Molecular Characterization of Plasmid-mediated Extended Spectrum Beta-lactamase Resistance in Urinary Escherichia coli from Patients in General Hospital, Maitama, Abuja, Nigeria

Aims: This study investigates and reports the production of extended spectrum beta-lactamase in Escherichia coli isolates from urine of patients sourced from General Hospital, Maitama, Abuja, Nigeria.

Study Design: Cross sectional study.

Place and Duration of Study: Department of Microbiology, Nasarawa State University, Keffi, between August 2020 and February 2022.

Methodology: Escherichia coli was isolated from the samples using standard cultural and microbiological methods. Antibiotic susceptibility testing and minimum inhibitory concentrations were evaluated as described by the Clinical and Laboratory Standards Institute (CLSI). The detection of ESBL production in E. coli isolates was carried out using double disc synergy test. In addition, molecular detection of ESBL genes was carried out using Polymerase Chain Reaction (PCR) method.

Results: 27.5% of samples isolated (33/120) had E. coli. Antibiotic resistance in the isolates in decreasing order were as follows: sulphamethoxazole/trimethoprim (91.7%), amoxicillin/clavulanic acid (72.2%), ceftriaxone (69.7%), cefotaxime (66.7%), ciprofloxacin (42.4%), meropenem (42.4%), ofloxacin (39.4%), imipenem (39.4%), gentamicin (33.3%), and nitrofurantoin (20.3%). The most common antibiotic resistant phenotypes were CTX-AMC-OFX-CRO-SXT-CIP-NET-IMP-MOR (16.7%) and CTX-AMC-OFX-CRO-CN-SXT-CIP-NET-IMP-MOR (16.7%). Multiple antibiotic resistance (MAR) was observed in 96.6% (29/30) of the isolates with the common MAR indices being 0.2 (23.3%), 0.9 (16.7%), and 1.0 (16.7%). Six of the twenty six cefotaxime/ceftriaxone jointly resistant isolates (23.1%) were confirmed ESBL producers. All six of the ESBL positive isolates (100.0%) carried bla genes as follows: blaTEM (6/6, 100.0%), blaSHV (2/6, 33.3%), and blaCTX-M (6/6, 100.0%).

Conclusion: The E.coli isolates were less resistant to nitrofurantoin, gentamicin, imipenem, ofloxacin and meropenem. In addition, ESBL genes were detected in confirmed E. coli isolates.