Thursday, 7 September 2017

Antibiotic resistance linked to household disinfectant triclosan


British scientists have found a connection between a significant mechanism of antibiotic resistance to the disinfectant triclosan. This chemical is found in many common domestic products. A report by Tim Sandle.
The research comes from two research centers: University of Birmingham and Norwich Research Park. For the scientists the results were unexpected and they discovered that certain bacteria which had mutated to develop resistance to quinolone antibiotics had also become more resistant to the common disinfectant triclosan. This is thought to happen because the quinolone-resistance mutation affected the way the bacteria hold DNA inside their cells. These mutants also appear to activate various self-defense mechanisms. The activation of these mechanisms-appears to provide triclosan resistance.
Quinolone antibiotics are a family of synthetic broad-spectrum antibiotic drugs. As medicines they exert an antibacterial effect by preventing bacterial DNA from unwinding and duplicating. Triclosan is an antibacterial and antifungal agent found in many consumer products, such as toothpaste, soaps, and detergents. Its efficacy as an antimicrobial agent is controversial. This relates to how well triclosan actually works as an antimicrobial agent and whether it makes a significant difference in killing or removing bacteria compared with, say, soap and water.
In addition, it may have an adverse environmental impact by accumulating in the environment and exerting influence over the ecosystem. For this reason triclosan has been banned in many regions, especially when used in hand hygiene products which readily run off into public sewers. Scientists are concerned that triclosan is increasingly detected in organisms living in waste-water and also in human blood plasma and in breast milk. The harmful effects, beyond water, are unknown but represented a cause for concern.
Commenting on the research findings, lead scientist Dr Mark Webber stated: "We think that bacteria are tricked into thinking they are always under attack and are then primed to deal with other threats including triclosan.” The effect was seen with Escherichia coli bacteria. The results are significant given the widespread use of triclosan and its tendency to remain in the environment.
What is unknown is whether the reverse can happen; that is if triclosan exposure could lead to the development of antibiotic resistant strains? This is a more controversial point since acquired bacterial resistance to disinfectants has not been definitively proven.
The research findings are published in the Journal of Antimicrobial Chemotherapy. The research is titled “Quinolone-resistant gyrase mutants demonstrate decreased susceptibility to triclosan.”


Posted by Dr. Tim Sandle