A plea to stop ignoring microbial ecosystem effects of antimicrobial agents

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Well, the stories just keep coming about antimicrobial agents we can use to kill off some pathogen in our environment.  Today’s is about plasma – yes plasma – and how it can deactivate norovirus in the environment: ‘Cold plasma’ kills off norovirus from the BBC.   The article discusses a new study in the journal mBio.  Some key sections of the article are below:

Cold plasma treatment led to a roughly 20- to 50-fold reduction in the number of virus particles.

The viruses were destroyed because cold plasma consists of highly noxious ions, called reactive nitrogen and oxygen species, which exhibit potent antimicrobial activity.

Moreover, the cold plasma generator, which produces the ions by applying an electric field to ambient air, could be designed as a handheld device. Alternatively, commonly contaminated surfaces, such as salad bars, could have cold plasma generators built into them.

Besides decontaminating surfaces, cold plasma may have other medical applications. For instance, its use in treating dental caries has recently completed phase II clinical trials in the United States.

So basically we have a new antimicrobial agent and, since it has been shown to kill pathogens, therefore, we should use it.  This type of logic is fundamentally flawed as it is the same logic which has led to overuse of antibiotics, which it turn contributed to the rise of antibiotic resistance and also, possibly, to the rise in various human ailments.

We desperately need to change the tenor of the whole conversation here.  We are not at war with all microbes.  If we apply cold plasma to every surface and other locations where norovirus or other pathogens might be found, we will also disturb the entire microbial community in those locations.  And I see nothing in this report or the study on how cold plasma alters the rest of the microbes in a location.  Nor do I see anything about resistance and how use of cold plasma might affect resistance to this or other agents.  Antimicrobial agents need to be used with caution and care – and they need to be tested not just for their affect on a pathogen of interest, but on the ecosystems where they are applied.

This is of course but one of 100s of examples of the promotion of antimicrobial agents without consideration of ecosystem level effects.  Yes, in many situations antimicrobial agents can be beneficial, but it is very clear we can no longer ignore how they affect microbial communities.


See also:

A disturbing trend — casual and reckless use of antimicrobial agents in building materials.

2 thoughts on “A plea to stop ignoring microbial ecosystem effects of antimicrobial agents

  1. The disruption of microbial ecology is an appropriate concern.

    Our efforts to kill microbes can have direct adverse consequences for human health and well-being, too. As an illustration, quoted below are three sentences from the introduction of a recently accepted paper in Indoor Air (DU Park et al., Estimating retrospective exposure of household humidifier disinfectants).

    “In South Korea, several types of disinfectants have been widely used in humidifiers since 1994 to prevent microbial contamination, but their use has been banned since 2011 due to concerns about their health effects. … South Korea is believed to be the only country where a disinfectant was added to the water in humidifiers for extended periods of time … Several epidemiological studies conducted in South Korea have concluded that humidifier disinfectants can cause fatal lung disease, including interstitial pneumonitis and wide spread lung fibrosis, necessitating lung transplantation.”


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Jonathan Eisen

I am an evolutionary biologist and a Professor at U. C. Davis. My lab is in the UC Davis Genome Center and I hold appointments in the Department of Medical Microbiology and Immunology in the School of Medicine and the Department of Evolution and Ecology in the College of Biological Sciences. My research focuses on the origin of novelty (how new processes and functions originate). To study this I focus on sequencing and analyzing genomes of organisms, especially microbes and using phylogenomic analysis (see my lab site here which has more information on lab activities).  In addition to research, I am heavily involved in the Open Access publishing and Open Science movements.