6.16 Control of Microbes

Question 1

What is a nosocomial infection?

Answer 1

Healthcare associated infection

Question 2

What is infection control?

Answer 2

• Sum of all means used to prevent HAI

- HAI’s are often antibiotic resistant

Question 3

Define Asepsis

Answer 3

Preventing contact between microorganisms and susceptible sites

Question 4

Define Sterilization

Answer 4

Destruction or removal of all microbial life inanimate objects, goal is to destroy endospores.

Question 5

Define disinfection

Answer 5

destruction of most microbial life (destruction or removal of vegetative pathogens but not endospores) inanimate objects

Question 6

Define antisepsis

Answer 6

Disinfection of living surface

Question 7

Rank microbes from most resistant to least resistant

Answer 7

1) Prion
2) Endospore
3) Biofilms
4) mycobacteria
5) Naked viruses
6) Protozoan cysts
7) Fungi
8) Most bacterial vegetative cells
9) Enveloped viruses
10 Protozoan Trophozoites

Question 8

What are factors affecting death rates

Answer 8

• Presence of interfering organic mater
• Completely cleaned of prior to disinfecting.
• Manual cleaning minimizes the chances of bacterial biofilm developing on tools
• Duration of exposure
• Temerature
• Concentration

Question 9

What are temperature requirements for cleaning?

Answer 9

• Endospores of Clostridium botulinum may survive 5 hours of boiling, but can be killed in 4 min at 121 degrees Celsius in autoclave.
• Autoclave 121 degrees celsius, 15 minutes
• Flash autoclaves 134 degree celsius 3 minutes
• Batch pasteurization 63-66 degree celsius for 30 minutes
• Flash pasteurization 72 degree celsius for 15 seconds

Question 10

What are concentration requirements of alcohol

Answer 10

• Ethanol, isopropanol

- optimum 60-90% in H2O

Question 11

What methods must be used to kill prions?

Answer 11

• Moist heat sterilization Autoclave 132 degrees celsius for 60-90 minutes
• Chemical sterilization: 1 N NaOH, for 1 hour

Question 12

What are autoclaves used for?

Answer 12

• Moist heat or steam
• Effective for most materials except temperature sensitive or water resistant substances like oils, waxes, or powders.
• Good for glassware, metallic instruments, non-heat sensitive liquids, or waste.

Question 13

What can survive the autoclave?

Answer 13

Lipid A

Question 14

What are the two types of Dry Heat sterilization?

Answer 14

• Hospital incinerator
  1) Disposal of infectious material
  2) syringes, dressing, pathology samples.
• Oven
  1) clinic, lab
  2) 150-180 degrees celsius for 2-4 hours
  3) Good for glassware, metallic instruments, oils, powders

Question 15

Define Filtration as a method of physical sterilization

Answer 15

• Pore size determines types of microbes removed
• Applications
  1) Liquids that can’t be heated, serum, vaccines, drugs, IV fluids.
  2) Enzymes, media, airborne contaminants
  3) DOES NOT REMOVE TOXIN

Question 16

Can cold/freezing be used for sterilization?

Answer 16

No, used to preserve

Question 17

Define ionizing radiation as a physical sterilization

Answer 17

• Gamma rays
• Speed, high penetrating power, no heat
• Used for Medical products: Drugs, vaccines, plastic medical instruments, syringes, surgical gloves, bone, skin heart valves.

Question 18

Define UV as a physical method of sterilization

Answer 18

Poor penetration used on air, surface sterilization

Question 19

Define chemicals as a method of sterilization

Answer 19

• Used for Heat sensitive items
• Endoscopes and other microsurgical instruments
• Remove organic mater first

Question 20

What are common antiseptic agents?

Answer 20

Ethyl, isopropyl alcohol, iodine, chlorhexidine, and triclosan

Question 21

What are methods of preventing HAI transmission in the operating room?

Answer 21

Sterile drapes, gowns, instruments, caps, and face mask

Question 22

What are methods of preventing HAI transmission in the hospital ward?

Answer 22

Sterile needles, medications

Question 23

What are methods of preventing HAI transmission in the outpatient clinic?

Answer 23

Segregate ill patients

Question 24

What is the number one reason for the spread of HAI’s?

Answer 24

Improper or lack of hand washing

Question 25

When does the WHO recommend using Soap and Water?

Answer 25

1) Visibly dirty
2) Visibly solid with blood or body fluids
3) After using the toilet
4) Exposure to potential endospore-forming pathogens

Question 26

When does the WHO recommend using alcohol hand rub?

Answer 26

Routine hand antisepsis in all other clinical situations

Question 27

What are two methods that food, milk, and pharmaceuticals can help prevent HAI?

Answer 27

Pasteurization of Milk or Desiccation of food and pharmaceuticals, does not kill all bacteria but most. Endospores survive.