Antimicrobial Resistance (AMR) of Public Health Concern Bacteria Isolated from Cows’ Raw Milk

Abstract

Milk is harboring both pathogenic and beneficial bacteria. This study aimed to investigate the emergence of antimicrobial resistance (AMR) foodborne pathogens in raw milk. The 100 milk samples of cow were aseptically collected from 10 randomly selected dairy farms of Dhaka City of Bangladesh during the period from August, 2022 to July, 2023. The collected milk samples were then processed and cultured on to selective media. The isolated microorganisms were identified based on staining, motility, cultural and biochemical properties according to standard laboratory methods. The isolated bacteria were also subjected to characterize their antibiotic sensitivity by disc diffusion method. Among 100 milk samples, 56% milk samples were reported as positive for Staphylococcus species, followed by Escherichia coli (23%), Klebsiella spp. (19%), and Salmonella spp. (9%) (P <0.001). On the other hand, 143 pathogenic bacteria were isolated and identified from the milk samples inspected of which 49.65% were Staphylococcus species, 25.17% were Escherichia coli, 18.88% were Klebsiella spp., and 6.29% were Salmonella spp. Multidrug resistant (MDR) property was observed in around 90% of the isolates (P <0.001). Among them, 100% of the Escherichia coli and Klebsiella spp. showed MDR properties followed by Staphylococcus spp. (81.69%), and Salmonella spp. (77.78%). Most of the isolates showed their resistance against ampicillin, amoxicillin, and tetracycline. Therefore, these findings will help the authority develop awareness among farmers regarding the judicious use of antibiotics in livestock production to reduce the transmission of AMR pathogens to humans through the food chain.