Scientists comment on the US Food and Drug Administration statement on antibacterial soap

 Tuesday 17 December 2013

 There have been some reports in the media about the use of antibacterials in over the counter soaps and their potential effects on health and bacterial resistance. See the links below for the story and my take on the issues raised are thereafter, story links: http://www.bbc.co.uk/news/world-us-canada-25405037 and http://www.dailymail.co.uk/news/article-2524701/FDA-say-antibacterial-soaps-pose-health-risks.html

My comments on the story:

“Whilst there is some evidence that bacteria have developed resistance to antimicrobial chemicals such as triclosan (amongst others) in the laboratory, this has not been reproducibly observed in the clinical or home based settings. What is clear is that there is a knowledge gap here that needs to be further studied to ensure we have a full understanding of how any changes may occur to effectively limit the potential of the emergence of antibiotic resistance in the future. We need to fully determine whether or not the inclusion of antimicrobial chemicals in ‘over the counter’ products provides any real benefit or greater efficacy when compared to what might be termed as ‘traditional’ products.

“Concerns regarding the inclusion of antimicrobial agents in ‘over the counter’ products such as soaps, is not new and the question has recently been raised again by the FDA. Some of these concerns relate to the possible development of antibiotic cross-resistance in some bacteria. Historically, the development of resistance following the inclusion of chemicals such as triclosan in products has been of limited concern. This is largely due to the broad spectrum activity of the chemical coupled with the targeting of multiple bacterial targets. This, in general terms, means that development of resistance is more difficult. However some studies have called this thinking into question following observations that certain bacterial components (an enzyme called enoyl‐acyl carrier protein reductase) can be affected by the action of the chemical. It has been suggested that the overproduction of this enzyme, blocking the transfer of triclosan into the cell or active pumping of the chemical out of the cell all might help lead to resistance to triclosan occurring. Another interesting observation is that at higher concentrations of chemicals such as triclosan work against several bacterial cell targets, but at lower concentrations (below those that are normally routinely used) the chemical becomes more selective in its targets.

“The link between chemicals like triclosan and antibiotic resistance have been examined and the findings suggest that, typically, the use of triclosan (at the correct concentration) was effective against many bacteria, with the exception of Pseudomonas aeruginosa, which is naturally resistant to the action of triclosan. Some studies have shown that in the laboratory the exposure to chemicals such as triclosan might help decrease bacterial sensitivity to some antibiotics in some strains. However, this correlation has not been reported in studies from a clinical setting, nor has it been shown in the home setting. Some laboratory based studies have shown that isolates of Salmonella species and E. coli have shown evidence of cross- resistance between antibiotics and antimicrobials used in the clinical setting. However, the study notes that this has not been confirmed in the clinical setting. So it is clear, especially in light of the ongoing concern with antibiotic resistance that we need to study any potential link with antimicrobial chemicals and the development of any antibiotic resistance.”