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Microbial Control Agents and Their Mechanisms

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Terms in this set (15)

  • Phenols mechanism and use

    Mechanism: Punch holes in membranes and denature proteins/enzymes.
    Use: Disinfectants in household products like Lysol; limited use on living tissue due to irritation and strong odor.

  • Halogens mechanism and use

    Mechanism: Strong oxidizers that damage proteins, DNA, and membranes.
    Use: Chlorine bleach for surfaces and water; iodine/iodophors as antiseptics on skin (pre-op wipes), though they can stain and irritate.

  • Alcohols mechanism and use

    Mechanism: Denature proteins and dissolve lipids/membranes, especially effective on enveloped viruses.
    Use: Antiseptic/disinfectant for skin and small surfaces; works best around 70%; evaporates fast and does not kill endospores well.

  • Heavy metals mechanism and use

    Mechanism: Bind to sulfhydryl (-SH) groups on proteins, inhibiting enzyme function.
    Use: Silver in creams, dressings, catheters; copper surfaces; limited use due to toxicity.

  • Soaps/detergents mechanism and use

    Mechanism: Emulsify oils and physically remove microbes; can disrupt membranes slightly.
    Use: Degerming by handwashing; reduces microbial load mainly by removal rather than killing.

  • Quaternary ammonium compounds (Quats) mechanism and use

    Mechanism: Cationic detergents that disrupt membranes and denature proteins.
    Use: Disinfect noncritical surfaces like counters and floors; less effective against endospores and some viruses; inhibited by soaps and hard water.

  • Ethylene oxide mechanism and use

    Mechanism: Alkylates proteins and DNA, preventing function and replication.
    Use: Sterilizes heat-sensitive items like plastic syringes and catheters; toxic and explosive, requires special handling and aeration.

  • Hydrogen peroxide mechanism and use

    Mechanism: Oxidizer that damages proteins, membranes, and DNA; bubbling helps lift debris.
    Use: Antiseptic and disinfectant; at high concentrations can sterilize surfaces and equipment.

  • Why are phenols limited in use on living tissue?

    Because they cause irritation and have a strong, unpleasant odor.

  • What is the main limitation of alcohols as disinfectants?

    They evaporate quickly and do not effectively kill endospores.

  • How do heavy metals inhibit microbial enzymes?

    By binding to sulfhydryl (-SH) groups on proteins, stopping enzyme activity.

  • What is the primary action of soaps in microbial control?

    They emulsify oils and physically remove microbes from surfaces, mainly by degerming.

  • Why are quaternary ammonium compounds less effective against some microbes?

    They are less effective against endospores, some nonenveloped viruses, and can be inhibited by soaps and hard water.

  • What safety concerns are associated with ethylene oxide?

    It is toxic, explosive, and requires special handling and aeration time after sterilization.

  • How does hydrogen peroxide help remove debris besides its oxidizing action?

    The bubbling action helps lift debris from surfaces.