Monday, January 11, 2016

Do antibacterial soaps and wipes have any effect on antibiotic resistance? Should we use them in the home?

Over the Christmas holiday, our kitchen has fed more people than normal and cleaning has therefore increased.  I have been giving a lot of thought to the possible benefits and risks of using antimicrobial cleaners and soaps.  When you get into this subject, you find it is actually quite complex.

I have written about something similar before, but there is now a lot of published work that suggests that in most cases, there is no benefit to using antibacterial soaps in the home - there is no statistically significant reduction in infectious disease if antibacterial preparations are used in preference to soap and water*.  Nevertheless, in the US alone, nearly $1 billion per year is spent on antibacterial soaps**.

Of course, many infectious diseases are caused by viruses; they are probably not affected by antibacterial compounds, which have a definite target in the bacterial cell.  Thus, an antibacterial soap or wipe will be no better at preventing transmission of cold viruses than a thorough cleaning with soap or detergent and water.

I have recently been asked to review a couple of scientific papers in which evidence is presented that suggests cleaning agents commonly used in the food industry may induce antibiotic resistance in bacteria.  Antibiotic resistance results when bacteria develop enzymes capable of breaking down the active component of the antibiotic.  One of the first instances of antibiotic resistance occurred very soon after the introduction of penicillin.  Bacteria developed the ability to break the beta-lactam ring of penicillin with an enzyme called beta-lactamase.  (Antibiotic resistance genes can often be transferred from one bacterium to another, so in time, many bacterial strains become resistant.)

We already know that many of our antibiotics are no longer effective because of resistance.  Overuse of antibiotics is blamed.  It is ironic that our cleaning agents may also be causing resistance.

But there is another potential driver for antibiotic resistance: sub-lethal exposure of bacteria to certain herbicides have been shown to change antibiotic susceptibility of Escherichia coli and Salmonella enterica serovar Typhimurium***.  This is not a straightforward relationship, but it is clear that there is the potential to select for antibiotic resistance in these bacteria, which, if transferred to humans by contact with animals and food, can potentially reduce the effectiveness of antibiotic therapy.

Well, that's fairly heavy for the first post of 2016, but it should cause us to think when purchasing home cleaning agents and soaps, or chemicals for use in agriculture and domestic gardens.




* Effect of Antibacterial Home Cleaning and Handwashing Products on Infectious Disease Symptoms.  Larson, Elaine L;Lin, Susan X;Gomez-Pichardo, Cabilia;Della-Latta, Phyllis.  Annals of Internal Medicine; Mar 2, 2004; 140, 5

** https://www.nrdc.org/health/files/antimicrobials.pdf

*** Kurenbach B, Marjoshi D, Amábile-Cuevas CF, Ferguson GC, Godsoe W, Gibson P, Heinemann JA. 2015. Sublethal exposure to commercial formulations of the herbicides dicamba, 2,4-dichlorophenoxyacetic acid, and glyphosate cause changes in antibiotic susceptibility in Escherichia coli and Salmonella enterica serovar Typhimurium.  
mBio 6(2):e00009-15. doi:10.1128/mBio.00009-15.










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