Identification of Species of Nontuberculous Mycobacteria Clinical Isolates from 8 Provinces of China

Abstract

Pulmonary diseases caused by nontuberculous mycobacteria (NTM) are increasing in incidence and prevalence worldwide. In this study, we identified NTM species of the clinical isolates from 8 provinces in China, in order to preliminarily provide some basic scientific data in the different species and distribution of NTM related to pulmonary disease in China. A total of 523 clinical isolates from patients with tuberculosis (TB) diagnosed clinically from 2005 to 2012 were identified to the species using conventional and molecular methods, including multilocus PCR, rpoB and hsp65 PCR-PRA, hsp65, rpoB, and 16S-23S internal transcribed spacer region sequencing. The isolates were identified into 3 bacterium genera, including NTM, Gordonia bronchialis, and Nocardia farcinica, and, for the 488 NTM isolates, 27 species were identified. For all the 27 species of NTM which were found to cause pulmonary infections in humans, the most prevalent species was M. intracellulare, followed by M. avium and M. abscessus. And seven other species were for the first time identified in patients with TB in China. NTM species identification is very important for distinguishing between tuberculosis and NTM pulmonary diseases, and the species diversity drives the creation of diverse and integrated identification methods with higher accuracy and efficacy.

Non-Tuberculous Mycobacterial Pulmonary Disease Prevalence Status in China

“…Interestingly, the occurrence of Gordonia is similar to some report in China [22]. Two Nocardia which often cause chronic lung diseases were isolated, as reported in the several article in China [23]. In addition, Tsukamurella infection case in Jiangxi province has previously been reported in in Southern-central China [6].…”

“…In another research from Guangdong and Shanghai province proved that M. intracellulare was the most commonly isolated NTM in Shanghai and the most frequently isolated species in Guangzhou is M. abscessus [22]. Some researches in eastern and northern region of China demonstrated the NTM prevalence rate is around 2.0%-3.0% and the predominated species is M. intracellulare, followed by M. abscessus [5,[21][22][23]. In our study, the NTM infection is more prevalent in southern than northern China and is more frequently in eastern than western China.…”

Investigation of non-tuberculous mycobacteria in a primary hospital from southeastern China

“…Our results showed that the most common NTM was represented by MAC strains, similar to the epidemiology of NTM in China and in many regions in the world. The predominant species among MAC in this study was M. chimaera, while M. intracellulare was the main one in other regions of China [15,16,23]. In addition, the M. colombiense and M. lentiflavum found in this study were hardly reported in China, indicating that some species of NTM were underestimated in clinical samples [23].…”

“…Indeed, M. chimaera could not be easily distinguished from the M. intracellulare based on 16S rRNA and rpoB sequencing, causing incorrect species identification by commonly used laboratory techniques [24,25]. Therefore, the common identification methods based on 16S rRNA in China may lead to an underestimated prevalence of M. chimaera [15,16,19]. In addition, the species varies across the different regions as reported, which may be explained by the heterogeneities in exposure routes and susceptibility of individuals [26,27].…”

“…Although accurate species identification of NTM has been conducted in big hospitals in some regions, there are rare data from primary hospitals where patients are firstly visited [15,16]. Due to insufficient attention to NTM related diseases, the diagnosis and therapy was commonly ignored in primary hospitals when compared to MTBC infection.…”