Didn't know about biofilms (bacterial or other) earlier. The basic idea is intuitive (which is why I gargle with salt water regularly), but googled biofilm now and found a lot of info - it is complex. Thanks for mentioning it!

Saw this:

https://en.wikipedia.org/wiki/Biofilm#Biofilms_and_infectiou...

https://en.wikipedia.org/wiki/Biofilm#Dental_plaque

The article says:

"Biofilms have been found to be involved in a wide variety of microbial infections in the body, by one estimate 80% of all infections"