Increasing Trend of Nontuberculous Mycobacteria Isolation in a Referral Clinical Laboratory in South Korea

Abstract

Background and Objectives: Nontuberculous mycobacteria (NTM) infections are increasing worldwide. We evaluated the annual trends of NTM isolation on acid-fast bacillus (AFB) culture, compared to that of Mycobacterium tuberculosis, and the distribution of NTM species nationwide in South Korea. Materials and Methods: The study was conducted in a diagnostic center that is a major referral laboratory for the diagnosis of tuberculosis and NTM in South Korea. All laboratory results of AFB culture from January 2014 to December 2019 were collected. All NTM identified were definitively identified to the species level. Results: A total of 345,871 tests were performed for the diagnosis of mycobacteria. The isolation rate of NTM and M. tuberculosis was 3.7% (12,969 cases) and 4.4% (15,081 cases), respectively. The annual isolation rate of NTM increased gradually from 2.7% in 2014 to 4.8% in 2019, whereas that of M. tuberculosis decreased from 6.2% to 3.3%. There were 4988 cases of NTM identified to the species level. M. avium complex (MAC) was the most common species isolated from pulmonary sites (59.8%), followed by M. gordonae (9.2%), M. abscessus (7.0%), and M. fortuitum (5.5%). Extrapulmonary NTM were identified in 29 cases (0.6%). MAC was also the most common NTM species isolated from extrapulmonary sites (65.5%), followed by M. kansasii (10.3%), M. abscessus (6.9%), and M. fortuitum (6.9%). Conclusions: The annual isolation rate of NTM has increased gradually, whereas that of M. tuberculosis has decreased. Follow-up studies of the increases in NTM identification and NTM infections in South Korea are needed.

Trends and Species Diversity of Non-tuberculous Mycobacteria Isolated From Respiratory Samples in Northern China, 2014–2021

“…Total 39 different NTM species were identified, indicating the diversity of NTM species circulating among patients in China. M. intracellulare was the most common NTM pathogen, which was similar to previous findings in Australia, Korea, India, Uruguay and so on (3,(16)(17)(18)(19). Furthermore, we found the incidence of M. avium grew faster than others from 2014 to 2021, and the ratio of M. avium to M. intracellulare increased each year, suggesting a more prominent role for M. avium infections in China.…”

Vaccination inducing durable and robust antigen-specific Th1/Th17 immune responses contributes to prophylactic protection against Mycobacterium avium infection but is ineffective as an adjunct to antibiotic treatment in chronic disease

“…Nevertheless, the prevalence and incidence of NTM disease in humans have become a global public health problem in recent decades [ 2 ]. Ninety percent of NTM infections cause pulmonary disease (PD) [ 5 ]. Representatively, the prevalence of NTM-PD was approximately 13.9/100,000 patients in the USA in 2013, 36.1/100,000 patients in South Korea in 2016, 24.9/100,000 patients in Japan in 2016, 46.0/100,000 patients in Taiwan in 2014, and 6.2/100,000 patients in five EU countries (United Kingdom, France, Germany, Italy, and Spain) in 2016 [ 5–10 ].…”

“…Ninety percent of NTM infections cause pulmonary disease (PD) [ 5 ]. Representatively, the prevalence of NTM-PD was approximately 13.9/100,000 patients in the USA in 2013, 36.1/100,000 patients in South Korea in 2016, 24.9/100,000 patients in Japan in 2016, 46.0/100,000 patients in Taiwan in 2014, and 6.2/100,000 patients in five EU countries (United Kingdom, France, Germany, Italy, and Spain) in 2016 [ 5–10 ]. Although the distribution of NTMs causing PD geographically differs, the Mycobacterium avium complex (MAC), mainly consisting of M. avium subspecies hominissuis (hereafter referred to as Mav) and M. intracellulare , is considered the main causative agent among NTM species worldwide [ 2 , 11 ].…”

A glimpse into the genotype and clinical importance of non tuberculous mycobacteria among pulmonary tuberculosis patients: The case of Ethiopia

“…NTMs are becoming epidemiologically important since their clinical significance is increasingly recognised [ 6 , 7 ]. In Western countries, MAC [ 8 , 9 ] and in parts of Africa, M . kansasi , and M .…”

“…NTMs are becoming epidemiologically important since their clinical significance is increasingly recognised [6,7]. In Western countries, MAC [8,9] and in parts of Africa, M. kansasi, and M. abscesses [10] have been the most common NTM species that are responsible for pulmonary infections. Unlike in developed countries, the distribution of NTM and the prevalence of their disease are not fully understood in the developing countries, including Ethiopia.…”