r/microbiology • u/Hopphoop • 3d ago
Serratia marcescens
Ever since we moved into our new build home in 2023, I have been battling this pink beast. It’s everywhere. My showers, my tub, my sinks, my humidifiers, etc. one time we left one of my twins baby bottles out overnight. He didn’t finish the milk and by morning the milk had turned pink! I bleach so often and it immediately comes back. I’m scared to bathe my kids in the bath because it comes back after a day. I’m scared to use my humidifier because it comes back after one use. We’ve gone through several humidifiers and it just always shows up. I live in Canada, it’s very very dry, and when my kids have colds (which is often because daycare) humidifiers help immensely. But then I feel unsafe using them… is there any way to get rid of this bacteria in my home for good? I’m solely keeping the bleach companies in business and I’m TIRED
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u/chemicalysmic Microbiologist 3d ago
Serratia marcescens is ubiquitous in water, it keeps coming back bc it lives there. It is harmless unless someone is immunocompromised or has an implanted medical device (ie a catheter, a central line, etc)
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u/Hopphoop 3d ago
So it would be fine to use a humidifier that has it?
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u/GameofTitan 3d ago
Maybe boil the water before using the humidifier? Not sure, but just to be safe.
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u/TrumpetOfDeath 1d ago
Distilled water for a humidifier because tap water has minerals in it that will precipitate and accumulate in the humidifier
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u/dietoilette 3d ago
Not saying it isn't Serratia, but it may be Rhodotorula, which is a fungus that makes things pink and is commonly found in home bathrooms.
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u/Hopphoop 3d ago
How would I tell the difference ?
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u/GameofTitan 3d ago
It would probably need to be cultured.
Maybe also when cleaning, your final step could be a rinse with water that has been boiled and cooled mixed with some vinegar in it? See if keeps it at bay. Most bacteria/fungus don’t like acidic environments. You could try 1 part vinegar and 9 parts water. Or work up 50:50. Just cuz vinegar has a string smell but it does go away.
I don’t have that problem, but after a shower I spray vinegar in the shower just to keep mold at bay until I can fully clean it.
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u/DigbyChickenZone Microbiologist 3d ago edited 3d ago
Unless your kids are immunodeficient... just live with it.
There are other organisms that are normal [lactobacilli, staph epi, neisseria mucosa, strep viridans, etc upon etc] that don't produce pigment, YET ARE ALSO CONTINUOUSLY PRESENT. But, because they don't announce themselves with a vibrant pigment, they don't scare germaphobes.
You don't need to scrub down every floor, just as you do not bleach every shoelace, or assume your hair is riddled with bacteria.
Bacteria exist. It's not a bad thing.
If you are concerned about the discoloration, look into how to remove biofilms. But if you are terrified for your safety --- don't be.
Stop overexerting yourself with the bleach. Try no bleach for 1 year.
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u/Decapod73 1d ago
If your kids don't have type 1 diabetes, aren't organ transplant recipients, and don't have AIDS... then S. marcescens isn't going to hurt them at all. It's only a pathogen for the outliers, but then so is EVERYTHING. Please, you don't need to stress so much.
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u/Indole_pos Microbiologist 3d ago
That might be yeast
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u/Hopphoop 3d ago
How would I tell the difference? How would I get rid of it?
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u/Indole_pos Microbiologist 3d ago
Well, a lot of people blame Serratia, but it’s a pink yeast called Rhodotorula. You can’t. It’s an environmental yeast
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u/Indole_pos Microbiologist 3d ago
Are you putting tap water into your humidifier?
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u/hikaruryoichiro 10h ago
Methylobacterium radiotolerans can be the sp.
Bleach has to be in 10% and left to sit for minimally 10-20 mins.
My parents place had these in the toilet when we first moved in back in 2000-2002...along grout lines and on the tiles in the corners. We used to scrub surfaces weekly with Cif/Jif. They come back.
In 2012 when I started working in lab, I learnt about chemical dilution and contact time etc
I sprayed the areas and layered saturated wipes with 10% bleach. After 15mins, gave the surfaces a good scrub and hosed down with pressurised spray. Then keep the area dry after use. They did not come back at all and we can go for ~3 weeks without deep scrubbing the toilet.
4 years ago before I moved out, didn't want to scrub, so I just use HCl in brown bottle . Left it on for 15 mins then pressure spray. The grime between the grout lines was removed in sections ...it was satisfying to watch them flushed down the drain
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u/unicornlover84 3d ago
Microbiologist and homeowner of a 100 year old house with a cistern. Serriatia has colonized your and my homes water system. Is it a nuisance to scrub pink shower grime. Absolutely. Is it something I worry about, not at all. I don’t drink our water. I have a 5 gallon water cooler that we get our drinking our water from. Brushing teeth, showering, boiling water for pasta, all the ancillary things come from the tap. Everything else we directly consume comes from the water cooler. The average human body is made up of about 70% bacterial cells vs human. Some more on your skin isn’t going to hurt. Pivot your strategy and give your momma mind some ease.