Atypical Mycobacterial Infection.Care & specialists in Tanzania
In Tanzania, atypical Mycobacterial Infection is managed by infectious diseases. Atypical mycobacterial infection — more commonly called non-tuberculous mycobacterial (NTM) infection — is caused by environmental mycobacteria other than Mycobacterium tuberculosis and Mycobacterium leprae, with Mycobacterium avium complex (MAC) responsible for over 80% of pulmonary cases in the US. NTM organisms live in soil, household water, and biofilms; infection follows inhalation, aspiration, or direct inoculation.
Acid-fast smear of Mycobacterium avium complex — the most common atypical mycobacterium. · Credit: CDC Public Health Image Library · Public Domain
aliases · Non-tuberculous mycobacterial (NTM) infection· Mycobactériose atypique· Infección por micobacterias atípicas· 非結核性抗酸菌症· reviewed May 13, 2026
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Reviewed by AIHealz Medical Editorial Board · Infectious DiseaseLast reviewed May 13, 2026
Atypical mycobacterial infection (ICD-10: A31) refers to disease caused by any of the more than 200 species of non-tuberculous mycobacteria (NTM), excluding M. tuberculosis complex and M. leprae. NTM are ubiquitous environmental organisms living in soil and water, including potable household water, hot tubs, and biofilms in showerheads and humidifiers.
key facts
Prevalence
US point prevalence ~47-86 per 100,000 (Adjemian 2012 Medicare data); rising 8% annually
Demographics
Female:male approximately 2:1 in pulmonary disease; peak age 65-75
Avg. age
Mean age at diagnosis 65-70 years for pulmonary NTM; younger in cystic fibrosis patients
Global cases
Conservative global estimate over 1 million infections per year; rising in most regions with rising bronchiectasis prevalence
Specialist
Infectious Disease
§ 02
How you might notice it
The key symptoms of Atypical Mycobacterial Infection are: Chronic productive cough lasting weeks to months, often the only respiratory symptom for years before diagnosis., Daily mucopurulent or blood-streaked sputum production, sometimes mistaken for chronic bronchitis or asthma., Progressive fatigue and reduced exercise tolerance over months as airway inflammation accumulates., Unintentional weight loss of 5-10% body weight over months, particularly with fibrocavitary disease., Low-grade fevers and night sweats — less prominent than in tuberculosis but commonly present in active NTM disease., Painless lymph node enlargement, usually unilateral cervical or submandibular, in children with NTM lymphadenitis., Slowly enlarging skin nodules, abscesses, or non-healing ulcers at the site of trauma, surgery, or aquatic exposure..
01Chronic productive cough lasting weeks to months, often the only respiratory symptom for years before diagnosis.
02Daily mucopurulent or blood-streaked sputum production, sometimes mistaken for chronic bronchitis or asthma.
03Progressive fatigue and reduced exercise tolerance over months as airway inflammation accumulates.
04Unintentional weight loss of 5-10% body weight over months, particularly with fibrocavitary disease.
05Low-grade fevers and night sweats — less prominent than in tuberculosis but commonly present in active NTM disease.
§ 03
How it’s diagnosed
HRCT chest showing bronchiectasis and tree-in-bud nodules characteristic of NTM lung disease. · Credit: Wikimedia Commons · CC BY-SA 3.0
diagnosis
Diagnosis of atypical mycobacterial infection requires fulfilling specific clinical, radiographic, and microbiologic criteria laid out in the 2020 ATS/ERS/ESCMID/IDSA guidelines. For pulmonary disease, all three are required: respiratory symptoms (cough, fatigue, weight loss), compatible radiographic findings (nodular, bronchiectatic, or cavitary disease on CT chest), and positive NTM cultures from at least two separate expectorated sputum samples or one bronchoalveolar lavage sample. A single positive sputum without symptoms or imaging changes is considered colonization and does not warrant treatment. Species identification by molecular methods (PCR, MALDI-TOF) is essential because treatment regimens vary substantially between MAC, M. kansasii, M. abscessus, and others. Drug susceptibility testing is recommended for macrolides and amikacin in MAC, and broader panels for M. abscessus and M. kansasii. For extrapulmonary disease, culture of NTM from a normally sterile site (lymph node, skin biopsy, blood) combined with compatible clinical syndrome is sufficient. Imaging with high-resolution CT is essential to characterize the form of pulmonary disease and to monitor response. Baseline workup includes complete blood count, liver and renal function, audiometry, and visual acuity to anticipate drug toxicities. HIV testing is recommended in any patient with disseminated or unusual NTM. In cystic fibrosis, annual sputum NTM cultures are part of routine care.
