezistentni enterokoki (VRE) prisutni su isključivo među sojevima E. faecium. Isti sojevi su rezistentni prema imipenemu, ampicilinu i gentamicinu. Zaključak: S obzirom na rastuću važnost vrsta iz roda Enterococcus kao uzročnika hospitalnih i vanbolničkih infekcija te sve veću učestalost glikopeptidne rezistencije, utvrđivanje čimbenika virulencije i njihove uloge u patogenezi infekcija mokraćnog sustava od posebnog je značenja.Aim: To investigate the selected virulence factors and the antimicrobial resistance profile of uropathogenic bacteria Enterococcus faecalis and Enterococcus faecium. Materials and Methods: A total of 96 urinary isolates of enterococci were identified by standard and automated biochemical procedures. Using phenotypic methods the presence of caseinase and gelatinase, as well as lipase were detected. Resistance to lysozyme was determined by the agar dilution method. Disk diffusion and microdilution methods were used to test the sensitivity/resistance of isolates to selected antibiotics. Results: Of the total number of uropathogenic enterococci, E. faecalis was identified in 79.2% and E. faecium in 20.8% of cases. The majority of uropathogenic enterococci strains exhibited lipolytic activity while gelatinase and caseinase production dominated in E. faecalis, and was absent in E. faecium. Resistance to lower concentrations of lysozyme was observed in 97% of the total number of uropathogenic enterococci. High levels of resistance to lysozyme were observed in 72% of all strains tested. All E. faecalis isolates were susceptible to glycopeptides and imipenem. Vankomycin (VanA phenotype) resistant enterococci (VRE) were present exclusively among E. faecium strains. The same strains were resistant to imipenem, ampicillin and gentamicin. Conclusion: Given the growing importance of Enterococcus species as a cause of hospital and infections in general population, as well as an increasing frequency of glycopeptide resistance, determining virulence factors and their role in pathogenesis of urinary tract infections is of particular significance