Direct molecular detection of amoxicillin-susceptible in urine samples from children with suspected urinary tract infection: A potential tool to improve antibiotic stewardship and patient care.

Background: Rapid detection of amoxicillin-susceptible (ASEC) urinary tract infections (UTIs) could have a significant impact on patient care and improve antibiotic stewardship. This is especially true for infants and children, for whom antibiotic choices are more limited than for adults.

Methods: A real-time polymerase chain reaction (PCR) uniplex panel for detection of ASEC using PCR assays for and five resistance genes ( , , , , and ) and an internal control was designed. PCR was then performed directly on pediatric urine samples using an inhibitor-resistant DNA polymerase. The main outcome measure was the performance of the PCR panel (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], accuracy) for the detection of ASEC. ASEC samples were defined as those that were PCR positive and PCR negative for all five resistance genes. PCR results were compared with the reference standard for culture and susceptibility testing.

Results: Two hundred and six urine samples with pyuria (>10 white blood cells/high power field) were tested with the PCR panel. Two samples showed PCR inhibition (1%). For ASEC detection, the PCR panel showed a sensitivity of 91.53% (95% CI 81.32% to 97.19%), specificity of 98.21% (95% CI 90.45% to 99.95%), PPV of 98.18% (95% CI 88.54% to 99.74%), NPV of 91.67% (95% CI 82.61% to 96.22%), and accuracy of 94.78% (95% CI 88.99% to 98.06%).

Conclusions: This PCR method could potentially enable amoxicillin or ampicillin to be used in a greater proportion of children with UTIs, improving antibiotic stewardship.