O serogroups, phylogeny, and virulence factors of cervicovaginal and rectal Escherichia coli isolates

Excerpt

Commensal Escherichia coli is a major component of flora in the healthy human gut; however, certain E. coli strains cause severe human disease [1]. E. coli is a major cause of gastrointestinal infections, and extra-intestinal pathogenic E. coli (ExPEC) that originate in the gut can cause infections at other sites, including urinary tract infections (UTI) and neonatal meningitis [1]. Uropathogenic E. coli (UPEC) is the primary cause of UTI, which affect 11% of women 18 years or older in the United States each year [2]. It is thought that the UPEC strain originates in the patient’s fecal flora, colonizes the perineum and urethra, and finally ascends into the bladder to cause a UTI [3]. Some studies suggest that vaginal colonization plays a role in UTI [4]. In addition, neonatal meningitis E. coli (NMEC) is the second leading cause of neonatal meningitis in industrialized countries, with a mortality rate as high as 29% [5], and it has been speculated that colonization of the mother’s vagina plays a role in transmission of NMEC to the neonate [6]. Despite the potentially important role of vaginal colonization in these diseases, only a few studies have examined vaginal isolates in detail [6‐9]. One possibility is that ExPEC strains are more likely to colonize the vagina than nonpathogenic strains. To test this possibility, we analyzed a collection of cervicovaginal E. coli (CVEC) isolates for the prevalence of ExPEC-associated virulence traits. For comparison, we analyzed rectal E. coli (REC) isolates as representatives of the normal, nonpathogenic flora. …