Phenotypic Detection of Extended-spectrum Beta-lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Hospital and Environmental Sources in Enugu Metropolis, Nigeria

Background: Extended -Spectrum Beta- Lactamases (ESBLs) are enzymes that confer resistance to a wide range of β-lactam antibiotics, including penicillins, third-generation cephalosporins, and aztreonam, but not to cephamycins or carbapenems, and are blocked by beta-lactamase inhibitors.

Aim: To evaluate the antimicrobial susceptibility profiles of Escherichia coli and Klebsiella pneumoniae and to determine the prevalence of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates from the hospital and environmental samples.

Methodology: The study was conducted from October 2020 to June 2021 in the Microbiological Laboratory of the University of Nigeria Teaching Hospital Ituku-Ozalla, Enugu. A total of 150 non-duplicate bacteria isolates were recovered from urine, wound swab, high vaginal swab, stool, sputum, and environmental sources. Isolates were identified and characterized using standard microbiological protocols. Antimicrobial susceptibility was performed using the Kirby-Bauer disc diffusion procedure. Phenotypic detection of ESBL production was determined using Double Disc Synergy Tvest.

Results: E. coli isolates from hospital samples were highly resistant to cefuroxime (100 %), cefixime (100 %) augmentin (100%), ciprofloxacin (91%), and cefotaxime(86.6%). However, nitrofurantoin and imipenem were highly potent 80.6 % and 76.1% respectively. Among the 67 strains of E. coli from hospital samples, 32(47.8%) were found to be ESBL producers. Of the 60 Klebsiella pneumoniae hospital isolates tested, 27(45%) were found to be ESBL-producers. Of the 18 strains of E. coli from environmental isolates, 12(66.7%) were found to be ESBL producers. Out of only five Klebsiella pneumoniae from environmental samples tested, 4(80%) were found to be ESBL producers. A total prevalence of 75(50%) ESBL producers from the 150 isolates were found.

Conclusion: The findings of this study showed an alarming rate of 50% ESBL-producing E. coli and Klebsiella pneumoniae in Enugu Metropolis, Nigeria with a high antimicrobial resistance in both ESBL and non-ESBL-producing isolates.