A novel rspA gene regulates biofilm formation and virulence of Salmonella Typhimurium

Salmonella spp. are facultative anaerobic, Gram-negative, rod-shaped bacteria and belongs to the Enterobacteriaceae family. Although much has been known about Salmonella pathogenesis, the functional characterizations of certain genes are yet to be explored. The rspA (STM14_1818) is one such gene wit...

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Bibliographic Details
Published in:Microbial pathogenesis 2023-12, Vol.185, p.106432-106432, Article 106432
Main Authors: Pradhan, Jasmin, Pradhan, Diana, Sahu, Jugal Kishor, Mishra, Satyajit, Mallick, Swarupa, Das, Surajit, Negi, Vidya Devi
Format: Article
Language:English
Subjects:
biofilm
Caenorhabditis elegans
cellulose
complement
death
epithelial cells
family
genes
innate immunity
macrophages
microbial load
mutants
pathogenesis
Salmonella Typhimurium
temperature
virulence
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Summary:Salmonella spp. are facultative anaerobic, Gram-negative, rod-shaped bacteria and belongs to the Enterobacteriaceae family. Although much has been known about Salmonella pathogenesis, the functional characterizations of certain genes are yet to be explored. The rspA (STM14_1818) is one such gene with putative dehydratase function, and its role in pathogenesis is unknown. The background information showed that rspA gene is upregulated in Salmonella when it resides inside macrophages, which led us to investigate its role in Salmonella pathogenesis. We generated the rspA knockout strain and complement strain in S. Typhimurium 14028. Ex-vivo and in-vivo infectivity was looked at macrophage and epithelial cell lines and Caenorhabditis elegans (C. elegans). The mutant strain differentially formed the biofilm at different temperatures by altering the expression of genes involved in the synthesis of cellulose and curli. Besides, the mutant strain is hyperproliferative intracellularly and showed increased bacterial burden in C. elegans. The mutant strain became more infectious and lethal, causing faster death of the worms than the wild type, and also modulates the worm's innate immunity. Thus, we found that the rspA deletion mutant was more pathogenic. In this study, we concluded that the rspA gene differentially regulates the biofilm formation in a temperature dependent manner by modulating the genes involved in the synthesis of cellulose and curli and negatively regulates the Salmonella virulence for longer persistence inside the host.
ISSN:0882-4010
1096-1208
DOI:10.1016/j.micpath.2023.106432