Prevalence and Characterization of Salmonella Isolates from Poultry Farms in Ilorin, Nigeria

Poultry birds are very important source of essential proteins in developing countries, but also play an important role in transmission of Salmonella to human and nonhuman. Exposure to this pathogen also occurs through use of poultry droppings as manure for crop and vegetable production. This study investigated prevalence of Salmonella in feces of poultry farms in Ilorin, Nigeria. Salmonella isolated were further characterized by molecular method. Fecal samples were cultured in pre-enrichment medium, Selenite F medium and finally sub-cultured on Salmonella-Shigella agar. None lactose fermenting colonies with black center were picked for presumptive identification using biochemical tests and confirmed by serological test by method previously described. Molecular characterization was carried out using 16S rRNA gene sequencing following standard procedure. Out of 170 samples collected and examined, 8 (4.7%) gave biochemical characteristics that resembled Salmonella, but only 6 (3.5%) were confirmed as Salmonella by polyvalent antisera. Molecular characterization revealed that serovars isolated were Salmonella Enteritidis 3 (1.8%) and Salmonella Paratyphi 3 (1.8%). Phylogenetic tree constructed by neighbor-joining method as derived from analysis of the 16S rRNA gene sequences showed close relationship to Salmonella Paratyphi strain FB0015 16S ribosoma RNA gene partial sequence to our Salmonella Paratyphi isolates. The detection of 3.5% prevalence rate of Salmonella serovar from feces of laying poultry birds my serve as potential source of transmission of this pathogen to human through chicken meat, egg or use of poultry dropping as manure in crop or vegetable production.