NONTUBERCULOUS MYCOBACTERIA (NTM)

Nontuberculous mycobacteria (NTM) are mycobacterial species that cause human disease. Data suggest rising numbers of cases in certain parts of the country. NTM thrives in soil and water but why people become infected with NTM is unclear. One theory suggests NTM infections are caused by respirating aerosolized NTM mycobacteria. 

Introduction

Germs, like plants and animals, have been classified into "families." One such family of germs is known as the Mycobacteriaceae. Within this family there are a number of species, some can cause human diseases (pathogenic), others do not cause human diseases (saprophytic).

The most infamous species of the group are Mycobacterium tuberculosis< (the organism that causes human tuberculosis) and Mycobacterium leprae (the organism that causes leprosy).

What is the difference between TB and NTM?

Nontuberculous mycobacteria (NTM) are other mycobacterial species that may cause human disease but do not cause TB. Every year in the United States approximately two people per 100,000 population develop infections caused by these lesser-known "cousins" of tuberculosis and leprosy. In fact, data suggest that there may be rising numbers of cases in certain parts of the country.

Unlike tuberculosis, which is spread from person to person, NTM infections are not considered contagious. There is no evidence that the infection can be transmitted from one person to another. Just how and why people become infected with NTM is not clear.

Although the germs are found easily in environmental locations such as water and soil, they do not affect most people. Physicians believe that some people who become infected have an unknown defect in their lung structure or function or in their immune systems. People who have damaged lung tissue from diseases such as emphysema, bronchiectasis or previous tuberculosis infection appear to be at greater risk for developing a NTM infection. People who are immunocompromised such as those with the Acquired Immune Deficiency Syndrome (AIDS) have a greater risk of developing a NTM infection that affects all organs of the body, not only the lungs.

What are the different types of NTM?

Under the microscope, NTM and tuberculosis appear similar. Careful laboratory studies must be performed to distinguish the organisms. While most laboratories are capable of carrying the testing process far enough to determine whether they are dealing with an NTM, fewer laboratories are equipped to determine exactly which organism it might be and what its susceptibility is to drugs.

The importance of identifying the exact organism can be illustrated with two of the organisms, Mycobacterium gordonae and Mycobacterium scrofulaceum.

These two are very similar and react identically in many laboratory tests. If the organism recovered from a human specimen turns out to be M. gordonae, treatment is seldom indicated. M. gordonae, found in water supplies so often that it is nicknamed "the tap water bacillus," is usually a laboratory contaminant and not a cause of human disease. M. scrofulaceum, on the other hand, is known to cause disease and may require specific forms of treatment.

What are the symptoms?

Like tuberculosis, an NTM infection primarily affects the lungs and the symptoms are similar. Most NTM infections progress slowly. Symptoms may include:

o       Fever

o        Weight loss

o       Cough

o       Lack of appetite

o       Night sweats

o       Blood in sputum

o       Loss of energy

How is NTM infection diagnosed?

An NTM infection can be more difficult to diagnose than tuberculosis. It is important for your health care provider to determine if the infection is TB or NTM, and if it is NTM, which specific type. In addition, it is important for the health care provider to determine whether the NTM infection requires treatment. Some people harbor the germs and remain well. They may need observation but no specific treatment. Others have or may be developing serious and progressive illness. A diagnosis is generally based on the following:

o       Medical history includeing your symptoms

o       Chest X-ray

o       Sputum culture – Several sputum cultures are often necessary and must be done at specialized laboratories

o       Other procedures – More complicated diagnostic procedures may be required

What is the treatment of NTM?

Most of the NTM infections are naturally resistant to many conventional antibiotics and it is necessary to use some of the same medications that are used to treat tuberculosis. In order to overcome drug resistance, the physician may be required to administer several different anti-TB medications at the same time. Because many of these medications have side effects, close monitoring is important. Furthermore, treatment may be necessary for as long as two years and sometimes indefinitely depending on the severity of the disease.

The most common organisms involved in human infection are M. kansasii, M. avium-complex, M. chelonae and M. abscessus. M. kansasii is relatively easy to treat and usually can be killed with only three anti-TB medications. On the other hand, organisms such as M. avium, M. chelonae and M. abscessu are among the most stubborn germs and are difficult to treat. Four to six medications may be needed, and depending on how localized the disease is, surgery also may be helpful.

 If your needs require screen testing of water for NTM, contact Vik Ahuja at Pure Air Control Services, VAhuja@PureAirControls.com or call Vik directly at (800) 422-7873, ext. 804