Nontuberculous Mycobacteria Isolation from Clinical and Environmental Samples in Iran: Twenty Years of Surveillance

Profile of non-tuberculous mycobacteria amongst tuberculosis presumptive people in Cameroon

BACKGROUND

Cameroon is a tuberculosis (TB) burden country with a 12% positivity among TB presumptive cases. Of the presumptive cases with a negative TB test, some are infected with Non-tuberculous Mycobacteria (NTM). However, the diagnosis of NTM infections remains difficult due to the lack of tools in many laboratories, particularly in resource limited laboratories and remote setting. The present study was undertaken to determine NTM profile and associated comorbidities among TB presumptive people.

METHODS

A retrospective study was conducted from December 2018 to December 2019 in the Tuberculosis-National Reference Laboratory (TB-NRL) for Bacteriological analysis of samples and Jamot Hospital of Yaounde (JHY) for clinical evaluation of confirmed NTM patients. We included in this study data of 5267 TB presumptive people previously diagnosed using three consecutive samples and having culture and SD Bioline results with or without Microscopy and reverse hybridization-based Line Probe Assay(LPA) results. The data on co-morbidities or history of people infected with NTM were then collected from the three participants with available clinical data.

RESULTS

We collected data of 5267 presumptive TB people. Among them, 3436 (65.24%), have a positive culture with 3200 (60.75%) isolates belong to Mycobacterium tuberculosis Complex (MBTC) and 236 (4.48%) to NTM. Our results showed that, 123 (52.11%) NTM were isolated from people with negative microscopy and 113 (47.88%) from people with positive microscopy. Among the 236 NTM, 108 (45.8%) isolates were identified using LPA. M. fortuitum was the most represented species (32.41%) followed by M. intracellulare (19.44%). Sputum had the highest proportion of NTM (56%), followed by bronchial aspirations (31%). The extra-pulmonary samples presented lower proportions of isolates compared to pulmonary samples. Some patients affected with NTM presented comorbidities as HIV infection, Pulmonary tuberculosis, Type 2 diabetes, Chronic bronchitis and Alveolar pneumonia.

CONCLUSIONS

Our study showed the presence of NTM strains among presumptive TB people with a predominance of M. fortuitum and M. intracellulare. It is important to implement a surveillance system of NTM in TB burden country and also to develop a point-of-care test for NTM identification in limited-resource settings.

Mycobacterium simiae Isolates Subtypes and Molecular Drug Susceptibility in Iran

Background: Despite the clinical and epidemiological importance of Mycobacterium simiae worldwide, including in Iran, there is no clear and effective treatment regimen for M. simiae and its different subtypes. Objectives: Concerning the superiority of molecular approaches, this study aims to identify the common M. simiae subtypes submitted to the National Reference Tuberculosis (TB) Laboratory of Iran and study the presence of drug resistance by molecular detection methods. Methods: We included sputum samples with M. simiae confirmation submitted to the National Reference TB Laboratory of Iran from May 2014 to May 2016. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used for drug susceptibility testing (DST). Results: Among 7200 TB suspected patients, a total of 60 M. simiae cases belonging to subtype I were identified. All the included clinical isolates met the American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) diagnostic criteria and were considered the disease’s causative pathogen. Males (58.33%), elderly (68.54%), and patients with a history of TB (51.42%) were shown to be more prone to infection with the disease. All clinical isolates of M. simiae were resistant to rifampin (RIF) and isoniazid (INH). Amikacin/kanamycin (AMK/KAN) and ciprofloxacin (CIP) susceptibility was found to be 91.66% and 88.33%, respectively. Conclusions: Subtype I was exclusively identified among M. simiae patients in Iran. Molecular detection of drug resistance suggests that amikacin/kanamycin and ciprofloxacin could be used to treat patients infected with M. simiae subtype I.

