POSSIBLE TRANSMISSION OF DRUG-RESISTANT SALMONELLA TYPHIMURIUM AND LISTERIA MONOCYTOGENES WITHIN THE BEEF INDUSTRY IN ABUJA, NIGERIA

Background: Widespread use of antibiotics in livestock production in large-scale across the globe has become of public and veterinary health importance because of its implication in antibiotic resistance. Adequate data in this area of research is not readily available in Nigeria; this study was undertaken in view of the possible link between antimicrobial resistance in farm animals and humans. Methods: We collected fifty samples of raw beef from different vendors and slaughter houses within Abuja and screened them for the presence of Listeria monocytogenes and Salmonella typhimurium using standard microbiological methods. The total bacterial and fungal counts, susceptibility of the isolates to different antibiotics and heat sensitivity at 55, 60 and 65ºC for 15 minutes were determined. Results: Our results show that ten isolates of Listeria monocytogenes and eighteen isolates of Salmonella typhimurium were isolated from the samples.  The total viable bacteria count range was 1x 10⁹ – 8x 10⁹cfu/g while the fungal count was 1x 10³ – 9x 10⁹cfu/g.  One (10 %) of the Listeria monocytogenes isolates was resistant to all antibiotics tested while all the Listeria monocytogenes isolates were resistant to cefuroxime. Eight (44.4%) of the Salmonella typhimurium isolates were resistant to at least three antibiotics. All the Listeria monocytogenes and Salmonella typhimurium isolates did not survive beyond 60 ^oC upon heat treatment. Conclusions: Our results indicate high prevalence of Salmonella typhimurium and Listeria monocytogenes in selected beef in Abuja. Beef therefore may represent a large reservoir for antimicrobial-resistant Salmonella typhimurium and Listeria monocytogenes.