Program Schedule

1033
Rapid detection of bacteriuria with a simple immunoassay test

Session: Poster Abstract Session: UTIs: Epidemiology and Diagnostic Testing
Friday, October 10, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
Background: Urinary tract infections (UTIs) are frequently encountered in clinical practice and most commonly caused by E. coli and other Gram negative uropathogens. Given current concerns about cost of treatment and antimicrobial resistance, rapid confirmation of bacteriuria in patients under consideration for empiric treatment of UTI would potentially reduce expenditures and unnecessary antimicrobial treatment. Current diagnostic methods are suboptimal: nitrite dipsticks have low sensitivity and specificity and cultures take days. We tested a rapid immunoassay for bacteriuria developed by Silver Lake Research Corporation (SLRC) in comparison with standard bacterial culture using urine specimens submitted to a clinical microbiological laboratory in an urban academic medical center.

Methods: Study urines (N = 966) were obtained as de-identified discarded specimens from the University of Washington Medical Center microbiology laboratory. SLRC’s immunoassay test was performed in accordance with instructions, providing a +/- result in about 15 minutes. Standard urine cultures were performed in parallel and all organisms were identified to the species level.

Results: 79% of urine specimens were from an outpatient setting and 21% were from inpatients. With urine culture used as the gold standard, the SLRC test kit identified as positive 244/270 (sensitivity 90%) of samples with E. coli or species of the genera Klebsiella, Proteus, Citrobacter, Pseudomonas, Serratia, Acinetobacter or Enterobacter at a level of ≥103 CFU/ml. The specificity of the test on samples with <103 CFU/ml of Gram negative uropathogens was 94% (523/555). 

Conclusion: A new rapid immunoassay test kit for direct detection of Gram negative bacteriuria in patient urine samples performed at high sensitivity (90%) and specificity (94%) as compared with standard culture of urine samples from both outpatient and inpatient settings. Using this assay in point-of-care diagnosis of UTI has the potential to reduce cost of treatment and overuse of antimicrobials for this common infection.

Ann Stapleton, MD, FACP, Medicine, University of Washington, Seattle, WA, Marsha Cox, MS, University of Washington, Seattle, WA, April Abbott, PhD, D(ABMM), Laboratory Medicine, University of Washington, Seattle, WA and Thomas Hooton, MD, FIDSA, Medicine, University of Miami, Miami, FL

Disclosures:

A. Stapleton, None

M. Cox, None

A. Abbott, None

T. Hooton, None

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