Multidrug-Resistant Enterococcus faecalis Clinical Isolates from a Tertiary Hospital in Gombe, Nigeria: Antibiotic Susceptibility Patterns and Implications for Therapy

The emergence of multidrug-resistant (MDR) Enterococcus faecalis represents a growing public health concern, particularly in resource-limited healthcare settings where treatment options may be constrained. This study determined the prevalence and antibiotic susceptibility profiles of E. faecalis clinical isolates obtained from patients at the Federal Teaching Hospital Gombe, Nigeria. Clinical specimens were collected and subjected to standard microbiological procedures. Presumptive isolates were identified phenotypically using Gram staining, catalase testing, growth in 6.5% NaCl, and bile esculin hydrolysis, followed by molecular confirmation using polymerase chain reaction (PCR) amplification. Antibiotic susceptibility testing was performed using the Kirby–Bauer disk diffusion method against eleven antibiotics, with results interpreted according to the Clinical and Laboratory Standards Institute (CLSI) M100, 35th Edition guidelines. Four clinical isolates were recovered, of which three were confirmed as E. faecalis by both phenotypic and molecular methods, while one was identified as Staphylococcus spp. All confirmed E. faecalis isolates exhibited multidrug resistance, with resistance recorded against seven of the eleven antibiotics tested: amoxicillin, ceftriaxone, levofloxacin, doxycycline, cefepime, cephalothin, and chloramphenicol. Conversely, the isolates remained susceptible to erythromycin, ciprofloxacin, and clindamycin, while intermediate susceptibility to rifampicin was observed. Each E. faecalis isolate demonstrated resistance to antibiotics belonging to at least three different antimicrobial classes, thereby meeting the criterion for multidrug resistance. These findings demonstrate the occurrence of MDR E. faecalis among clinical isolates at the study hospital and underscore the importance of routine antimicrobial susceptibility testing, continuous resistance surveillance, and strengthened antimicrobial stewardship to guide effective therapy and limit further emergence and dissemination of resistant strains.