Clinical characteristics and treatment outcomes of patients with macrolide-resistant Mycobacterium avium complex pulmonary disease: a systematic review and meta-analysis

Clinical and genomic features of Mycobacterium avium complex: a multi-national European study

BACKGROUND

The Mycobacterium avium complex (MAC) comprises the most frequent non-tuberculous mycobacteria (NTM) in Central Europe and currently includes twelve species. M. avium (MAV), M. intracellulare subsp. intracellulare (MINT), and M. intracellulare subsp. chimaera (MCH) are clinically most relevant. However, the population structure and genomic landscape of MAC linked with potential pathobiological differences remain little investigated.

METHODS

Whole genome sequencing (WGS) was performed on a multi-national set of MAC isolates from Germany, France, and Switzerland. Phylogenetic analysis was conducted, as well as plasmids, resistance, and virulence genes predicted from WGS data. Data was set into a global context with publicly available sequences. Finally, detailed clinical characteristics were associated with genomic data in a subset of the cohort.

RESULTS

Overall, 610 isolates from 465 patients were included. The majority could be assigned to MAV (n = 386), MCH (n = 111), and MINT (n = 77). We demonstrate clustering with less than 12 SNPs distance of isolates obtained from different patients in all major MAC species and the identification of trans-European or even trans-continental clusters when set into relation with 1307 public sequences. However, none of our MCH isolates clustered closely with the heater-cooler unit outbreak strain Zuerich-1. Known plasmids were detected in MAV (325/1076, 30.2%), MINT (62/327, 19.0%), and almost all MCH-isolates (457/463, 98.7%). Predicted resistance to aminoglycosides or macrolides was rare. Overall, there was no direct link between phylogenomic grouping and clinical manifestations, but MCH and MINT were rarely found in patients with extra-pulmonary disease (OR 0.12 95% CI 0.04-0.28, p < 0.001 and OR 0.11 95% CI 0.02-0.4, p = 0.004, respectively) and MCH was negatively associated with fulfillment of the ATS criteria when isolated from respiratory samples (OR 0.28 95% CI 0.09-0.7, p = 0.011). With 14 out of 43 patients with available serial isolates, co-infections or co-colonizations with different strains or even species of the MAC were frequent (32.6%).

CONCLUSIONS

This study demonstrates clustering and the presence of plasmids in a large proportion of MAC isolates in Europe and in a global context. Future studies need to urgently define potential ways of transmission of MAC isolates and the potential involvement of plasmids in virulence.

Characterisation and antimicrobial susceptibility pattern of non-tuberculous mycobacteria

Background

Non-tuberculous mycobacteria (NTM) management comprises prolonged therapy that includes macrolides. Non-tuberculous mycobacteria can cause disease in patients with predisposing conditions such as HIV and structural lung disease. Local data on NTM disease and macrolide resistance are scarce, and routine antimicrobial susceptibility testing is currently not performed for NTM in South Africa.

Objectives

This study aims to characterise NTM isolated at Tshepong National Health Laboratory Service (NHLS) according to species and antimicrobial susceptibility pattern.

Method

A retrospective data analysis of NTM isolates from Tshepong NHLS was performed from January to June 2020. GenoType® NTM-DR was performed on selected isolates where the assay can confirm the species and determine resistance to macrolides and aminoglycosides.

Results

Of the 194 collected NTM isolates, 183 were included in the study. Patients' ages ranged from 1 day to 81 years (median 36 years). The most common specimen was sputum (84.7%), followed by gastric aspirate (6.6%). The most common NTM isolated were Mycobacterium (M.) intracellulare (67.6%), M. fortuitum (12.6%), M. species (4.3%), M. kansasii (3.9%), and M. scrofulaceum (3.9%). Macrolide resistance occurred in 2.8% of tested isolates; no aminoglycoside resistance was detected. Although most isolates were from males (62.3%), resistance was observed only in females.

Conclusion

M. intracellulare predominated, with only two M. intracellulare and two M. abscessus isolates showing macrolide resistance; aminoglycoside resistance was absent.

Contribution

This study highlights the need for increased awareness of NTM, regular nationwide NTM surveillance, and monitoring of resistance trends to guide future patient management and ensure good treatment outcomes.

Treatment of Mycobacterium avium Complex Pulmonary Disease: When Should I Treat and What Therapy Should I Start?

