Evaluation of BacT/ALERT 3D System for Mycobacteria Isolates

Background: The rapid diagnosis of mycobacterial infections is essential to implement the adequate antimicrobial therapy. This study evaluates the performance of the BacT/ALERT 3D system for isolates and identification of mycobacteria from clinical samples. Methods: 1011 clinical specimens from nonsterile and sterile body sites were studied from August 2010 to December 2012 at the National Reference Laboratory of Tuberculosis, IPK, Cuba. The results obtained were compared with respect to time detection of mycobacteria and contamination rates, and performance indicators of BacT/ALERT 3D were calculated. Results: The time detection of growth (TDG) for Mycobacterium tuberculosis (Mtb) and nontuberculous mycobacteria (NTM) by BacT/ALERT 3D was 16,435 and 10,956, respectively; by LJ the TDG was 33.577 for Mtb and 35.952 for NTM. By culture method used the TDG for LJ was 33,577 and 6.435 by BacT/ALERT 3D, this difference being statistically significant. The overall contamination rate (CR) for BacT/ALERT 3D was 4.6% and 7.8% for LJ. Conclusions: BacT/ALERT 3D were a suitable method for recovering mycobacteria from clinical samples. It demonstrated a shorter time to detection of mycobacteria growth; it was very useful to provide faster treatment and a better prognosis in patients AFB smear negative with HIV. The use of LJ culture and BacT/ALERT 3D System was useful to assure a total mycobacterial recovery.