Comparative evaluation of the mycobacteria growth indicator tube with the BACTEC 460 TB system and Löwenstein-Jensen medium for isolation of mycobacteria from clinical specimens.
METHODS
The utilization of new simples and rapid methods of diagnosis is currently of great interest for tuberculosis control.


OBJECTIVE
The Mycobacteria Growth Indicator Tube (MGIT) was evaluated and compared with the BACTEC 460 TB system and Löwenstein-Jensen (LJ) medium for isolation capacity and detection time of mycobacteria.


METHODS
In total 337 specimens from various body sites of 276 patients were tested for the presence of mycobacteria. Specimens were decontaminated using the standard Na OH-NALC method, then processed in MGIT broth, in BACTEC vial, and on LJ medium for comparative study. Ziehl Neelsen staining was used as a reference.


RESULTS
MGIT had 95.4% sensitivity, 100% specificity, 100% positive predictive value, and 89.3% negative predictive value. The clinical concordance between MGIT and LJ medium was 0.87 and between MGIT and BACTEC, 0.96. The mean time to detection for Mycobacterium tuberculosis was 11 days (range 7-31 days) with MGIT. For M. avium and other atypical mycobacteria, the mean time to detection were 3 and 8 days, respectively.


CONCLUSIONS
The Mycobacteria Growth Indicator Tube appears to be a rapid, easy-to-use system with a high accuracy for detecting mycobacteria directly from clinical specimens.
Casal
M
M
Reina Sofía University Hospital, Clinical Microbiology Service, Faculty of Medicine, University of Córdoba, Spain.
Gutierrez
J
J
Vaquero
M
M
D001431:Bacteriological Techniques / Q000295:instrumentation* / Q000592:standards; D001826:Body Fluids / Q000382:microbiology; D016009:Chi-Square Distribution; D017077:Culture Media, Conditioned; D004866:Equipment Contamination; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000254:growth & development / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013030:Spain; D014376:Tuberculosis / Q000175:diagnosis*
D017077:Culture Media, Conditioned