286. Rapid detection of bacteriuria using a new rapid immunoassay
Session: Poster Abstract Session: Diagnostic Microbiology; Novel Molecular Methods
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background: Urinary tract infections (UTIs), most commonly caused by E. coliand other Gram negative uropathogens, are common in all age groups and both genders, and represent substantial costs for diagnosis and treatment in settings ranging from outpatient clinics to intensive care units. Current non-culture based methods for detecting bacteriuria, urine nitrite dipsticks, have shown low sensitivity and specificity. Using urine specimens submitted to a clinical microbiological laboratory in an urban academic medical center, we compared a new, rapid immunoassay developed by Silver Lake Research Corporation (SLRC) with standard bacterial culture for detection of bacteriuria. 

Methods: Study urines (N = 989) were obtained as de-identified discarded specimens from the University of Washington Medical Center microbiology laboratory, focusing on specimens originating from outpatient clinics.  SLRC’s immunoassay test was performed in accordance with instructions, providing a +/- result in < 15 minutes. Standard urine cultures were performed in parallel and all organisms were identified to the species level.

Results: Using urine culture as the gold standard, the SLRC test kit identified as positive 222/229 (sensitivity 97%) of samples with E. coli, Klebsiella spp, Proteus spp, or Enterobacter spp. at a level of 105 CFU/ml and 272/303 (90%) at a level of 104 CFU/ml. The specificity of the test on samples with < 103CFU/ml of Gram negative uropathogens was >97% (592/610).

Conclusion: A new rapid immunoassay test kit for direct detection of Gram negative bacteriuria in fresh patient urine samples performed at high sensitivity (90%) and specificity (97%) as compared with standard culture of random urine samples. This assay is promising for use in point-of-care diagnosis of UTI.

Marsha Cox, MS, University of Washington, Seattle, WA, April Abbott, PhD, D(ABMM), Laboratory Medicine, University of Washington, Seattle, WA and Ann E. Stapleton, MD, Medicine, University of Washington, Seattle, WA


M. Cox, Silver Lake Research Corporation: Grant Investigator, Research support

A. Abbott, None

A. E. Stapleton, Silver Lake Research Corporation: Grant Investigator, Research support

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