Prevalence and Antimicrobial Susceptibility of Non-tuberculous Mycobacteria Isolated from Sputum Samples of Patients with Pulmonary Infections in China

Abstract

Background: Non-tuberculous mycobacteria (NTM) are widely associated with pulmonary diseases. Evidence is lacking on the transmission of NTM from one person to another. Hence, it has gained lower public health priority than tuberculosis. Objectives: We determined the prevalence and antibiotic resistance rate of NTM isolated from sputum samples of patients with pulmonary infections. Methods: A total of 375 duplicate sputum samples were collected from 375 patients on consecutive days. The NTM growth was assessed using BACTEC 960 mycobacterial growth indicator tubes. The GenoType Mycobacterium CM/AS line probe assay was used for the species-level identification of mycobacteria. Antibiotic susceptibility tests were performed using the auto-MODS assay. Results: The overall NTM prevalence rate was 34.4%. Mycobacterium avium complex (24.8%) was the predominant species identified, followed by Mycobacterium kansasii (24%) and Mycobacterium abscessus complex (20.2%). Of the 129 NTM isolates tested for antibiotic susceptibility, 62.8% were resistant to rifampicin, 60.5% to levofloxacin, 58.1% to ofloxacin, 55.8% to ethambutol, 49.6% to isoniazid, 48.1% to streptomycin, and 41.9% to amikacin. Seventy-three (56.6%) isolates were identified as multidrug-resistant (MDR) isolates. Conclusions: M. avium complex was the predominant species identified, and the majority of the organisms were resistant to commonly used anti-tuberculosis drugs. The high prevalence of NTM and drug resistance towards the tested antibiotics suggests that NTM can no more be ignored as a contaminant, reiterating the need for periodic surveillance and species-specific treatment for effective management of diseases caused by NTM.

Molecular epidemiology of nontuberculous mycobacteria isolated from tuberculosis-suspected patients

“…This study showed that the most common NTM isolates were M. fortuitum, followed by M. simiae, M. kansasii, M. gordonae, and M. conceptense. Aside from that, a variety of studies have been conducted on the prevalence of NTM infections, in particular M. avium-intracellulare (MAC) infection, M. abscessus, M. chelonae, M. fortuitum, and M. kansasii (Chiang et al 2021;Zhou et al 2021). Our study revealed that in the majority of cases, M. simiae, M. fortuitum, M. kansasii and M. marinum were detected.…”