Reducing Exposure to NTM

There is empirical evidence that NTM infection may occur by exposure to organisms in the environment such as our water or soil.

In a substantial percentage of cases, patients with NTM have some subtle underlying vulnerability that is either genetic or structural in nature. These underlying conditions can include cystic fibrosis, deficiency of a blood protein called alpha-1 antitrypsin, prior lung infection (including TB or histoplasmosis, a fungus common in the Midwest), prior inhalation of inorganic dust including silica, spillage of material from the mouth or stomach into the lungs, or cigarette-induced lung injury. Other underlying conditions that may increase vulnerability to NTM infection include bronchiectasis, COPD, emphysema, and Primary Ciliary Dyskinisia (PCD).

Doctors believe that some patients with these underlying lung conditions may become infected with NTM from inhalation of mycobacteria that become aerosolized when the patient showers in an enclosed shower stall or sits in an indoor hot tub.

For this reason, if you have an underlying condition that might make you susceptible to NTM infection, you may wish to speak to your doctor about the advisability of bathing in a tub rather than showering.

Actions You Can Take Today and Continue Regularly to Reduce Exposure to NTM

Written by Dr. Joseph Falkinham, III, Virginia Tech University

Reduce Exposure to NTM Aerosols

  1. Reduce NTM aerosols in showers by opening a window in the bathroom and ensuring plenty of ventilation. Check whether your bathroom fan is really capable of removing aerosols by placing a piece of tissue paper over the grill. If the fan is really removing aerosols, the tissue paper should be sucked up and stick on the grill.

    Rationale: NTM are readily aerosolized in droplets that can be inhaled and small enough to enter the smallest spaces in the lung…the alveoli.

  2. Avoid spas and hot tubs or any water with an aerator. If you need to lie in hot water, use a tub, open the window to ensure ventilation, and don’t splash. That means no toys in the tub.

    Rationale: As above, NTM are readily aerosolized from waters.

  3. Reduce your exposure to dusts from potting soils and peat moss. Keep the potting soil moist, so when you handle it there is no dust, and use a mask to keep out the dust particles.

    Rationale: NTM are found in high numbers in peat, a major component of potting soils. There can be as many as 1 million NTM per gram of potting soil or peat.

Reduce the Numbers of NTM in Your Household Water System

  1. Clean your showerhead. Remove the showerhead and disassemble it to the best of your ability. Place it in soapy water and scrub all the surfaces. Vinegar can be used to get rid of the calcium buildup (it will bubble when placed in vinegar).

    Rationale: NTM like to stick to surfaces and can grow in the slime-like covering (biofilm) in pipes. That biofilm, in turn, becomes a source of NTM.

  2. Clean taps. Use a cotton swab or wash cloth and twist it around to scrub the interior surface.

    Rationale: Same as for cleaning showerheads.

  3. Drain the sediment from the water heater using a hose and run it in the garden. Refill the water heater, drain again, and fill.

    Rationale: NTM like to attach to surfaces, so they will be bound to the sediment that collects in the bottom of everyone’s water heater.

  4. Clean and disinfect any humidifier or dehumidifier. Take the instrument outside where there is plenty of air and the disinfectant will not harm plants. Ordinary bleach or Lysol right out the bottle will do quite well. Expose for 1 hour.

    Rationale: NTM are killed (slowly) by disinfectants and anything that contains water will accumulate NTM on its surfaces.

  5. Replace filters in any in-line filtration or water purification device at least every three (3) weeks.

    Rationale: NTM can be bound to in-line filters where they grow on the organic matter trapped by the filter (one of its functions). However effective the filter is initially, after 3 weeks NTM start appearing in the water coming out of the filter unit, so the filter becomes an NTM source.

Actions that Might Reduce Exposure

  1. Place in-line filters in showers and water taps to collect NTM and reduce NTM numbers passing filter. The filters are the type available in hardware stores and do it yourself (DIY) stores. However, filters need to be changed every 3 weeks.

    Rationale: NTM have been shown to be bound to water filters, but once attached, grow and the filter can become a source of NTM. The Virginia Tech lab will be measuring the ability of in-line filter units to reduce the number of NTM in filtered water and whether the filter unit reduces the number of aerosolized NTM.

  2. Raise the temperature of your water heater (CAREFUL!) to 55° C (131° F). Be careful because the temperature is high enough to scald.

    Rationale: Research has shown that NTM will be killed by exposure to 55° C (131° F). The VT lab has studied the behavior of NTM in water heaters and has determined that hot water heaters provide conditions promoting the survival, growth, and persistence of NTM.

Indoor Air Quality is another area that affects exposure to NTM. Click here to read more.


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