Biotyping and Antimicrobial Susceptibility of Enterococcus faecalis and E. faecium Isolated from Urine and Stool Samples

Abstract

Background: Enterococci are one of the opportunistic pathogenic microorganisms that can cause significant problems for human and animal health. Enterococcus faecium seems to be more resistant to antibiotics than E. faecalis. It is thought that pathogenic E. faecium can develop antibiotic resistance very quickly, and the ability to transfer this feature is considered to be an important health risk. Objectives: This study aimed to determine the prevalence, biotypes, and in vitro antimicrobial susceptibility of E. faecalis and E. faecium strains isolated from 267 routine urine and stool samples that were brought to the microbiology laboratory of Regional Training and Research Hospital of Van, with permission of the patients. Methods: In the present study, enterococci using species-specific primers to examine E. faecalis and E. faecium multiplex PCR technique was applied. Biotyping of the isolates was used to identify them as E. faecalis and E. faecium by molecular techniques, and antibiotic susceptibility of all samples was examined, as well. Results: The isolates were identified by multiplex PCR using species-specific primers for E. faecalis and E. faecium. Biotyping based on 13 biochemical tests showed that 72.5%, 12.5%, and 15% of E. faecalis strains were of biotypes I, II, and III, respectively, whereas E. faecium strains could be divided into biotype I (10%), biotype II (12.5%), biotype III (27.5%), and biotype IV (50%). Additionally, all E. faecalis strains were found to be susceptible to penicillin G and imipenem. On the other hand, 95% of the E. faecalis strains were found to be resistant to clindamycin, 77.5% to tetracycline and trimethoprim/sulfamethoxazole, 42.5% to erythromycin, 32.5% to gentamicin, and 17.5% to ciprofloxacin. Of E. faecium strains, 37.5% were found to be resistant to clindamycin, 32.5% to penicillin G, 27.5% to erythromycin and imipenem, 20% to ciprofloxacin, 17.5% to tetracycline and trimethoprim/sulfamethoxazole, 15% to gentamicin, and 5% to vancomycin. Conclusions: In conclusion, the identification of E. faecalis and E. faecium strains by PCR is reliable and faster than biochemical tests. Additionally, the results of antimicrobial susceptibility tests may provide important contributions to the clinical approach.