Nontuberculous mycobacteria (NTM) are mycobacteriaceae species that can cause the onset of illness in humans. NTM are present naturally in the soil and air. But NTM are not the causative agents of tuberculosis. These bacteria have been classified as nontuberculosis to set them apart from the tuberculosis-causing bacteria, also known as the Mycobacterium tuberculosis complex.
Among the more common NTM that must be therapeutically addressed are M. avium, M. intracellulare, M. kansasii, M. abscessus, M. chelonae, M. fortuitum, M. terrae, M. xenopi, and M. simiae.
Treatment is a Challenge
How to treat a NTM-related condition is not be a simple, straightforward decision for a clinician to make. Most often, treatment will involve the administration of a variety of antibiotics. But NTM have antibiotic resistance. Moreover, treating NTM with only one drug might actually cause the condition to become more antibiotic-resistant than if several drugs are administered.
A successful treatment will necessitate the use of two or three therapeutics. Therapies recommended by the American Thoracic Society to treat pulmonary NTM include: azithromycin, rifampin, ethambutol, and streptomycin. The precise drugs to be administered will be determined by the exact nature of the bacteria, the extent of infection, and which drugs the bacteria may be sensitive to. Therapy must continue until cultures of the respiratory system yield negative results for one year.
Specific regimens will vary. The susceptibility of the bacteria to specific drugs is one determining issue. The exact nature of the treatment will also be influenced by the patient’s age, overall health, the specific symptoms, personal preferences, and if they are allergic to any of the drugs.
The American Thoracic Society and Infectious Diseases Society of America offer extensive treatment plans. Their drug plans cover frequency, duration, dosage, toxicity, and preventive treatment. Distinctions are made as to how to deal with different types of bacteria, as well as how to address slow- and fast-growing infections.
For example, in order to treat Mycobacterium avium Complex pulmonary disease and M. kansasii, which represent the most common causes of lung-based NTM disease, a patient must receive three drugs, depending on the severity of the condition. These might be administered each day or on three days of the week. On the other hand, several months of treatment with intravenously-administered drugs, oral, and inhaled antibiotic drugs are needed for those suffering from M. abscessus. Health outcomes are sometimes not good for patients, and surgery may be required to take out damaged areas of the lung.
Also helpful for infected individuals would be to force mucus from their lungs by applying physical therapy to the chest, undertaking aerobic exercise, or administering therapies as a mist inhaled into the lungs. It also would be important for patients to maintain a healthy weight and consume healthy and nutritious products. Regardless of whether a patient is treated or not, they must be monitored to determine if the condition becomes worse.
NTM therapeutics may cause side effects that can be cause for concern. For instance, they may be poorly tolerated among certain populations. Many therapies are costly, and the expense grows the longer the patient is required to remain on the treatment regimen. Despite these, it is necessary to balance the risks against the benefits for each individual, and to consider the outcome if the condition is not addressed and treated, especially if the symptoms are severe.
It is possible to become infected with NTM either by breathing in air by drinking water so, to avoid future infections, individuals should become more aware of where the bacteria might exist in the environment. Avoiding hot tubs and exposure to certain bodies of water and soil will help lessen the likelihood of reinfection, as would boiling tap water intended for drinking.
Reviewed by Afsaneh Khetrapal BSc (Hons)