DISTRIBUTION OF DRB GENES-CODING FOR DR BINDING ADHESINS AMONG UROPATHOGENIC AND FECAL ESCHERICHIA-COLI ISOLATES AND IDENTIFICATION OF NEW SUBTYPES

The Dr family of related adherence structures, some fimbriated and oth ers afimbriated, bind to decay-accelerating factor molecules on human cells. Dr is associated with recurring urinary tract infection (UTI), but the distribution of Dr subtypes among uropathogenic Escherichia co li causing UTI among otherwise healthy women has yet to be described. A total of 787 UTI and fecal E. coli isolates from college women were screened for the presence of Dr sequences (drb). Fifteen percent of UT I strains were drb positive, compared to 5% of fecal strains. The adhe sin (E gene) subtype of each drb-positive strain was determined by typ e-specific PCR followed by restriction enzyme analysis. Among 78 drb-p ositive strains, we found 14 (18%) afaE1, 1 (1.3%) afaE2, 1 (1.3%) afa E3, 9 (12%) draE, 9 (12%) draE-afaE3 hybrid, 1 (1.3%) daaE, 32 (41%) a faE5, 4 (5.1%) F131 E gene-like, and 7 untypeable strains. All untypea ble E genes were cloned and sequenced, revealing four additional new c lasses of E genes, including two similar to the previously identified nonfimbrial E series. While a great range of diversity exists among th e E genes, restriction fragment length polymorphism analysis demonstra ted that all of these drb operons share a highly conserved gene struct ure. The most common subtype, afaES, occurred three times as often amo ng UTI than fecal strains, Over half of the drb-positive strains and 8 0% of those positive for afaE5 have the same virulence signature (posi tive for aer, kpsMT, ompT, and fim), suggesting an association of this profile with UTI pathogenesis.