Key tests
01
Sputum mycobacterial culture and smearFoundation of diagnosis. Requires at least two separate positive expectorated sputum cultures or one positive bronchoalveolar lavage to fulfill microbiologic criterion for pulmonary NTM disease.
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Treatment & cost
medical treatments
✓Azithromycin 500 mg orally (three times weekly or daily based on disease form)
✓Ethambutol 15-25 mg/kg orally (daily or three times weekly)
✓Rifampin 600 mg orally daily or three times weekly
✓Amikacin liposome inhalation suspension (590 mg once daily)
surgical options
Lobectomy or wedge resection for localized diseaseAdjunctive surgery in carefully selected patients raises sustained culture conversion to 70-90%; surgical morbidity 5-15% in experienced centers.
Lymph node excisional biopsyCure rates of 80-95% with complete excision alone; chronic draining sinuses in 5-10%.
Surgical debridement of skin and soft tissue infectionCure rates above 90% with combined surgical and antibiotic therapy.
§ 05
Causes & risk factors
known causes
Mycobacterium avium complex (MAC)
Includes M. avium and M. intracellulare, responsible for over 80% of pulmonary NTM disease in the US. Ubiquitous in soil, water, and household plumbing biofilms. Slow-growing and relatively drug-susceptible, but requires prolonged combination therapy.
Mycobacterium abscessus complex
Rapidly growing mycobacteria found in water and soil. Causes both pulmonary disease (particularly in cystic fibrosis) and skin and soft tissue infection (especially after cosmetic procedures and contaminated injections). Highly resistant to antibiotics, making cure difficult.
Mycobacterium kansasii
Photochromogenic slow-growing mycobacterium causing fibrocavitary lung disease resembling tuberculosis. Found in municipal water supplies. Responds well to rifamycin-based regimens.
Other rapidly growing mycobacteria (M. fortuitum, M. chelonae)
Cause skin and soft tissue infections after trauma, surgery, or cosmetic procedures (tattoos, pedicures, liposuction). Variable drug susceptibility requires species identification and susceptibility testing.
Mycobacterium marinum and M. ulcerans
Cause specific skin syndromes — fish tank or swimming pool granuloma (M. marinum) and Buruli ulcer (M. ulcerans). Both follow inoculation through skin in aquatic or wetland exposure.
Immunosuppression and structural lung disease
Underlying bronchiectasis, COPD, cystic fibrosis, prior tuberculosis, and immunosuppressive therapy create the substrate for NTM colonization to become invasive disease. Anti-IFN-gamma autoantibodies and IFN-gamma receptor defects predispose to disseminated NTM.
risk factors
Bronchiectasis
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Living with it
01Reduce aerosolized water exposure by routinely cleaning and disinfecting showerheads, humidifiers, and hot tubs in homes of immunocompromised or bronchiectatic patients
02Maintain effective antiretroviral therapy in HIV to keep CD4 above 100 and substantially reduce disseminated MAC risk
03Use sterile saline (not tap water) for sinus rinses, neti pots, and contact lens cleaning
04Practice airway clearance (saline nebulizers, postural drainage, oscillating vests) in patients with bronchiectasis or COPD to reduce mucus stasis and NTM colonization
05Screen with annual sputum NTM cultures in cystic fibrosis and high-risk bronchiectasis patients per current consensus
recommended foods
•High-calorie, high-protein diet (1.2-1.5 g protein per kg/day) to counter chronic infection-related muscle wasting
•Vitamin D-rich foods or supplementation to maintain 25-OH-D above 30 ng/mL
•Iron-rich foods if anemic, with iron studies guiding therapy
•
§ 07
When to seek help
why see an infectious disease
Atypical mycobacterial infection should be managed by an infectious disease specialist or pulmonologist with NTM experience, given the complexity of diagnosis, prolonged multi-drug therapy, and frequent adverse events. Reference centers and academic centers offer access to drug susceptibility testing, clinical trials, and surgical thoracic teams experienced in NTM resections. M. abscessus disease in particular should be managed by centers with proven outcomes.
