Evaluation of Microscopic Observation Drug Susceptibility Assay in Detection of Mycobacterium tuberculosis / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To set up and evaluate the microscopic observation drug susceptibility assay(MODS)technology and use it to detect rapidly Mycobacterium tuberculosis(MTB).METHODS The 24-hole cell culture plate method of liquid culture were used to set up MODS technology.The MODS technology was used to detect MTB and non-M.tuberculosis(NMT)isolates comparing with Lowenstein-Jensen(L-J) method.RESULTS When bacterial concentration was 3?103 CFU/ml,the time of reading test-result was the seventh day by MODS;four kinds of NMT(M.phlei,M.kansasii,M.chelonaeand M.marinum) in the liquid medium in the observation was similar to the growth of cording,it was difficult to distinct from the cording of MTB in the liquid medium;When using the 4-Nitro-benzoic acid 800 ?g/ml,thiophene-2-carboxylic acid hydrazine 2.5 ?g/ml for testing conditions,the correct diagnosis can be improved;the test results of clinical isolates by MODS were highly concordance rate with the results of L-J.If the results of L-J was the golden standard,the sensitivity,specificity,positive and negative predictive value as well as accuracy by MODS was 95.7%,100%,100%,99.9% and 97% respectively.CONCLUSIONS The results of MODS in detection of MTB are highly concordance wih the results of L-J method;MODS assay can be used for rapid detection of tuberculosis,with a rapid,simple,inexpensive,and other advantages.