AUTHOR=Sun Qing , Yan Jun , Liao Xinlei , Wang Chaohong , Wang Chenqian , Jiang Guanglu , Dong Lingling , Wang Fen , Huang Hairong , Wang Guirong , Pan Junhua 

TITLE=Trends and Species Diversity of Non-tuberculous Mycobacteria Isolated From Respiratory Samples in Northern China, 2014–2021

JOURNAL=Frontiers in Public Health

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2022.923968

DOI=10.3389/fpubh.2022.923968

ISSN=2296-2565

ABSTRACT=<sec><title>Background</title><p>Pulmonary non-tuberculous mycobacteria (NTM) infection has become a public health concern in China and around the world. The objective of this study was to describe the longitudinal changes in the frequency and diversity of NTM in northern China.</p></sec><sec><title>Methods</title><p>We retrospectively analyzed data on mycobacterium species in Beijing Chest Hospital from January 2014 to December 2021. The isolates were identified to species level by targeted DNA sequencing.</p></sec><sec><title>Results</title><p>After excluding duplicates, 1,755 NTM strains were analyzed, which were from 27 provinces in China over 8 years. Among all mycobacteria, the proportion of NTM increased each year, from 4.24% in 2014 to 12.68% in 2021. Overall, 39 different NTM species were identified, including 23 slow growing mycobacteria (SGM) and 16 rapid growing mycobacteria (RGM). The most common species were <italic>M. intracellulare</italic> (51.62%), <italic>M. abscessus</italic> (22.22%), <italic>M. kansasii</italic> (8.32%), <italic>M. avium</italic> (7.75%) and <italic>M. fortuitum</italic> (2.05%). The number of NTM species identified also increased each year from 9 in 2014 to 26 in 2021. Most species showed stable isolation rates over the years; however, the proportion of <italic>M. avium</italic> increased from 3.85 to 10.42% during the study period. Besides, 81 non-mycobacteria strains, including <italic>Gordonia</italic> (21 isolates), <italic>Nocardia</italic> (19 isolates) and <italic>Tsukamurella</italic> (17 isolates), etc., were also discovered.</p></sec><sec><title>Conclusion</title><p>The proportion of NTM and species diversity increased considerably in northern China from 2014 to 2021. <italic>M. intracellulare</italic> was the most common NTM isolated among respiratory specimens, followed by <italic>M. abscessus</italic> and <italic>M. kansasii</italic>. Rare NTM species and non-mycobacteria pathogens also need attention.</p></sec>