Evidence of Commonality between Canine and Human Extraintestinal Pathogenic Escherichia coli Strains That Express papG Allele III

Abstract

Although dogs have been proposed as carriers of extraintestinal pathogenic Escherichia coli (ExPEC) with infectious potential for humans, presumed host species-specific differences between canine and human ExPEC strains have cast doubt on this hypothesis. The recent discovery that allele III of papG (the P fimbrial adhesin gene) predominates among human cystitis isolates and confers an adherence phenotype resembling that of canine ExPEC prompted the present reevaluation of the canine-human ExPEC connection. Sixteen paired pappositive urine and rectal E. coli isolates from dogs with urinary tract infection were studied. papG (adhesin) and papA (pilin) allele type, agglutination phenotypes, virulence factor genotypes, and randomly amplified polymorphic DNA and pulsed-field gel electrophoresis fingerprints were analyzed and compared with those of human ExPEC controls. The 16 canine strains contained predominantly papG allele III. Agglutination phenotypes segregated strictly according to papG allele status and were homogeneous among strains with the same papG allele profile irrespective of their human versus canine origin. Canine and human PapG variant III peptide sequences were highly homologous, without host species-specific differences. The most prevalent canine papA allele was F48, a novel variant recently identified among human urosepsis isolates. In addition to pap, human ExPEC-associated virulence genes detected among the canine strains included sfa/focDE, sfaS, fyuA, hlyA, cnf1, cdtB, kpsMT-II and -III, rfc, traT, ompT, and a marker for a pathogenicity-associated island from archetypal human ExPEC strain CFT073. Molecular fingerprinting confirmed the fecal origin of all but one canine urine isolate and showed one pair of O6 canine urine and fecal isolates to be extremely similar to an O6 human urosepsis isolate with which they shared all other genotypic and phenotypic characteristics analyzed. These data demonstrate that canine ExPEC strains are similar to, and in some instances essentially indistinguishable from, human ExPEC strains, which implicates dogs and their feces as potential reservoirs of E. coli with infectious potential for humans.

Commonality among Fluoroquinolone-Resistant Sequence Type ST131 Extraintestinal Escherichia coli Isolates from Humans and Companion Animals in Australia

“…This supports previous evidence that extraintestinal pathogenic E. coli (ExPEC) from humans and companion animals, particularly strains belonging to group B2, share similar virulence genotypes and phylogenetic origins (25,31).…”

Escherichia coli in Infants' Intestinal Microflora: Colonization Rate, Strain Turnover, and Virulence Gene Carriage

“…One may speculate that E. coli from a family cat could be transferred to the infant, because E. coli causing urinary tract infection in cats and dogs frequently carry the papG III adhesin type, and these strains arise from the intestinal flora of the animals (16,17). We saw no effect on E. coli gene carriage by dog-ownership.…”

“…These recognize the Gal␣134Gal␤ disaccharide, with slight differences in binding specificity (13). The class II variety of the papG adhesin is common among E. coli causing pyelonephritis (14), whereas the class III variety is common in cystitis strains from humans (15), dogs (16), and cats (17). Intestinal persistence of E. coli has been linked to the class II variety of the adhesin (10).…”

Molecular Characterization and Antimicrobial Resistance of Uropathogenic Escherichia coli

“…List of primers used for detection of the virulence genes, and antibiotic resistance genes are shown in Table 1 (4,5,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Table 2 presents PCR conditions.…”