6.16 Control of Microbes Flashcards
What is a nosocomial infection?
Healthcare associated infection
What is infection control?
- Sum of all means used to prevent HAI
- HAI’s are often antibiotic resistant
Define Asepsis
Preventing contact between microorganisms and susceptible sites
Define Sterilization
Destruction or removal of all microbial life inanimate objects, goal is to destroy endospores.
Define disinfection
destruction of most microbial life (destruction or removal of vegetative pathogens but not endospores) inanimate objects
Define antisepsis
Disinfection of living surface
Rank microbes from most resistant to least resistant
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
What are factors affecting death rates
- 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
What are temperature requirements for cleaning?
- 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
What are concentration requirements of alcohol
- Ethanol, isopropanol
- optimum 60-90% in H2O
What methods must be used to kill prions?
- Moist heat sterilization Autoclave 132 degrees celsius for 60-90 minutes
- Chemical sterilization: 1 N NaOH, for 1 hour
What are autoclaves used for?
- 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.
What can survive the autoclave?
Lipid A
What are the two types of Dry Heat sterilization?
- 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
Define Filtration as a method of physical sterilization
- 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
Can cold/freezing be used for sterilization?
No, used to preserve
Define ionizing radiation as a physical sterilization
- Gamma rays
- Speed, high penetrating power, no heat
- Used for Medical products: Drugs, vaccines, plastic medical instruments, syringes, surgical gloves, bone, skin heart valves.
Define UV as a physical method of sterilization
Poor penetration used on air, surface sterilization
Define chemicals as a method of sterilization
- Used for Heat sensitive items
- Endoscopes and other microsurgical instruments
- Remove organic mater first
What are common antiseptic agents?
Ethyl, isopropyl alcohol, iodine, chlorhexidine, and triclosan
What are methods of preventing HAI transmission in the operating room?
Sterile drapes, gowns, instruments, caps, and face mask
What are methods of preventing HAI transmission in the hospital ward?
Sterile needles, medications
What are methods of preventing HAI transmission in the outpatient clinic?
Segregate ill patients
What is the number one reason for the spread of HAI’s?
Improper or lack of hand washing
When does the WHO recommend using Soap and Water?
1) Visibly dirty
2) Visibly solid with blood or body fluids
3) After using the toilet
4) Exposure to potential endospore-forming pathogens
When does the WHO recommend using alcohol hand rub?
Routine hand antisepsis in all other clinical situations
What are two methods that food, milk, and pharmaceuticals can help prevent HAI?
Pasteurization of Milk or Desiccation of food and pharmaceuticals, does not kill all bacteria but most. Endospores survive.
