Abstract:
Meat is an excellent source of protein and due to its nutritive nature, it provides a good medium for the growth and reproduction of microorganisms, but it is often implicated in foodborne diseases. Meat can be contaminated by pathogenic bacteria during slaughtering thus posing a safety concern in meat production. Despite the reported decline in mortality, diarrhea remains one of the principal causes of morbidity in developing countries. The emergence of multidrug-resistant Escherichia coli, Klebsiella pneumoniae, and Listeria monocytogenes strains poses a major challenge in the management and treatment of associated foodborne illnesses in resource-limited countries like Kenya. Although there has been a noticeable rise in antibiotic resistance among these organisms, the molecular mechanisms underlying this resistance and the factors contributing to contamination have not been adequately explored in Kenya. A cross-sectional study was conducted from March 2021 to December 2021 to determine the prevalence, antimicrobial susceptibility patterns, resistance genotypes, and risk factors associated with meat contamination in E. coli, Klebsiella spp, and L. monocytogenes contaminating raw meat collected from retail outlets in Nairobi; Kibera, Lang’ata, and Karen. Isolation and identification of the strains were done using the standard culture methods and PCR. Detection of E. coli pathotypes, L. monocytogenes, and the presence of antibiotic resistance genes was done using the PCR method. Antimicrobial susceptibilities of recovered strains were determined using disk diffusion while univariate analyses and multivariable logistic regression analyses were conducted to identify putative risk factors for contamination. Of 270 samples collected, 185 (66%) were contaminated with at least one bacterial species. Out of these 163 (60%) Escherichia coli, 19 (7%) Klebsiella spp, and 3 (1.1%) L. monocytogenes were recovered. The study also detected 28.8% diarrheagenic E. coli, as follows Enteropathogenic E. coli 24.4%, Shiga toxigenic E. coli 2.2%, and enteroaggregative E. coli 2.2%. High antibiotic resistance was found to erythromycin (98%) and ampicillin (54%) among E. coli and Klebsiella spp and low resistance to Imipenem (1%), ceftazidime (10%), aztreonam (8%), and chloramphenicol (8%), one Listeria monocytogenes strain, showed resistance to Trimethoprim-sulfamethoxazole. The prevalence of MDR was 52.2% and ESBL was confirmed in isolates that harbored: bla TEM (65%), bla CTX-M, (44%), and bla OXA (33%) while sul and qnrS were detected in (46.7%) and (13.6%) respectively. Although some putative risk factors such as the origin of the sample, Meat spoilage caused by spoilage microorganisms, food handlers with unhygienic practices, and handling meat when the food handlers have lesions were found to be significantly associated with meat contamination in the univariate analysis (p< 0.05). None of these risk factors remained associated with contamination at the multivariable stage.The findings from this study showed substantial contamination of retail meat sold in Nairobi that may act as a reservoir for the transmission of diarrheagenic E. coli and L. monocytogenes pathogens, therefore, posing a health risk among consumers through the consumption of raw/under-cooked meat or cross-contamination of other food products. Multiple drug-resistant and ESBL isolates detected in the present study may pose a threat to humans and further limit therapeutic options. Therefore, coordinated actions are needed to reduce or eliminate the risks posed by these organisms at various stages in the food chain.
