Abstract

Urinary Tract Infections (UTI) occurs in up to 7% of febrile infants and young children (1). The most common uropathogen is Escherichia coli (E.coli) (2). Presence of pyuria (≥10 white blood cells per cubic millimetre (≥10 WBC/mm³) on urinalysis is essential to diagnose UTI (2). We set out to examine whether there is a link between the absence of pyuria and a positive urine culture for a known uropathogen.

This was a retrospective cohort study of 248 patients admitted with symptomatic UTI between January 2015 and December 2016. Mean (SD) age was 31.27 (42.54) months and 101 (40.7%) patients were male. Of 248 patients with UTI, E. coli was documented as the causative pathogen in 221 cases (89.1%), Klebsiella species in 8 (3.2%), Proteus species in 8 (3.2%), Pseudomonas species in 7 (2.8%), Enterococcus species in 3 (1.2%) and Group B streptococcus in 1 (0.4%). All patients with UTI due to E.coli infection exhibited > 10 WBC/mm³ on urinalysis (p value 0.001). However, in those with UTI caused by non-E.coli uropathogens, < 10 WBC/mm³ on urinalysis was documented in two of eight (25%) patients with UTI secondary to Proteus infection, two of eight (25%) individuals with Klebsiella UTI, one of seven (14.3%) patients with UTI due to Pseudomonas infection and one of three (33.3%) patients with UTI caused by Enterococcus species.

In conclusion, 9 in 10 patients with UTI experienced E.coli uropathogen on urine culture. Pyuria with > 10 WBC/mm³ on urinalysis was documented in all patients with E.coli uropathogen. However approximately one fifth of patients with UTI due to non-E.Coli uropathogens experienced absence of pyuria on urinalysis. Considering the possibility of absence of pyuria in those with UTI due to non-E.coli uropathogens, using reliable adjunctive biomarkers in diagnosis UTI while waiting urine culture need to be explored through further research.