Solid waste dumpsite leachate and contiguous surface water contain antibiotic-resistant Escherichia coli with a high burden of extended spectrum β-lactamase (ESBL) genes

Abstract

Abstract Background Dumpsites generate leachates containing bacteria that may carry antibiotic-resistant genes, such as extended-spectrum β-lactamase (ESBL). However, the contribution of dumpsite leachates in the environmental spread of ESBL genes has not been investigated in greater detail. This study aimed to quantify the impact of Ajakanga dumpsite leachates on the spread of ESBL genes through surface water. Methods and Results Escherichia coli isolates obtained from leachates in dumpsites and the accompanying surface water were evaluated for antibiotic resistance and for phenotypic ESBL production using Kirby-Bauer disk diffusion and double disc synergy assays, respectively. The detection of ESBL genes in the isolates was carried out using primer-specific PCR. Of the 32 isolates obtained from leachates and 12 recovered from surface water, 26 and nine were respectively positive for ESBL phenotype. Altogether, the 35 ESBL-producing E. coli carried blaCTX−M, while 21/35 (60%) carried blaTEM. None of the isolates harboured blaSHV. The ESBL-producing isolates showed a high level of resistance to the 3rd generation cephalosporin antibiotics, with low resistance observed to imipenem and azithromycin. Conclusion This study found that ESBL-producing isolates from leachates and nearby surface water had identical resistance signatures which indicates that dumpsite leachates can contribute to the spread of ESBL-producing bacteria and their genes in receiving surface water. The review of the guidelines and operational procedures of dumpsites is highly recommended to forestall a public health challenge.