Comparative evaluation of BACTEC MGIT 960 with BACTEC 9000 MB and LJ for isolation of mycobacteria in The Gambia.
BACKGROUND
The BACTEC MGIT 960 was evaluated and compared with BACTEC 9000 MB and Lowenstein-Jensen medium for recovery rate of mycobacteria, time to detection, and contamination rate.


METHODS
147 sputum samples obtained from patients with suspicion of tuberculosis were processed and inoculated into BACTEC MGIT 960, BACTEC 9000 MB and Lowenstein-Jensen medium using standardized procedures.


RESULTS
BACTEC MGIT 960 detected 57.1%; BACTEC 9000 MB detected 57.8%; and LJ medium detected 43.5% specimens with Mycobacterium tuberculosis complex (MTBC). BACTEC MGIT 960 had the shortest mean number of days (10.3) to detection, followed by BACTEC 9000 MB (13.2) and LJ medium (26.1). Sign rank test showed all three methods had significant difference in days to detection (each P<0.0001). About 39% of detection by BACTEC MGIT 960 took place within the first week, compared to 27.0% and 0.0% by BACTEC 9000 MB and LJ medium respectively. The best yield was obtained with BACTEC 9000 MB, but when compared with the BACTEC MGIT 960, it was not statistically significant. Performances were the same when the combination of a liquid plus a LJ medium were measured (P=0.05). Contamination rates were significantly higher in BACTEC MGIT 960 (12%) than in BACTEC 9000 MB (7%) (P=0.041) and LJ (4%) medium (P=0.022). BACTEC 9000 MB and LJ medium have lower contamination rates (P=0.607).


CONCLUSIONS
BACTEC MGIT 960 had a shorter time to detection of MTBC than BACTEC 9000 MB and L J medium. Despite a higher contamination rate, its performance did not appear to be inferior.
Otu
Jacob
J
Medical Research Council Laboratories, Banjul, The Gambia, West Africa.
Antonio
Martin
M
Cheung
Yin Bun
YB
Donkor
Simon
S
De Jong
Bouke C
BC
Corrah
Tumani
T
Adegbola
Richard A
RA
D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods; D003470:Culture Media; D004866:Equipment Contamination; D005714:Gambia; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000254:growth & development / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000382:microbiology
D003470:Culture Media