Susceptibility of Mycobacterium tuberculosis to first-line antimycobacterial agents in a Brazilian hospital: assessing the utility of the tetrazolium (MTT) microplate assay
Mem. Inst. Oswaldo Cruz
;
105(5): 661-664, Aug. 2010. tab
Article
in English
| LILACS
| ID: lil-557226
ABSTRACT
We conducted a cross-sectional, hospital-based study between January 2006-March 2008 to estimate the resistance of Mycobacterium tuberculosis to first-line drugs in patients with tuberculosis at a Brazilian hospital. We evaluated the performance of the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide] (MTT) microplate assay compared with the Bactec-MGIT 960 system for mycobacteria testing. The prevalence of resistance in M. tuberculosis was 6.7 percent. Multidrug-resistance [resistance to rifampicin (RMP) and isoniazid (INH)], INH-resistance and streptomycin (SM)-resistance accounted for 1 percent, 3.8 percent and 3.8 percent of all resistance, respectively, and all isolates were susceptible to ethambutol (EM). The resistance was primary in four cases and acquired in three cases and previous treatment was associated with resistance (p = 0.0129). Among the 119 M. tuberculosis isolates, complete concordance of the results for INH and EM was observed between the MTT microplate and Bactec-MGIT 960TM methods. The observed agreement for RMP was 99 percent (sensitivity 90 percent) and 95.8 percent for SM (sensitivity 90.9 percent), lower than those for other drugs. The MTT colourimetric method is an accurate, simple and low-cost alternative in settings with limited resources.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Tetrazolium Salts
/
Thiazoles
/
Tuberculosis
/
Microbial Sensitivity Tests
/
Coloring Agents
/
Anti-Bacterial Agents
/
Mycobacterium tuberculosis
Type of study:
Observational study
/
Prevalence study
/
Risk factors
Limits:
Adult
/
Female
/
Humans
/
Male
Country/Region as subject:
South America
/
Brazil
Language:
English
Journal:
Mem. Inst. Oswaldo Cruz
Journal subject:
Tropical Medicine
/
Parasitology
Year:
2010
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Secretaria de Saúde do Estado de São Paulo/BR
/
Universidade Estadual de Campinas/BR
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