Nontuberculous Mycobacteria in Humans, Animals, and Water in Zambia: A Systematic Review

Nontuberculous mycobacteria (NTM) are environmental opportunistic pathogens of humans and animals that are emerging with a serious public health impact particularly in individuals with Acquired Immunodeficiency Syndromes. Recent scientific evidence is shifting from NTMs being known as traditional environmental organisms to serious pathogenic organisms in both animals and humans. In humans, factors attributable to this rise have been linked mainly to Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome pandemic. In recent years there has been an increase in multidrug resistant Tuberculosis in Zambia and it is thought that NTMs could possibly be the cause. This study was therefore formulated to review available information on the prevalence of NTM in humans, animals and the environment, species distribution, zoonotic potential and public health importance in Zambia. This review was conducted in accordance with PRISMA guidelines. A literature search was done in PubMed and Google scholar using predefined search terms such as ‘nontuberculous mycobacteria’, ‘atypical mycobacteria’, ‘mycobacteria other than mycobacterium tuberculosis’ and ‘Zambia’, in combination with Boolean operators (AND, OR). This particular systematic review draws findings based on literature search between 2000 and 2020. Through literature search 243 papers were identified, 23 duplicates were identified and removed and 206 articles were excluded as they did not meet the inclusion criteria. The full text of the remaining 14 articles were considered for this review. The overall prevalence of NTM in humans was 24.39%, in water 21.5%, in animals 16.05% of which the prevalence in cattle was 14.81% and Kafue Lechwe 1.23%. Mycobacterium intracellulare was the most common isolated nontuberculous mycobacteria in humans and cattle while Mycobacterium gordonae was the most common in water, and Mycobacterium stomatepiae sp Nov in Kafue Lechwe. Nontuberculous mycobacteria are an emerging public health threat in Zambia both in humans and animals and this calls for the need for molecular information on the zoonotic transmission of nontuberculous mycobacteria. Increased awareness of nontuberculous mycobacteria diseases among clinicians and laboratory personnel is crucial for patient management and an essential step for facilitating the identification of nontuberculous mycobacteria species in laboratories.

The emerging role of exosomal miRNAs as a diagnostic and therapeutic biomarker in Mycobacterium tuberculosis infection

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), has been the world's driving fatal bacterial contagious disease globally. It continues a public health emergency, and around one-third of the global community has been affected by latent TB infection (LTBI). This is mostly due to the difficulty in diagnosing and treating patients with TB and LTBI. Exosomes are nanovesicles (40-100 nm) released from different cell types, containing proteins, lipids, mRNA, and miRNA, and they allow the transfer of one's cargo to other cells. The functional and diagnostic potential of exosomal miRNAs has been demonstrated in bacterial infections, including TB. Besides, it has been recognized that cells infected by intracellular pathogens such as Mtb can be secreting an exosome, which is implicated in the infection's fate. Exosomes, therefore, open a unique viewpoint on the investigative process of TB pathogenicity. This study explores the possible function of exosomal miRNAs as a diagnostic biomarker. Moreover, we include the latest data on the pathogenic and therapeutic role of exosomal miRNAs in TB.

The Use of Amikacin Liposome Inhalation Suspension (Arikayce) in the Treatment of Refractory Nontuberculous Mycobacterial Lung Disease in Adults

Nontuberculous mycobacteria (NTM) can cause and perpetuate chronic inflammation and lung infection. Despite having the diagnostic criteria, as defined by the American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA), clinicians find it challenging to diagnose and treat NTM-induced lung disease. Inhaled antibiotics are suitable for patients with lung infection caused by Pseudomonas aeruginosa and other organisms, but until recently, their utility in NTM-induced infection was not established. The most common NTM pathogens identified are the slow-growing Mycobacterium avium complex (MAC) and the rapid-growing M. abscessus complex (MABSC), both of which include several subspecies. Other less commonly isolated species include M. kansasii, M. simiae, and M. fortuitum. NTM strains are frequently more resistant than what is found in bacterial sputum cultures. Until recently, there was no approved inhaled antibiotic therapy for patients who were culture positive for pulmonary NTM infection. Of late, inhaled amikacin has been under investigation for the treatment of NTM-induced pulmonary infection. The FDA approved Arikayce (amikacin liposome inhalation suspension or ALIS) based on results from the ongoing Phase 3 CONVERT trial. In this study, the use of Arikayce met its primary endpoint of sputum culture conversion by the sixth month of treatment. The addition of Arikayce to guideline-based therapy led to negative sputum cultures for NTM by month 6 in 29% of patients compared to 8.9% of patients treated with guideline-based therapy alone. The effectiveness of Arikayce holds promise. However, due to limited data on Arikayce's safety, it is currently useful only for a specific population, particularly patients with refractory NTM-induced lung disease. Future trials must verify the target group and endorse the clinical benefits of Arikayce.

