Purpose: The purpose of our study was to evaluate the overall bacterial diversity, as well as the prevalence of antibiotic resistance genes (ARGs) in bacterial communities of foods sold at retail outlets in low and high SES areas in Memphis-Shelby County, Tennessee.
Methods: We utilized next generation sequencing of the 16S rRNA genes, shotgun metagenomics, PCR, as well as culture-dependent methods to evaluate the bacterial community of selected foods (lettuce, cabbage, deli meat, and chicken legs; n=200) procured from retail outlets.
Results: Foods from low SES areas contained higher bacterial counts and a different microbial composition compared to high SES areas. Firmicutes and Proteobateria were the most abundant phyla in produce and animal products. Enterobacter and Pantoea in produce, and Bacillus and Aeromonas in animal products were the most abundant genera. The prevalence and abundance of ARGs in bacterial communities of foods sold by retailers from different SES areas varied significantly. The highest abundance of ARGs was found in low SES deli meat, including ARGs to carbapenem and multidrug efflux systems. ARGs to amphenicols and erythromycin were present in all high SES lettuce and deli meats, respectively. The class 1 integron-integrase genes were detected in all chicken samples.
Significance: Consumption of foods containing substantially different microbiota and ARGs may expose populations of low SES to a differential risk of contracting foodborne illness than that of high SES.