Phenotypic and Genotypic Characterisation of Antibiotic Resistance in Escherichia coli, Klebsiella spp., and Listeria monocytogenes Isolates from Raw Meat Sold in Nairobi

Abstract

Worldwide, the increase in antimicrobial resistance (AMR) is a public health concern. Food-borne associated antibiotic-resistant pathogens can contami nate raw meat during slaughter, transportation, and at sale points. A cross- sectional study was conducted from March 2021 to December 2021 to deter mine antimicrobial susceptibility patterns and characterize the molecular basis of resistance in E. coli, Klebsiella spp., and L. monocytogenes contaminating raw meat collected from retail outlets in Nairobi. Isolation and identification of the strains were done using the standard culture methods and PCR. Antimi crobial susceptibilities of the recovered strains were determined using disk diffusion while the presence of antibiotic resistance gene determinants; blaTEM, blaCTX-M, blaOXA, sul, and qnrS was done using PCR. Of 270 samples collected, 163 (60%) Escherichia coli, 19 (7%) Klebsiella spp., and L. monocytogenes 3 (1.1%) were recovered. Among Escherichia coli, high antibiotic resistance was found to Erythromycin 161 (98%) and ampicillin 88 (54%) while low resis tance was found against imipenem 2 (1%). Similarly, high resistance was found among Klebsiella spp. to Erythromycin 19 (100%) and ampicillin 12 (63%) low resistance to ceftazidime 1 (5%), cefotaxime 1 (5%), aztreonam 1 (5%), and chloramphenicol 1 (5%). One isolate among the three Listeria mo nocytogenes strains isolated was resistant to Trimethoprim-sulfamethoxazole. No resistance was exhibited to gentamycin by all Klebsiella spp. The preva lence of multidrug-resistant (resistance to three or more classes of antibiotics) isolates was 95/182 (52.2%). The common resistance pattern observed was Erythromycin, ampicillin, tetracycline, and trimethoprim-sulfamethoxazole with a prevalence of 19 (20%). ESBL was confirmed in isolates that harbored: blaTEM (65%), blaCTX-M (44%), blaOXA (33%) while sul and qnrS were detected DOI: 10.4236/aim.2022.1211042 Nov. 7, 2022 603 Advances in Microbiology A. Chepkemei et al. in 46.7% and 13.6% respectively. Circulation of antibiotic-resistant and MDR isolates found in this study could play a role in the dissemination of AMR among food-borne bacteria and suggest potential food safety and public health risk. Therefore, enhanced surveillance for antibiotic-resistant organ isms in raw meat for early detection of emerging resistant bacteria species in the food chain is recommended. Keywords Raw Meat, Escherichia coli, Listeria monocytogenes, Multidrug Resistance, Extended Spectrum β-Lactamase (ESBL)