Antimicrobial susceptibility and biofilm-forming ability of Enterococcus faecalis strains isolated from the urogenital tract of outpatients

Abstract

Enterococci are increasingly associated with infections of urogenital tract. The two species Enterococcus faecalis and Enterococcus faecium are the third most commonly isolated pathogens in catheter-associated UTIs. Both species are capable of producing biofilms, with E. faecalis being more frequently isolated. This study explores the antimicrobial resistance and biofilm formation ability of 72 Enterococcus faecalis isolates, collected for one-year period from the urogenital tract of outpatients. The results showed that urinal tract infections (UTIs), caused by enterococci are more frequent among children up to 10 years of age, while genital tract infections (GTI) are most often observed in women in reproductive age. Antimicrobial resistance was low, with higher levels for UTI agents compared to GTI isolates. The results demonstrate 100% susceptibility to penicillins, which are the most effective agents for treatment of infections caused by Enterococcus faecalis. The resistance to fluoroquinolones was < 19%, with clearly defined cross-resistance. Biofilm formation was established for 26% of the tested strains after 24 h of cultivation on tryptic soy broth, with OD₆₃₀ values for the biofilms in range 0.050-0.200. This categorizes the isolates as low-grade biofilm-forming strains. The susceptibility profile of strains in present study confirms need always to detect resistance of isolates before antibiotic prescriptions from physicians.