Pulmonary NTM disease — fibrocavitary formResembles tuberculosis with upper-lobe cavitation and infiltrates. Predominantly affects men with COPD or prior pulmonary disease. Often caused by M. avium complex or M. kansasii.
Pulmonary NTM disease — nodular bronchiectatic formMid-lung and lingular bronchiectasis with tree-in-bud nodules on CT, classically described in slim postmenopausal women (Lady Windermere syndrome). M. avium complex is the most common cause.
Cervicofacial lymphadenitisPainless cervical or submandibular lymph node swelling, predominantly in children aged 1-5, usually unilateral. M. avium complex is the most frequent cause. Often resolves with surgical excision alone.
Skin and soft tissue infectionLocalized nodules, abscesses, ulcers, or sinus tracts after skin breach. Causes include M. marinum (fish tank granuloma), M. ulcerans (Buruli ulcer), M. fortuitum, M. chelonae, and M. abscessus.
Disseminated NTM diseaseBloodstream and multi-organ involvement, almost exclusively in patients with advanced HIV (CD4 below 50), organ transplant, hematological malignancy, or anti-IFN-gamma autoantibodies.
Living with Atypical Mycobacterial Infection
Timeline
Symptomatic improvement on effective NTM therapy typically begins after 1-3 months — reduced cough, improved energy, weight stabilization. Culture conversion (consistently negative sputum cultures) usually occurs by 4-6 months in MAC and M. kansasii; by 6-12 months or longer in M. abscessus. Total treatment duration is 12-24 months for pulmonary NTM and 4-6 months for most skin infections. Follow-up sputum cultures continue at intervals for 12 months after completion to confirm sustained conversion.
Lifestyle
01Stop smoking — accelerates lung damage and worsens NTM outcomes regardless of species
02Maintain or gain weight if underweight — low BMI is independently associated with poor NTM outcomes
03Perform daily airway clearance with prescribed devices and nebulized hypertonic saline if you have bronchiectasis
04Adhere to the full multi-drug regimen exactly as prescribed; non-adherence is the leading cause of macrolide resistance and treatment failure
05Track and report side effects promptly — vision change, hearing change, severe nausea, or jaundice may signal serious drug toxicity
06Limit hot tub and steam room exposure if you have known structural lung disease
Daily management
01Take all NTM antibiotics exactly as prescribed; missing doses promotes macrolide resistance and treatment failure
Choosing a doctor
Look for an infectious disease physician or pulmonologist who treats NTM regularly, working in a center with access to a reference mycobacteriology laboratory, audiology and ophthalmology for treatment monitoring, and experienced thoracic surgery for cases requiring resection. In cystic fibrosis, NTM care should be integrated within the CF center. Continuity matters because therapy lasts 12-24 months or longer.
Patient support resources
NTM Info & Research (NTMir) →US patient organization providing education, online support groups, and links to clinical centers.
Atypical mycobacterial infection — also called non-tuberculous mycobacterial (NTM) infection — is a disease caused by environmental mycobacteria other than tuberculosis or leprosy. Mycobacterium avium complex causes over 80% of pulmonary cases. The organisms live in soil and water and infect humans through inhalation, aspiration, or direct skin inoculation.
Is atypical mycobacterial infection contagious?▾▴
Atypical mycobacterial infection is generally not contagious person-to-person, with the rare exception of suspected M. abscessus transmission between cystic fibrosis patients. NTM is acquired from environmental sources — soil, household water, hot tubs, and biofilms. Family members of patients are not at increased risk in everyday life.
What is the difference between TB and atypical mycobacteria?▾▴
Tuberculosis is caused by Mycobacterium tuberculosis, is highly contagious between humans, and is treated with 6 months of four-drug therapy. Atypical mycobacterial infection involves over 200 environmental species, is not contagious, and requires 12-24 months of species-specific therapy. Both can cause chronic cough and lung damage and may look similar on chest imaging.
How do you get NTM lung disease?▾▴
NTM lung disease is acquired by inhaling aerosolized water or soil containing the organism. Showerhead biofilms, hot tubs, humidifiers, and household plumbing are common sources. Most exposure does not cause disease — bronchiectasis, COPD, postmenopausal female phenotype, cystic fibrosis, and immunosuppression are the main predispositions for environmental exposure to progress to disease.
