Prevalence of extended-spectrum beta-lactamase production in clinical Escherichia coli isolates in Ibadan metropolis, south-west Nigeria

Abstract

Background: Escherichia coli is a major extended spectrum beta-lactamase-producing organism. Extended spectrum beta-lactamases (ESBLs) inactivate newer cephalosporins through hydrolysis increasing therapeutic failure and antibiotic resistance worldwide. This prospective experimental study aimed to determine the antibiotic susceptibility profile and ESBL production by clinical E. coli isolates.

Methods: Fifty-one clinical E. coli isolates were obtained from the microbiology laboratories of University College Hospital, Adeoyo Maternity Hospital, Our Lady of Apostle Hospital, and a private diagnostic laboratory all in Ibadan metropolis. They were identified and confirmed using standard biochemical tests. Kirby-Bauer disc diffusion method was used to determine the antibiogram and interpreted using clinical laboratory standard institute (CLSI) guideline. ESBL production was determined by the double disk synergy test (DDST).

Results: The prevalence of ESBL production was observed to be 78.4%(40). Resistance was common to sulphamethozaxole/trimethoprim 96.0%(49), ceftazidime 94.1%(48), amoxicillin and tetracycline 92.1%(47), fosfomycin 84.3%(43), cefotaxime 76.4%(39), ciprofloxacin 60.7%(31), amoxicillin/clavulanic acid 58.8%(30), and chloramphenicol 50.9%(26). Meropenem was observed to be the most sensitive (100.0%), followed by nitrofurantoin 78.4%(40), and gentamicin 70.5%(36). Multiple antibiotic resistance (MAR) index greater than 0.2 was observed in 98.0%(50) of the isolates.

Conclusion: Majority of the clinical isolates of E. coli were ESBL producers which are resistant to frequently used antibiotics.

Keywords: Escherichia coli, Extended spectrum beta-lactamase, Antibiotic resistance