title: Rapid identification and susceptibility testing using the VITEK 2 system using culture fluids from positive BacT/ALERT blood cultures.
abstract: OBJECTIVE
  In order to reduce the turnaround time for laboratory diagnosis of bacteremia, the efficacy of identification and antimicrobial susceptibility testing using samples taken directly from positive BacT/ALERT standard aerobic and standard anaerobic blood culture bottles was evaluated.
  
  
  METHODS
  160 positive blood culture bottles were examined and incubated at 35 degrees C in 5% carbon dioxide for 4-24 h, and an aliquot of the culture fluid was Gram stained. Samples containing Gram-negative bacilli were inoculated on VITEK 2 ID-GNB (identification-Gram-negative bacilli) and AST (antimicrobial susceptibility testing)-GN04 cards, and those containing Gram-positive cocci were inoculated on ID-GPC (identification-Gram-positive cocci) and AST-P526 cards. The same samples were also examined by the standard method, involving subculture from positive BacT/ALERT standard blood culture bottles.
  
  
  RESULTS
  Eighty seven of 97 Gram-negative bacilli (89.7%) and 21 of 63 Gram-positive cocci (33.3%) were correctly identified to the species level. For antimicrobial susceptibility testing, the direct method had an overall error rate of 5.4% for Gram-negative bacilli, with 0.9% very major, 0.9% major, and 3.6% minor discrepancies compared to the standard method. The overall error rate in antimicrobial susceptibility testing for the 13 Staphylococcus spp. was 10.3%, with 6.0% very major, 2.6% major, and 1.7% minor discrepancies.
  
  
  CONCLUSIONS
  These data suggest that VITEK 2 cards inoculated with samples taken directly from positive Bact/ALERT blood culture bottles would provide acceptable identification and antimicrobial susceptibility testing results for Gram-negative bacilli, but not for Gram-positive cocci. Compared to the standard method, the direct method would reduce turnaround time by at least 24 h.
authors.affiliation: Department of Neuroscience, Tzu-Ai General Hospital, Hsilo, Yulin, Taiwan.
authors.forename: Jiunn-Rong
authors.initials: JR
authors.lastname: Chen
authors.forename: Shih-Yi
authors.initials: SY
authors.lastname: Lee
authors.forename: Bing-Heng
authors.initials: BH
authors.lastname: Yang
authors.forename: Jang-Jih
authors.initials: JJ
authors.lastname: Lu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000175:diagnosis*; D001419:Bacteria / Q000187:drug effects* / Q000302:isolation & purification*; D001431:Bacteriological Techniques / Q000379:methods*; D001769:Blood / Q000382:microbiology*; D003951:Diagnostic Errors; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents