Antibiotic resistant bacteria in raw cow milk and milk products retailed in the northern region of Ghana; a food safety challenge

Abstract

The presence of antimicrobial resistant foodborne bacteria is a major food safety challenge for food that is consumed raw. Abuse and overuse of antibiotics in the agriculture sector has been identified as a contributory factor to the rising threat of antibiotic resistance. In many developing countries where milk is marketed and consumed raw through informal channels, the occurrence of bacterial contamination is high and poses a major public health risk. This situation is exacerbated when caused by antimicrobial resistant bacteria. Hence this study was conducted to determine the antimicrobial resistant pattern of bacteria in raw cow milk and milk products retailed in the Northern Region of Ghana. Antibiotic resistance profiles were established for 150 bacteria isolates (Escherichia coli, E. coli O157:H7, Klebsiella pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella spp. Shigella spp. and Proteus spp.) obtained from the culture of raw milk (n=210) and milk products (n=60) retailed within the Northern region of Ghana. Susceptibility to nine antimicrobials commonly used in veterinary and human medical practice was performed on all the isolates using the agar disc diffusion method according to Clinical and Laboratory Standards Institute guidelines. Isolates showed highest resistance to Nalidixic acid followed by Chloramphenicol, Gentamicin, Trimethoprim-sulfamethoxazole and Ceftriaxone but were most susceptible to Ciprofloxacin and Ampicillin. About 25 – 47.6 % of Staphylococcus aureus showed resistance to Cefoxitin. Milk and milk products sold in the northern region of Ghana are contaminated with bacterial pathogens with high levels of antimicrobial resistance. A one health approach is required to curtail the threat of antibacterial resistant bacteria in the food chain.