The Study Of PhaB Assay Detection Of MTB In Sputum And Drug Resistance

Objective:To use of phage amplified biologically(PhaB)assay detect rapidly Mycobacterium tuberculosis(MTB) and the resistance to rifampin(RFP), isoniazid(INH) and levofloxacin(LVFX). To establish a high specific and sensitive MTB susceptibility test methods.Methods:To test the detect and culture of MTB and drug sensitivity by phage detection method. Absolute concentration method as the control, to analyze the sensitivity, specificity of PhaB assay and the degree of compliance with the traditional methods in order to using in clinical diagnosis and treatment.Results:(1) Using 10 cases of Mycobacterium tuberculosis at 102,5×102,103,104, 105 CFU/ml concentration respectively, (Mcfarland 3.0 turbidity equivalent concentration of bacteria 107 CFU/ml) detec Mycobacterium tuberculosis by PhaB assay. The lowest detection concentration is 5×102 CFU/ml. (2) To detct Pseudomonas aeruginosa, Streptococcus pneumoniae, Staphylococcus aureus, E. coli and other respiratory tract bacteria through PhaB, the results were all negative. Application PhaB to detect 10 strains non-tuberculousis Mycobacterium,10 strains Mycobacterium bovis,10 strains Mycobacterium tuberculosis, the results were all positive. (Bacterial concentration are 105-CFU/ml), and its specificity is 100%. (3) 105 strains TB which come from clinical sputum samples were detected directly PhaB method. The detection rate which culture specimens and smear specimens were both positive was 95.2%, and smear-positive and culture-negative rate was75.0%, smear-negative and culture-negative rate was 23.1%. (4) The degree of compliance of PhaB method with the traditional methods is 87.7%, RFP 88%, INH 85.3%, LVFX 90%, respectively.Conclusion:The MTB in sputum can be detected rapidly using PhaB assay, by which the detection rate of pulmonary tuberculosis is higher than using smear method, and the PhaB assay has high sensitivity and specificity. Compared with the traditional methods, the consistent rate of drug-sensitive is higher while detecting resistance of MTB for isoniazid, rifampin and levofloxacin by using PhaB assay, the report time only need 3 d, and meanwhile no special equipment is required and the cost is low, which has the significance for the directions of clinical early diagnosis and treatment.