What is Lady Windermere syndrome?▾▴
Lady Windermere syndrome is the classic presentation of nodular bronchiectatic Mycobacterium avium complex disease in slim, postmenopausal women without major underlying lung disease. It is named after a fictional character thought to suppress coughing for social reasons. Imaging shows tree-in-bud nodules and bronchiectasis predominantly in the lingula and middle lobe.
How is NTM lung disease diagnosed?▾▴
Diagnosis requires compatible respiratory symptoms, characteristic findings on high-resolution CT chest, and positive NTM cultures from at least two separate sputum samples or one bronchoalveolar lavage. A single positive culture without symptoms or imaging changes is considered colonization. Species identification by molecular methods guides treatment.
How long is NTM treatment?▾▴
Pulmonary NTM is treated for at least 12 months past culture conversion — typically 18-24 months total. Cervicofacial lymphadenitis in children often resolves with surgical excision alone. Skin and soft tissue infections require 4-6 months of combination antibiotics. M. abscessus disease may require even longer therapy with intravenous and inhaled drugs.
Is NTM curable?▾▴
Cure rates depend on species and form. M. kansasii has cure rates above 90% with rifampin-based therapy. Macrolide-susceptible MAC achieves sustained culture conversion in 60-80% with the standard three-drug regimen. M. abscessus is the most difficult, with sustained conversion in 30-50%. Adherence and absence of macrolide resistance are the strongest predictors of cure.
What are the main drugs used for NTM?▾▴
Standard MAC treatment combines azithromycin, ethambutol, and rifampin. M. kansasii uses rifampin, ethambutol, and isoniazid or a macrolide. M. abscessus requires intravenous amikacin plus imipenem or cefoxitin and oral macrolides, tigecycline, or linezolid based on susceptibility. Inhaled amikacin liposome suspension is approved for refractory MAC.
Can I get NTM from a hot tub?▾▴
Yes. Hot tub lung is a hypersensitivity pneumonitis or true NTM infection (most often M. avium complex) acquired by inhaling aerosolized hot tub water. Symptoms include cough, fever, and breathlessness developing weeks to months after exposure. Avoidance of the hot tub and treatment of the infection, sometimes with corticosteroids, leads to recovery.
What are the side effects of NTM treatment?▾▴
Common side effects include ethambutol-induced optic neuritis with color vision loss, aminoglycoside-related hearing loss and kidney injury, rifampin-induced hepatitis and many drug interactions, macrolide-related QT prolongation, and clofazimine-induced orange-red skin discoloration. Regular monitoring by audiometry, ophthalmology, and bloods is essential during treatment.
Why does NTM mostly affect older women?▾▴
Postmenopausal women, particularly slim women with scoliosis or pectus deformity, disproportionately develop nodular bronchiectatic MAC disease. The reasons are not fully understood but probably involve airway clearance mechanics, estrogen-related immunity changes, and subtle bronchiectasis. Men are more likely to have fibrocavitary disease related to COPD or prior tuberculosis.
Can NTM come back after treatment?▾▴
Yes. Recurrence occurs in 30-40% of MAC patients over 5 years. Many recurrences are reinfections from environmental sources rather than relapses of the original strain, as shown by molecular typing. Reducing ongoing environmental exposure and maintaining good airway clearance lowers recurrence risk.
What is Buruli ulcer?▾▴
Buruli ulcer is a specific NTM skin infection caused by Mycobacterium ulcerans. It causes painless, slowly enlarging skin ulcers, predominantly on the limbs, in tropical regions of West Africa, Australia, and Latin America. WHO recommends combination rifampin and clarithromycin for 8 weeks, often with wound care or surgical excision.
Should I have my home water tested for NTM?▾▴
Routine residential water testing is not recommended in most cases because NTM is ubiquitous in household water systems and a positive test does not predict infection. For severely immunocompromised patients or those with persistent NTM despite environmental modification, point-of-use filters and shower disinfection may be considered with specialist input.
