Comparative genomics of Escherichia coli strains causing urinary tract infections

RM Vejborg, V Hancock, MA Schembri… - Applied and …, 2011 - Am Soc Microbiol
RM Vejborg, V Hancock, MA Schembri, P Klemm
Applied and environmental microbiology, 2011Am Soc Microbiol
The virulence determinants of uropathogenic Escherichia coli have been studied extensively
over the years, but relatively little is known about what differentiates isolates causing various
types of urinary tract infections. In this study, we compared the genomic profiles of 45 strains
from a range of different clinical backgrounds, ie, urosepsis, pyelonephritis, cystitis, and
asymptomatic bacteriuria (ABU), using comparative genomic hybridization analysis. A
microarray based on 31 complete E. coli sequences was used. It emerged that there is little …
Abstract
The virulence determinants of uropathogenic Escherichia coli have been studied extensively over the years, but relatively little is known about what differentiates isolates causing various types of urinary tract infections. In this study, we compared the genomic profiles of 45 strains from a range of different clinical backgrounds, i.e., urosepsis, pyelonephritis, cystitis, and asymptomatic bacteriuria (ABU), using comparative genomic hybridization analysis. A microarray based on 31 complete E. coli sequences was used. It emerged that there is little correlation between the genotypes of the strains and their disease categories but strong correlation between the genotype and the phylogenetic group association. Also, very few genetic differences may exist between isolates causing symptomatic and asymptomatic infections. Only relatively few genes that could potentially differentiate between the individual disease categories were identified. Among these were two genomic islands, namely, pathogenicity island (PAI)-CFT073-serU and PAI-CFT073-pheU, which were significantly more associated with the pyelonephritis and urosepsis isolates than with the ABU and cystitis isolates. These two islands harbor genes encoding virulence factors, such as P fimbriae (pyelonephritis-associated fimbriae) and an important immunomodulatory protein, TcpC. It seems that both urovirulence and growth fitness can be attributed to an assortment of genes rather than to a specific gene set. Taken together, urovirulence and fitness are the results of the interplay of a mixture of factors taken from a rich menu of genes.
American Society for Microbiology