Environmental Stress Modulates Expression of Biofilm-Related Genes in Salmonella

Abstract Aims Biofilms formed by Salmonella are a significant concern in the poultry industry due to their role in pathogen persistence. However, there is a lack of data observing the expression of biofilm related genes in different Salmonella serovars. The aim of this study was to investigate the expression patterns of key biofilm-associated genes across three Salmonella serovars, namely S. Typhimurium, Kentucky, and Reading, throughout their biofilm growth cycles. Methods and Results The expressions of csgD, bapA, bcsA, adrA, and luxS were analyzed in cultures representing different biofilm growth phases: 12 h and 24 h planktonic cells, 4-day old biofilms, and 5-day old biofilms under nutrient deprivation. The findings from this study revealed that only S. Reading exhibited upregulation of these genes at the 24 h planktonic stage at a maximum of 9.58-fold. In contrast, a downregulation of all five genes was noted in the 4-day old biofilms for all serovars. Most notably, bapA was downregulated by 3,765-fold in S. Typhimurium. Upon subjecting the biofilms to nutrient deprivation, there was a notable recovery in the activity of these genes across all serovars with the exception of csgD in S. Typhimurium. Conclusion These results suggest that expression of biofilm-associated genes is stimulated by nutrient availability even at biofilm maturity and may vary among different serovars.