Isolation and Characterization of Salmonella Gallinarum from Outbreaks of Fowl Typhoid in Kaduna State, Nigeria

Abstract

This study was carried out to isolate and characterize the causative agent of fowl typhoid in some outbreaks in chickens. Seventy isolates of Salmonella Gallinarum were recovered from culturing visceral organs and cloacal swabs obtained from 30 different outbreaks affecting 29 poultry farms in 8 parts of Kaduna State, Nigeria within two years, February, 2011 – January, 2013. Real-Time Polymerase Chain Reaction was carried out using primers targeting invA gene which confirmed all isolates as Salmonella. Multiplex PCR was carried out to target glgC and speC genes in order to differentiate between biovars Gallinarum and Pullorum. Results showed that all the isolates possessed both genes, confirming that they were biovar Gallinarum. Ten isolates were selected and characterized by XbaI Pulsed-Field Gel Electrophoresis (PFGE). The selected isolates represented farms in various parts of the three Local Government Areas (LGAs) where outbreaks occurred. Out of these ten isolates, six isolates were chosen from 55 isolates recovered from 22 affected farms in Sabon Gari LGA. Three isolates were chosen from 9 isolates recovered from 5 affected farms in Kaduna North LGA; while 1 isolate was chosen from 5 isolates recovered from the 2 farms affected in Kaduna South LGA. The PFGE profiles showed >78% degree of relatedness among Salmonella isolates. This study provides information that the poultry industry in Kaduna State, Nigeria is still plagued with outbreaks of fowl typhoid caused by closely related Salmonella Gallinarum which were isolated.