Iranian Journal of Medical Microbiology

Background: A lot of children suffer from urinary infections which can lead to pyelonephritis and cystitis. The main cause of these infections is uropathogenic strains of Escherichia coli.  Serogroups and virulence factors of this bacterium play an important role in occurrence of infection’s symptoms. Unfortunately, due to the occurrence of antibiotic resistances, common treatments are ineffective and costly. The aim of this study was to study the distribution of virulence factors, serogroups and antibiotic resistance properties of uropathogenic Escherichia coli isolated from pediatrics with pyelonephritis and cystitis.

Material and Methods: In this study which was conducted during the year 2012 to 2013, 121 Escherichia coli strains were isolated from boys (51 samples) and girls (70 samples) with pyelonephritis and cystitis impatient in Baqiat-alah Hospital, Tehran. Antibiotic resistance of the isolates against commonly used antibiotics in the cases of urinary infections was investigated using disk diffusion method. Finally, PCR reactions using specific primers were done in order to detect  virulence factors, serogroups and antibiotic resistance genes.

Results: Totally, 45.09% of boys and 55.71% of girls were positive for presence of uropathogenic Escherichia coli. The highest distribution of bacterium was seen in less than one year old boys (71.42%) and 5-12 years old girls (75%). Results showed that the distribution of Escherichia coli in children with pyelonephritis and cystitis were 55.55% and 44.89%, respectively. The most commonly detected serogroups in children with pyelonephritis were O1, O2, O4 and O7 while, the most commonly detected serogroups in children with cystitis were O1, O2, O6 and O16. The most frequent virulence factors in the cases of pyelonephritis were pap (100%), afa (97.5%), sfa (95%), hly (95%) and cnf-1 (92.5%) and their most frequent in the cases of cystitis were fim (100%), pap (72.7%), afa (63.6%) and hly (45.4%). The genes which encode antibiotic resistance against gentamicin (aac(3)-IV) (96.7%), beta-lactams (blaSHV and CITM) (90.3% and 88.7%, respectively), tetracycline (tetA) (82.2%), had the highest incidence in the bacterial isolates. Escherichia coli isolates had the highest antibiotic resistance against gentamicin (95.1%), ampicillin (91.9%), amikacin (85.4%) and ciprofloxacin (83.8%).

Discussion: Determination of the antibiotic resistance pattern in uropathogenic Escherichia coli isolated from children with urinary infections is important in each area or in hospital. Imipenem, due to its low antibiotic resistance, can be an effective drug for treatments of children with pyelonephritis and cystitis.