Abstract: In the assay, we used heat inactivation, ultrasonic cracking and ultraviolet irradiation three methods to prepare the death bacterial suspension of Mycobacterium tuberculosis, compared the effects of these three methods on the result of PMA-qPCR coupling technology. To choose the best preparation method of the dead bacterial suspension for subsequent experiments and explore the scopes of application and limitations of PMA-qPCR detection technology. The results showed that dead bacterial suspensions prepared by both methods of heat inactivation and ultrasonic cracking affected the changes of Ct values detected by PMA-qPCR. The dead bacterial suspension prepared by ultraviolet irradiation method had no effect on Ct values of PMA-qPCR detection technology.Heat inactivation method was the best method for the preparation of bacterial suspension of died Mycobacterium tuberculosis.PMA-qPCR coupling method was not suitable for the detection of dead bacteria prepared by the lethal method without cell membrane injury.

Key words: PMA-qPCR coupling technology; heat inactivation; ultrasonic cracking; ultraviolet irradiation