Molecular Characterization of ESBLs and QnrS Producers From Selected Strains Isolated From Commercial Poultry Production Systems in Kiambu County, Kenya

Background: The emergence and spread of Extended-spectrum β-lactamases (ESBLs) in through the plasmid-mediated exchange have become a major threat to public health by complicating the treatment of severe infections in both animals and humans. Therefore, the current study focused on evaluating the manifestation of ESBLs production from the fecal isolates of , , , and in commercial poultry production systems of Kiambu County, Kenya.

Materials And Methods: Out of 591 isolates identified as , , , and from 437 fecal samples, only 78 were phenotypically suggestive to be ESBL producers. The possible ESBL producers were screened for the presence of TEM, CTX-M, OXA, and SHV using the PCR technique. These isolates were also screened for carriage of the QnrS gene that confers resistance to the fluoroquinolone class of drugs.

Results: The most detected ESBL gene from the isolates was OXA (n = 20; 26%), followed by TEM (n = 16, 21%), with the majority of them detected in . The CTX-M was identified in all the 4 enteric's bacteria-type isolates tested. Three and respectively were found to harbor all the 5 antimicrobial resistance (AMR) gene types. The TEM, OXA, SHV, and QnrS genes were not detected from and . Additionally, most of the AMR gene co-carriage was detected in both and as follows TEM + OXA (n = 4); TEM + QnrS (n = 3); TEM + OXA + QnrS (n = 3), concurrently.

Conclusion: Our findings highlight the significance of commercial poultry production in disseminating transferable antibiotic resistance genes that act as potential sources of extensive drug resistance in livestock, humans, and the environment, leaving limited therapeutic options in infection management.