title: [Rapid identification and susceptibility testing of Gram-positive cocci in BacT/ALERT blood cultures by direct inoculation into the Vitek 2 system].
abstract: BACKGROUND
  To provide the clinician with early information about blood culture results allows a better prognosis and a reduced mortality rate of the patient with sepsis. In order to contribute to this aim, we performed a study for the identification and susceptibility profiling of positive blood cultures by direct inoculation into the automated Vitek 2 system.
  
  
  METHODS
  Blood cultures of 57 patients with monomicrobial bacteriaemia due to gram-positive cocci were evaluated. Addition of saponin to the fluid from blood culture bottles was performed prior to the inoculation of Vitek 2 system cards. The same samples were also examined with the standard method starting from agar plate grown subcultures.
  
  
  RESULTS
  Comparison between the results obtained with the standard method and the direct method revealed that 82% of the samples were correctly identified and that 97% of the isolates showed a concordant antimicrobial susceptibility profile for all drugs tested. Compared to the standard method, the very major error rate of the direct method was just 0.5%, the major error rate was 0.5%, and the minor error rate was 2%.
  
  
  CONCLUSIONS
  These data suggest that addition of saponin to the fluid from blood culture bottles of the BacT/ALERT(®) 3D before inoculation of the appropriate Vitek 2 cards leads to the rapid and reliable identification and susceptibility profiling of gram-positive cocci in blood samples. Compared to the standard method, the direct method would reduce turnaround time by at least 24 hours.
authors.affiliation: Laboratorio de Microbiología y Parasitología Clínica, Servicio de Análisis Clínicos, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, Spain. alison_bcn@hotmail.com
authors.forename: A
authors.initials: A
authors.lastname: Barreales
authors.forename: M
authors.initials: M
authors.lastname: Lara
authors.forename: I
authors.initials: I
authors.lastname: Hernández
authors.forename: O
authors.initials: O
authors.lastname: Díez
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology; D058491:Bacterial Load; D016908:Gram-Positive Bacterial Infections / Q000097:blood / Q000175:diagnosis / Q000382:microbiology*; D006095:Gram-Positive Cocci / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000295:instrumentation*; D011446:Prospective Studies
chemical_list: D000900:Anti-Bacterial Agents