Control Of Microbial Growth

Question 1

Sterilization

Answer 1

Absolute removal or destruction of all microbial life and viruses - all microorganism must be removed including endspores

Question 2

Disinfection

Answer 2

Destruction of pathogenic microorganism - kills most but not all microbes

Question 3

Antisepsis

Answer 3

Disinfection of living tissue - requires less harsh of a chemical treatment

Question 4

Degerming

Answer 4

Removal of most microbes from a limited area

Question 5

Sanitization

Answer 5

Lowering the microbial counts on a surface such that they are at a safe level

Question 6

Bacteriocidal

Answer 6

An agent that kills microbes

Question 7

Bacteriostatic

Answer 7

An agent that stops the growth of microbes

Question 8

Asepsis (aseptic)

Answer 8

This is when an area is free of significant contamination

Question 9

Heat

Answer 9

Kills microbes by destroying their fundamental enzymes- bacteriocidal

Question 10

Boiling

Answer 10

Disrupts the protein structure and accomplishes disinfection

Question 11

Autoclave

Answer 11

Uses 15psi of pressure and 121°c of steams.kills all endospores and organisms. Best method for sterilization

Question 12

Pasteurization

Answer 12

Eliminates pathogens and reduce microbial counts -classic treatment is 63°c for minutes

Question 13

HTST pasteurization

Answer 13

High temperature , short-time:72°c for 15 second

Question 14

UHT pasteurization

Answer 14

Ultra - high temperature: 140° for 3 seconds

Question 15

Dry heat sterilization

Answer 15

Several method, kill via oxidation

Question 16

Direct flaming

Answer 16

Sterilize inoculation needles and crops, metallic instruments must be red to be considered sterile

Question 17

Incineration

Answer 17

Effective way to sterilize and dispose of contaminated materials

Question 18

Drying oven

Answer 18

Non - temperature sensitive materials are kept at 170°c for 2 hours

Question 19

Filtration

Answer 19

Vacuum is used to force liquid through a filter with very small pores,used to sterilize temperature sensitive liquid.

Question 20

Air filtration

Answer 20

High efficiency particulate Air(HEPA)filters used in some operating room to remove all microbes langer then 0.30 micrometer in diameter

Question 21

Refrigeration

Answer 21

Slows or stops microbial growths,and freezing stops microbial growth

Question 22

High pressure

Answer 22

High pressure, disturbs protein/ molecular structure, it is bacteriocidal but does not accomplish sterilization

Question 23

Desiccation

Answer 23

Used to control microbial growth so it is bacteriostatic, occurs through removal of water (drying), microbes can remain viable in a dehydrated state.

Question 24

Osmotic pressure

Answer 24

Movement of water from high to low concentration, it can kill some bacteria so it’s both bacteriocidal and bacteriostatic

Question 25

Radiation

Answer 25

Destroys DNA, x- ray and gamma rays penetrate materials, uv and high energy electron beams are used on surfaces.

Question 26

Microwaves

Answer 26

Use longer wavelengths,not of high energy to kill organism directly but the high temperature created by the microwaves are used disinfect materials

Question 27

The disk diffusion method

Answer 27

1. ) a disk of filter paper is soaked in the chemical disinfectant 2. ) the dish is placed on an agar plate that has been inoculated with bacteria. 3. ) the chemical will diffuse from the paper to the plate 4. ) the plate is incubated until the bacteria grow 5. ) the zone of clearance around the bacteria is used to determine the effectiveness of the disinfectant

Question 28

Phenolics and bisphenols

Answer 28

Disrupts The plasma membrane and denature protein making it bacteriocidal. Very effective, long lasting and stable with other organic compounds making it suitable for disinfection of surfaces entamimated by saliva, pus and feces. These are mixed with other compound to Lower their toxicity

Question 29

Phenolics examples

Answer 29

Lysol used for household disinfection

Question 30

Bisphenol example

Answer 30

Hexachlorophene- useful against bacteria that cause skim infection, use with caution because it may cause neurological disorders Triclosan - used in personal hygiene products and cosmetics

Question 31

Biguanides - chlorhexidine

Answer 31

Attacks the plasma membrane, it has broad spectrum of activity and is used to control the skin and mucous membranes.it is bacteriocidal but does not kill endospores

Question 32

Halogens

Answer 32

These are chlorine and iodine, they impair protein synthesis and alter membrane. Used as household bleach and iodine which is a every effective antiseptic.

Question 33

Chlorine

Answer 33

Used as gas or combined with other chemical. it is a strong oxidizing agent that destroys enzymes.

Question 34

Iodine

Answer 34

Most effective antibiotics, available as tincture in solution in aqueous alcohol and lodophore a combination of Iodine and organic molecule.

Question 35

Alcohols

Answer 35

Denature proteins, disrupts lipid membranes, it does not kill endospores or non-enveloped viruses. Ethanol and isopropanol are 2 types of alcohol most commonly used.

Question 36

Heavy metal

Answer 36

Metals such as copper, silver, zinc, and mercury can inhibit microbes. They are bacteriostatic

Question 37

Silver nitrate (1%)

Answer 37

Used as an antiseptic, eye drop for newborn to protect against gonorrhea of the eye

Question 38

Silver sulfadiazine

Answer 38

Combination of silver and sulfadiazine drug used as a tropical cream for burns

Question 39

Soaps and detergents

Answer 39

Surface agents - Do not work as antiseptics, they are important in the mechanical removal of microbes, soap break up the oil on the skin and the water washes it away , therefore they are good Degerming agents

Question 40

Quaternary ammonium compounds (quats)

Answer 40

Cationic detergents: kills most bacteria, fungi and some viruses, they are less effective against gram negative and affect the plasma membrane.

Question 41

Gaseous chemosterilizer

Answer 41

Chemical gas used for sterilization

Question 42

Gaseous chemosterilizer example

Answer 42

Ethylene oxide kills all microbes including endospores and viruses, is highly penetrating and requires 4-18 hours of exposure

Question 43

Oxidizing agents

Answer 43

Oxidize and denature proteins, it is useful against anaerobic organisms

Question 44

Hydrogen peroxide

Answer 44

Common antiseptics for wounds

Question 45

Ozone

Answer 45

Used with chlorine to disinfect water

Question 46

Benzoyl peroxide

Answer 46

Used as an antiseptic on skin, kills anaerobic bacteria living in tissue