Abstract:

Objective To explore epidemiologic characteristics of non-tuberculous mycobacterium (NTM) in Shenzhen to provide the basis for the control strategies of NTM.Methods Sputum were collected from 37630 suspected tuberculosis patients selected from Shenzhen Center for Chronic Disease Control or each County Chronic Disease Control Hospital from 2013 to 2017. All the samples were cultured using BACTEC MGIT 960 and traditional culture, of them, 8850 strains were detected positive. MPB64 method and traditional PNB test were used to identify Mycobacterium tuberculosis complex and NTM preliminary. The initial NTM was further identified by the HAIN genotyping method. The year of onset, sex, age, infection types, regions, household registration source and the distribution characteristics of NTM strains were analyzd using Chi-squeare test, P<0.05 was considered statistically significant.Results With prevalence of 4.14% (366/8850),366 initial NTM strains were identified by 8850 mycobacterial strains. Two hundred and ninety-three NTM were further identified with the identification rate of 80.05% (293/366) by HAIN genotyping method. The prevalence of NTM showed a slight upward trend from 2013 to 2017 in Shenzhen (3.81% (71/1864)-4.50% (82/1821)), but there was no statistically significant difference (χ ²=1.159, P=0.885). In 366 NTM patients, the prevalence for female (4.87% (144/2957)) was more higher than male(3.77% (222/5893)) (χ ²=6.038,P=0.014). The infection peak age of NTM patients was 25-34-year-old for both male and female (28.83% (64/222) and 23.61% (34/144)), but no statistically significant was found (χ ²=1.213,P=0.271). The NTM rates in new patients, suburban patients, floating patients and suburban floating patients (2.31% (187/8104), 1.77% (105/5909), 3.89% (324/8323)and 1.61% (91/5663), respectively) were significantly lower than those of retreatment patients (23.99% (179/746)), downtown patients (8.87% (261/2941)), register patients (7.97%(42/527)) and downtown floating patients (8.77% (235/2681)) (χ ²=810.400, 249.512, 20.778 and 248.418, respectively, all P=0.000). Of the 293 NTM, Mycobacterium abscessus (41.64% (122/293)), Mycobacterium avium (22.18% (65/293)) and Mycobacterium kansas (16.04% (47/293)) were most common. In addition, mixed infection were found in 7 cases (2.39%(7/293)). Conclusion The prevalence of NTM has been stable in Shenzhen in recent years and NTM is various. Mycobacterium abscessus, Mycobacterium avium and Mycobacterium kansasii are the main strains isolated and the prevalence is higher in young adults. The epidemic situation of female patients, retreatment patients, downtown patients, register patients and downtown patients should be paid more attention.

Key words: Mycobacteria, atypical, Disease attributes, Epidemiologic studies, Small-area analysis