Understanding the Significance of Ydcp, a Putative Peptidase Encoding Gene, in Virulence of Salmonella

Abstract

Salmonella is a recognised enteric pathogen which infects several mammalian and avian hosts through faeco-oral route and establishes either a localised gastrointestinal inflammation and diarrhoea or a systemic fever, depending on the diversity of mechanisms underlying its pathogenesis. However, the complete molecular landscape governing different aspects of its virulence are yet to be unveiled. Apart from the canonical virulence determinants, recent studies are discovering multifarious strategies adopted by the pathogen en route to successful invasion of host and subsequent intra-host multiplication. In its entire genome, Salmonella Typhimurium contains four genes encoding U32 peptidases: putative peptidases with yet uncharacterised structure and catalytic mechanism. ydcP is one such gene whose absence has been correlated so far with reduced intestinal invasion and compromised passage through blood-brain barrier by the pathogen. However, no role of this gene or its product has been clearly characterised during the systemic phase of infection. This study reveals ydcP to be essential for intramacrophage sustenance and multiplication of Salmonella both in vitro as well as in vivo conditions. Also, a positive relation between presence of this gene and oxidative stress resistance by the bacterium is drawn from the experimental evidences, which joins the dots between this gene and its indispensability during the intraphagocytic oxidative burst against the pathogen