Clinical and bacteriologic correlates of the papG alleles among Escherichia coli strains from children with acute cystitis

Background, papG is the Gal(alpha 1-4)Gal-specific adhesin gene of Escherichia coli P fimbriae. The three alleles of papG are associated with different receptor-binding preferences, occur in different lineages of E. coli and appear differentially associated with specific clinical syndromes, e.g. allele II with pyelonephritis and allele III with cystitis. However, no data are available regarding associations of the papG alleles with clinical outcomes. Methods. Alleles I, II and III of papG were sought among 38 E. coli urine isolates from children with acute cystitis by a polymerase chain reaction-based assay. The papG genotype was compared with other bacterial characteristics and with response to therapy. Results. papG was detected in 13 (34%) strains. It was associated positively with sfa and hly (which encode S fimbriae and hemolysin) and negatively with afa (which encodes Dr-binding adhesins), Allele II predominated over allele III (29% of strains, vs. 5%; P < 0.01). Allele II was significantly associated with serogroups O1 and O16 and with agglutination of both human and sheep erythrocytes, whereas allele III was associated with sfa, hly, serogroup O6 and preferential agglutination of sheep erythrocytes. The presence of papG predicted recurrent bacteriuria among children receiving 3-day treatment and Allele III predicted same-strain recurrence. Conclusions. These findings conflict with existing data associating allele III with cystitis, confirm and extend previous associations of papG alleles II and III with other bacterial properties and suggest that papG genotype may predict clinical outcomes.