Prevalence of Nontuberculous Mycobacteria in a Tertiary Hospital in Beijing, China, January 2013 to December 2018 [post]

2019 unpublished
To investigate the species distribution of non-tuberculous mycobacteria (NTM) among tuberculosis (TB) specimens collected from January 2013 to December 2018 at Peking Union Medical Hospital (Beijing), China. NTM species identification was carried out by DNA microarray chip. Results Mycobacterial species were detected in 1514 specimens from 1508 patients, among which NTM accounted for 37.3% (565/1514), increasing from a prevalence of 15.6% in 2013 to 46.1% in 2018 ( P <0.001). Among the 565 NTM
more » ... ositive specimens, the majority (55.2%) were from female patients. Furthermore, patients aged 45-65 years accounted for 49.6% of the total patients tested. Among 223 NTM positive specimens characterized further, the majority (86.2%) were from respiratory tract, whilst 3.6% and 3.1% were from lymph nodes and pus, respectively. Mycobacterium intracellulare (31.8%) and Mycobacterium chelonae / Mycobacterium abscessus (21.5%) were the most frequently detected species, followed by M. avium (13.5%), M. gordonae (11.7%), M. kansasii (7.6%), and others. Conclusion The proportion of NTM among mycobacterial species detected in a tertiary hospital in Beijing, China, increased rapidly from year 2013 to 2018. Middle-aged patients are more likely to be infected with NTM, especially females. Mycobacterium intracellulare and Mycobacterium chelonae / Mycobacterium abscessus were the most frequently detected NTM pathogens. Accurate and timely identification of NTM is important for diagnosis and treatment. Background The substantial increase in the number of patients with immunodeficiency in recent years has contributed to the rise in infectious diseases caused by a variety of rare organisms, including nontuberculous mycobacteria (NTM)(1, 2). The clinical manifestations of infections caused by NTM are similar to those of Mycobacterium tuberculosis (MTB)(3). However, the treatment strategies used for management of infections by these two groups of organisms are quite different(4). Thus accurate identification of Mycobacteria strains to species level is crucial for managing infections. In China, patients diagnosed with TB or suspected of having TB, are referred to a thoracic specialist hospital for further treatment. However, clinical manifestations of NTM diseases and TB are quite intracellulare (65/193, 33.7%) was the most commonly detected species in respiratory tract samples, followed by M. chelonei / M. abscessus (37/193, 19.2%), M.avium (27/193, 14.0%), M.gordonae (24/193, 12.4%). So MAC (92/193, 47.7%) was still the most common NTM pathogen in respiratory tract, which is consistent with previous findings in US, . Although MAC is the most common pathogen in NTM pulmonary disease, the relative frequency of MAC varies widely among different geographical regions. For example, MAC represented 31% of isolates from South America, 52% from North America and 42.1% from China in this study. Many factors such as the climate type and population density can affect the distribution of NTM species (2). In the present study, NTM infection was much more common in women(55.2%) than men(44.8%). Furthermore, the age range of infected people was relatively wide, being most common in the 45-65 year age group (49.6%), probably due to some issues related to the function of the immune system(17). This finding is in agreement with those of multiple studies in US(18), Japan(19, 20) and South Korea (16) , which all indicated that older women were more susceptible to NTM infection. According to a previous study, abnormal expression of adipokines, sex hormones, and/or TGF-β may predispose slender, older women to NTM infection(21). However, contrasting findings have been reported in Europe, where patients with NTM pulmonary disease were more likely to be male, possibly owing to smoking history and chronic obstructive pulmonary disease (COPD)(9, 20). DNA microarray chip method (Mycobacteria Identification Array Kit, CapitalBio Corporation, Beijing, China) can accurately distinguish between M. avium and M. intracellulae, which have quite similar phenotypes. We found out that the prevalence of M. intracellulae(31.8%) was always higher than M. avium(13.5%) from 2013 to 2018. It is important to distinguish between M. avium and M. intracellulae because theyshow different pathogenic characteristics. M. intracellulae is more virulent compared to M. avium, indicating a more intensive therapeutic strategy (22). However, the DNA microarray chip method could not distinguish between M. chelonei and M. abscessus, and between M. marinum and M. ulcerans. This is because M. chelonei and M. abscessus have the same 16S rRNA gene sequences,
doi:10.21203/rs.2.18053/v1 fatcat:xjr4tnhvezcdtjwm2mauv4slam