1887

Abstract

In cases of bacteraemia, a rapid species identification of the causal agent directly from positive blood culture broths could assist clinicians in the timely targeting of empirical antimicrobial therapy. For this purpose, we evaluated the direct identification of micro-organisms from BacT/ALERT (bioMérieux) anaerobic positive blood cultures without charcoal using the Microflex matrix-assisted laser desorption/ionization (MALDI) time of flight MS (Bruker), after bacterial extraction by using two different methods: the MALDI Sepsityper kit (Bruker) and an in-house saponin lysis method. Bruker’s recommended criteria for identification were expanded in this study, with acceptance of the species identification when the first three results with the best matches with the MALDI Biotyper database were identical, whatever the scores were. In total, 107 monobacterial cultures and six polymicrobial cultures from 77 different patients were included in this study. Among monomicrobial cultures, we identified up to the species level 67 and 66 % of bacteria with the MALDI Sepsityper kit and the saponin method, respectively. There was no significant difference between the two extraction methods. The direct species identification was particularly inconclusive for Gram-positive bacteria, as only 58 and 52 % of them were identified to the species level with the MALDI Sepsityper kit and the saponin method, respectively. Results for Gram-negative bacilli were better, with 82.5 and 90 % of correct identification to the species level with the MALDI Sepsityper kit and the saponin method, respectively. No misidentifications were given by the direct procedures when compared with identifications provided by the conventional method. Concerning the six polymicrobial blood cultures, whatever the extraction method used, a correct direct identification was only provided for one of the isolated bacteria on solid medium in all cases. The analysis of the time-to-result demonstrated a reduction in the turnaround time for identification ranging from 1 h 06 min to 24 h 44 min, when performing the blood culture direct identification in comparison with the conventional method, whatever the extraction method.

Loading

Article metrics loading...

/content/journal/jmm/10.1099/jmm.0.044750-0
2012-11-01
2024-03-28
Loading full text...

Full text loading...

/deliver/fulltext/jmm/61/11/1511.html?itemId=/content/journal/jmm/10.1099/jmm.0.044750-0&mimeType=html&fmt=ahah

References

  1. Barbuddhe S. B., Maier T., Schwarz G., Kostrzewa M., Hof H., Domann E., Chakraborty T., Hain T. 2008; Rapid identification and typing of Listeria species by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Appl Environ Microbiol 74:5402–5407 [View Article][PubMed]
    [Google Scholar]
  2. Bizzini A., Greub G. 2010; Matrix-assisted laser desorption ionization time-of-flight mass spectrometry, a revolution in clinical microbial identification. Clin Microbiol Infect 16:1614–1619 [View Article][PubMed]
    [Google Scholar]
  3. Buchan B. W., Riebe K. M., Ledeboer N. A. 2012; Comparison of the MALDI Biotyper system using Sepsityper specimen processing to routine microbiological methods for identification of bacteria from positive blood culture bottles. J Clin Microbiol 50:346–352 [View Article][PubMed]
    [Google Scholar]
  4. Descy J., Meex C., Melin P., Hayette M. P., Huynen P., De Mol P. 2010; [MALDI-TOF mass spectrometry in clinical bacteriology or how to identify a bacteria within one minute]. Rev Med Liege 65:Spec no29–34 (in French) [PubMed]
    [Google Scholar]
  5. Ferroni A., Suarez S., Beretti J.-L., Dauphin B., Bille E., Meyer J., Bougnoux M.-E., Alanio A., Berche P., Nassif X. 2010; Real-time identification of bacteria and Candida species in positive blood culture broths by matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Clin Microbiol 48:1542–1548 [View Article][PubMed]
    [Google Scholar]
  6. Gaillot O., Blondiaux N., Loïez C., Wallet F., Lemaître N., Herwegh S., Courcol R. J. 2011; Cost-effectiveness of switch to matrix-assisted laser desorption ionization-time of flight mass spectrometry for routine bacterial identification. J Clin Microbiol 49:4412 [View Article][PubMed]
    [Google Scholar]
  7. Juiz P. M., Almela M., Melción C., Campo I., Esteban C., Pitart C., Marco F., Vila J. 2012; A comparative study of two different methods of sample preparation for positive blood cultures for the rapid identification of bacteria using MALDI-TOF MS. Eur J Clin Microbiol Infect Dis 31:1353–1358 [View Article][PubMed]
    [Google Scholar]
  8. Kumar A., Ellis P., Arabi Y., Roberts D., Light B., Parrillo J. E., Dodek P., Wood G., Kumar A. other authors 2009; Initiation of inappropriate antimicrobial therapy results in a fivefold reduction of survival in human septic shock. Chest 136:1237–1248 [View Article][PubMed]
    [Google Scholar]
  9. Loonen A. J., Jansz A. R., Stalpers J., Wolffs P. F., van den Brule A. J. 2012; An evaluation of three processing methods and the effect of reduced culture times for faster direct identification of pathogens from BacT/ALERT blood cultures by MALDI-TOF MS. Eur J Clin Microbiol Infect Dis 31:1575–1583 [View Article][PubMed]
    [Google Scholar]
  10. Martiny D., Dediste A., Vandenberg O. 2012; Comparison of an in-house method and the commercial Sepsityper™ kit for bacterial identification directly from positive blood culture broths by matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry. Eur J Clin Microbiol Infect Dis 31:2269–2281 [CrossRef]
    [Google Scholar]
  11. Neville S. A., Lecordier A., Ziochos H., Chater M. J., Gosbell I. B., Maley M. W., van Hal S. J. 2011; Utility of matrix-assisted laser desorption ionization-time of flight mass spectrometry following introduction for routine laboratory bacterial identification. J Clin Microbiol 49:2980–2984 [View Article][PubMed]
    [Google Scholar]
  12. Saffert R. T., Cunningham S. A., Mandrekar J., Patel R. 2012; Comparison of three preparatory methods for detection of bacteremia by MALDI-TOF mass spectrometry. Diagn Microbiol Infect Dis 73:21–26 [View Article][PubMed]
    [Google Scholar]
  13. Schubert S., Weinert K., Wagner C., Gunzl B., Wieser A., Maier T., Kostrzewa M. 2011; Novel, improved sample preparation for rapid, direct identification from positive blood cultures using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. J Mol Diagn 13:701–706 [View Article][PubMed]
    [Google Scholar]
  14. Szabados F., Michels M., Kaase M., Gatermann S. 2011; The sensitivity of direct identification from positive BacT/ALERT (bioMérieux) blood culture bottles by matrix-assisted laser desorption ionization time-of-flight mass spectrometry is low. Clin Microbiol Infect 17:192–195 [View Article]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/jmm/10.1099/jmm.0.044750-0
Loading
/content/journal/jmm/10.1099/jmm.0.044750-0
Loading

Data & Media loading...

Supplements

Supplementary File 1

PDF
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error