Prevalence of nontuberculous mycobacteria and high efficacy of d-cycloserine and its synergistic effect with clarithromycin against Mycobacterium fortuitum and Mycobacterium abscessus

Background

The prevalence of pulmonary disease caused by nontuberculous mycobacteria (NTM) is reportedly on the rise in the world. Some of the species are resistant to various antibiotics; hence, limited treatment options are available. The aims of this study were to investigate the prevalence of NTM and to determine the effect of d-cycloserine against Mycobacterium fortuitum and Mycobacterium abscessus isolated from clinical specimens to find out the synergistic effect of d-cycloserine and clarithromycin.

Methods

A total of 95 nonduplicate pulmonary isolates of NTM were collected from three major Regional Tuberculosis (TB) Centers. NTM isolates were identified by conventional tests and PCR sequence analysis of the rpoB gene. PCR sequencing of erm-41 was performed for detecting the inducible resistance to macrolides. In vitro susceptibilities and activities of d-cycloserine-clarithromycin combinations were accessed using the broth microdilution method.

Results

Among 714-positive acid-fast bacilli from TB-suspected cases, 95 isolates were identified as NTM (13.3%). The prevalence of identified isolates was as follows: M. fortuitum 46 (48.4%), Mycobacterium simiae 16 (16.8%), Mycobacterium kansasii 15 (15.7%), M. abscessus 7 (7.3%), Mycobacterium thermoresistibile 4 (4.2%), Mycobacterium elephantis 3 (3.2%), Mycobacterium porcinum 2 (2.1%), and Mycobacterium chimaera 2 (2.1%). In addition, rpoB sequence analysis could identify all NTM isolates. The effect of d-cycloserine was better than that of clarithromycin. The synergistic effect of d-cycloserine with clarithromycin was observed for six (100%) and five (71.5%) strains of M. fortuitum and M. abscessus, respectively.

Conclusion

In the present study, we demonstrated a wide range of NTM in processed samples from different provinces of Iran. Our observations indicated that d-cycloserine was very active against M. abscessus and M. fortuitum; hence, d-cycloserine, either alone or in combination with clarithromycin, may be promising for the treatment of M. abscessus- and M. fortuitum-associated diseases.

Epidemiology of and risk factors for extrapulmonary nontuberculous mycobacterial infections in Northeast Thailand

Background

Nontuberculous mycobacterial (NTM) infection is increasing worldwide. Current epidemiological data and knowledge of risk factors for this disease are limited. We investigated the trends in and risk of NTM infection in Northeast Thailand during 2012–2016.

Methods

Patient demographics, infection site(s), and underlying disease or conditions from 530 suspected cases of NTM infections were retrieved from medical records, reviewed and analyzed. A diagnosis of true NTM infection was accepted in 150 cases. Risk factor analyses were done for extrapulmonary NTM infections compared to pulmonary NTM infections and for Mycobacterium abscessus compared to members of the Mycobacterium avium complex (MAC). Trend analysis among NTM species causing NTM infections was performed.

Results

The most common species of NTMs causing extrapulmonary (n = 114) and pulmonary (n = 36) NTM infections in Northeast Thailand were M. abscessus (25.4% of extrapulmonary infected cases and 27.8% of pulmonary cases) followed by MAC (14.9% of extrapulmonary and 13.9% of pulmonary cases). Presence of anti-IFN-γ autoantibodies was the major risk factor for extrapulmonary (odds ratio (OR) = 20.75, 95%CI [2.70–159.24]) compared to pulmonary NTM infection. M. abscessus infection was less likely (OR = 0.17; 95%CI [0.04–0.80]) to be found in patients with HIV infection than was MAC infection. The prevalence of NTM infection, especially M. abscessus, in Northeast Thailand has recently increased. Extrapulmonary NTM and complicated NTM infections have increased in concordance with the recent trend of increasing frequency of anti-IFN-γ autoantibodies in the population.

