The Study And Use Of Bacteriophage Detecting Ethambutol Resistance Of Mycobacterium Tuberculosis

Objective The aim of our research was to study the optimum test conditions in detecting Ethambutol resistance of Mycobacterium tuberculosis by Phage Amplified Biologically Assay (PhaB). At the same time we could approach the clinical use value of phaB and use it in the detection of Ethambutol resistance rapidly.Methods①The study of experiment technology: EMB with the different concentrations acted on MTb which were known the results of susceptibility test for EMB at different time(24h,48h and 72h). Using PhaB detected these MTb. According to comparing the numbers of plaque, the optimum test conditions were studied and chosen in detecting Ethambutol resistance of Mycobacterium tuberculosis by PhaB rapidly.②Clinical use: We detected the EMB resistance of 230 clinical isolates of Mycobacterium tuberculosis by PhaB and compare it with the results of absolute concentration method and BACTEC-960 system. For all discrepancy isolates, we detected their minimum inhibitory concentration (MIC) of Ethambutol by the liquid culture method in order to verify their result of the drug susceptibility test.Results①The optimum condition of phaB assay detecting EMB resistance of MTb: The best working concentration of mycobacteriophage was 109 PFU/ml and infecting time was 1h at 37℃.The working concentration of EMB was 5μg /ml. The optimum incubation time was 48h for EMB and MTB at 37℃. At this time, the drug tube had a lot of plaques in EMB-resistant isolates and a little of plaques in EMB-susceptible isolates. The reduction ratio of plaques was the biggest in the drug- susceptible isolates and the drug- resistant isolates.②Clinical use: We detected the EMB resistance of 230 clinical isolates of Mycobacterium...