Treatment of M avium pulmonary disease requires a three-drug, macrolide-based regimen that is administered for 12 months beyond culture conversion. The regimen can be administered 3 days a week in non-cavitary, nodular bronchiectatic disease but should be given daily when cavitary disease is present. For treatment refractory disease, amikacin liposome inhalation suspension is added to the regimen. Parenteral amikacin or streptomycin should be administered in the setting of extensive radiographic involvement or macrolide resistance. Recurrence of disease is common and often due to reinfection. Novel and repurposed agents are being evaluated in clinical trials.

Non-tuberculous mycobacterial disease: progress and advances in the development of novel candidate and repurposed drugs

Non-tuberculous mycobacteria (NTM) are opportunistic pathogens that can infect all body tissues and organs. In particular, the lungs are the most commonly involved organ, with NTM pulmonary diseases causing serious health issues in patients with underlying lung disease. Moreover, NTM infections have been steadily increasing worldwide in recent years. NTM are also naturally resistant to many antibiotics, specifically anti-tuberculosis (anti-TB) drugs. The lack of drugs targeting NTM infections and the increasing drug resistance of NTM have further made treating these mycobacterial diseases extremely difficult. The currently recommended NTM treatments rely on the extended indications of existing drugs, which underlines the difficulties of new antibiotic discovery against NTM. Another challenge is determining which drug combinations are most effective against NTM infection. To a certain extent, anti-NTM drug development depends on using already available antibiotics and compounds. Here, we aimed to review new antibiotics or compounds with good antibacterial activity against NTM, focusing on their mechanisms of action, in vitro and in vivo antibacterial activities.

Monotherapy: Key cause of macrolide-resistant Mycobacterium avium complex disease

BACKGROUND

Macrolide-resistant Mycobacterium avium complex (MAC) disease is very difficult to cure. Macrolide-resistance emerges in patients and is largely preventable by appropriate screening and treatment practices.

METHODS

Patients with macrolide-resistant MAC isolates between March 2019 and March 2022 were retrieved from the mycobacteriology reference laboratory database at Radboudumc, Nijmegen, the Netherlands. Clinical consultation reports were extracted from the database to assess the cause of macrolide resistance.

RESULTS

Sixteen patients with macrolide-resistant MAC disease were included, from a total of 815 patients with MAC isolates (2%); Macrolide monotherapy in bronchiectasis or CF was the most frequent cause of development of macrolide-resistance MAC disease (n = 8; 50%). Short (n = 3; mean duration 9 months, range 6-12) or guideline non-compliant (n = 2) treatment regimens and patient non-adherence (n = 2) were other key causes of macrolide-resistance.

CONCLUSIONS

Macrolide monotherapy after inappropriate screening is the most frequent cause of macrolide-resistant Mycobacterium avium complex disease in the Netherlands. Educational efforts are needed to prevent this.

A narrative review of nontuberculous mycobacterial pulmonary disease: microbiology, epidemiology, diagnosis, and management challenges

INTRODUCTION

Nontuberculous mycobacteria (NTM) are a diverse group of mycobacterial species that are ubiquitous in the environment. They are opportunistic pathogens that can cause a range of diseases, especially in individuals with underlying structural lung disease or compromised immune systems.

AREAS COVERED

This paper provides an in-depth analysis of NTM infections, including microbiology, environmental sources and transmission pathways, risk factors for disease, epidemiology, clinical manifestations and diagnostic approaches, guideline-based treatment recommendations, drugs under development, and management challenges.

EXPERT OPINION

Future approaches to the management of NTM pulmonary disease will require therapies that are well tolerated, can be taken for a shorter time period and perhaps less frequently, have few drug-drug interactions, and are active against the various strains of pathogens. As the numbers of infections increase, such therapies will be welcomed by clinicians and patients.

Amikacin liposome and Mycobacterium avium complex: A systematic review

INTRODUCTION

The prevalence of Mycobacterium avium complex (MAC) is increasing globally. Macrolide-based multidrug regimens have been recommended as the first-line treatment for patients with MAC pulmonary disease. However, developing macrolide resistance was associated with poor treatment outcomes and increased mortality. In 2018, the U.S. Food and Drug Administration approved liposomal amikacin for inhalation (LAI) to treat refractory MAC pulmonary disease. The current systematic review aimed to evaluate LAI's outcomes and adverse events in MAC pulmonary disease.