Conclusions

M. abscessus was the commonest NTM pathogen followed by MAC. The prevalence of NTM infections and anti-IFN-γ are showing an upward trend. Autoimmune disease due to anti-IFN-γ is the major risk factor for extrapulmonary NTM infection in Northeast Thailand.

Characterization of non-tuberculous mycobacterium from humans and water in an Agropastoral area in Zambia

Background

The non-tuberculous mycobacteria include those mycobacterium species that are not members of the Mycobacterium tuberculosis complex, the causative agent of pulmonary tuberculosis and Mycobacterium leprae. In Zambia, Non-tuberculous Mycobacteria are gaining recognition as pathogens of public health significance. However, there is scanty information on the isolation and speciation of these organisms for better patient management, consequently reducing the burden of these infections. Given the above information, the thrust of this study was to isolate and characterize NTM from humans and water in Namwala district of Zambia.

Method

This was a cross-sectional study were 153 individuals with suspected TB were sampled from four health facilities in Namwala district, sputum samples were also collected. Additionally, 149 water samples were collected from different water drinking sources such as Tap water, Borehole water, rivers, wells and streams. Standard TB culture methods were employed to isolate Non-tuberculous Mycobacteria and later 16S–23S internal transcribed spacer region Sequencing was employed to characterize NTM.

Results

Seven (7, 4.6%) NTM species were identified from humans with M. arupense (3, 42.9%) being the most common organism, while twenty three (23, 15.4%) NTM were identified from water with the common species being Mycobacterium gordonae (5, 21.7%). Mycobacterium avium and Mycobacterium fortuitum were both identified from human and water samples.

Conclusion

This study has shown the isolation of NTM species from humans and water. The isolation of NTM from drinking water sources could signify a public health risk to humans.

Body habitus in patients with and without bronchiectasis and non-tuberculous mycobacteria

Background

Female gender, tall stature, presence of bronchiectasis are associated with pulmonary nontuberculous mycobacterial (NTM) infections. The biologic relationship between the body habitus and NTM infection is not well defined and the body habitus profile of the patients with NTM and concurrent bronchiectasis is completely unknown.

Methods

We conducted a case control study at the Miami VA Healthcare System and the University of Illinois Medical Center on patients with pulmonary NTM infections between 2010 and 2015. We compared pulmonary NTM subjects with and without bronchiectasis. NTM infection was confirmed by using the American Thoracic Society/ Infectious Disease Society of America criteria. Standard radiological criteria were used to define bronchiectasis in chest CT-scan.

Results

Two hundred twenty subjects with pulmonary NTM were enrolled in the study. Sixty six subjects (30%) had bronchiectasis on CT scan of the chest. Subjects in the bronchiectasis group included more women (p = 0.002) and were significantly older (p = 0.005). Those patients who had bronchiectasis tended to have a significantly lower weight (less than 50kg) and height ≤155 cm (p <0.0001 and p = 0.018, respectively). Kaplan–Meier analysis confirmed that subjects who had bronchiectasis were shorter and weighed less, after adjusting for gender.

Conclusions

This study defines a new sub-phenotype of NTM subjects with bronchiectasis who tend to be short with lower body weight. Further studies are needed to better understand and define the body habitus profiles of this new sub-phenotype and their clinical implications.

High rates of nontuberculous mycobacteria isolation from patients with presumptive tuberculosis in Iran

Nontuberculous mycobacteria (NTM) can cause disease which can be indistinguishable from tuberculosis (TB), posing a diagnostic and therapeutic challenge, particularly in low- and middle-income settings. We aimed to investigate the mycobacterial agents associated with presumptive clinical pulmonary TB in Iran. A total of 410 mycobacterial isolates, obtained between March 2014 and January 2016, from 7600 clinical samples taken from consecutive cases of presumptive diagnosis of TB were identified. Phenotypic and molecular tests were used to identify the isolated organisms to the species level. Single-locus and multilocus sequence analysis based on 16S rRNA, rpoB, hsp65 and ITS locus were used to confirm the results. Of 410 consecutive strains isolated from suspected TB subjects, 62 isolates (15.1%) were identified as NTM. Patients with positive NTM cultures met American Thoracic Society diagnostic criteria for NTM disease. Mycobacterium simiae was the most frequently encountered (38.7%), followed by Mycobacterium fortuitum (19.3%), M. kansasii (17.7%) and M. avium complex (8.0%). Isolation of NTM, including M. simiae, from suspected TB cases is a serious public health problem and merits further attention by health authorities, physicians and microbiologists.

