Can a simple urinalysis predict the causative agent and the antibiotic sensitivities?

Area of Science:

• Pediatric Infectious Diseases
• Clinical Microbiology
• Diagnostic Accuracy Studies

Background:

• Urinary tract infections (UTIs) are common in febrile children.
• Accurate diagnosis of UTI and pathogen identification is crucial for appropriate treatment.
• The predictive value of urinalysis (UA) in identifying specific bacterial causes of UTI requires further investigation.

Purpose of the Study:

• To assess the reliability of urinalysis (UA) in predicting UTIs in febrile children.
• To determine if UA findings can differentiate between *Escherichia coli* (E. coli) and non-E. coli UTIs.
• To inform empiric antibiotic selection based on predicted E. coli versus non-E. coli infections.

Main Methods:

• Retrospective chart review of febrile children (2 months to 2 years) with positive urine cultures.
• Comparison of UA findings (WBC count, leukocyte esterase, nitrites) with urine culture results.
• Multivariate logistic regression used to calculate likelihood ratios for UA parameters in predicting infection type.
• Analysis of antibiotic sensitivities for E. coli and non-E. coli isolates.

Main Results:

• Urinalysis results were significantly associated with the type of organism causing UTI (P < 0.001).
• Positive leukocyte esterase, nitrites, and WBC count showed moderate likelihood ratios for predicting E. coli UTIs.
• Antibiotic sensitivities varied: cefazolin, cefuroxime, and nitrofurantoin were highly effective against UA-positive (likely E. coli) infections, while trimethoprim-sulfamethoxazole showed higher sensitivity in UA-negative (likely non-E. coli) cases.

Conclusions:

• Urinalysis is not a highly accurate predictor of UTI in febrile children.
• Negative UA results in suspected UTIs may indicate non-E. coli pathogens, potentially responsive to trimethoprim-sulfamethoxazole.
• Positive UA results are often associated with E. coli, suggesting empiric treatment with cefazolin or cefuroxime.