Zoonotic Escherichia coli is a potential Driver of Antimicrobial Resistance among Pastoralist Communities in Uganda: A Laboratory based Cross sectional Study
Background Non-prescribed use of antimicrobials in Agriculture incurs a transfer risk of resistant pathogens to humans, complicating treatment. The aim of this study was to determine the potential of Zoonotic E. coli to serve as drivers of antimicrobial resistance among animals and humans in pastoralist communities in Kasese district, so as to protect the community.Materials and methods A laboratory based cross-sectional study was done using archived E. coli isolates previously obtained from humans in pastoralist communities of Kasese district, Uganda. Recovery of the isolates was done by conventional culture, and Identification by biochemical methods, serotyping and PCR. Antimicrobial resistance profiling was done by using Kirby Bauer disc diffusion method. The isolates were also screened for resistance mechanisms including Extended Spectrum β-lactamase (ESBL), Carbapenemase and AmpC production using disc diffusion based methods.Results The prevalence of Enterohemorrhagic E.coli (EHEC) was 16% (28/180). These EHEC isolates belonged to phylogroups; B 1 (94%, 26/28), B2 (3%, 1/28) and A (3%, 1/28). The most prevalent virulence gene was Stx1 (100%, 28/28) followed by Stx2e (94%, 26/28); none of the isolates was Stx2 positive. Highest resistance was seen to Cotrimoxazole (89%, 25/28), Tetracycline (71%, 20/28), Ampicillin (65%, 18/28) and Nitrofurantoin (28%, 8/28), these are the most commonly used antimicrobials in the agricultural sector in Uganda. Minimal resistance was observed to the antimicrobials that are commonly used in human medicine especially β-lactams, β-lactam+inhibitors and Carbapenems. Of the 28 zoonotic E. coli isolates, 17%, (5/28) were ESBL positive and among these 1 (3%, 1/28) was a Carbapenemase producer.Conclusion There is a high prevalence of highly pathogenic and resistant zoonotic E. coli among humans in pastoralist communities in Uganda. We suspect that these pathogens, along with their AMR genes, were acquired from animals because they largely contained the animal specific Vero toxin gene VT2e and majority belonged Pylo-group B 1 which has been documented as the most common EHEC phylo-group inhabiting domestic animals. We recommend that studies involving relatedness of drug resistant isolates from humans and animals should be conducted to ascertain the role of enterohemorrhagic E. coli in the zoonotic spread of antimicrobial resistance in pastoralist communities.