M.J. FOYSAL, F. MOMTAZ, M.H. HAQUE1, M.N. HOSSAIN, M.M. RAHMAN AND S.H. PRODHAN
Abstract
Development of molecular techniques for detection of virulence gene is an imperative section in determining the pathogenicity and virulence properties of any isolates because these genes act multi-functionally and multi-factorially. Pathogenesis of Salmonellosis depends upon a large number of multi-functional factors controlled by an array of genes that synergize into the actual virulence of Salmonella. In this study the lipA gene encoding an extracellular lipase and protease specific elastase gene primer allows precise detection of lipase and elastase gene of Salmonella typhimurium by Polymerase Chain Reaction (PCR). This is the first report of lipase gene in Salmonella typhimurium. All isolates of Salmonella typhimurium were collected from patients suffering from typhoid and urinary tract infection (UTI). A total of 14 isolates viz., ST1, ST2, ST3, ST4, ST5, ST6, ST7, ST8, ST9, ST10, ST11, ST12, ST13 and ST14 were used in present study in which lipase gene was amplified in 3 isolates viz., ST1, ST2, ST3 and ST10 with expected PCR product of 1055bp whereas elastase gene was amplified in 6 isolates viz., ST1, ST2, ST4, ST11, ST13 and ST14 and gave the expected 467bp PCR product after visualization under gel documentation system. At the same time 14 samples were examined in-vitro for their putative virulence characteristics viz. proteolytic, lipolytic and hemolytic activity. High lipolytic activity was observed for isolates containing lipase whereas high proteolytic activity was observed for isolates containing elastase. Isolates containing both lipase and elastase showed elevated in-vitro virulence properties with significant P value of <0.05.