METHODS

The systematic search was performed in PubMed/Medline, EMBASE, and the Cochrane Controlled Register of Trials (CENTRAL) up to March 8, 2022. The search terms included Mycobacterium avium complex, MAC, amikacin, and liposomal amikacin.

RESULTS

After reviewing 1284 records, four papers met the inclusion criteria, including three clinical trials and one prospective cohort study. These studies showed that adding LAI to guideline-based therapies can increase sputum culture conversion rate and achieve early sustained (negative sputum culture results for 12 months with treatment) and durable (negative sputum culture results for three months after treatment) negative sputum culture. In addition, extended LAI use was a potential benefit in patients considered refractory to initial treatment. The most prevalent treatment-emergent adverse events (TEAE) reported in the LAI group were the respiratory TEAE.

CONCLUSIONS

LAI could increase the sputum culture conversion rate and achieve early sustainable, durable negative sputum culture. However, additional large-scale research is required to confirm the results.

Nontuberculous Mycobacteria Lung Disease (NTM-LD): Current Recommendations on Diagnosis, Treatment, and Patient Management

Nontuberculous mycobacteria (NTM) are a group of ubiquitous environmental bacteria that can be found in soil, dust, and water. Mycobacterium avium complex (MAC) is the most common pathogen and the one most associated with chronic pulmonary disease. In recent years, the prevalence of Mycobacterium avium complex-related pulmonary disease (MAC-PD) has increased and is an emerging public health concern. This is due to a combination of environmental and geographic factors, dynamic changes in organism virulence and antimicrobial susceptibility, and evolving host susceptibility. Given the dynamic nature of the disease, management of NTM pulmonary disease (NTM-PD) often includes a multimodal approach including antimicrobial therapy, airway clearance techniques, limiting environmental exposures, and reducing susceptibility to NTM through prevention of reflux and maintenance of body weight. This review will explore the most recent concepts in the diagnosis, treatment, and management of individuals with NTM pulmonary infection.

Pharmacologic management of Mycobacterium chimaera Infections: A Primer for Clinicians

Mycobacterium chimaera, a member of the Mycobacterium avium complex, can cause infections in individuals after open heart surgery due to contaminated heater-cooler units. The diagnosis can be challenging, as the incubation period can be quite variable, and symptoms are nonspecific. In addition to aggressive surgical management, combination pharmacologic therapy is the cornerstone of therapy, which should consist of a macrolide, a rifamycin, ethambutol, and amikacin. Multiple second-line agents may be utilized in the setting of intolerances or toxicities. In vitro susceptibility of these agents is similar to activity against other species in the Mycobacterium avium complex. Drug–drug interactions are frequently encountered, as many individuals have chronic medical comorbidities and are prescribed medications that interact with the first-line agents used to treat M. chimaera. Recognition of these drug–drug interactions and appropriate management are essential for optimizing treatment outcomes.

Case studies to illustrate good practice in the management of non-tuberculous mycobacterial pulmonary disease

Pulmonary disease caused by non-tuberculous mycobacteria (NTM-PD) can be a complex condition for health care providers to manage, and delayed diagnosis and treatment failure are common. Here we present three case studies that illustrate key challenges in the diagnosis and treatment of NTM-PD, and provide guidance on these issues. In addition, we make recommendations on how the overall management of NTM-PD may be improved, through strategies such as physician education to recognise NTM-PD, and the development of multidisciplinary teams and patient-support groups.

Management of Mycobacterium avium complex and Mycobacterium abscessus pulmonary disease: therapeutic advances and emerging treatments

Nontuberculous mycobacterial pulmonary disease (NTM-PD) remains a challenging condition to diagnose and treat effectively. Treatment of NTM-PD is prolonged, frequently associated with adverse effects and has variable success. In this review, we consider the factors influencing clinicians when treating NTM-PD and discuss outcomes from key studies on the pharmacological management of Mycobacterium avium complex pulmonary disease and M. abscessus pulmonary disease. We highlight issues relating to treatment-related toxicity and provide an overview of repurposed and emerging therapies for NTM-PD.

