Controlling Microbial Growth In The Environment Flashcards

1
Q

Antisepsis

A

Reduction in the number of microorganisms and viruses, particularly potential pathogens on living tissue

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2
Q

Aseptic

A

Refers to an environment or procedure free of pathogenic contaminants

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3
Q

-cide or -cidal

A

Suffixes indicating destruction of a type of microbe

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4
Q

Degerming

A

Removal of microbes by mechanical means

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5
Q

Disinfection

A

Destruction of most microorganisms and viruses on non-living tissue

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6
Q

Pasteurisation

A

Use of heat to destroy pathogens and reduce the number of spoilage microorganisms in food and beverages

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7
Q

Sanitisation

A

Removal of pathogens from objects to meet public health standards

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8
Q
  • stasis

- static

A

Suffixes indicating inhibition but not complete destruction of a type of microbe

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9
Q

Sterilisation

A

Destruction of all microorganisms and viruses in or on an object

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10
Q

Action of antimicrobial agents

A

Alteration of cell walls - when damaged effects of osmosis can cause cell to burst
Cytoplasmic membrane- contents leak out
Non-enveloped viruses can better tolerate harsh conditions
Damage to proteins and nucleic acids -alter or destroy, fatal mutants, halt synthesis

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11
Q

Most resistant to least resistant

A
Prions
Bacterial endospores
Mycobacterium
Cysts of Protozoa
Active stage Protozoa (trophozoites)
Most gram negative bacteria
Fungi
Nonenveloped viruses
Most gram positive bacteria
Enveloped viruses
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12
Q

High level germicides

A

Kill all pathogens including endospores

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13
Q

Intermediate-level germicides

A

Kill fungal spores, protozoan cysts, viruses and pathogenic bacteria

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14
Q

Low-level germicides

A

Kill vegetative bacteria, fungi, Protozoa and some viruses

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15
Q

Moist heat

A

Used to disinfect, sanitise, sterilise and pasteurise
Denatures proteins and destroys cytoplasmic membranes
More effective than dry heat

Boiling
Autoclaving
Pasteurisation
Ultrahigh-temperature sterilisation

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16
Q

Desiccation and lyophilisation

A

Desiccation (drying) inhibits growth due to removal of water
Lyophilisation (freeze-drying) used for long term preservation of microbial cultures - prevents formation of damaging ice crystals

17
Q

Radiation

A

Particulate radiation - high speed sub atomic particles

Electromagnetic radiation - energy without mass travelling at the speed of light

18
Q

Phenol and phenolic

A

Denature proteins and disrupt cell membranes
Effective in presence of organic matter
Remain active for prolonged time
Commonly used in health care settings, labs and homes
Have disagreeable odour and possible side effects

19
Q

Alcohols

A

Intermediate-level disinfectants
Denature proteins and disrupt cytoplasmic membranes
More effective than soap
Swabbing skin with alcohol prior to injection removes most microbes

20
Q

Halogens

A

Include iodine, chlorine, bromine and fluorine
Intermediate-level antimicrobial chemicals
Damage proteins by denaturation

21
Q

Oxidising agents

A
Peroxide’s, ozone, and peracetic acid
Kill by oxidation of microbial enzymes
High-level disinfectant
Hydrogen peroxide can disinfect and sterilise wounds because of catalase activity
Ozone treatment of drinking water
22
Q

Surfactants

A

Surface active chemicals
Reduce surface tension of solvents
Soaps and detergent
Low-level disinfectants

23
Q

Heavy metals

A

Heavy-metal ions denature proteins
Low-level bacteriostatic and fungistatic agents
Thimerosal used to preserve vaccines
Copper controls algal growth

24
Q

Aldehydes

A

Compounds containing -CHO groups
Denature proteins and inactivate nucleic acids
Glutaraldheyde disnifects and sterilises
Formalin used in embalming and in disinfection of rooms and instruments

25
Q

Enzymes

A

Antimicrobial enzymes act against microorganism
Human tears contain lysozyme - digests peptidoglycan wall of bacteria
Lysozyme is used to reduce the number of bacteria in cheese