Direct tetrazolium microplate assay (TEMA) for rapid drug susceptibility test screening of Mycobacterium tuberculosis
- Author:
Wan Nor Amilah, W.A.W.
;
Mohammad Lukman, Y.
;
Noor Izani, N.J.
- Publication Type:Journal Article
- From:Tropical Biomedicine
2016;33(4):814-823
- CountryMalaysia
- Language:English
-
Abstract:
Rapid and inexpensive assays for drug susceptibility testing (DST) of Mycobacterium
tuberculosis (MTB) are urgently required especially in developing countries where tuberculosis
cases are prevalent. In response to this necessity, a direct microplate-based colorimetric
assay which excludes the use of pre-testing culture isolate was evaluated. MTB susceptibility
to the first line anti-tuberculosis drugs was tested directly on sputum specimens using
tetrazolium microplate assay (TEMA) method and the sensitivity, specificity, accuracy as
well as mean turn-around time of TEMA were compared to the standard absolute concentration
method (ACM). TEMA was performed on 41 acid fast bacilli (AFB) positive sputum specimens
by direct inoculation of the processed specimens into the microplate wells containing serialdiluted
first line anti-tuberculosis drugs using tetrazolium dye as growth indicator. Indirect
TEMA was performed on MTB isolates of the corresponding samples. The minimum inhibitory
concentrations (MICs) of isoniazid (INH), rifampicin (RMP), ethambutol (EMB) and streptomycin
(SM) were obtained for direct and indirect TEMA with reference to the absolute concentration
method (ACM). After establishing the breakpoint MIC of each drug using receiver operating
characteristics (ROC) curve, reliable results from direct TEMA were obtained for INH and
SM, with excellent levels of sensitivity, specificity, and accuracy (more than 90%). The
predictive values for susceptibility were 100% for INH, EMB and SM as well as 96% for RMP.
A shorter mean turn-around time of 14 days was observed for direct TEMA (P < 0.05). Thus
direct TEMA is potentially rapid, reliable and inexpensive DST screening method of MTB in
countries with high prevalence rates of drug resistance tuberculosis
- Full text:P020170124578470723268.pdf
