Leachate Generated from a Public Abattoir in Nigeria is a Repository of Escherichia coli Carrying a High Burden of Extended Spectrum Β-Lactamase (ESBL) Genes

Indiscriminate dumping of wastes from abattoirs has contributed to the proliferation of antibiotic resistance in the environment. Most studies in Nigeria have focused on the phenotypic detection of extended spectrum β-lactamase (ESBL) production in bacteria from the abattoir environment, with few carrying out ESBL genotyping of the isolates. This study characterized and genotyped ESBL- producing Escherichia coli associated with leachate generated from the waste dumps of a public abattoir. Presumptive ESBL-producing E. coli were isolated on chromogenic medium from leachates collected from three designated points. Fifty-five non-duplicated isolates showing carriage of uidA gene were selected for further studies. The resistance manifested to a panel of five selected antibiotics by the fifty-five isolates was: imipenem (0%), enrofloxacin (14.5%), sulfamethoxazole-trimethoprim (69.1%), oxytetracycline (78.2%) and cefotaxime (98.2%). Thirty-five of the isolates showed resistance to three or more classes of antibiotics and were termed multidrug-resistant. It was observed that blaCTX-M was the most predominant ESBL gene with 51/55 (92.7%) isolates carrying the gene, 27/55 (49.5%) carried blaTEM while one isolate carried blaSHV. Twenty-four isolates (43.6%) carried two of the three targeted ESBL genes, while one isolate carried all the three ESBL genes. Twenty-eight of the isolates (50.9%) carried only one gene, while two isolates were devoid of any of the ESBL genes. This study has shown that abattoir leachates is a repository of multidrug resistant and ESBL- producing E. coli, highlighting the need for adequate waste disposal and proper waste treatment in abattoirs.