Non-tuberculous mycobacteria (NTM) are a group of environmental opportunistic pathogens, which typically occur in drinking water systems, soils, and dusts. For immunosuppressed, immunocompromised, and other at-risk populations, NTM can cause a variety of infections to those exposed. NTM-caused infections can include those to the lungs, soft tissue, blood, and lymph nodes.
NTM can be transmitted through improperly reprocessed medical devices, direct contact with drinking water, aerosolized water, and even ice machines. NTM has been known to be found in significantly higher quantities in shower heads than in the main piping system, making aerosolization risk much higher (1). There has also been data to confirm some person-to-person spread of NTM (2).
Several species of NTM have become better-known due to increased incidence (3). Mycobacterium avium, for example, is responsible for Mycobacterium avium complex lung and pulmonary disease. Surgical site and lung infections are common sites of M. abscessus infections. M. abscessus is frequently found in cystic fibrosis patients (4). Mycobacterium chimaera is a species implicated in several outbreaks from heater coolers devices used in open heart surgery.
Concerns: Antimicrobial resistance, treatment, and costs
Globally, the prevalence of NTM is growing rapidly (3). According to the literature, in the United States cases rose from 2.8 cases per 100,000 population in the 1980’s to 15.2 per 100,000 population in 2013 (1). Cases can be hard to diagnose and even harder to treat, as NTM can develop antimicrobial resistance (1) and is difficult to culture. In some cases, these infections can incubate for five or more years before showing symptoms and, when contracted, can require prolonged treatment with high morbidity.
Further, the costs of these infections tend to be very high for hospitals and healthcare facilities. NTM infections can be almost as costly as a Legionella pneumophila infection, somewhere around $25,985 USD per episode (4). The length of patient stays for NTM infections is typically as long or longer than a patient with Legionella pneumophila and evidence supports higher rates of NTM infections when compared to Legionella pneumophila (5).
Risk and prevention
As with many waterborne pathogens, at-risk populations are more likely to acquire an NTM infection. Waterborne NTM in plumbing systems readily form biofilms and have multilayer outer membranes which are thicker than many other bacteria. This membrane helps make NTM especially resistant to chemicals and temperature (6). Further, NTM require specific conditions to be cultured in a laboratory to confirm their presence.
Understanding the unique challenges of NTM can help us build a more robust water safety and management plan. It may be necessary to incorporate different or additional control measures in your plan to account for this pathogen.
- Ratnatunga CN, Lutzky VP, Kupz A, Doolan DL, Reid DW, Field M, et al. The Rise of Non-Tuberculosis Mycobacterial Lung Disease. Front Immunol. Published 2020 Mar 3. doi:10.3389/fimmu.2020.00303.
- Bryant JM, Grogono DM, Rodriguez-Rincon D, Everall I, Brown KP, Moerno P, et al. Emergence and spread of a human-transmissible multidrug-resistant nontuberculous mycobacterium. Science. 2016;354(6313):751-757. doi:10.1126/science.aaf8156.
- Falkinham JO 3rd. Common features of opportunistic premise plumbing pathogens. Int J Environ Res Public Health. 2015;12(5):4533-4545. Published 2015 Apr 24. doi:10.3390/ijerph120504533.
- Johnson MM, Odell JA. Nontuberculous mycobacterial pulmonary infections. J Thorac Dis. 2014;6(3):210-120. doi:10.3978/j.issn.2072-1439.2013.12.24.
- Collier SA, Stockman LJ, Hicks LA, Garrison LE, Zhou FJ, Beach MJ, et al. Direct healthcare costs of selected diseases primarily or partially transmitted by water. Epidemiol Infect. 2012;140(11):2003-2013. doi:10.1017/S0950268811002858.
- Dowdell K, Haig S-J, Caverly LJ, Shen Y, LiPuma JJ, Raskin L. Nontuberculous mycobacteria in drinking water systems - the challenges of characterization and risk mitigation. Curr Opin Biotechnol. 2019;57:127-136. doi:10.1016/j.copbio.2019.03.010.
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Author bio
Marissa Khoukaz - Business Development Manager — Hospital Water
Marissa is a Business Development Manager for Hospital Water and manages the prefiltration portfolio globally at Cytiva. She works with high-risk units to reduce waterborne pathogen risk to patients.