Salmonella enterica Serovar Typhimurium Requires the Lpf, Pef, and Tafi Fimbriae for Biofilm Formation on HEp-2 Tissue Culture Cells and Chicken Intestinal Epithelium

Abstract

Recent work has demonstrated that Salmonella enterica serovar Typhimurium forms biofilms on HEp-2 tissue culture cells in a type 1 fimbria-dependent manner. To investigate how biofilm growth of HEp-2 tissue culture cells affects gene expression in Salmonella, we compared global gene expression during planktonic growth and biofilm growth. Microarray results indicated that the transcription of ϳ100 genes was substantially altered by growth in a biofilm. These genes encode proteins with a wide range of functions, including antibiotic resistance, central metabolism, conjugation, intracellular survival, membrane transport, regulation, and fimbrial biosynthesis. The identification of five fimbrial gene clusters was of particular interest, as we have demonstrated that type 1 fimbriae are required for biofilm formation on HEp-2 cells and murine intestinal epithelium. Mutations in each of these fimbriae were constructed in S. enterica serovar Typhimurium strain BJ2710, and the mutants were found to have various biofilm phenotypes on plastic, HEp-2 cells, and chicken intestinal tissue. The pef and csg mutants were defective for biofilm formation on each of the three surfaces tested, while the lpf mutant exhibited a complete loss of the ability to form a biofilm on chicken intestinal tissue but only an intermediate loss of the ability to form a biofilm on tissue culture cells and plastic surfaces. The bcf mutant displayed increased biofilm formation on both HEp-2 cells and chicken intestinal epithelium, while the sth mutant had no detectable biofilm defects. In all instances, the mutants could be restored to a wild-type phenotype by a plasmid carrying the functional genes. This is the first work to identify the genomic responses of Salmonella to biofilm formation on host cells, and this work highlights the importance of fimbriae in adhering to and adapting to a eukaryotic cell surface. An understanding of these interactions is likely to provide new insights for intervention strategies in Salmonella colonization and infection.

Identification of genetic and phenotypic differences associated with prevalent and non-prevalent Salmonella Enteritidis phage types: analysis of variation in amino acid transport

“…This suggests that other epidemicity factors play important roles in these cases. The pef genes are known to be virulence-associated, and are often involved in adhering to epithelial cells, and biofilm formation on HEp-2 cells and chicken intestinal epithelium (Baumler et al, 1996;Ledeboer et al, 2006;van der Velden et al, 1998;Weening et al, 2005). Salmonella contains at least 13 putative fimbrial operons on its chromosome, including bcf, sti, stf, saf, stb, fim (SEF21, type 1 fimbriae), agf (csg, SEF17, curli), stc, ste, std, lpf, sef (SEF14) and sth.…”

Role of the sRNA GcvB in regulation of cycA in Escherichia coli

“…The samples were centrifuged at 2000 g for 5 min and cell pellets were frozen at 280 uC. Total cellular RNA was isolated from cells by phenol extraction (Ledeboer et al, 2006) and DNase I-treated for 1 h at 37 uC, and RNA pellets were resuspended in 30 ml diethylpyrocarbonate (DEPC)-treated water. RNA was quantified using a NanoDrop ND-1000 spectrophotometer.…”

“…Bacterial strains GS162 (WT), GS1144 (DgcvB), GS1148 (Dhfq), GS1149 (DgcvABDhfq) and GS1144 transformed with the single-copy plasmid pGS594 (WT gcvB) were grown in 5 ml of LB to OD 600~0 .5. Total cellular RNA was isolated from cells by phenol extraction (Ledeboer et al, 2006) and DNase I-treated for 1 h at 37 uC, and RNA pellets were resuspended in 30 ml DEPC-treated water. RNA was quantified using a NanoDrop ND-1000 spectrophotometer.…”

The role of stj fimbrial operon in the intestinal persistence of Salmonella Typhimurium in mice

“…S. enterica serotype Typhimurium (S. Typhimurium) is a motile pathogen that has adapted to invading and surviving for long periods in its human and mouse hosts (Tükel et al 2005Weening et al 2005). S. Typhimurium related human gastroenteritis is initiated by the colonization of intestinal epithelium followed by invasion of M cells and enterocytes (Ledeboer et al 2006). Fimbriae play a critical role in virulence of Salmonella by allowing these bacteria to interact with intestinal epithelium (Edwards et al 2000;.…”

“…Fimbriae are thin, proteinaceous, polymeric non-motile structures which mediate adhesion of the cell to host tissue or to bacteria of same or different species. These interactions are committed steps leading to subsequent colonization of epithelial surfaces, entry into host cells or bacterial conjugation (Duguid et al 1966;Cogan et al 2004;Ledeboer et al 2006;Chessa et al 2008a). Many of gene clusters corresponding to fimbrial system are present in genomes of enteric bacteria.…”