Antimicrobial Agents in Household Use Triclosan

Antimicrobial Agents in Household Use: Triclosan

Describe how Triclosan works on a molecular level. Explain how Triclosan differs from soap and bleach in its antimicrobial activity.

Triclosan blocks the active site of the enoyl-acyl carrier protein reductase enzyme (ENR), this is the vital enzyme in the synthesis of fatty acid in bacteria (Levy et a, 1999). Blocking this active site by triclosan leads to the inhibition of the enzyme thus preventing the synthesis of the fatty acid by the bacteria, a process needed for building cell membranes and reproduction. Given the fact that this ENR enzyme exists in humans, triclosan has been considered to be relatively friendly to humans. Due to its strong nature of inhibition, powerful antibacterial action can be achieved using only a small amount of triclosan.

Triclosan differs from soap and bleach in the mechanism of action. Levy et al. (1999) also clarify that whereas triclosan interferes with a specific bacterial enzyme, soap and bleach destroys and dislodges bacteria microbes. Soap and bleach merely break open the cell while triclosan easily penetrates the bacterial cell wall since it is fat-soluluble, on penetrating the cell it attacks an enzyme which is responsible for producing fatty acids that are necessary for functioning of the cell.

2. How does Triclosan-resistance lead to cross-resistance? Explain.

The mode-of-action of triclosan described above gives the possibility of development of antibiotic resistance. When triclosan is used for a long period the non-resistant bacterial strains would be killed, this leaves only the bacteria whose enzyme system have undergone evolution to resist triclosan. The overuse of triclosan could reduce effectiveness of antibiotics which are currently useful especially those targeting the same enzyme system as triclosan (Poole, 2002).

3. Describe the effect of having "antimicrobial" household products on the bacterial population in the home. Consider the evolutionary pressure that is being applied to that environment.

Antimicrobial such as trichlosan have been reported to have effect to both humans and the environment. This includes increased allergy especially in children, creation bacterial resistance and production of harmful by-products, toxicity to the environment as well as possible human carcinogen. With such possible effects health experts have been campaigning for the withdrawal of antimicrobial products, however, withdrawing such products may not seriously affect the bacterial population in the home since there are effective alternatives to triclosan such as nonorganic antibiotics.

4. Can Triclosan be found in the waterways? What is the result of this?

Triclosan can be found in the waterways especially through runoff which usually enters the drains untreated flowing directly into waterways and other water bodies, this is not likely with wastewater which is treated unlike most runoff. When water is treated a very small percentage of triclosan remains, the efficiency is dependent on the treatment plant operations (Bester, 2003). This presence of triclosan in waterways is harmful to aquatic organisms since triclosan is toxic. Lindstrom and others (2002) note that the structure and function of algal communities may also be influenced by the presence of triclosan and this can lead to a shift in the processing capacity of nutrient and the natural structure of the food web.

5. Does Triclosan bio-accumulate in humans and/or animals?

Given that triclosan is lipophilic, it has the ability of bio-accumulating in faty tissues thus can be absorbed in both the human and animal body. Studies have also revealed bioaccumulation of triclosan in fish and this is dangerous since the concentrations found in fish are much higher than in water column. Bioaccumulation of triclosan is also enhanced by the relative stability of a transformation product, methyl triclosan, in the environment making it available (Levy et al., 1999).