Association of Interferon-γ Receptor-1 Gene Polymorphism with Nontuberculous Mycobacterial Lung Infection among Iranian Patients with Pulmonary Disease

Nontuberculous mycobacteria (NTM) cause significant pulmonary infections in humans. Researchers have reported an association between interferon-gamma receptor-1 (IFN-γR1 or IFNGR1) deficiency and susceptibility to NTM, but the relevance of polymorphism within these genes is not yet clear. In this study, a single nucleotide polymorphism (SNP), T to C, at position-56 in NTM patients with pulmonary disease was investigated. Molecular identification of Mycobacterium isolates was performed with hsp65 genes using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Then, the host genomic DNA from confirmed NTM patients (N = 80) and control subjects (N = 80) were screened for SNPs of IFNGR1 (T-56C) by PCR-RFLP. The results indicated that NTM patients had higher TC (26/80; 32.5%) or CC (46/80; 57.5%) genotypes in comparison with control groups (TC genotypes [22/80, 27.5%]; CC genotypes [6/80, 7.5%]) (P < 0.05). In this regard, all the patients infected with rapid-growing Mycobacterium (RGM, i.e., Mycobacterium chelonae and Mycobacterium fortuitum) had CC genotypes (100%). In contrary, only 50.7% (35/69) of infected patients with slow-growing Mycobacterium (i.e., Mycobacterium simiae, Mycobacterium kansasii, and Mycobacterium avium-intracellulare) had CC genotypes. Thus, patients with CC mutation in IFNGR1 at position-56 are more likely to develop RGM infection. In overall, there is a significant association between SNP of IFNGR1 at position-56 and susceptibility to NTM infection. Based on these data, we propose SNP of IFNGR1 at position-56 as a suitable "biomarker" for identifying populations at higher risk of infection.

Molecular identification and distribution of non-tuberculous mycobacteria isolated from clinical specimens by PCR-sequencing method in West of Iran

BACKGROUND AND AIMS

Infections by non-tuberculous mycobacteria (NTM) has rapidly increased in recent years, due to high infection rates related to the populations at risk like immunocompromised individuals, patients predisposed by prior pulmonary. The aim of this study was to investigate the presence of NTM in clinical samples and genetic diversity using 16S rRNA and rpoB sequence analysis.

METHODS

A cross-sectional study was conducted on 45 diverse isolates collected from sputum in 2 years 2014-2015 using standard decontamination procedure. All mycobacterial isolates were grown on LJ medium and also conventional tests for preliminary identification of mycobacteria rely on traits and then DNA extraction. PCR was performed, and sequencing of 16S rRNA and rpoB genes was applied for NTM strains identification.

RESULTS

A total of 45 isolates collected, 37 samples (83%) were evaluated as NTM. All NTM strains using molecular methods by sequencing 16S rRNA and rpoB gene were identified, by this way 12 different species have been identified which sequencing of rpoB was able to identify all species. The major species obtained were Mycobacterium simiae (22%), M. fortuitum (19%), and M. abscessus (13%).

CONCLUSIONS

The results of our study showed that the patients were infected by a wide range of atypical mycobacteria. It was concluded that 16S rRNA gene sequencing coupled with rpoB marker is a high discriminatory power in identification of NTM. The presence of various species in clinical samples in Iran emphasizes the use of molecular method like sequence analysis of genes is necessary for reliable identification.

Mycobacterium vaccae induces a strong Th1 response that subsequently declines in C57BL/6 mice

