Micro CH 9 Flashcards
Highly Resistant Microbes
Endospores- Very resistant to heat and chemicals
Naked viruses- Hard to kill without an envelope
Mycobacterium- Tough cell wall, making them harder to kill
Levels of Microbe Removal
Sterilization- Kills all microbes, including endospores
Disinfection- Kills most microbes except endospores
Sanitization- Reduces microbes to safe level
Antisepsis- Kills microbes in living tissue
Degermation- Reduces microbes on skin before procedures, mainly
Targets of Antimicrobial Agents
Cell Wall- Agents disrupt the cell wall, causing the cell to burst.
Cell Membrane- Agents disrupt the cell membrane, causing leakage of cell contents
Proteins- Agents denature proteins, making them nonfunctional
DNA/RNA- Some agents inhibit DNA/RNA synthesis, preventing cell replication
Factors that Influence Factors of Control Agents
PH, Temperature, Concentration, Organic Matter, and Time
Methods of Sterilization
Autoclaving- Uses mpist heat under pressure to kill all microbes, including spores
Dry Heat- Requires higher temperature and longer exposure to kill microbes
Inoculating Loop- Sterilized by flaming, killing any microbes on the loop
Filtration- Removes microbes from air and liquid, effective for heat-sensitive materials
Radiation- Uses UV light and gamma rays to kill microbes by damaging DNA
Methods of Disinfection
Chemical Disinfectants-
Alcohols- Disrupt cell membranes
Chlorine- Is effective against bacteria, fungi, and viruses
Physical Disinfection-
UV Light- Damages microbial DNA and is used for surface disinfection
Boiling- Kills most microbes but spores
Moist vs Dry Heat
Moist Heat
- More effective than dry heat
- Autoclaving is an example under steam and pressure to sterilize
- Boiling kills most microbes but spores
Dry Heat
-Less effective than moist heat. Used for sterilizing glassware and inoculating loop
-Needs longer exposure and higher temperature
Factors that Affect Germicidal Activity
Temperature, presence of organic matter, concentration, microbe type, and time
