Identification of Probable Urinary Tract Infection in Children Using Low Bacterial Count Thresholds in Urine Culture

Area of Science:

• Pediatric Nephrology
• Infectious Diseases
• Urology

Background:

• Urinary tract infections (UTIs) are common in children.
• Accurate diagnosis is crucial for timely intervention and preventing complications.
• The standard bacterial colony count threshold for UTI diagnosis can be debated.

Purpose of the Study:

• To determine the proportion of symptomatic children with UTI whose urine cultures show a single bacterial species >10^4 CFU/mL.
• To compare patient and disease characteristics between children with low bacterial counts (>10^4-10^5 CFU/mL) and higher counts (>10^5 CFU/mL).

Main Methods:

• A prospective observational study included 216 symptomatic children aged 1 month to 12 years.
• Urine samples were collected via clean-void or catheterization and cultured.
• Children with single species >10^4 CFU/mL were evaluated for imaging studies per guidelines.

Main Results:

• 17.6% of children had single species growth >10^4 CFU/mL.
• 13.4% were diagnosed with UTI at the >10^5 CFU/mL cutoff.
• An additional 4.2% had 'probable low-count UTI' (>10^4 to 10^5 CFU/mL), with one case showing significant urological abnormalities.

Conclusions:

• Lowering the bacterial colony count cutoff to >10^4 CFU/mL may identify more symptomatic children with probable UTI.
• This revised threshold could help detect underlying urological abnormalities in pediatric patients.
• The findings support considering a lower diagnostic cutoff for UTI in children using clean-voided or catheterized urine samples.