Alleles I, II, and III of the P adhesin gene papG were sought by PCR among 75 Escherichia coli blood isolates from adults with urosepsis, and the papG genotype was compared with associated bacterial characteristics and host compromise status. Allele II predominated over allele III in the total population (71% of the strains versus 7% for allele III; P < 0.01). Allele I was not encountered. In comparison with allele II, allele III was significantly associated with the presence of hly and the absence of iuc (which encode hemolysin and aerobactin biosynthesis), nonagglutination of digalactoside-coated beads, absence of aerobactin production, membership in serogroups O6 and O18, and host compromise, particularly cancer and upper urinary tract abnormalities.