Isolation and antibiogram of Salmonella species from slaughtered cattle and the processing environment in Abuja abattoirs, Nigeria

Bacteria of the genus Salmonella are a significant food safety concern in many parts of the world, especially in developing countries like Nigeria. In the present study, a total of 422 samples were collected with the aim of isolating Salmonella species and determining the antibiogram of the isolates to 12 routinely prescribed antibiotics. Samples were obtained from cattle carcasses, cattle rectum, cattle hides, abattoir floor, water, butcher's hands and butcher's knives at Kubwa, Karu and Gwagwalada abattoirs in Abuja, Nigeria. Salmonella was isolated according to conventional cultural and serological methods, alongside further biochemical and molecular screening using Microbact™ 12E kit and invA specific polymerase chain reaction respectively. Out of the 422 samples investigated, 11 (2.6%) were positive for Salmonella. Total sample-specific isolation frequencies were 1.6% from carcass swabs, 1.6% from rectal swabs, 4.8% from hide swabs, 6.3% from floor swabs, 2.3% from water, 1.6% from hand swabs and 0% from knife swabs. The invA virulence gene was detected in all (100%) of the isolates, which also exhibited resistance to between 3 and 5 antibiotic classes. The most common multi-drug resistance (100%) was to beta lactams, macrolides and beta lactam/beta lactamase inhibitors. Cefepime, Enrofloxacin and Ofloxacin were found to be most (100%) effective. This study confirms the presence of multi-drug resistant Salmonella species in slaughtered cattle and the processing environment at the abattoirs in Abuja, Nigeria. However, we observed a lower Salmonella isolation compared to many other studies, which may be a result of some hygienic practices, low Salmonella status of the animals, among others.