Of your corresponding MG1655 F9 deletion mutants (Fig. 2). Ultimately, we tested no matter if yiaF, stfE, rcsA, yliE and ypjC could also play a reciprocal function in E. coli 55989a capability to colonize a commensal biofilm. Although stfE was absent in the 55989 genome, a ypjC mutant could not be obtained in spite of repeated attempts. We consequently introduced only a yiaF, rcsA or yliE mutation inside the 55989a strain, and we showed that none of those 3 mutations had a important impact on colonization outcome, suggesting that the observed colonization phenotypes specifically impacted pathogen colonization in commensal biofilm, but not the reverse (Fig. three). Taken together, these benefits indicated that colonization of commensal MG1655 F9 biofilm by the diarrheaFigure three. Colonization resistance genes are strainspecific. Comparison of the impact on colonization of mutations introduced into commensal MG1655 F9 (C) or into pathogenic strain 55989a (P). Final results are represented as ratio of colonization of mutant mixed MG1655 F9Dgene (C) P or C55989aDgene (P) biofilms compared to wildtype mixed CP biofilm. Black bar represents extent of wildtype colonization in CP mixed biofilms arbitrarily set to a single. White bars represent colonization levels of CDgene P mixed biofilm (mutation introduced into commensal and wildtype pathogens). Light gray bars represent colonization levels of CPDgene mixed biofilm formed by wildtype commensal and mutant pathogens. Names of deleted genes are indicated beneath the line. Results are averages of at least six replicates 6 typical deviation from the imply. Asterisks indicate mutant mixed biofilm with a colonization level drastically distinctive from that of wildtype MG1655 F9 55989a mixed CP biofilm, P,0.05. doi:ten.1371/journal.pone.0061628.gFigure two. Constitutive expression of possible colonization resistance genes. Estimate of E. coli 55989a (P) colonization in mixed biofilms with wildtype E. coli MG1655 F9 (C), corresponding deletion mutants (MG1655Dgene: C) or overexpressed (MG1655PcLgene: C) derivative strains. Final results are represented as ratio of colonization l of mutant mixed biofilms to wildtype mixed CP biofilms. Black bar represents wildtype colonization in CP mixed biofilms arbitrarily set to a single. White bars represent colonization of pathogen in mixed CDgene P biofilms. Stripped bars show pathogen colonization in mixed CPcLgene P biofilms with commensal overexpressing potential colonization resistance genes. Genes deleted or overexpressed are indicated below the bars. Final results are averages of no less than 12 replicates six regular deviation with the mean. The extent of colonization in CDgene P mixed biofilm was significantly various from that of wildtype CP biofilm p,0.Price of 1340313-49-6 05; asterisks indicate important difference involving extent of colonization in overexpressed and deletion mutants, p,0.250674-51-2 Chemscene 05.PMID:33686214 doi:10.1371/journal.pone.0061628.gPLOS One | www.plosone.orgColonization Resistance in E. coli Biofilmsgenic pathogenic strain 55989a triggers expression of commensal genes contributing to colonization resistance for the pathogen.Popular genetic responses of commensal biofilm upon colonization by distinct pathogensWe investigated whether or not in vitro commensal biofilm colonization by a bacterium aside from E. coli 55989a could trigger comparable genetic responses. We inoculated a preformed MG1655 F9 commensal biofilm using the biofilmforming opportunistic enterobacterium Klebsiella pneumoniae strain LM 21 (hereafter known as KpLM21) responsible for a wid.