Non-tuberculous mycobacteria (NTM), also known as environmental mycobacteria, are a group of over one hundred bacteria related to mycobacterium tuberculosis that are not contagious. Of that large group, approximately ten have been described as causing human respiratory infection. Mycobacterium avium-intracellulare, (MAI or MAC) and M. kansasii, and are the most common, and in the past have required up to eight weeks to grow in the laboratory (as does tuberculosis). There are so-called rapid growers, M, chelonei, M. fortuitum and M. abscessus that grow in two weeks.
Many non-tuberculous mycobacteria live in soil and water. This bacteria favors warm conditions where the bacteria can grow. Non-tuberculous mycobacteria can be found growing in the warm water of a hot tub and, less commonly, in shower heads. When a person is exposed to the vapors of these contaminating waters, the bacteria is breathed in and can result in infection.
Although exposure to this bacteria can cause infection, no recommendation has been made to avoid any water, except hot tubs, and much investigation is being done to better understand human interaction with the mycobacteria germs.
Because mycobacteria are highly resistant to heat and most water cleaning agents, they are present in nearly all drinking and bathing water. The bacteria may enter the body in drinking water and enter the bronchial tubes in one of two ways. If the swallowing process allows the water to “go down the wrong way” material may be aspirated into the lung and cause infection, if not repelled. Similarly, if the water is swallowed correctly and enters the esophagus, or food passage, it may come back up the esophagus via esophageal reflux (GERD or LPR) and linger around the voice box and later be brought down to the bronchial tubes during normal breathing.
Normally, the bronchial tubes have numerous mechanisms for repelling foreign material that could cause infection. If the lungs or the bronchial tubes are damaged (bronchiectasis, prior pneumonia, sarcoidosis, etc.) the mycobacteria can take hold in the small bronchial tubes and cause infection. If the body’s immune defenses are weakened by deficiency of immunoglobulins needed to kill bacteria, similar infection may occur.
Because there are no symptoms unique to this type of infection, a CT scan is most often needed to detect a mycobacterial infection. Once an infection is suspects, multiple sputum, or phlegm are collected for culture to isolate these bacteria. Mycobacteria are never isolated “by accident” as they require special conditions to grow.
A NTM infection can be managed by treating the damaged areas of the esophagus where the bacteria has entered the body. Typically, measures are taken to prevent aspiration and esophageal reflux and to compensate for the bronchial tubes’ inability to sufficiently cleanse themselves. A method used to clear mucus and secretions from the airways, known as the "pulmonary toilet," may be performed by the patient, with the assistance of a spouse or partner, or under the treatment of a therapist. Devices to engage the "pulmonary toilet," including acapella® valves and others are available to facilitate the clearance.
Antibiotics are more complex, typically including a regimen of three or more antibiotics taken for 18-24 months. Fortunately, it has been the experience of many physicians that careful pulmonary toilet and aspiration/aspiration prevention allow patients to thrive without medications.
Visits with the doctor every several months are preferred as an active infection is ongoing, but listening to the patient’s history, examining the patient and monitoring the status of the small bronchial tube function with breathing tests are preferred over serial CT scans and allow the physician to ascertain that the infection is in check and not in need of antibiotics.
Dr. Kamelhar has successfully managed hundreds of NTM infection cases and is currently the principle investigator of a multi-institutional prospective study to scientifically demonstrate this treatment method as the preferred management course. A retrospective study has been presented at the American Thoracic Society in this matter and was very well received.
If a patient has symptoms of an NTM infection that cannot be otherwise managed, e.g. fever, weight loss, blood spitting, breathing difficulty and the like, antibiotics may be initiated.
Further, if the balance of containment of the infection is tipped by use of corticosteroids (e.g. prolonged prednisone in high doses), chemotherapy, the use of TNF alpha inhibitors (e.g. Remicade, Embrel, Humira and the like), the body may no longer be able to contain the infection and antibiotics may be started.
Dr. Kamelhar published his first paper about the course of mycobacterial disease while still in training at Bellevue Hospital, an institution with a century-old tradition of caring for tuberculosis and related infections. He has worked closely with experts at National Jewish as the prevalence of the NTM infection increased in the 1980’s and into the 1990’s. He continues to follow patients diagnosed with bronchiectasis and NTM from those years and sees several hundred different patients per year with NTM infection. His emphasis has been on “managing” rather than treating; that approach is published in a review article of complications of antibiotic treatment in elderly patients. Certainly there is a time to treat as well.
He is Co-Director of the NYU Bronchiectasis program and is responsible for initiating a regular conference for house staff and fellows at NYU Langone Medical Center on NTM. He is the Co-director of the annual NYULMC day-long symposium on NTM with an emphasis on mechanisms of disease as well as understanding of diagnostic and treatment advances. National experts participate as speakers with both formal presentations as well as open discussion among them for exchange of newer ideas for research.
Dr. Kamelhar has recently presented a retrospective analysis of patients managed without treatment for their NTM at the American Thoracic Society and is Principle Investigator of a multi-institutional prospective study to formally examine the course of newly diagnosed NTM infection to analyze predisposing factors as well as outcomes of the management approach. This study is started and actively enrolling patients with NTM, not on medication. It is an observational study with no change in diagnostic or therapeutic approach to the patient.
Dr. Kamelhar believes strongly in the teaching needed for NTM-related diseases to be optimally diagnosed and managed. He has been an active participant with NTMInfo with attendance at multiple Washington, D.C. lobbying efforts and as a Clinical Affairs and Program Advisor with them.
Dr. Kamelhar has lectured locally and internationally on bronchiectasis and nontuberculous mycobacterial infection.
These initiatives as well as others have been recognized with recent academic advancement to rank of Clinical Professor of Medicine in the Division of Pulmonary, Critical Care and Sleep Medicine.