Genetic determinants inSalmonella entericaserotype Typhimurium required for overcoming stressors in the host environment

Abstract

AbstractSalmonella entericaserovar Typhimurium (S. Typhimurium), a non-typhoidalSalmonella(NTS), result in a range of diseases, including self-limiting gastroenteritis, bacteremia, enteric fever, and focal infections representing a major disease burden worldwide. There is still a significant portion ofSalmonellagenes whose functional basis to overcome host innate defense mechanisms, consequently causing disease in host, largely remains unknown. Here, we have applied a high-throughput transposon sequencing (Tn-seq) method to unveil the genetic factors required for the growth or survival of S. Typhimurium under various host stressors simulatedin vitro. A highly saturating Tn5 library ofS. Typhimurium 14028s was subjected to selection during growth in the presence of short chain fatty acid (100 mM propionate), osmotic stress (3% NaCl) or oxidative stress (1 mM H2O2) or survival in extreme acidic pH (30 min in pH3) or starvation (12 days in 1X PBS). We have identified an overlapping set of 339 conditionally essential genes (CEGs) required byS. Typhimurium to overcome these host insults. Interestingly, entire eight genes encoding F0F1-ATP synthase subunit proteins were required for fitness in all five stresses. Intriguingly, total 88 genes inSalmonellapathogenicity island (SPI), including SPI-1, SPI-2, SPI-3, SPI-5, SPI-6 and SPI-11 are also required for fitness under thein vitroconditions evaluated in this study. Additionally, by comparative analysis of the genes identified in this study and the genes previously shown to be required forin vivofitness, we identified novel genes (marBCT,envF,barA,hscA,rfaQ,rfbIand putative proteins STM14_1138, STM14_3334, STM14_4825, and STM_5184) that has compelling potential to be exploited as vaccine development and/or drug target to curb theSalmonellainfection.