Distribution and drug resistance of nontuberculous Mycobacteria in Beijing

Abstract

Objective: To analyze the distribution and drug resistance of nontuberculous mycobacteria(NTM) in Beijing. Methods: Using PCR-fluorescence probe method we identified 1 552 mycobacterial isolates in 2009 and 1 553 mycobacterial isolates in 2013, which were stored by Beijing Research Institute for Tuberculosis Control.All identified NTM strains were confirmed by 16S rRNA gene sequencing, and drug sensitivity testing was performed by using 1% ratio method.SPSS 13.0 was used for statistical analysis. Results: The isolation rate for NTM in 2009 and 2013 was 3.8%(59/1 552), and 4.6%(71/1 553) respectively. A total of 130 NTM strains were identified to 13 species by 16S rRNA gene sequencing, including M. intracellulare strains 39.2%(51/130), M. kansasii strains 37.7%(49/130), M. avium strains 6.9%(9/130), M. abscessus strains 5.4%(7/130), M. fortuitum strains 3.0%(4/130), M. gordonae strains 1.5%(2/130), M. xenopi strains 1.5%(2/130), M. scrofulaceum, M. Phlei, M. smegmatis, M. vaccae, M. neoaurum, M. kumamotonense 1 strain each. For the patients infected with NTM, 87 were male and 43 were female, with an average age of 55 years. The results of drug sensitivity test from 97 strains of NTM showed that isoniazid and p-aminosalicylic acid showed the highest drug resistant rate of 98%(95/97), followed by streptomycin 94.8%(92/97), capreomycin 81.4%(79/97), amikacin 69.1%(67/97), levofloxacin 56.7%(55/97), rifampicin 54.6%(53/97), prothionamide 51.5%(50/97), and ethambutol 50.5%(49/97). Conclusions:Mycobacterium intracellulare and Mycobacterium kansasii were the main strains isolated from patients infected with NTM in Beijing. Patients infected with NTM were mostly males. NTM showed high resistance to anti-tuberculosis drugs.