Prevalence of nontuberculous mycobacteria isolated from pulmonary specimens in Wenzhou during 2014 to 2016 / 中华临床感染病杂志

ABSTRACT

Objective To investigate the isolation rate, distribution and trend of nontuberculous mycobacteria (NTM) in Wenzhou during 2014 to 2016.Methods Sputum or alveolar lavage specimens of patients with suspected pulmonary tuberculosis were collected for mycobacteria culture from January 2014 to December 2016.Mycobacterium culture positive strains were further identified by gene chip, 16S rRNA and hsp65 gene sequencing.SPSS 19.0 software was used to analyze the data.Results After excluding repetitive strains, 3 295 mycobacteria strains (MTB) were isolated from respiratory specimens, included 3 032 mycobacterium tuberculosis complex strains, 238 NTM strains, 20 Gordon genera strains, 3 Nocardia genera strains and 2 Tsukamurella genera strains.The proportion of NTM among confirmed mycobacteria was 8.5％ (86/1 006), 6.7％ (72/1 079) and 6.8％ (80/1 185) in 2014, 2015 and 2016, respectively (x2 =2.459,P ＞ 0.05).The overall prevalence of NTM was 7.3 ％ (238/3 270).There were 15 species of NTM, and the most common NTM strain was Mycobacterium intracellulare (52.5％,125/238), followed by Mycobacterium abscessus (22.7％, 54/238) and Mycobacterium avium (10.1％, 24/238), other species were only accounted for 14.7％ (35/238).The ranking of Mycobacterium avium went up rapidly from the fifth in 2014 to the second in 2016 (x2 =18.259, P ＜ 0.01), while proportion of Mycobacterium abscess, dropped from 34.9％ (30/86) in 2014 to 17.5％ (14/80) in 2016 (x2 =7.335, P＜0.01).Among patients from whom the NTM strains were isolated, 56.7％ (135/238) were male and most of them were aged 45 years or above (79.8％, 190/238).Conclusions In the past three years, the trend of NTM isolation rate in Wenzhou is steady.The most prevalent NTM species is Mycobacterium intracellulare, followed by Mycobacterium abscessus and Mycobacterium avium.Mycobacterium avium shows a continuously upward trend, while the separation of Mycobacterium abscessus shows a downward trend.