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Abstract: FR-PO1089

Aptamer-Based Proteomics Analysis Reveals a Urine Protein Signature That Differentiates UTIs from Culture-Negative Pyuria and Normal Urine

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Schwaderer, Andrew L., Indiana University, Zionsville, Indiana, United States
  • Hains, David S., Indiana University, Zionsville, Indiana, United States
Background

UTIs account for 7% of pediatric emergency department antibiotic prescriptions. UTI diagnosis is typically made at the point-of-care by symptoms and the identification of nitrites and/or leukocyte esterase (LE) on urinalysis (UA). Growth of ≥ 50,000 colony forming bacterial units on culture is used to confirm a UTI. However accurate urine culture results can be dependent on collection methodology and take 24-72 hours to complete. UAs have limitations as well. The sensitivity/specificity for LE to detect childhood UTIs is 83%/78%.

Methods

An aliquot of urine was obtained from pediatric Emergency Department patients who had a sample collected for clinical urine culture. Included samples consisted of 16 with urinary tract infection (UTI), 8 culture negative (CN) pyuria, and 8 with normal UAs. The levels of 1,310 proteins were quantified as relative fluorescent units/ml using the SOMAscan platform (Somalogic Inc, Boulder, CO) and the normalized to urine creatinine (mg/dl). The results were filtered for proteins that were (a) significantly higher in the UTI vs CN pyuria samples and in the UTI vs normal urine samples with a p value of < 0.01 and that had an area under the curve (AUC) of > 0.9 which is used to define an “excellent” biomarker.

Results

Eight candidate biomarkers met this stringent filtering criteria and are presented along with the threshold urine biomarker to creatinine ratio with the highest likelihood ratio to differentiate UTI from non UTI samples in Figure 1.

Conclusion

A biomarker panel containing some of the candidates identified via this study has the potential to improve the timeliness and accuracy of UTI detection. Prospective studies evaluating levels measured by ELISA and conversion to a point of care testing modality are the next investigative steps.

Funding

  • Private Foundation Support