Importance of asking a social history: atypical pulmonary infections and occupational hazards

Non-tuberculous mycobacteria (NTM) are ubiquitous in the environment, but NTM infection is limited to individuals with risk factors. We present a case of a 62-year-old man who presented with a 1 year history of cough and shortness of breath. History was notable for significant tobacco use and work as a sandblaster without the use of personal protective equipment. His chest X-ray showed bilateral upper lobe cavitary lesions, which were redemonstrated on chest CT. A sputum Gram stain was positive for acid-fast bacilli, but his tuberculosis QuantiFERON was negative. He was started on empiric tuberculosis treatment. Sputum cultures ultimately returned for Mycobacterium avium intracellulare complex, and treatment was narrowed to azithromycin, rifampin and ethambutol. The case highlights risk factors for NTM infection, notably for this patient, occupational exposures that likely lead to the development of pneumoconiosis. Healthcare providers should ask about occupational history and counsel patients about protection from occupational hazards.

Pulmonary Nontuberculous Mycobacterial Infection in Infants: A Systematic Review

Limited information and literature exist examining pulmonary infections caused by nontuberculous mycobacterial specifically in an infant population. The objective of our study was to summarize clinical characteristics and outcomes of infant patients with nontuberculous mycobacterial pulmonary infection via systematic literature review to identify common diagnostic and treatment regimens for this infection in infants. A search of MEDLINE and PubMed databases in October 2019 using MeSH search terms “infant,” “NTM,” “pulmonary,” and “Mycobacterium abscessus” yielded 139 articles. Inclusion criteria were i) English-language studies including cases and case series with ii) established nontuberculous mycobacterial pulmonary infection in iii) a patient population of infants no older than 24 months. Patients with cystic fibrosis and any study which did not contain relevant information such as infection and age were excluded. This yielded data on 37 patients extracted from 28 studies analyzed. The most common strain was Mycobacterium avium complex, isolated in 56.8% of patient diagnoses. Bronchoscopy/thoracoscopy with a subsequent culture were the most common diagnostic techniques, utilized in 64.9% of cases. Drug therapeutic treatment was utilized in 86% of cases, with a median of three drugs administered. Notable limitations of this study are the small sample size and its retrospective nature, which relies on information reported in previous case studies. Although there is limited formal clinician consensus on the treatment of NTM pulmonary infection and how it may differ in an infant population, our findings indicate an informal consensus typically involving diagnostic lung specimen culture and antibiotic therapy.

Exploring Potential COPD Immunosuppression Pathways Causing Increased Susceptibility for MAC Infections among COPD Patients

Although there has been a drastic decline in the cases of Tuberculosis in the United States, the prevalence of infections caused by Mycobacterium avium Complex (MAC) has steadily increased in the past decades. Mycobacterium avium (M. avium) is one of the most abundant microorganisms in the MAC species. The mycobacterium genus is divided into two major groups: tuberculosis causing mycobacteria and non-tuberculous mycobacteria. MAC is most prominent among the non-tuberculous mycobacteria. MAC is an opportunistic pathogen that is present in soil, water, and droplets in the air. MAC infections can result in respiratory disease and can disseminate in affected patients. MAC infections are especially prevalent in patients with preexisting respiratory conditions such as Chronic Obstructive Pulmonary Disease (COPD). COPD is one of the most common lung conditions in the world with the primary cause being smoking in developed countries. COPD involves chronic inflammation of lung tissue resulting in increased susceptibility to infection. There is a lack of research regarding the pathophysiology that leads COPD patients to be susceptible to MAC infection. Our review paper therefore aims to investigate how the pathogenicity of MAC bacteria and immune decline seen in COPD patients leads to a greater susceptibility to MAC infection among COPD patients.

Liposomal drug delivery to manage nontuberculous mycobacterial pulmonary disease and other chronic lung infections

Nontuberculous mycobacterial (NTM) pulmonary disease is a chronic respiratory infection associated with declining lung function, radiological deterioration and significantly increased morbidity and mortality. Patients often have underlying lung conditions, particularly bronchiectasis and COPD. NTM pulmonary disease is difficult to treat because mycobacteria can evade host defences and antimicrobial therapy through extracellular persistence in biofilms and sequestration into macrophages. Management of NTM pulmonary disease remains challenging and outcomes are often poor, partly due to limited penetration of antibiotics into intracellular spaces and biofilms. Efficient drug delivery to the site of infection is therefore a key objective of treatment, but there is high variability in lung penetration by antibiotics. Inhalation is the most direct route of delivery and has demonstrated increased efficacy of antibiotics like amikacin compared with systemic administration. Liposomes are small, artificial, enclosed spherical vesicles, in which drug molecules can be encapsulated to provide controlled release, with potentially improved pharmacokinetics and reduced toxicity. They are especially useful for drugs where penetration of cell membranes is essential. Inhaled delivery of liposomal drug solutions can therefore facilitate direct access to macrophages in the lung where the infecting NTM may reside. A range of liposomal drugs are currently being evaluated in respiratory diseases.

