Analysis of causative agents of urinary tract infections in children and their antibiotic sensitivity pattern: A hospital based study

Introduction: Urinary tract infections (UTIs) are an important cause of morbidity and mortality in children. 

Objective: To determine the common bacterial pathogens causing UTI in children less than 12 years old and their antimicrobial susceptibility patterns at the Colombo South Teaching Hospital, Sri Lanka.

Method: A prospective study was done by analyzing records of urine samples received at the Department of Microbiology, Colombo South Teaching Hospital, from 1^st May 2011 to 30^th April 2012. Urine samples were inoculated on Cystine Lactose Electrolyte Deficient agar, according to standard operating procedures. The isolates were initially identified by Gram staining and colony characteristics. Gram positive organisms were further identified by catalase, coagulase and bile-aesculin tests. Lactose fermentation or non-lactose fermentation (NLF) of Gram negative organisms was recorded. The NLF isolates were further identified by oxidase, urease and Kleigler Iron Agar tests. Antibiotic susceptibility tests were carried out using the Stokes method. 

Results: A total of 2620 urine samples was analyzed. Of the 426 (16.3%) pure growths, Gram negative isolates of bacteriuria (>10⁵ colony forming units/ml of urine) and Gram positive isolates of bacteriuria (>10⁴ colony forming units/ml of urine) were found in 264 (62%) and 56 (13.1%) patients respectively. The female: male ratio of the total positive samples was 2.1:1. LF and NLF Coliforms (excluding Proteus, Providencia, and Morganella spp.) were isolated in 142 (33.3%) and 68 (16%) samples respectively. Proteusspp. were isolated in 43 (10.1%) samples 38 (88.4%) of which were identified in males. The sensitivity of LF Coliforms to nitrofurantoin, cephalexin and ampicillin was 83.9%, 57.4% and 11.3% respectively. The sensitivity of NLF Coliforms to nitrofurantoin, cephalexin and ampicillin was 85.3%, 36.8% and 7.4% respectively.

Conclusions: Enterobacteriaceae were the predominant pathogens causing UTI in our population and showed high resistance against am­picillin and cephalexin. Proteus infections were predominant in males.

Sri Lanka Journal of Child Health, 2015; 44(4): 197-201