Does NTM cause weight loss?▾▴
Yes. Chronic pulmonary NTM disease frequently causes unintentional weight loss of 5-10% of body weight over months, along with fatigue, night sweats, and chronic cough. Low body mass index is a known risk factor for nodular bronchiectatic MAC and is associated with worse outcomes. Nutritional support is an important component of treatment.
Can children get atypical mycobacterial infection?▾▴
Yes, although pulmonary NTM is rare in children. The most common pediatric NTM presentation is painless cervicofacial lymphadenitis in children aged 1-5, usually caused by M. avium complex. Complete surgical excision is curative in over 90% of cases. Pulmonary NTM in children almost always reflects underlying cystic fibrosis or immunodeficiency.
What is the role of surgery in NTM disease?▾▴
Surgical resection of localized cavitary or nodular disease is considered in patients with refractory or M. abscessus pulmonary disease, raising sustained culture conversion to 70-90% in selected cases. Surgical excision is the primary treatment for cervicofacial lymphadenitis in children and a useful adjunct to antibiotics in skin and soft tissue NTM.
Does NTM affect cystic fibrosis differently?▾▴
NTM is identified in 5-30% of cystic fibrosis patients, with M. abscessus being especially difficult to eradicate. CF Foundation guidance recommends annual sputum NTM cultures, prolonged intensive multi-drug therapy when infection is established, and integration of NTM management within the CF center.
06Painless lymph node enlargement, usually unilateral cervical or submandibular, in children with NTM lymphadenitis.
07Slowly enlarging skin nodules, abscesses, or non-healing ulcers at the site of trauma, surgery, or aquatic exposure.
08Recurrent pulmonary exacerbations in patients with underlying bronchiectasis, COPD, or cystic fibrosis.
09In disseminated disease: persistent fever, weight loss, hepatosplenomegaly, anemia, and chronic diarrhea in profoundly immunosuppressed patients.
early warning signs
•Chronic cough or sputum production not improving with two or more courses of standard antibiotics
•Repeated isolation of acid-fast bacilli or NTM on sputum culture in a patient with respiratory symptoms
•New nodules or bronchiectasis on CT chest performed for chronic cough, especially in the mid-lung or lingula
•Persistent fevers, night sweats, or weight loss in a person with HIV or other immunosuppression
•Slow-healing skin lesion after fish tank exposure, contaminated cosmetic procedure, or surgical wound
● emergency signs
•Massive hemoptysis from a cavitary lesion — requires urgent bronchial artery embolization or surgery
•Acute respiratory failure or progressive hypoxia in established pulmonary NTM disease
•Disseminated NTM with septic features (high fever, hypotension, multiorgan involvement) in profoundly immunosuppressed patients
•Severe drug-induced hearing or vision loss while on aminoglycoside or ethambutol — stop the offending drug and arrange specialist review urgently
•Severe drug-induced liver injury on multidrug NTM therapy — jaundice, dark urine, or right upper quadrant pain warrants prompt evaluation
02
Species identification (line probe assay, MALDI-TOF, sequencing)Identifies the specific NTM species, which determines treatment regimen. MAC, M. kansasii, M. abscessus, and other species require markedly different antibiotic combinations.
03
Drug susceptibility testingTests macrolide and amikacin susceptibility in MAC; broader panels in M. abscessus, M. kansasii, and other species. Guides drug selection and prognosis.
04
High-resolution CT chestCharacterizes disease form (fibrocavitary, nodular bronchiectatic, isolated nodule). Tree-in-bud nodules in the lingula and middle lobe are characteristic of MAC disease. Used at baseline and to monitor response.
05
Bronchoscopy with bronchoalveolar lavageUsed when sputum samples are unavailable, contaminated, or negative despite high clinical suspicion. Permits sampling of specific affected lobes.
06
Skin or lymph node biopsy with mycobacterial cultureFor cutaneous, lymph node, or other extrapulmonary disease. Tissue is sent for histopathology and culture; granulomatous inflammation supports the diagnosis even if culture is negative.
07
HIV testing and CD4 count when disseminated NTM suspectedIdentifies underlying HIV infection driving disseminated MAC. CD4 below 50 cells/µL is the major risk profile.
