AUTHOR=Bessaiah Hicham , Pokharel Pravil , Habouria Hajer , Houle Sébastien , Dozois Charles M. 

TITLE=yqhG Contributes to Oxidative Stress Resistance and Virulence of Uropathogenic Escherichia coli and Identification of Other Genes Altering Expression of Type 1 Fimbriae

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00312

DOI=10.3389/fcimb.2019.00312

ISSN=2235-2988

ABSTRACT=<p>Urinary tract infections (UTIs) are common bacterial infections and the vast majority of UTIs are caused by extraintestinal pathogenic <italic>Escherichia coli</italic> (ExPEC) strains referred to as uropathogenic <italic>E. coli</italic> (UPEC). Successful colonization of the human urinary tract by UPEC is mediated by secreted or surface exposed virulence factors—toxins, iron transport systems, and adhesins, such as type 1 fimbriae (pili). To identify factors involved in the expression of type 1 fimbriae, we constructed a chromosomal transcriptional reporter consisting of <italic>lux</italic> under the control of the fimbrial promoter region, <italic>fimS</italic> and this construct was inserted into the reference UPEC strain CFT073 genome at the <italic>att</italic>Tn7 site. This <italic>fimS</italic> reporter strain was used to generate a Tn<italic>10</italic> transposon mutant library, coupled with high-throughput sequencing to identify genes that affect the expression of type 1 fimbriae. Transposon insertion sites were linked to genes involved in protein fate and synthesis, energy metabolism, adherence, transcriptional regulation, and transport. We showed that YqhG, a predicted periplasmic protein, is one of the important mediators that contribute to the decreased expression of type 1 fimbriae in UPEC strain CFT073. The Δ<italic>yqhG</italic> mutant had reduced expression of type 1 fimbriae and a decreased capacity to colonize the murine urinary tract. Reduced expression of type 1 fimbriae correlated with an increased bias for orientation of the <italic>fim</italic> switch in the OFF position. Interestingly, the Δ<italic>yqhG</italic> mutant was more motile than the WT strain and was also significantly more sensitive to hydrogen peroxide. Taken together, loss of <italic>yqhG</italic> may decrease virulence in the urinary tract due to a decrease in production of type 1 fimbriae and a greater sensitivity to oxidative stress.</p>