[kpozin]

Note:

> biocide-exposed spores were spiked onto surgical scrubs and patient gowns and recovery was determined by a plate transfer assay

The article says nothing about washing scrubs and gowns. They put bleach-treated spores onto fabric, did not treat the fabric, and then collected samples from the fabric.

[TeMPOraL]

I.e. this is less of a "spores on gowns surviving disinfection" case, and more of a "you bleached this surface, you thought it's enough, but your gown touched it too early and the fabric 'rescued' the spores" one, am I right?

[haldujai]

Yes, the relevance is providers don’t change scrubs between patients (although do wear typically disposable gowns and gloves when entering a patient room with c. diff).

Also relevant for things that travel between rooms and are disinfected in between, like ultrasound machines.

Other studies have reported that spores can survive washing processes in use.

https://pubmed.ncbi.nlm.nih.gov/30322417

[vaidhy]

The fact the spores were treated with bleach and were still active means that you treating the fabric with the same biocide will not kill the spores.

Spores alone survive the bleach. Spores + fabric will survive the bleach. Hence treated fabric cannot be considered safe.

[derefr]

You don't just sterilize fabric with bleach. (How would that even work? Hang the gown, spray the bleach on it, and let it drip off?) You sterilize fabrics with bleach + water + detergent + heat + agitation — with the goal not being to lyse the spores/other germs, but rather to detach all the contaminants from the fabric and suspend them in the water — which then gets flushed away.

In theory, bleach could help decrease the adhesion of the spore to a surface. A possible mechanism would be if it oxidized — and so weakened/destroyed — some spiky organic hooks that the spores were using to adhere to the fabric.

Of course, agents other than bleach — things not normally considered biocides, in fact — would likely be a lot more effective at removing spores during fabric washing, since the goal is detachment, not lysing the spore.

The obvious things (detergents themselves, and other soaps) would work, of course, to varying degrees.

But also, less-obvious things could provide benefits here. For example, if spores tended to stay adhered to fabrics because they possessed a rough proteinous exosporium that acted sort of like nano-scale velcro, then conditioners (yes, like the kind you use in hair) might get that protein coat to relax and lay flatter, in a way that disrupts the velcro-like effect.

Lubricants might also work, by "filling up" the rough valleys of the spore's surface. (Of course, you'd then need an extra wash cycle to remove the lubricants.)

[exmadscientist]

There are some really amazing detergents out there. My go-to for cleaning anything I don't have specific information about is Tergajet. It's gentle, extremely powerful, low-foaming (so machine compatible), oxidizing, bleach compatible, and contains a protein degradation enzyme potent enough to disrupt prions: https://technotes.alconox.com/detergents/tergazyme/do-enzyme...

The downside to this magic stuff is that it's fairly expensive ($45 for 4 pounds). So, not for wanton use. But well worth it to solve tough problems or when time is more important than money.

[hinkley]

oxidizing and bleach compatible is an unusual pairing is it not? There are a bunch of chemicals you can't mix with bleach because you create chemical weapon precursors if you do. Even the precursors can send you to the ER.

[thfuran]

>oxidizing and bleach compatible is an unusual pairing is it not?

I don't think it is. Isn't bleach itself an oxidizing agent?

[jojobas]

Additionally, if the spore didn't get detached in the washing process, it's veeeery unlikely to get detached when you're just walking around being a nurse.

It might activate within the fabric if the conditions are right, but that's not very fast and you shouldn't be wearing scrubs contaminated by a nutritional substance for too long anyway.

[askvictor]

Indeed; this is why washing hands with soap is effective even though the soap doesn't kill the pathogens.

[haldujai]

The drying is probably the more effective part for mechanical disruption.

Similarly why bleach wipes > soaking in bleach for disinfecting surfaces, as alluded to in this paper.

[chiefalchemist]

Perhaps. But why not test that then? Why the special non-real life case? Because it got a result worth sensationalizing? For me, it makes me wonder what other study "gymnastics" they used.

I hear ya. But to mitigate any doubt they should have covered all their bases, or at least the base most inline witb real life.

[haldujai]

This is a real life case.

This article explores surface disinfection (commonly bleach in the hospital). Although provider gowns are removed after entering contaminated rooms, disinfected surfaces commonly come into contact with provider scrubs which are not laundered in between same day patient encounters as well as other patients (such as the table of a CT or MRI).

I don’t see the gymnastics you’re referring to, other studies have looked at laundering processes which is not the focus of this study.

https://pubmed.ncbi.nlm.nih.gov/30322417/

https://academic.oup.com/lambio/article/75/6/1449/6989408

[refulgentis]

That doesn't necessarily follow --

it's tempting because it seems obvious.

If X + Y = Z, X on surface + Y = Z _must_ follow, because "on surface" was just a hidden term in X + Y = Z anyway...right?

But, both biology and fabrics have a lot of hidden surface (pun intended :P)