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.
Shaikh N, Morone NE, Bost JE, Farrell MH. Prevalence of urinary tract infection in childhood: a meta-analysis. Pediatr Infect Dis J 2008;27:302–8.
Shaikh N, Shope TR, Hoberman A, Vigliotti A, Kurs-Lasky M, Martin JM. Association Between Uropathogen and Pyuria. Pediatrics 2016;138.
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