virulence factors of uropathogenic escherichia coli of urinary tract infections and asymptomatic bacteriuria in children backgroundpurpose the clinical aspects of virulence genes of uropathogenic escherichia coli upec are not fully understood this study compared the presence of virulence genes in upec isolated from urinary tract infections utis and asymptomatic bacteriuria abu in childrenmethods the study included children with uti n 15 or abu n 49 treated at chungang university yongsan hospital between 2010 and 2011 the strains were acquired from each urine sample collected and 18 major virulence genes were detected by polymerase chain reaction antimicrobial susceptibility of all upec isolates was determinedresults sixtyfour e coli strains were isolated from the urine samples the most commonly identified virulence gene in both groups was fimh 1000 in the uti group and 959 in the abu group the uti isolates showed a higher prevalence of papef and fyua and a lower prevalence of feob than abu isolates p 001 for all the profile of virulence gene fimhkpsmtiifeob also showed a significant difference between the two groups p 001 isolates from abu were more resistant to most antimicrobials tested the presence of papef feob and fyua also correlated with the antimicrobial susceptibility of upecconclusion the virulence gene repertoire was different in the upec of uti and abu the papef feob and fyua genes showed meaningful differences between the two groups and may have an important role in the pathogenesis of overt uti