Association Between Uropathogen and Pyuria.

OBJECTIVE: We sought to determine factors associated with the absence of pyuria in symptomatic children whose urine culture was positive for a known uropathogen.

METHODS: We obtained data on children evaluated at the Children's Hospital of Pittsburgh emergency department between 2007 and 2013 with symptoms of urinary tract infection (UTI) who had paired urinalysis and urine cultures. We excluded children with an unknown or bag urine collection method, major genitourinary anomalies, immunocompromising conditions, or with multiple organisms on culture. We chose a single, randomly-selected urine specimen per child and limited the analysis to those with positive cultures.

RESULTS: There were 46 158 visits during the study period; 1181 children diagnosed with UTI met all inclusion criteria and had a microscopic urinalysis for pyuria. Pyuria (≥5 white blood cells per high-powered field or ≥10 white blood cells per cubic millimeter) was present in 1031 (87%) children and absent in 150 (13%). Children with Enterococcus species, Klebsiella species, and Pseudomonas aeruginosa were significantly less likely to exhibit pyuria than children with Escherichia coli (odds ratio of 0.14, 0.34, and 0.19, respectively). Children with these organisms were also less likely to have a positive leukocyte esterase on dipstick urinalysis. Results were similar when we restricted the analysis to children whose urine samples were collected by bladder catheterization.

CONCLUSIONS: We found that certain uropathogens are less likely to be associated with pyuria in symptomatic children. Identification of biomarkers more accurate than pyuria or leukocyte esterase may help reduce over- and undertreatment of UTIs.