thank you!

I know a few bacterial pathogens can get through mucus at the very least, and those all have some fun ways of doing so. i know one that chemically alters the mucus around it to be less goopey. heliobacter pylori I believe but this is off the cuff

mucus is stuffed full of commensal bacteria though, and thwy provide quite a barrier to most pathogens. on top of mucus being turbo viscous. its sort of like a peace offering of "here you go microbes, go live here and not on my tissues pleas". many microbes can actually eat mucin so theres a minor arms race between the commensal guys and pathogenic bacteria in that regard

so your mucus is this living microbiome! i say commensal but some evidence points to borderline mutualistic symbioses, too! theres some bacteria in there which seem to have really positive health effects. i love mucus i love microbiota i love bacteria