Antimicrobial Resistance Profiles of Enterococcus Faecalis and Enterococcus Faecium Isolated from Clinical Specimens at Kitwe Teaching Hospital in Zambia

Abstract

This research examined the occurrence of Enterococcus faecalis and Enterococcus faecium in clinical samples processed at Kitwe Teaching Hospital Laboratory, along with their resistance to antimicrobials and presence of virulence determinants. A total of 230 clinical specimens were analyzed to identify suspected Enterococcus strains. Standard laboratory techniques were employed to isolate, characterize, and confirm the species of Enterococcus, followed by testing their susceptibility to antimicrobials and detection of resistance and virulence genes using polymerase chain reaction. Among the 230 cultured specimens, 89 were stool samples, 3 were swabs, and 138 were urine specimens. Out of these, 71 isolates were confirmed Enterococcus by PCR using genus specific primers. The resulting prevalence rate of 30.9% was thus obtained. The most prevalent species was Enterococcus faecalis, accounting for 56.3% of the 71 Enterococcus isolates. The prevalence of E. faecium was 14.1%. All tested E. faecalis isolates displayed resistance to ciprofloxacin and erythromycin. Furthermore, high rates of resistance were observed among E. faecalis isolates for chloramphenicol and tetracycline (97.5%), vancomycin (90.0%), nitrofurantoin (75.0%), penicillin (75.0%) and ampicillin (67.5%). Only two E. faecium isolates exhibited susceptibility to tetracycline and vancomycin, while the remaining isolates were 100% resistant to all other tested antimicrobials. Multidrug resistance was detected in all E. faecium isolates. In addition, various antibiotic resistance genes (aac(6′)-Ie-aph(2″)-LA, ermA, ermB, tetK, tetL, tetM, tetX, vanA) were identified in both E. faecalis and E. faecium isolates. A positive association between phenotype and genotype was found for tetracycline and erythromycin.