(P) Lec 2: Microbial Control Flashcards
The agent that kills the microorganism
Bactericidal
Community of bacteria
Biofilm
Are chemical agents applied to inanimate objects
Disinfectant
A substance applied to the skin for the purpose of eliminating
or reducing the number of bacteria present
Antiseptic
T or F: Antiseptic kills spores.
F (they don’t)
Also known as sodium hypochlorite
Bleach
Ratio when cleaning surfaces with sodium hypochlorite
1:5 or 1:10
List the types of organisms from most resistant to least resistant.
Prions
Bacterial spores
Mycobacteria
Nonlipid viruses
Fungi
Bacteria
Lipid viruses
List the types of organisms from least resistant to most resistant.
Lipid viruses
Bacteria
Fungi
Nonlipid viruses
Mycobacteria
Bacterial spores
Prions
Have coats rich in proteins, lipids, and carbohydrates as well as cores rich in dipicolinic acid and calcium
Bacterial endospores
What makes up the protection of the spores?
- Coats rich in proteins, lipids, and carbohydrates
- Cores rich in dipicolinic acid and calcium
Are rich in lipids, which may account
for their resistance to chemical and
environmental stresses, particularly
desiccation
Cell walls of mycobacteria
Containing lipid-rich envelopes are
more susceptible to the effects of
detergents and wetting agents
Viruses
Microorganisms living together in
communities
Biofilms
Also provide protection to the
microorganisms against chemical and
physical means of destruction
Biofilms
The organisms known today to be the
most resistant to the actions of heat,
chemicals, and radiation
Prions
Known as naked (put clothes on) pieces of protein
Prions
Are thought to be the agents that
cause a number of degenerative
diseases of the nervous system
Prions
These agents are transmitted to
humans through contaminated
medicinal products, therapeutic
devices, body fluids, and food
products
Prions
Prions are transmitted to humans through:
- Contaminated medicinal products
- Therapeutic devices
- Body fluids
- Food products
What are the two methods of disinfection and sterilization?
Physical and chemical methods
Physical Methods
Most common method used for the elimination of microorganisms
Heat
Physical Methods
Heat can be used in the following ways:
- Moist Heat/Heat under steam pressure
- Autoclaving
- Dry Heat
- Boiling (100°C)
- Pasteuraztion
Different Ways to Use Heat
The agent used in autoclaves
Moist Heat/Heat under steam pressure
Different Ways to Use Heat
Putting steam under 1 atm of pressure, or 15 psi, achieves a temperature of 121° C.
Moist Heat/Heat under steam pressure
Different Ways to Use Heat
Putting steam under ____ atm of pressure, or ____ psi, achieves a temperature of ____° C
1 atm of pressire
15 psi
121°C
Different Ways of Using Heat
Heat in water is transferred more readily to a cool body than heat in air
Moist Heat/Heat under steam pressure
Different Ways of Using Heat
The sterilization method of choice for heat-stable objects
Moist Heat
Different Ways of Using Heat
The most effective method of moist heat sterilization
Autoclaving
Different Ways of Using Heat
T or F: Autoclaves can destroy the sporeformers
T
Different Ways of Using Heat
May also be used as a sterilizing agent
Dry Heat
Different Ways of Using Heat
Requires much longer exposure times and higher temperatures
Dry Heat
Different Ways of Using Heat
Are methods that achieve disinfection but not sterilization
Boiling and Pasteurization
Different Ways of Using Heat
T or F: Boiling and pasteurization are able to eliminate spores
F (they do not)
Different Ways of Using Heat
Kills most microorganisms in
approximately 10 minutes
Boiling
Different Ways of Using Heat
Used mostly in the food industry
Pasteurization
Different Ways of Using Heat
Reduces food-borne pathogens and
organisms responsible for food
spoilage
Pasteurization
Different Ways of Using Heat
It is generally performed at 72° C (161° F) for 15 seconds
Flash Pasteurization
Different Ways of Using Heat
The Main Advantage: Treatment at this temperature reduces spoilage of food without affecting its taste
Pasteurization
Give the temperature, time duration, and application
Dry Heat
Temperature: 160 - 180°C
Time: 1.5 - 3 hours
Application/s: Sterilizes
Give the temperature, time duration, and application
Moist Heat
Temperature: 121.6°C
Time: 15 minutes at 15 psi
Application/s: Sterilizes, Kills Spores
Give the temperature, time duration, and application
Boiling
Temperature: 100°C
Time: 15 mins
Application/s: Vegetative Forms, Endospores survive
Give the temperature, time duration, and application
Batch Pasteurization
Temperature: 63°C
Time: 30 mins
Application/s: Vegetative Forms, Milkborne pathogens, Endospores survive
Give the temperature, time duration, and application
Flash Pasteurization
Temperature: 72°C
Time: 15 secs
Application/s: Vegetative Forms, Milkborne pathogens, Endospores survive
What are the other ways heat is utilized in sterilization and disinfection?
Hot Air Oven: 170°C for 2 hours
Incineration: 300 to 400°C (Infectious Waste)
Cremation: Control of communicable diseases
Flaming: Inoculating needles
Physical Methods
May be used with both liquid and air
Filtration
Physical Methods
The liquid is pulled (vacuum) or pushed (pressure) through the filter matrix
Filtration
Physical Methods
Most common application of filtration
The sterilization of heat-sensitive solutions (parenteral
solutions, vaccines, and antibiotic solutions)
Physical Methods: Filtration
Uses vacuum for parental/antibiotic solutions, toxic
chemical and vaccines
Plastic Polymers or Cellulose Esters (0.22um)
Physical Methods: Filtration
For isolation rooms and BSC
HEPA Filters
Physical Methods: Filtration
Removes microorganisms larger than 0.3um
HEPA Filters
Physical Methods
May be used in two forms (ionizing and non-ionizing)
Radiation
Ionizing Radiation or Non-Ionizing Radiation
In the form of x-rays, gamma rays and electron beams
Ionizing Radiation
Ionizing Radiation or Non-Ionizing Radiation
Short wavelength and high energy
Ionizing Radiation
Ionizing Radiation or Non-Ionizing Radiation
Used by the medical field for the sterilization of disposable supplies such as syringes, catheters, and gloves
Ionizing Radiation
Ionizing Radiation or Non-Ionizing Radiation
In the form of ultraviolet rays is of long wavelength and low energy
Non-ionizing Radiation