As vaginal colonization by UPEC is a possible previous step to urinary tract infection, this work was designed to see if there is any difference in papG alleles' distribution (especially papG allele II) among E. coli vaginal isolates from pregnant and nonpregnant women and also to evaluate the possible ability of papG allele II+ isolates to cause pyelonephritis by genotypic analyses of E. coli phylogenetic groups and extraintestinal pathogenic E. coli virulence factors (ExPEC VFs). The gene discussed is PAPOLG; the disease is pyelonephritis.