Background and aims Urinary Tract Infection (UTI) is most common genitourinary disease and second common infection in childhood. The purpose of this study was to identify the most common of bacteria causing UTI and detection of antibiotics susceptibility of isolates in children under 18 years of age.

Methods Overall 456 children who suspected to UTI were investigated for urine cultures, urinalysis, and antibiotic susceptibility patterns. Antibiogram test was performed by gel-diffusion method of Kirby-Bauer. Twelve antibiotics including ciprofloxacin, naledixic acid, amikacin, ceftizoxime, gentamicin, ampicillin, nitrofurantoin, co-trimoxazole, ceftriaxone and tobramycin, tetracycline and amoxicillin were used.

Results Out of 456 children suspected to UTI, 156 children (34.2%) had positive bacterial culture that 88.5% of isolates was gram-negative bacilli and 11.5% was also gram-positive cocci. The most common isolates were Escherichia coli (57.8%), Enterobacter sp.(9.6%), Kelebsiella oxytoca (6.4%), Staphylococcus aureus (5.8%), Psuedomonas aeroginosa (5.1%). The most effective antibiotics against isolates were nitrofurantoin, ciprofloxacin, naledixic acid, amikacin, ceftizoxime and ceftriaxone while most of isolates showed high resistance against ampicillin, co- trimoxazole, tetracyline and amoxicillin.

Conclusions The present study showed that gram-negative bacilli in particular E. coli and Enterobacter sp. are predominant causes of bacterial agents of UTIs in children under 18 years of age. Most species showed high resistance against routine antibiotics such as amoxicillin, ampicillin, co-trimoxazole and tetracycline.