Rapid Detection of Pediatric Bacteriuria Using Narrow Angle Forward Laser Scattering Technology (NAFLST) with Bacterioscan

BACKGROUND: Pediatric urinary tract infections (UTI) are common, but culture-based diagnosis can take up to 48 hours. This time delay means patients are exposed to potentially unnecessary antibiotics. The sensitivity of screening urinalysis can vary, so rapid detection of UTI by another means would be beneficial. Narrow Angle Forward Laser Scattering Technology (NAFLST) with Bacterioscan can rapidly detect bacteriuria by shining a laser continuously through a liquid sample containing replicating bacteria, and graphing the degree of light refraction over time. Higher degrees of light refraction represent higher initial bacterial load and continued bacterial growth. After 3 hours, the optical scatter classifies a sample as either Likely Positive or Likely Negative. We compared Bacterioscan results to culture data in pediatric patients to assess the ability to diagnose UTI and avoid unnecessary urine culture. METHODS: This protocol was approved by the UNC Biomedical Institutional Review Board. Over one month, 169 pediatric (<18 yo) urine cultures were collected as part of routine patient care. An individual urine sample and 2.5mL of Sterile Tryptic Soy Broth were pipetted into a Bacterioscan micro-curette. Bacterioscan labeled the specimen as Likely Positive or Likely Negative after a 3 hour period. Results were then compared with urine culture results obtained by routine microbiologic methods. RESULTS: Of the 169 urine cultures, 96 were positive, but only 27 were positive for uropathogens. Bacterioscan was 100% sensitive and 58.4% specific in predicting clinically relevant/pathogenic bacterial growth in culture (PPV 31.3%, NPV 100%), and 70.8% sensitive and 75.3% specific in predicting any bacterial growth (PPV 79.0%, NPV 66.2%). If a “Likely Positive” Bacterioscan result had been used in our study population to screen urine samples for culture, then 58% (83/142) of negative urine cultures would have been eliminated with no UTIs missed. CONCLUSION: By rapidly identifying urine cultures likely to be positive, NAFLST with Bacterioscan can safely obviate the plating of every urine sample and reduce empiric antibiotic use while waiting for culture results. Larger studies are required to confirm these results. DISCLOSURES: A. Cline, Bacterioscan: Equipment necessary to perform this study was provided by Manufacturer, Equipment necessary to perform this study; R. Jhaveri, Gilead: Investigator, Research support; Abbvie: Investigator, Research support; Merck: Grant Investigator, Research grant