title: Identification of urinary tract pathogens after 3-hours urine culture by MALDI-TOF mass spectrometry.
abstract: Complicated urinary tract infections, such as pyelonephritis, may lead to sepsis. Rapid diagnosis is needed to identify the causative urinary pathogen and to verify the appropriate empirical antimicrobial therapy. We describe here a rapid identification method for urinary pathogens: urine is incubated on chocolate agar for 3h at 35°C with 5% CO2 and subjected to MALDI-TOF MS analysis by VITEK MS. Overall 207 screened clinical urine samples were tested in parallel with conventional urine culture. The method, called U-si-MALDI-TOF (urine short incubation MALDI-TOF), showed correct identification for 86% of Gram-negative urinary tract pathogens (Escherichia coli, Klebsiella pneumoniae, and other Enterobacteriaceae), when present at >10(5)cfu/ml in culture (n=107), compared with conventional culture method. However, Gram-positive bacteria (n=28) were not successfully identified by U-si-MALDI-TOF. This method is especially suitable for rapid identification of E. coli, the most common cause of urinary tract infections and urosepsis. Turnaround time for identification using U-si-MALDI-TOF compared with conventional urine culture was improved from 24h to 4-6h.
authors: Department of Clinical Microbiology, University of Helsinki and Helsinki University Hospital, HUSLAB, Helsinki, Finland. Electronic address: johanna.haiko@alumni.helsinki.fi.
authors: Johanna
authors: J
authors: Haiko
authors: Department of Clinical Microbiology, University of Helsinki and Helsinki University Hospital, HUSLAB, Helsinki, Finland. Electronic address: laura.e.savolainen@hus.fi.
authors: Laura E
authors: LE
authors: Savolainen
authors: Department of Clinical Microbiology, University of Helsinki and Helsinki University Hospital, HUSLAB, Helsinki, Finland. Electronic address: risto.hilla@hus.fi.
authors: Risto
authors: R
authors: Hilla
authors: Department of Clinical Microbiology, University of Helsinki and Helsinki University Hospital, HUSLAB, Helsinki, Finland. Electronic address: anu.patari-sampo@hus.fi.
authors: Anu
authors: A
authors: Pätäri-Sampo
mesh_terms: D001431:Bacteriological Techniques / Q000295:instrumentation; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity; D006090:Gram-Negative Bacteria / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis / Q000382:microbiology*; D006801:Humans; D018805:Sepsis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013997:Time Factors; D014552:Urinary Tract Infections / Q000175:diagnosis / Q000382:microbiology*; D014556:Urine / Q000382:microbiology*
keywords: MALDI-TOF; Rapid identification; Urinary tract infection; Urine culture