Molecular Detection of Extended Spectrum Beta-lactamase Resistance in Escherichia coli from Poultry Droppings in Karu, Nasarawa State, Nigeria

Aims: This study investigates and reports the production of extended spectrum beta-lactamase in Escherichia coli isolates in poultry droppings sourced from selected poultry farms in Karu, Nigeria

Study Design: Cross sectional study

Place and Duration of Study: Department of Microbiology, Nasarawa State University, Keffi, between August 2019 and February 2020.

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: All (100%) samples collected had E. coli. Antibiotic resistances in the isolates in decreasing order were as follows: ampicillin (96.7%), streptomycin (94.4%), sulphamethoxazole /trimethoprim (87.8%), amoxicillin/ clavulanic acid (61.1%), gentamicin (52.2%), ciprofloxacin (40.0%), ceftazidime (35.6%), cefotaxime (31.1%), imipenems (22.2%), cefoxitin (13.3%). The commonest antibiotic resistant phenotype was AMP-SXT-S-CTX-CN (8.8%). Multiple antibiotic resistance (MAR) was observed in 92.2% (83/90) of the isolates with the common MAR indices being 0.5 (26.5%), 0.6 (19.2%), 0.4 (13.2%) and 0.9 (10.8%). Fifty nine of the eighty beta-lactam resistant isolates (73.7%) were confirmed ESBL producers. 55 of the 59 ESBL positive isolates (93.2%) carried bla genes as follows: blaSHV (50/55, 90.9%), blaTEM (31/55, 56.3%) and blaCTX-M (46/55, 83.6%). Thirty six (65.5%) of the 55 isolates carried two bla genes (blaSHV and blaTEM, blaTEM and blaCTX-M, and blaCTX-M and blaSHV).

Conclusion: The E. coli isolates showed lower resistances to cefoxitin, imipenem, cefotaxime, ceftazidime, and ciprofloxacin and most isolates were MAR, with resistance to 5 antibiotics being the most predominant. In addition, blaSHV gene was the most common ESBL gene detected in the confirmed ESBL-producing E. coli isolates.