title: New procedure for rapid identification of microorganisms causing urinary tract infection from urine samples by mass spectrometry (MALDI-TOF).
abstract: BACKGROUND
  Matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry is widely established as a technique in clinical microbiology laboratories for the identification of microorganisms. Using this technique, it is also possible to obtain the identification of microorganisms from untreated urine samples.
  
  
  METHODS
  In this study, a differential centrifugation protocol and a criterion for validation of the results in order to achieve microbial identification from untreated urine samples are proposed. Additionally, the sensitivity of the analytical procedure in monobacterial urine samples has been evaluated.
  
  
  RESULTS
  A 90% sensitivity (confidence interval of 81.96%-94.84%) was obtained in urine samples with bacterial counts of ≥1×10(5)CFU/ml, and it was possible to improve the percentages of direct identifications from urine samples with bacterial counts of <1×10(5)CFU/ml.
  
  
  CONCLUSIONS
  It is concluded that the MALDI-TOF system is both fast and reliable in the identification of individual microorganisms from untreated urine samples with counts of ≥1×10(5)CFU/ml.
authors.affiliation: Departmento de Microbiología, Facultad de Medicina, Universidad de Valladolid, Spain. Electronic address: gmr810@hotmail.com.
authors.forename: Gabriel Alberto
authors.initials: GA
authors.lastname: March Rosselló
authors.affiliation: Departmento de Microbiología, Facultad de Medicina, Universidad de Valladolid, Spain.
authors.forename: María Purificación
authors.initials: MP
authors.lastname: Gutiérrez Rodríguez
authors.affiliation: Departmento de Microbiología, Facultad de Medicina, Universidad de Valladolid, Spain; Servicio de Microbiología, Hospital Clínico Universitario de Valladolid, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Ortiz de Lejarazu Leonardo
authors.affiliation: Departmento de Microbiología, Facultad de Medicina, Universidad de Valladolid, Spain; Servicio de Microbiología, Hospital Clínico Universitario de Valladolid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Orduña Domingo
authors.affiliation: Departmento de Microbiología, Facultad de Medicina, Universidad de Valladolid, Spain; Servicio de Microbiología, Hospital Clínico Universitario de Valladolid, Spain.
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: Bratos Pérez
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001419:Bacteria / Q000302:isolation & purification*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors; D014552:Urinary Tract Infections / Q000382:microbiology* / Q000652:urine*; D055815:Young Adult
keywords: Direct identification; Identificación directa; MALDI-TOF; Orina; Urine