Prevalence and antibiotic susceptibility of Listeria monocytogenes in raw milk from cattle herds within Sokoto Metropolis, Nigeria

Abstract

One hundred and ninety two raw milk samples were collected from lactating cows identified in Fulani herds and small scale dairy farms within Sokoto metropolis in order to investigate the presence and determine the antibiotic susceptibility of Listeria monocytogenes in the milk. Selective culture and identification method was employed for the bacterial isolation and Kirby-Bauer technique was used for the antibiotic susceptibility test. Seventy six samples (39.58%) were positive for Listeria species, which upon biochemical characterization 39(51.3%) were Listeria innocua, 14(18.4%) Listeria ivanovii, 17(22.4%) Listeria monocytogenes, 4(5.3%) Listeria welshimeri and 2(2.6%) Listeria seeligeri. Antibiotic susceptibility test of the isolates revealed high resistance to am picillin (100%), and streptomycin (80%), followed by ampiclox (70%), tetracycline (30%), then gentamycin (20%) while, there was no resistance to ciprofloxacin and chloranphenicol. The findings of this study necessitate the need for extension personnel to educate the Fulani herdsmen, milk handlers and other livestock producers on the significance of hygiene especially during milking and the effect of indiscriminate use of drugs particularly antibiotics. There is also need for the agencies concerned such as the National Agency for Food and Drugs Administration and Control (NAFDAC) to regulate the sales and use of both human and veterinary drugs by drug hawkers and other non-professional veterinary practitioners.