Question

5. Look up the chemical formulas for bleach, isopropyl alcohol, and chlorhexidine gluconate (the active ingredient in Hibiclens®). How does each chemical achieve its germicidal properties on the molecular level?

6. What are some real-world applications for a study like this? For instance, how would these results influence cleaning practices in a doctor's office or treatment of a disease?

Answer 1

5. Bleach

Bleach is the common name for Sodium hypochlorite (NaOCl) made up of sodium cation (Na⁺) and hypochlorite anion (Clo^-). It exhibits broad spectrum anti-microbial activity and hence is used as a disinfectant. Bleach is diluted in water depending on the intend of use. When dissolved in water, a weak acid, hypochlorous acid (HClO) is formed due to dissolution of chlorine in water. Hypochlorous acid, the active ingredient of bleach has the ability to denature proteins by oxidizing the cellular protein of bacteria. When heat and bleach act on the bacterial surface, the proteins present in the bacteria unfold and clump together, thus killing them.

Isopropyl alcohol

Isopropyl alcohol is a colorless, volatile, and flammable liquid with a strong odor. Its chemical formula is C₃H₇OH. It is a structural isomer of 1-propanol. It is a common ingredient of several household and industrial chemicals, detergents, antiseptics, and disinfectant.

It is not very effective in dehydrating living tissue and thus is a good source of disinfecting skin. It is therefore used for surface disinfection. These compounds have fast and high germicidal activity. They work by denaturing proteins and dissolving lipids, effectively destroying many bacterial and viral cells.

Hibiclens® is an antiseptic, antimicrobial skin cleanser. It is used in cleaning of skin to prevent the spread of infection. It is used during injection, surgery, or skin injury.

Chlorhexidine gluconate

The chemical formula of this compound is C₃₄H₅₄Cl₂N₁₀O₁₄. It is the gluconate salt form of chlorhexidine. Chlorhexidine gluconate is positively charged and has the ability to react with negatively charged microbial cell surface. This reaction destroys the integrity of cell membrane. In course of time, this compound penetrates into the bacterial cell and causes leakage of intercellular components leading to the death of cells. Gram positive bacteria are more sensitive to this agent owing to the fact that these bacteria have more negative charge.

6. Controlling infection is essential in a health care setting. Infection control is related to spread of infections within the health care setting, including prevention of the spread of infection. Some of the infection control facilities include hand hygiene, sterilization, cleaning, and disinfection.

Most of the disinfectants demonstrate broad spectrum antimicrobial activity, however knowing the mode of action of these chemicals is highly essential. For example, isopropyl alcohol as well as ethyl alcohol are considered to be effective against bacteria. But isopropyl alcohol is more efficacious against bacteria and ethyl alcohol against viruses. This is due to the fact that isopropyl alcohol has greater lipophilic property than ethyl alcohol.

Hence, knowing the specific mode of action of these chemicals is critical. Therefore, knowing germicidal properties of the disinfectants is essential in treatment strategies, cleanliness as well as controlling the spread of infection in a health care facility.