Pleiotropic Roles of uvrY on Biofilm Formation, Motility and Virulence in Uropathogenic Escherichia coli CFT073

Abstract

Urinary tract infections primarily caused by uropathogenic strains of Escherichia coli (E. coli) remain a significant public health problem in both developed and developing countries. An important virulence determinant in uropathogenesis is biofilm formation which requires expression of fimbriae, flagella, and other surface components such as lipopolysaccharides. In this study, we explored the regulation of uvrY and csrA genes in biofilm formation, motility and virulence determinants in uropathogenic E. coli. We found that mutation in uvrY suppressed biofilm formation on abiotic surfaces such as polyvinyl chloride, polystyrene and glass, and complementation of uvrY in the mutant restored the biofilm phenotype. We further evaluated the role of uvrY gene in expression of type 1 fimbriae, an important adhesin that facilitates adhesion to various abiotic surfaces. We found that phase variation of type 1 fimbriae between fimbriated and afimbriated mode was modulated by uvrY at its transcriptional level. Deletion mutant of uvrY lowered expression of fimbrial recombinase genes, such as fimB, fimE, and fimA, a gene encoding major fimbrial subunit. Furthermore, transcription of virulence specific genes such as papA, hlyB and galU was also reduced in the deletion mutant. Swarming motility and expression of flhD and flhC was also diminished in the mutant. Taken together, our findings unravel a possible mechanism in which uvrY facilitates biofilm formation, persistence and virulence of uropathogenic E. coli.

Regulation of Bacterial Virulence by Csr (Rsm) Systems

“…Uropathogenic E. coli (UPEC) strains commonly cause urinary tract infections, where they replicate in intracellular and extracellular locations with the help of a battery of virulence factors that include fimbriae, toxins, and iron siderophores (323). The BarA/UvrY TCS and CsrA have been implicated in regulating UPEC virulence in animal models and virulence factors expressed in vitro, although the mechanisms for these effects have not been determined (324)(325)(326).…”

Identification by PCR signature-tagged mutagenesis of attenuated Salmonella Pullorum mutants and corresponding genes in a chicken embryo model

“…Deletion mutations of uvrY lowered expression of fimbrial recombinase genes, such as fimB, fimE, and fimA, and reduced transcription of virulence specific genes, such as papA, hlyB and galU. Swarming motility and expression of flhD and flhC were also diminished in the mutant [15].…”

“…uvrY has been shown to be beneficial to biofilm formation and the persistence and virulence of uropathogenic E. coli [15]. The uvrY gene encodes a DNA-binding response regulator of the BarA/UvrY two-component regulatory system, which responds to short chain carboxylates [16,17].…”

Emerging Antibiotic Resistance and Plasmid DNA in Escherichia coli Isolated from Respiratory Tract Infections in Bangladesh

“…The existence of virulence genes of iutA, fimA, and neuC in E.coli are even cited in some studies [20,21,22], which may contribute to their rising AR. These are believed to be the important virulence factors in many infections including RTIs caused by E.coli [23]. Further studies are thus recommended to explore the association of virulence factors of E.coli with AR in RTIs.…”