Inducible adhesion and biofilm formation in Salmonella linked to adaptive fatty acid metabolism

초록

Salmonella is one of the leading causes of foodborne illness, worldwide. The biofilm formation of this bacterium may be caused by its persistence in the food environment. However, the trigger factors and adaptive metabolism in Salmonella for biofilm formation are not fully known. Here, we observed the distinct biofilm formation of S. typhimurium 2220 in response to the presence of medium-chain fatty acids and found that the level of biofilm formation was positively linked to the chain length of the medium-chain fatty acids. Through dynamics analysis of biofilm formation, we discovered that decanoic acid (10-carbon fatty acid, C10) enhanced the initial attachment of strain 2220 on both biotic and abiotic surfaces, while compromising motility. The attachment was not achieved due to the inhibition of flagella expression but driven by enhanced energy metabolism which was shown as intracellular acidification and elevated ATP level. We found the S. typhimurium 2220 strain could adaptively metabolize fatty acid by enhancing the expression of fadL gene. In summary, Salmonella biofilm formation was inducible by adaptive fatty acid metabolism which resulted in the enhanced attachment. Our results uncovered valuable insights into the physiological alteration of this foodborne pathogen, suggesting the potential biofilm trigger in the food environment. These findings could facilitate the development of a new antibiofilm strategy.

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