Abstract:

Objective To evaluate the accuracy of Mycobacterial species identification kit (molecular hybridization method), and to investigate the rapid and accurate approaches for the identification of mixed infection caused by Mycobacterium tuberculosis complex (MTC) and non-tuberculosis Mycobacterium(NTM). Methods A total of 200 clinical Mycobacterium isolates were identified by molecular hybridization method. The mixed infection was simulated by the mixture of Mycobacterium tuberculosis and Mycobacterium intracellular, Mycobacterium tuberculosis and Mycobacterium kansasii, Mycobacterium tuberculosis and Mycobacterium fortuitum. The gene sequencing, gene chip array and Hain test were used to evaluate the accuracy of Mycobacterium-mixed infection. Resutls As reference to pnitrobenzoic acid(PNB) tests, the sensitivity and specificity of molecular hybridization method were 65.12%(65/86) and 98.25%(112/114), respectively. Among 13 different proportions of Mycobacterium tuberculosis and NTM, gene chip array and Hain test accurately detected all of the mixed infections. Gene sequencing can only detect the mixed infection caused by Mycobacterium tuberculosis and Mycobacterium fortuitum at a range from 10% to 90%. Conclusions The specificity of molecular hybridization method for the identification of Mycobacterium tuberculosis is high. The kit following the method for NTM has a significant diagnosis value. Once the mixed infection is identified in the culture, gene chip array and Hain test can identify the species of mixed culture for the common pathogenic Mycobacterium.

Key words: Non-tuberculosis , Mixed infection, Molecular hybridization method