Yesterday, we finished our discussion of fish- and how what we buy (actually who grows them) is increasing antibiotic resistance.  After all, if we keep feeding fish a slew of antibiotics, it shouldn’t be surprising that more microbes learn how to fight off our pharmaceutical defenses.

But, there are other problems when we try to get rid of infections in our bodies.  Like our use of antibacterial chemicals.  We are now finding that our (nearly indiscriminate) use of triclosan in soaps, cleansers, and toothpastes is doing the opposite of what we’d expect.  Triclosan is helping MRSA (methicillin-resistant Staphylococcus aureus)  counteract the effects of our antibiotics.

Triclosan doesn’t kill microbes- instead, this additive stops them from multiplying.  We call this compound an ‘anti-bacterial  or an ‘anti-fungal’ agent.  But, our widespread usage (triclosan is used in soaps, detergents, toothpastes, surgical cleaners, among other applications) of the compound has allowed the MRSA to develop a greater immunity to other drugs.  Which is why the FDA (Food and Drug Administration) has banned triclosan in consumer hand soaps (this is effective as of September 2017).  And, the FDA may spread the ban to other products.

Dr. Petra Levin and her postdoc Dr, Corey Westfall of Washington University (St. Louis) just published a study of triclosan in conjunction with some antibiotics to determine effectiveness against Escherichia coli (e. coli) and Staphhylococcus aureus.  When streptomycin or ciprofloxacin were augmented with triclosan, the microbes were some 10,000 more likely to survive than if triclosan was omitted from the cocktail. When kanamycin was tested with triclosan, resistance was some 1000 X normal levels.  And, triclosan protected (rather than inhibited) MRSA from vancomycin, one of the last antibiotics with effectiveness against such infections.

The problem is we don’t know the pathway or mechanisms that afford triclosan its ability to retard microbial growth.   (For example, a new study just demonstrated that there is no effect on our intestinal microbiota.  We are only sure that triclosan is an endocrine disruptor. [it mimics/alters thyroid, estrogen, and testosterone functionality.])  It is possible that when triclosan inhibits microbial growth, the bacteria don’t complete all their life cycles stages.  As such, the almost dormant microbe uses this dormancy period to ‘learn’ how to become resistant (it adapts)  to the various antibiotics.

Another example of too much of a good thing is not so good…

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