[Rapid rifampicin susceptibility test by using recombinant mycobacteriophages].

OBJECTIVE

To set up a fast, sensitive and specific way to detect mycobacteria and rifampicin susceptibility to mycobacteria by using recombinant mycobacteriophages and bioluminescent method.

METHODS

Firstly detected the luciferase activity in different bacteria by using mycobacteriophages, then assessed the best drug concentration of rifampicin for drug susceptibility test in luciferase reporter assay, and lastly used the above conditions to decide rifampicin susceptibilities to different mycobacteria and compare the result with L-J medium culture.

RESULTS

Bacteriophages had high light production specifically in mycobacteria and only very low light production in E. coli, the difference being obvious. The light production of rifampicin-resisitant mycobacterium strains was much higher than that of sensitive strains in culture with rifampicin(P < 0.05). Different drug concentrations of rifampicin were used to optimize drug concentration for rifampicin drug susceptibility test and the optimum concentration was found to be 2 micrograms/ml. The correlation of drug susceptibility test between luciferase reporter phages to L-J medium in standard strains and clinical isolates was the sarce. Temperature sensitive Phage 88 was more sensitive than Phage 40(P < 0.05). The time for drug resistance test was 72 hours.

CONCLUSIONS

Luciferase reporter phage can detect mycobacteria specifically and can be used in rifampicin susceptibility test. This assay is a fast, sensitive and specific method to detect mycobacterium strains and their resistance to rifampicin.