Occurrence of Salmonella Species in Local and Commercial Chickens Slaughtered at Samaru and Sabongari Live Bird Markets, Kaduna State

Abstract

Salmonellosis is a bacterial infection caused by members of the genus Salmonella. It is one of the most common and important zoonotic diseases. The route of infection from animals to humans is usually through contaminated food, water and environment. Bacteriological investigation on 303 cloacal swab samples collected from local (139) and commercial (164) chickens slaughtered at Samaru and Sabon-gari live bird markets, Kaduna State was carried out to determine the occurrence of Salmonella species. Cultural isolation and identification using conventional biochemical tests, microgen test kit™ and Polymerase Chain Reaction (PCR) amplification of invA gene of the Salmonella isolates was carried out. Isolates were subjected to antimicrobial susceptibility tests, phenotypic detection of Extended Spectrum Beta Lactamases (ESBLs) producing Salmonella isolates using the modified Clinical and Laboratory Standards Institute (CLSI) ESBL confirmatory test. The occurrence of Salmonella species based on cultural and biochemical tests was found to be 13 (4.29%), microgen kit identified 7 (53.8%) of the 13 Salmonella species while PCR based on invA gene confirmed 9 (69.2%) as the overall occurrence rate of Salmonella species. Meanwhile, the study also revealed rate of occurrence of Salmonella species in local chickens 8 (61.5%) which was higher compared to commercial chickens 1 (7.69%) with a statistical significant association (χ2 = 8.775, P = 0.003) between the occurrence of Salmonella species in local and commercial chickens. Antimicrobial susceptibility testing was carried out using panel of 12 antibiotics from 8 different antibiotic classes. Highest rate of sensitivity of the isolates to antibiotics was observed for Ofloxacin with 90%, while all the isolates (100%) were resistant to Nalidixic Acid, Cefazolin, Amoxicillin + Clavulanic Acid, Oxacillin and Penicillin. This study revealed multidrug-resistance (MDR) profile of Salmonella with a total of (25%) of Salmonella isolates being resistant to 5 antibiotics belonging to 4 different classes of antimicrobials with the highest multiple antibiotic-resistant (MAR) indices ranging from 0.58 to 0.91. All the nine (9) isolates of Salmonella tested were found to be negative for ESBLs production. Therefore, it is concluded that Salmonella species are present in local and commercial chickens slaughtered at Samaru and Sabon-gari live bird markets, Kaduna State and could pose serious public health risks to handlers and to consumers of poultry meat and its products.