Detection of inv A virulence gene by polymerase chain reaction (PCR) in Salmonella spp. isolated from captive wildlife

possesses genes that are responsible for virulence and establishment of infection in host cells. One of such genes is inv A gene which is responsible for the invasion of the bacteria into host cells and is essential for full virulence in Salmonella. The gene is specific for members of the genus Salmonella and have been said to always be present in Salmonella spp. In this investigation, Salmonella spp. isolated from captive wildlife were screened for inv A virulence gene. Eight isolates were tested by polymerase chain reaction (PCR) assay using primers that amplify the 284 base pair fragment of the Salmonella inv A gene. Five out of the eight isolates were positive for inv A gene. They were isolates from striped hyena, lion, spotted hyena, African hawk eagle and peafowl while those from bateleur eagle, chimpanzee and another from African hawk eagle were negative. Salmonella isolates carrying the inv A virulence genetic sequence are able to invade host cells and cause infection while those without it may be unable to do that. The finding of this study also suggests that inv A gene may not always be present in all Salmonella spp.