Infiltration of Matrix-Non-producers Weakens the Salmonella Biofilm and Impairs Its Antimicrobial Tolerance and Pathogenicity

Abstract

Bacterial biofilms display a collective lifestyle, wherein the cells secrete extracellular polymeric substances (EPS) that helps in adhesion, aggregation, stability, and to protect the bacteria from antimicrobials. We asked whether the EPS could act as a public good for the biofilm and observed that infiltration of cells that do not produce matrix components weakened the biofilm of Salmonella enterica serovar Typhimurium. EPS production was costly for the producing cells, as indicated by a significant reduction in the fitness of wild type (WT) cells during competitive planktonic growth relative to the non-producers. Infiltration frequency of non-producers in the biofilm showed a concomitant decrease in overall productivity. It was apparent in the confocal images that the non-producing cells benefit from the EPS produced by the Wild Type (WT) to stay in the biofilm. The biofilm containing non-producing cells were more significantly susceptible to sodium hypochlorite and ciprofloxacin treatment than the WT biofilm. Biofilm infiltrated with non-producers delayed the pathogenesis, as tested in a murine model. The cell types were spatially assorted, with non-producers being edged out in the biofilm. However, cellulose was found to act as a barrier to keep the non-producers away from the WT microcolony. Our results show that the infiltration of non-cooperating cell types can substantially weaken the biofilm making it vulnerable to antibacterials and delay their pathogenesis. Cellulose, a component of EPS, was shown to play a pivotal role of acting as the main public good, and to edge-out the non-producers away from the cooperating microcolony.

Biofilm Producing Salmonella Typhi: Chronic Colonization and Development of Gallbladder Cancer

“…On the other hand, it has been shown that Salmonella colonization can be compromised by infiltrating cells that do not produce biofilm together with biofilm producing bacteria. In fact, the infiltration with biofilm non-producer cells gave rise to a delayed and milder disease development in the murine model, which was accompanied by a higher susceptibility to antibacterial agents [ 101 ]. Thus, biofilm formation appears to be a key adaptive strategy adopted by S. Typhi in order to allow microbial persistence, sustaining an increased resistance against antibiotics and the host immune response while ensuring microbial spreading in the host and the community.…”

Anti-biofilm Activities from Resveratrol against Fusobacterium nucleatum

“…Biofilm formation is a complex and multifactorial process that involves at least two steps. The first step involves the adherence of the bacterial cells to the host surface; subsequently, adherent cells form a multilayer biofilm covered by an extracellular matrix ( Flemming and Wingender, 2010 ; Trappetti et al, 2011 ; Srinandan et al, 2015 ). The microorganisms in the biofilm undergo profound changes during the shift from a planktonic lifestyle.…”

Analysis of Shigella flexneri Resistance, Biofilm Formation, and Transcriptional Profile in Response to Bile Salts

“…Given that the appearance of bacterial aggregates and the clumping phenotype resembled biofilm formation by other pathogens (17)(18)(19)(20)(21)(22), additional assays were performed to verify and quantify the observations. First, crystal violet staining was performed based on previous observations of bile-induced biofilm formation in Vibrio cholerae (17).…”