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Nontuberculosis Mycobacteria on the rise

A recent news bulletin aired by WUSF, a National Public Radio affiliate in South Florida, is sounding the alarm about an increasingly common type of lung infection that is on the rise in Florida, Hawaii, California, and the gulf states.

The disease is called a Nontuberculosis Mycobacterial infection (NTM) and can be contracted from breathing contaminated air from poorly maintained hot tubs and swimming pools, among other sources.

NTM bacterial infections of the lungs and skin, akin to tuberculosis, are estimated to affect 200,000 people nationwide, according to Max Salfinger, a retired public health professor at the University of South Florida and collaborating professor in the infectious diseases division at the USF Morsani College of Medicine.

“Florida is one of the hotspots,” said Salfinger. Salfinger has studied NTM for years and used to lead a state health department lab in Florida.

The bacteria that cause it is found in soil and both natural and manmade water sources, such as showers, hot tubs, and swimming pools. In the pool and spa industry, this type of NTM infection is referred to as “hot tub lung,” and it causes asthma-like symptoms that can be life threatening.

People with hot tub lung may suffer from shortness of breath, coughing, weight loss, fatigue, low oxygen levels, and fever. In most cases, the bacterium that causes hot tub lung is Mycobacterium avium (M. avium) and can get into the lungs and cause infection from breathing aerosolized bubbling hot water and the mist that it creates.

Nontuberculous mycobacteria (NTM) are mycobacterial species other than those belonging to the Mycobacterium tuberculosis complex (For example, M. tuberculosis, M. bovis, M. africanum, M. microti, and M. leprae — the bacterium that causes leprosy). Scientists have identified more than 200 NTM species.

The bacteria responsible for the disease are resistant to most water disinfectants such as chlorine. This is because they have a waxy, relatively impermeable cell wall. Further, they both are and produce some of the components present in biofilm, making traditional chlorine disinfection difficult.

That said, a 2007 American-based study found that the concentrations of NTM were significantly lower in chlorine- and bromide-disinfected pools than in pools disinfected with hydrogen peroxide and ultraviolet light.

It is not uncommon to find Nontuberculosis Mycobacteria in swimming pools and spas. The 2007 study found M. avium and other NTM in 72% of air and water samples randomly taken from 18 pool facilities.

And more recent studies state that NTM infections are increasing — cases are rising at a rate of 8 percent a year.

'There are very few diseases that are increasing at 8% per year. So, that's quite dramatic,' said Charles Daley, chief of the division of mycobacterial and respiratory infections at National Jewish Health in Denver.

The severity of the illness seems to vary dramatically from person to person, and by the strain contracted. Mycobacteria are ubiquitous, and the particular strains vary somewhat regionally. M. avium, the most commonly found NTM in hot tub lung infections, presents a lesser treatment challenge than some of the other strains.

Myra Mendible contracted an NTM infection that has sent her to urgent care multiple times. The particular strain she has was not reported. She was in her mid-60s and believes she contracted it while clearing land and mulching trees at her newly purchased, overgrown property in Fort Meyers, Florida. Just prior to her infection, she felt strong and healthy. After becoming infected, she took five different antibiotics for 18 months, and although she improved for a while, a year and a half later, she was back in the hospital. She says it’s very difficult to get rid of it once you have it. She’s currently not optimistic that she will ever be cured.

In 2018, a 17-year-old Australian boy became infected with NTM while convalescing from an ankle surgery in a room adjacent to the family’s indoor pool. The family had recently converted the pool’s sanitation regime to UV and hydrogen peroxide. Subsequent analysis of the pool water found M. intracellulare, as well as M. avium and M. marinum. The boy was admitted to the emergency room with severe difficulty breathing and required supplemental oxygen.

Ultimately, his entire family contracted the disease, but after treatment, they were cured.

A follow-up medical visit two years later showed that their respiratory symptoms were gone, although they did show mild but possibly permanent lung damage.

In 2013, a study was published in the European Respiratory Review that identified hot tub lung as “an occupational hazard.” In the article, the authors presented seven separate NTM cases of people (ages 30 to 64) whose job it was to clean hot tubs at three different hotels. Five of the workers became very sick while two were totally asymptomatic but tested positive for M. avium.

The three spa facilities were similar in construction and maintenance. They all used UV light and hydrogen peroxide as disinfectants, and the workers all cleaned the nylon-sheet particle filters with pressure washers.

All of the workers recovered spontaneously without antibiotics or corticosteroids when the filters were replaced with sand filters and the pressure washing stopped.

The authors of the study recommend that pressure washing filters should be avoided.

It is important to note that in the U.S., chlorine and bromine are the preferred and recommended sanitizers so as to maintain a constant sanitizer residual, and UV or ozonebased disinfectants are recommended to be used on a secondary and/or supplemental basis.

Furthermore, such a pool or spa with a constant halogen-based residual prevents the formation of the biofilms that harbor the disease in pools and spas.

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