title: Prospective Evaluation of Light Scatter Technology Paired with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Rapid Diagnosis of Urinary Tract Infections.
abstract: Urinary tract infections are one of the most common reasons for health care visits. Diagnosis and optimal treatment often require a urine culture, which takes an average of 1.5 to 2 days from urine collection to results, delaying optimal therapy. Faster, but accurate, alternatives are needed. Light scatter technology has been proposed for several years as a rapid screening tool, whereby negative specimens are excluded from culture. A commercially available light scatter device, BacterioScan 216Dx (BacterioScan, Inc.), has recently been advertised for this application. Paired use of mass spectrometry (MS) for bacterial identification and automated-system-based susceptibility testing straight from the light scatter suspension might provide dramatic improvement in times to a result. The present study prospectively evaluated the BacterioScan device, with culture as the reference standard. Positive light scatter specimens were used for downstream rapid matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS organism identification and automated-system-based antimicrobial susceptibility testing. Prospective evaluation of 439 urine samples showed a sensitivity of 96.5%, a specificity of 71.4%, and positive and negative predictive values of 45.1% and 98.8%, respectively. MALDI-TOF MS analysis of the suspension after density-based selection yielded a sensitivity of 72.1% and a specificity of 96.9%. Antimicrobial susceptibility testing of the samples identified by MALDI-TOF MS produced an overall categorical agreement of 99.2%. Given the high sensitivity and negative predictive value of results obtained, BacterioScan 216Dx is a reasonable approach for urine screening and might produce negative results in as few as 3 h, with no downstream workup. Paired rapid identification and susceptibility testing might be useful when MALDI-TOF MS results in an organism identification, and it might decrease the time to a result by more than 24 h.
authors.affiliation: Children's Hospital of Philadelphia, Infectious Disease Diagnostics Laboratory, Philadelphia, Pennsylvania, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Montgomery
authors.affiliation: Children's Hospital of Philadelphia, Infectious Disease Diagnostics Laboratory, Philadelphia, Pennsylvania, USA.
authors.forename: Kiana
authors.initials: K
authors.lastname: Roman
authors.affiliation: Children's Hospital of Philadelphia, Infectious Disease Diagnostics Laboratory, Philadelphia, Pennsylvania, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Ngyuen
authors.affiliation: Children's Hospital of Philadelphia, Infectious Disease Diagnostics Laboratory, Philadelphia, Pennsylvania, USA.|Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Cardenas
authors.affiliation: Children's Hospital of Philadelphia, Infectious Disease Diagnostics Laboratory, Philadelphia, Pennsylvania, USA.|Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: James
authors.initials: J
authors.lastname: Knox
authors.affiliation: BacterioScan, Inc., St. Louis, Missouri, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Tomaras
authors.affiliation: Children's Hospital of Philadelphia, Infectious Disease Diagnostics Laboratory, Philadelphia, Pennsylvania, USA grafe@email.chop.edu.|Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Erin H
authors.initials: EH
authors.lastname: Graf
mesh_terms: D000293:Adolescent; D001431:Bacteriological Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014552:Urinary Tract Infections / Q000382:microbiology*
keywords: mass spectrometry; susceptibility testing; urinary tract infection