[MICRO20] Lec 5: Strategies of Microbial Control (Flashcards)

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Mesophiles

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Mesophiles

Medically important entities and microorganisms that survive in temperatures that also support human life

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6.5 to 7.5

Optimum pH level for bacterial growth

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Obligate aerobe

Organisms, such as bacteria, that only grow in an aerobic environment.

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Obligate anaerobe

Oxygen is toxic to their survival. These are microorganisms killed by normal atmospheric concentrations of oxygen.

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Sterilization

This is done for the removal or destruction of all living microorganisms.

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Disinfection

This is done for the destruction of vegetative (non-endospore-forming) pathogens on inanimate objects.

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Antisepsis

This is done for the destruction of vegetative (non-endospore-forming) pathogens on living tissue

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Degerming or degermation

This is done for the removal of microbes from a limited area

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Sanitization

This is done to lower microbial counts to safe public health levels and minimize the chances of disease transmission from one user to another.

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  1. Number of microbes

  2. Environmental influences

  3. Time of exposure

  4. Microbial characteristics

The rate of microbial death is affected by which factors

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Autoclaving

A process wherein steam at a pressure of about 15 psi (121 degrees C) will kill all organisms (but not prions) and their endospores in about 15 minutes.

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Pasteurization

A process applied to more viscous material and to food with high fat content

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Filtration

Type of Physical method that is used to sterilize heat-sensitive materials. For example: High-efficiency particulate air (HEPA) filters.

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Desiccation specifically Lyophilization or freeze-drying

A process in which water is removed from a product after it is frozen and placed under a vacuum.

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UV light

Type of nonionizing radiation that damages the DNA of exposed cells by causing bonds to form between adjacent pyrimidine bases, usually thymidines, in DNA chains.

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Diffusion method

Used to know if the chemicals are able to inhibit microbial growth. Petri dishes are inoculated with bacteria, together with discs that have chemicals in them.

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Bacterial spores

These microorganisms were known to be resistant because they have tested different disinfectants and yet most of them had no effects on the bacterial spores.

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Phenols

  • Can injure lipid-containing plasma membranes

  • Remain active in the presence of organic compounds

  • Persist for long periods after application

  • These days, we rarely use phenols as it irritates the skin and has a disagreeable odor.

The information above refers to what?

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Joseph Lister

The use of phenols as an antiseptic was first done by _______, a British surgeon. He used a phenolic compound during his surgery, in wounds, and other surgical site infections.

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1% silver nitrate

This metal was historically used to prevent the occurrence of neonatal conjunctivitis caused by gonorrhea.

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Formalin

It is called the solution of formaldehyde and water.

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Ethylene oxide

It is a chemical sterilizer that kills all microbes and endospores but requires a lengthy exposure period of several hours.

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Hydrogen peroxide

Not a good antiseptic for open wounds (only forms bubbles when used on skin due Staphylococcus aureus on the skin acting on the hydrogen peroxide). It is, however, effective in disinfecting inanimate objects.

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Biofilm

Thin, slimy layer encasing bacteria that adheres to a surface.

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Quorum sensing

Cell-to-cell chemical communication, allows bacteria to coordinate their activity and group together into communities

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Quaternary Ammonium Compounds

It is strongly bactericidal against gram-positive bacteria and less active against gram-negative bacteria.

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Benzoyl Peroxide

Established anti-acne because it has action towards the microbial agent that contributes in formation of acne which is Propionibacterium acnes.

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Inducer

Bacteria that use quorum sensing produce and secrete a signaling chemical called an ______.

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Iodine

This type of halogen impairs protein synthesis. It also alters cell membranes by forming complexes with amino acids and unsaturated fatty acids.

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True

TRUE OR FALSE

No single disinfectant is appropriate for all circumstances.

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