Liposome-encapsulated antibiotics can optimise respiratory disease treatment. Amikacin liposomal inhalation suspension is effective in nontuberculous mycobacterial pulmonary disease that has failed to convert following oral guideline-based therapy.https://bit.ly/3f3ixIu

Population Pharmacokinetic Analysis of Bedaquiline-Clarithromycin for Dose Selection Against Pulmonary Nontuberculous Mycobacteria Based on a Phase 1, Randomized, Pharmacokinetic Study

Based on the in vitro profile of bedaquiline against mycobacterial species, it is being investigated for clinical efficacy against pulmonary nontuberculous mycobacteria (PNTM). Being a cytochrome P450 3A substrate, pharmacokinetic interactions of bedaquiline are anticipated with clarithromycin (a cytochrome P450 3A inhibitor), which is routinely used in pulmonary nontuberculous mycobacteria treatment. This phase 1, randomized, crossover study assessed the impact of steady-state clarithromycin (500 mg every 12 hours for 14 days) on the pharmacokinetics of bedaquiline and its metabolite (M2) after single-dose bedaquiline (100 mg; n  =  16). Using these data, population pharmacokinetic modeling and simulation analyses were performed to determine the effect of clarithromycin on steady-state bedaquiline exposure. Although no effect was observed on maximum plasma concentration of bedaquiline and time to achieve maximum plasma concentration, its mean plasma exposure increased by 14% after 10 days of clarithromycin coadministration, with slower formation of M2. Simulations showed that bedaquiline plasma trough concentration at steady state was higher (up to 41% until week 48) with clarithromycin coadministration as compared to its monotherapy (400 mg once daily for 2 weeks, followed by 200 mg 3 times a week for 46 weeks; reference regimen). The overall exposure of a simulated bedaquiline regimen (400 mg once dialy for 2 weeks, followed by 200 mg twice a week for 46 weeks) with clarithromycin was comparable (<15% difference) to the monotherapy. Overall, combination of bedaquiline (400 mg once daily for 2 weeks, followed by 200 mg twice a week for 46 weeks) with clarithromycin seems a suitable regimen to be explored for efficacy and safety against pulmonary nontuberculous mycobacteria.

A tale of two images: From mycobacterium avium complex-lung disease (MAC-LD) to mycobacterium avium complex-pleural disease

The typical radiographic presentation for Mycobacterium avium complex lung disease (MAC-LD) is either nodular bronchiectasis or cavitary lung disease. The former is seen most commonly in middle-aged or elderly Caucasian females with the characteristic asthenic phenotype, and the latter in middle-aged male smokers with COPD. We present the case of a young, otherwise healthy woman, with no significant risk factors, who was incidentally found to have MAC-LD with associated bronchiectasis. The patient's treatment and clinical course over a period of 5 years was marred by erratic follow up, intermittent treatment and poor adherence to guideline-based antibiotic therapy. Over this period of time, the patient developed significant worsening of her MAC-LD, macrolide resistance and failure to thrive. Upon presentation 5 years after her initial diagnosis, she had developed MAC-Pleural Disease with an empyema and broncho-pleural fistula. This case illustrates the progression of MAC-LD from nodular bronchiectasis to cavitary disease and pleural involvement leading to clinical deterioration. It highlights challenges related to short and long term management of macrolide resistant MAC-LD and the importance and need for surgical intervention and drainage procedures in patient with MAC-Pleural Disease.

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Non-Adherence to comprehensive guideline based therapy contribute to disease progression in patients with MAC-LD.

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Untreated or erratically treated MAC-LD can progress to MAC-PD in immunocompetent hosts with no underlying risk factors.

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A combined medical and surgical approach is essential in managing patients with MAC-PD.

