Nontuberculous Mycobacteria in China-incidence and Antimicrobial Resistance Spectrum From a Nationwide Survey

Abstract Background: Information on prevalence and resistance spectrum of nontuberculous mycobacteria (NTM) in China is mainly based on regional or local data. A national survey of NTM pulmonary disease was carried out based on acid-fast positive sputum samples collected in 2013. Methods: Sputum samples collected from enrolled presumptive cases were cultured using L-J medium in 72 nationwide tuberculosis surveillance sites from the 31 Chinese mainland provinces and isolates were sent to national tuberculosis reference laboratory (NTRL). The species of re-cultured strains were identified by MALDI-TOF MS and minimal inhibitory concentrations (MICs) were determined to evaluate the drug susceptibility of NTM isolates. Results: Of 4917 mycobacterial isolates cultured, 317 (6.4%, 95% CI, 5.8% to 7.2%) were confirmed as NTM, among which 287 (7.7%, 95% CI, 6.9% to 8.6%) were from the southern region. In inland and coastal China, 87.7% (95% CI, 78.7% to 93.2%) and 50.0% (95% CI, 43.7% to 56.3%) of isolates, respectively, were slow growing mycobacteria (SGM), with the remaining rapid growing mycobacteria (RGM). A total of 29 species were detected, M. abscessus had higher clarithromycin-inducible resistance rates than M. massiliense (65.67% vs 2.22%). M. kansasii was present lower resistance rates in linezolid and moxifloxacin than Mycobacterium avium-intracellulare complex and other SGM. Conclusions: More NTM pulmonary disease was observed in southern and coastal China (p<0.01). SGM was widely distributed, and more RGM are present in southern and coastal China (p<0.01). The antimicrobial resistance spectrum of different NTM species was significant different, accurate species identification would be facilitated to NTM pulmonary disease treatment.