Shower Precautions and Mycobacterium Avium Complex (MAC) Lung Infections
NTM and Water: Practical Ways to Reduce Exposure in the Bathroom
I have had a nontuberculous mycobacterial (NTM) lung infection called Mycobacterium avium complex (MAC).
If you’ve been around our bronchiectasis and NTM community for a while, you probably know that these infections can be difficult to treat. MAC treatment often involves multiple antibiotics for an extended period, generally continuing for at least 12 months after cultures become negative.
Having been through MAC myself, I would prefer not to invite it back!
So I take reasonable precautions to reduce my exposure to NTM. The emphasis here is on reasonable. I don’t believe we can, or should, try to live in a sterile bubble.
The good news is that many people with bronchiectasis will never develop an NTM infection. But for those of us who have MAC now or have had it in the past, it makes sense to understand where these bacteria live and what we can reasonably do to reduce our exposure.
So, What Does Water Have to Do With MAC?
Quite a bit.
Water is one of the environmental sources of NTM. Environmental microbiologist Dr. Joseph Falkinham, has spent decades studying NTM and water systems, and I have learned so much from his work over the years.
NTM can be found in municipal water systems.
You may be thinking, Wait a minute. Isn’t our water chlorinated?
Yes, it is. But NTM have what I like to call a few superpowers.
One of those superpowers is their unusual waxy, lipid-rich cell wall. This helps make them much more resistant to disinfectants than many other bacteria. The concentrations of chlorine normally used to treat drinking water simply aren’t enough to reliably eliminate NTM.
And if that weren’t enough, NTM have another trick up their sleeves.
Meet the Biofilm
NTM don’t necessarily hang out alone. They can become part of communities of microorganisms attached to surfaces and surrounded by a protective matrix.
The scientific word is biofilm.
I sometimes think of them as little protective gangs!
Biofilms can develop along the inside of our household plumbing and accumulate on faucets and showerheads. Once microorganisms become established in a biofilm, they can be difficult to remove.
That’s why mechanical cleaning and heat are important when we talk about reducing exposure.
Why Pay Particular Attention to the Shower?
Because showers create aerosols.
Those wonderful tiny droplets floating around in the steam can be inhaled into our respiratory tract. For most people, this isn’t something they need to spend much time thinking about. But if you have bronchiectasis and especially if you’ve had an NTM infection, it may be worth making a few simple changes.
Does this mean I’m afraid to take a shower?
Absolutely not.
I take showers. I wash my hair. I live my life.
The goal isn’t to eliminate every NTM organism from our environment. That would be impossible. The goal is to reduce unnecessary exposure where we reasonably can.
What Can We Do in the Bathroom?
Here are some practical strategies you may want to consider:
Ventilate the bathroom. Open a window if you have one or run the exhaust fan while showering and afterward.
Keep showers relatively short. Less time standing in a steamy bathroom means less time breathing aerosolized water.
Consider a simple showerhead with larger holes. Showerheads with many tiny openings and complex internal structures provide more surfaces where biofilm can accumulate.
Clean your showerhead regularly. Mechanical cleaning helps break up and remove biofilm.
Consider periodically replacing an inexpensive showerhead. Sometimes the easiest way to deal with an old showerhead with lots of buildup is simply to replace it.
Talk with a professional before increasing your hot-water temperature. Higher temperatures may help discourage NTM growth, but hotter water also increases the risk of scalding. Anti-scald protection is important.
Flush plumbing that hasn’t been used for a while. If you arrive at a vacation home or have a bathroom that hasn’t been used for days or weeks, let the water run before using it.
Should We Let the Water Run Before Using It?
This is another recommendation you may have heard.
Water that sits in household plumbing provides an opportunity for microorganisms associated with plumbing biofilms to accumulate. Flushing the line brings fresh water through the pipes.
This may be particularly useful for a faucet or shower that hasn’t been used for an extended period.
But I don’t think we need to turn every trip to the bathroom into an infection-control procedure!
There is a balance.
I try to understand the science, make the changes that are easy and reasonable for me, and then move on with my day.
What About Turning Up the Hot Water?
Heat is one of NTM's weaknesses, so naturally the temperature of our household water comes into the conversation.
Dr. Falkinham and other experts have discussed water heater temperatures as one way to reduce NTM in household plumbing.
But please don’t read this blog and immediately run downstairs and crank up your water heater.
Hot water can cause serious burns.
If you are considering changing the temperature of your water heater, talk with a qualified professional and make sure appropriate anti-scald protections are in place. This is especially important in homes with children, older adults, or anyone who may have reduced sensation.
We Can Reduce Exposure. We Cannot Eliminate It.
I think this is one of the most important messages for our community.
NTM are environmental organisms. They are part of our world.
They are found in water, soil, dust, and other places we encounter in everyday life.
We cannot completely avoid them.
And I don’t want anyone reading this to become frightened of taking a shower, turning on a faucet, gardening, traveling, or simply living their life.
I look at environmental precautions the same way I look at so many things related to bronchiectasis: learn the science, understand your own risk, make reasonable changes, and don’t let the disease take over your life.
There is a big difference between being informed and being afraid.
Want to Learn More about Bronchiectasis?
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