Novel therapies for treatment of resistant and refractory nontuberculous mycobacterial infections in patients with cystic fibrosis

Respiratory infections caused by non-tuberculous mycobacteria (NTM) are a major cause of morbidity for patients living with cystic fibrosis (CF), as NTM pulmonary disease (NTM-PD) is challenging to both diagnose and eradicate. Despite the lengthy courses of the established regimens recommended by the Cystic Fibrosis Foundation (CFF) and European Cystic Fibrosis Society (ECFS) consensus guidelines, only about 50% to 60% of patients achieve culture conversion, and treatment regimens are often complicated by antibiotic resistance and toxicities. Since publication of the CFF/ECFS guidelines, several new or alternative antibiotic regimens have been described for patients with CF who have NTM-PD. These regimens offer new options for patients who do not clear NTM with standard therapies or cannot utilize the usual regimens due to toxicities or drug-drug interactions.

Exposure of Mycobacterium avium subsp. homonissuis to Metal Concentrations of the Phagosome Environment Enhances the Selection of Persistent Subpopulation to Antibiotic Treatment

Mycobacterium avium subspecies hominissuis (MAH) is an opportunistic intracellular pathogen causing infections in individuals with chronic lung conditions and patients with immune-deficient disorders. The treatment of MAH infections is prolonged and outcomes many times are suboptimal. The reason for the extended treatment is complex and reflects the inability of current antimicrobials to clear diverse phenotypes of MAH quickly, particularly, the subpopulation of susceptible but drug-tolerant bacilli where the persistent fitness to anti-MAH drugs is stimulated and enhanced by the host environmental stresses. In order to enhance the pathogen killing, we need to understand the fundamentals of persistence mechanism and conditions that can initiate the drug-tolerance phenotype in mycobacteria. MAH can influence the intracellular environment through manipulation of the metal concentrations in the phagosome of infected macrophages. While metals play important role and are crucial for many cellular functions, little is known how vacuole elements influence persistence state of MAH during intracellular growth. In this study, we utilized the in vitro model mimicking the metal concentrations and pH of MAH phagosome at 1 h and 24 h post-infection to distinguish if metals encountered in phagosome could act as a trigger factor for persistence phenotype. Antibiotic treatment of metal mix exposed MAH demonstrates that metals of the phagosome environment can enhance the persistence state, and greater number of tolerant bacteria is recovered from the 24 h metal mix when compared to the viable pathogen number in the 1 h metal mix and 7H9 growth control. In addition, bacterial phenotype induced by the 24 h metal mix increases MAH tolerance to macrophage killing in TNF-α and IFN-γ activated cells, confirming presence of persistent MAH in the 24 h metal mix condition. This work shows that the phagosome environment can promote persistence population in MAH, and that the population differs dependent on a concentration of metals.

Epidemiology, diagnosis & treatment of non-tuberculous mycobacterial diseases

Non-tuberculous mycobacteria (NTM) are ubiquitously present in the environment, but NTM diseases occur infrequently. NTM are generally considered to be less virulent than Mycobacterium tuberculosis, however, these organisms can cause diseases in both immunocompromised and immunocompetent hosts. As compared to tuberculosis, person-to-person transmission does not occur except with M. abscessus NTM species among cystic fibrosis patients. Lung is the most commonly involved organ, and the NTM-pulmonary disease (NTM-PD) occurs frequently in patients with pre-existing lung disease. NTM may also present as localized disease involving extrapulmonary sites such as lymph nodes, skin and soft tissues and rarely bones. Disseminated NTM disease is rare and occurs in individuals with congenital or acquired immune defects such as HIV/AIDS. Rapid molecular tests are now available for confirmation of NTM diagnosis at species and subspecies level. Drug susceptibility testing (DST) is not routinely done except in non-responsive disease due to slowly growing mycobacteria ( M. avium complex, M. kansasii) or infection due to rapidly growing mycobacteria, especially M. abscessus. While the decision to treat the patients with NTM-PD is made carefully, the treatment is given for 12 months after sputum culture conversion. Additional measures include pulmonary rehabilitation and correction of malnutrition. Treatment response in NTM-PD is variable and depends on isolated NTM species and severity of the underlying PD. Surgery is reserved for patients with localized disease with good pulmonary functions. Future research should focus on the development and validation of non-culture-based rapid diagnostic tests for early diagnosis and discovery of newer drugs with greater efficacy and lesser toxicity than the available ones.