Outlook
Outcomes in atypical mycobacterial infection vary substantially by species and disease form. For macrolide-susceptible Mycobacterium avium complex with full three-drug therapy and adequate duration, sustained culture conversion at 12 months past completion is achieved in 60-80% of patients, with recurrence in 30-40% over 5 years — many of which represent reinfection from environmental sources rather than relapse. M. kansasii has the most favorable prognosis, with cure rates above 90% on rifampin-based regimens. M. abscessus has the poorest outcomes, with sustained culture conversion in only 30-50% of pulmonary cases despite intensive multi-drug therapy and frequent surgical adjuncts. Untreated NTM in symptomatic patients with bronchiectasis or cavitary disease progresses to respiratory failure over years. NTM-related mortality is most often a consequence of progressive structural lung damage or comorbidities rather than direct overwhelming infection. Children with cervicofacial NTM lymphadenitis treated surgically have cure rates above 90%. Cosmetic-procedure-associated skin NTM infections cure with combined surgery and antibiotics in over 80% of cases. Long-term prognosis is best in patients who adhere to full multi-drug therapy, control underlying lung disease, optimize nutrition, and minimize ongoing environmental exposure.
non-modifiable
Most important predisposition for pulmonary NTM disease. NTM is identified in 10-50% of patients with bronchiectasis. Treatment of the underlying bronchiectasis is integral to NTM management.
COPD and chronic structural lung diseasemodifiable
Smoking-related COPD with cavitation is the substrate for fibrocavitary NTM disease, particularly M. avium complex and M. kansasii. Smoking cessation slows progression.
Postmenopausal female phenotypenon-modifiable
Slim, postmenopausal women with low body mass index and scoliosis or pectus deformity classically develop nodular bronchiectatic MAC disease (Lady Windermere syndrome). Estrogen decline may impair airway clearance.
Cystic fibrosisnon-modifiable
CF patients have NTM colonization in 5-30%, with M. abscessus particularly difficult to eradicate. Routine annual sputum NTM screening is recommended in CF care.
HIV with CD4 below 50modifiable
Major risk factor for disseminated MAC. Effective antiretroviral therapy with immune recovery reduces risk dramatically; prophylaxis is no longer routinely recommended in current ART era.
TNF inhibitors raise NTM risk roughly 5-fold; chronic corticosteroids and transplant regimens raise risk significantly. Screen with chest imaging before starting biologics if symptoms are present.
Anti-IFN-gamma autoantibodiesnon-modifiable
Adult-onset immunodeficiency, more common in patients of Southeast Asian descent, manifests as disseminated NTM and other intracellular infections. Increasingly recognized as a cause of unexplained NTM in HIV-negative adults.
Aquatic and soil exposureenvironmental
Hot tubs, household water systems, swimming pools, and aquariums are sources of NTM exposure. Showerhead biofilms commonly contain MAC. Reducing aerosol exposure can lower acquisition risk.
Adequate hydration with safe drinking water — boil household water before drinking in immunocompromised patients with documented NTM
•Probiotic-containing foods or supplements during prolonged antibiotic therapy to reduce Clostridioides difficile risk
foods to avoid
•Alcohol during rifampin therapy — increases hepatotoxicity risk
•Grapefruit and grapefruit juice while on macrolides due to CYP3A4 interactions
•Excessive iron supplementation during active infection without indication
•Raw water from streams, untreated wells, or recreational hot tubs while immunosuppressed
•Herbal CYP-inducing supplements (St John's wort) that can reduce antibiotic levels
07Recurrent disease from reinfection by environmental NTM in 30-40% over 5 years
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02Attend monthly clinic visits for sputum cultures, blood tests, audiometry, and visual checks during active treatment
03Perform daily airway clearance and saline nebulization if you have bronchiectasis
04Report new symptoms — vision changes, hearing changes, balance problems, jaundice, or severe rash — same day to the clinical team
05Keep an up-to-date medication list and share with all clinicians, given the many drug interactions with rifampin
06Carry a card noting your NTM species, current regimen, and contact details for your specialist team
Exercise
Pulmonary rehabilitation with supervised aerobic and resistance exercise is recommended for patients with pulmonary NTM disease and bronchiectasis — it improves exercise tolerance, quality of life, and adherence. Programs typically run 6-12 weeks. Once stable on therapy, regular walking, cycling, and swimming (in chlorinated pools, avoiding hot tubs) are encouraged. Avoid exercise in dusty or aerosolized water environments where NTM exposure is high.
