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

Abstract

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.