Abstract：Objective To explore the characteristics of mpt64 gene mutation of MPT64-negative clinical isolates of Mycobacterium tuberculosis complex (MTC). Methods MTC clinical isolates cultured by BACTEC MGIT 960 in Hunan Chest Hospital from January and June in 2017 were collected. All the isolates were identified by biochemical and molecular biological methods. DNA extraction, mpt64 gene amplification sequencing and sequence alignment analysis were performed in some MPT64-positive isolates and all MPT64-negative isolates randomly selected from MTC, and the characteristics ofmpt64 gene mutation of MPT64-negativeclinical isolates of MTC were analyzed. Results A total of 2,560 Mycobacterium tuberculosis isolates were recovered from sputa, bronchoalveolar lavage fluid or other samples from tuberculosis patients hospitalized in Hunan Chest Hospital from January to June in 2017. Among the 2,560 isolates, 102 (3.98%) isolates were MPT64-negative. No mutation was foundin mpt64 genein 20 randomly selected MPT64-positive isolates. Among 85 successfully sequenced MPT64-negative clinical isolates, 81 isolates had a 63-bp deletion, and 4 isolates had a single base mutation, including 2 isolates with G→A at 402 and 2 isolates with a 1-bp (C) insertion between 613 and 614. Conclusion The 63-bp deletion was the dominant mutation type for mpt64 gene in MPT64-negative clinical isolatesof MTCin Hunan Chest Hospital.
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2020, Vol. 27 
