Salmonella enterica Serovar Typhimurium and C. elegans: An ideal host pathogen interaction model for microbial adaptation

Abstract

Salmonella infection and its host range always has raised concern over worldwide disease manifestation, mortality and morbidity. The emergence of drug resistant bacteria further increases the risk factor and shows the need to develop an efficient strategies against Salmonella infection and associated consequences. Currently in my laboratory, we are trying to address the microbial evolutionary adaptability aspect using Caenorhabditis elegans (C. elegans) as model organism and also we are studying the infection mediated developmental defects in worm. Evolutionary adaptations has been considered and reported also as an important survival strategy of all living organism including microorganism. We have observed that Salmonella have adapted better when they we repeatedly exposed to same host environment in C. elegans for many generation and in LB or F media as well. The emerged Salmonella strain shows hypermobility, increased biofilm formation, size etc., which may help them in increased virulence and better survivability in host. The bug was able to invade better in epithelial cells than its unpassaged counterpart, but to our surprise fold proliferation was comparable, in phagocytic cell (U937) they are better survivor and proliferate better which indicate that microbe has adapted themselves to survive better in host environment. Salmonella infection mediated neonatal mortality and fetal loss during pregnancy is known. Hence in another study using nematode model (C. elegans) of Salmonella infection, we found that Salmonella infection in able to cause certain developmental defect in worm, like increased egg retention, delayed hatching, and 8-10% reduction in egg hatching etc. These study further increase the concern over what will be the outcome on developmental stages of host if we have adapted/emerged bacterial infection? So the current study shows that Salmonella infection in host can be ground for pathogen’s evolution and can further increase the infection associated risk including mortality, morbidity and even various developmental defect. With time such microbe will be more infectious and we need to develop combat strategies by targeting the responsible gene of such pathogenic phenotype.