Mycobacterium (M.) vaccae is a fast-growing species of saprophytic bacteria that is widely distributed. To understand the host immune responses induced by M. vaccae isolated from bovine submaxillary lymph nodes, C57BL/6 mice were infected with reference strain M. bovis Bacillus Calmette-Guérin (BCG) and isolated M. vaccae using intraperitoneal injections. Comparison of the bacterial replication and organ pathology between M. vaccae and M. bovis BCG revealed that M. vaccae was more malignant than M. bovis in mice. We also demonstrated that serum from the M. vaccae-infected mice contained a higher expression level of gamma-interferon (IFN-γ), tumor necrosis factor alpha, monocyte chemoattractant protein-1, interleukin (IL)-4, IL-12, IL-10 and transforming growth factor beta than did the other groups, especially after week 4. Furthermore, when the numbers of CD3⁺CD4⁺IFN-γ⁺ and CD3⁺CD4⁺IL4⁺cells in the infected mice were observed by flow cytometry, we found that a powerful T helper 1 (Th1) response was induced by M. vaccae infection, which was associated with the emergence of CD3⁺CD4⁺IFN-γ⁺cells. However, the Th1 response declined over time, which was associated with appearance of the CD4⁺CD25⁺FoxP3⁺ and CD4⁺CD25⁺CD152⁺Treg cell reaction. In addition, a strong Th2 response was found. Finally, we found that M. vaccae infection increased the production of type I IFNs, which was associated with a reduced Th1 response.

Prevalence of nontuberculous mycobacteria isolated from environmental samples in Iran: A meta-analysis

BACKGROUND

While the most nontuberculous mycobacteria (NTMs) species are considered as opportunistic pathogens, some of them are related to several human infections. It is believed that environment is the main source for these infections. Distribution and scattering pattern of NTMs has not been well studied in Iran and a few studies about this subject have been done, so the aim of this study was to determine prevalence of NTMs in environmental samples from Iran.

MATERIALS AND METHODS

Data about prevalence of NTMs in environmental samples from Iran were obtained by searching databases. The studies presenting cross-sectional or cohort and the papers with sample size ≥30 were included. Then, the meta-analysis was performed using Comprehensive Meta-Analysis software and Cochran's Q and I² tests. The strategy search was based PRISMA protocol is available online (PRISMA, http://www.prisma-statement.org).

RESULTS

The results of this meta-analysis showed that overall combined prevalence of NTMs in environmental samples from Iran was 38.3%. The frequency of NTM was higher in the north of Iran (73.2%). The most prevalent rapid-growing mycobacterium was Mycobacterium fortuitum (19.8%), and the most dominant slow-growing mycobacterium was Mycobacterium flavescens (16.8%).

CONCLUSION

In regard to increasing incidence of disease in immunocompromised patients and existence of different types of mycobacteria species in environmental samples, efforts should be focused on measures that will specifically remove NTMs from habitats where susceptible individuals are exposed.

Distribution of non-tuberculosis mycobacteria strains from suspected tuberculosis patients by heat shock protein 65 PCR-RFLP

The genus Mycobacterium contains more than 150 species. Non-tuberculosis mycobacteria (NTM) often cause extrapulmonary and pulmonary disease. Mycobacteria detection at species level is necessary and provides useful information on epidemiology and facilitates successful treatment of patients. This retrospective study aimed to determine the incidence of the NTM isolates and Mycobacterium tuberculosis (Mtb) in clinical specimens collected from Iranian patients during February 2011–December 2013, by PCR–restriction fragment length polymorphism analysis (PRA) of the hsp65 gene. We applied conventional biochemical test and hsp65–PRA identification assay to identify species of mycobacteria in specimens from patients suspected of having mycobacterial isolates. This method was a sensitive, specific and effective assay for detecting mycobacterial species and had a 100% sensitivity and specificity for Mtb and Mycobacterium avium complex (MAC) species. Using PRA for 380 mycobacterial selected isolates, including 317 Mtb, four Mycobacterium bovis and of the 59 clinical isolates, the most commonly identified organism was Mycobacterium kansasii (35.6%), followed by Mycobacterium simiae (16.9%), Mycobacterium gordonae (16.9%), Mycobacterium fortuitum (5.1%), Mycobacterium intracellulare (5.1%), Mycobacterium avium (5.1%), Mycobacterium scrofulaceum (3.4%), Mycobacterium gastri (3.4%), Mycobacterium flavescens (3.4%), Mycobacterium chelonae (3.4%) and Mycobacterium nonchromogenicum (1.7%). PRA method, in comparison with classical methods, is rapid, useful and sensitive for the phylogenetic analysis and species detection of mycobacterial strains. Mycobacterium kansasii is the most common cause of infection by NTM in patients with non-HIV and HIV which demonstrated a high outbreak and diversity of NTM strains in our laboratory.