Association of Pyuria with Uropathogens in Young Children

Objective: To examine the association between uropathogens and pyuria in children <24 months of age. Study design: A retrospective study of children <24 months of age evaluated in the emergency department for suspected urinary tract infection (UTI) with paired urinalysis and urine culture during a 6-year period. Bagged urine specimens or urine culture growing mixed/multiple urogenital organisms were excluded. Analysis was limited to children with positive urine culture as defined by the American Academy of Pediatrics clinical practice guideline culture thresholds. Results: Of 30 462 children, 1916 had microscopic urinalysis and positive urine culture. Urine was obtained by transurethral in-and-out catheterization in 98.3% of cases. Pyuria (≥5 white blood cells per high-powered field) and positive leukocyte esterase (small or more) on the urine dipstick were present in 1690 (88.2%) and 1692 (88.3%) of the children respectively. Children with non-Escherichia coli species were less likely to exhibit microscopic pyuria than children with E coli (OR 0.24, 95% CI 0.17-0.34) with more pronounced effect on Enterococcus and Klebsiella (OR 0.08, 95% CI 0.03-0.18 and OR 0.18, 95% CI 0.11-0.27 respectively). Similarly, positive leukocyte esterase was less frequently seen in non-E coli uropathogens compared with E coli. Conclusions: Pyuria and leukocyte esterase are not sensitive markers to identify non-E coli UTI in young children. More sensitive screening biomarkers are needed to identify UTI with these uropathogens.