Evaluation Of Microscopic Observation Drug Susceptibility Assay In Detection Of Mycobacterium Tuberculosis And Drug Resistance In Mycobacterium Tuberculosis

Objective: To set up MODS technology and use it to detect rapidly mycobacterium tuberculosis and evaluate microscopic observation drug susceptibility assay for simultaneous MTB detection and determination 4 of first-line anti-TB drug susceptibility and 4 of second-anti-tuberculosis-drugs.Methods: use the 24-hole cell culture plate method of liquid culture to set up MODS technology and discuss its methodology;use the found MODS technology to detect 100 clinical isolates comparing to the result with Lowenstein-Jensen (L-J) method and use 24-hole cell culture plates were used to test drug susceptibility of MTB on liquid medium. On the base of optmistic detect condition of MODS assay,60 clinical isolates to streptomycin(SM) ,isoniazid(INH), rifampin(RFP), ethambatal (EMB), protionamide(PTH) ,amikacin (AMK),capreomycin(CPM) and levofloxacin (LVF) at the same time,comparing the results with L-J and then all the inconco- rdance of isolates between MODS and L-J culture tested the minimal inhibitory concentrations(MIC).Results: Bacilli concentration of 3×10~3 CFU/ml when the use of MODS technology ,the time of reading test- result is the seventh day; Four kinds of NTM (M.phlei, M kasasii, M.chclonae, M.marinum) in the liquid medium in the observation was similar to the growth of cording , it is difficult to distinct from the cording of MTB in the liquid medium; To the p-nitrobenzoic acid(PNB) 800μg/ml, thiophene -2 - carboxylic acid hydrazine (TCH) 2.5μg/mlfor testing conditions, the correct diagnosis can improve;the test results of clinical isolates by MODS were highly concordance rate with the results of L-J ; if the results of L-J is the golden standard,the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV)as well as accuracy by MODS was 95.7%, 100%, 100%, 99.9%,97%. Concordance rates of the susceptibility to SM,INH, RFP,EMB, PTH, CPM,AMK and LVF in 60 clinical isolates detected by MODS and L-J are 95.0%,98.0%,98.0%,93.3%,91.7%,98.0%,91.7%,96.7%,The results obtained by L-J taken as the golden standard,the sensitivity,specificity,positive and negative predictive value(PPV and NPV) as well as accuracy of susceptibility test to SM detected by MODS are92.0 % ,97.1%,95.8%,94.4%;to INH95.0%,98.0%,100 % , 97.6%,100%;to RFP 95.8%,98.0%,100 % , 97.3%,100%;to EMB 93.3%,93.9%,76.9 % , 97.9%,90.9%;to PTH100%, 87.5%,87.5%, 100%,96.7%;to AMK 90.0%,90.0%,90.05%,100%,98.0%; to CPM76.9%,95.7%,83.3%,93.8%,91.7%;toLVF100%,96.0%,83.3%, 100%,96.7%; There were nineteen inconsistent result yielded of eight isolates by comparing MODS with L-J,MIC yielded fourteen results of those eight isolates identical results with MODS, while five results of other two isolates identical with L-J.Conclusions:The results of microscopic observation drug susceptibility in detection of mycobacterium tuberculosis were highly concordance rate wih the results of Lowenstein-Jensen (L-J) method ; MODS assay can be used for rapid detection of tuberculosis,with a rapid, simple, inexpensive and other advantages. The results of microscopic observation drug susceptibility assay in detection of mycobacterium tuberculosis were highly concordance rate wih the results of Lowenstein-Jensen (L-J) method ; MODS assay can be used for rapid detection of tuberculosis,with a rapid, simple, inexpensive and other advantages.