AUTHOR=Mandal Rabindra K. , Kwon Young M. 

TITLE=Global Screening of Salmonella enterica Serovar Typhimurium Genes for Desiccation Survival

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01723

DOI=10.3389/fmicb.2017.01723

ISSN=1664-302X

ABSTRACT=<p><italic>Salmonella</italic> spp., one of the most common foodborne bacterial pathogens, has the ability to survive under desiccation conditions in foods and food processing facilities for years. This raises the concerns of <italic>Salmonella</italic> infection in humans associated with low water activity foods. <italic>Salmonella</italic> responds to desiccation stress via complex pathways involving immediate physiological actions as well as coordinated genetic responses. However, the exact mechanisms of <italic>Salmonella</italic> to resist desiccation stress remain to be fully elucidated. In this study, we screened a genome-saturating transposon (Tn5) library of <italic>Salmonella</italic> Typhimurium (<italic>S</italic>. Typhimurium) 14028s under the <italic>in vitro</italic> desiccation stress using transposon sequencing (Tn-seq). We identified 61 genes and 6 intergenic regions required to overcome desiccation stress. <italic>Salmonella</italic> desiccation resistance genes were mostly related to energy production and conversion; cell wall/membrane/envelope biogenesis; inorganic ion transport and metabolism; regulation of biological process; DNA metabolic process; ABC transporters; and two component system. More than 20% of the <italic>Salmonella</italic> desiccation resistance genes encode either putative or hypothetical proteins. Phenotypic evaluation of 12 single gene knockout mutants showed 3 mutants (<italic>atpH, atpG</italic>, and <italic>corA</italic>) had significantly (<italic>p</italic> &lt; 0.02) reduced survival as compared to the wild type during desiccation survival. Thus, our study provided new insights into the molecular mechanisms utilized by <italic>Salmonella</italic> for survival against desiccation stress. The findings might be further exploited to develop effective control strategies against <italic>Salmonella</italic> contamination in low water activity foods and food processing facilities.</p>