LEC EXAM #3 CHP. 13 Flashcards
Fomite:
Inanimate object that can harbor microorganisms
Exotic:
Derived from a foreign location
Sterile technique:
Technique that minimize/eliminate pathogen contamination
Sterilization:
Complete removal of all vegetative cells, endospores, and viruses from an item or environment
-Ex: steam/autoclave
Sterilant:
Chemical used to achieve sterilization
Asepsis:
The absence of bacteria or microbes from an area
Sepsis:
Presence of bacteria or microbe
Commercial sterilization:
Technique that involves using low enough temp to preserve food quality but high enough to kill pathogens
Disinfection:
- Removes most microbes from fomites from surfaces but does NOT sterilize
- Ex: vinegar, bleach
Anti-septic:
- Disinfection on living surface (skin or tissue)
- Ex: Hydrogen peroxide, isopropyl alcohol
Food canning/sterilization temperature:
121 C for 2.5 minutes
BSL-1:
- Minimal risk of disease
- Ex: Nonpathogenic strains of E. coli
BSL-2:
- Moderate risk
- Indigenous and exotic
- Ex: S. aureus
BSL-3:
- Indigenous and exotic
- Cause lethal diseases
- Ex: Mycobacterium tuberculosis
BSL-4:
- High risk of aerosol-transmitted infections
- Dangerous and exotic
- Ex: Ebola and Marburg
Clostridium botulinum:
- Forms endospores and difficult to treat
- Grows in canned food due to low O2
C. botulinum produce:
Neurotoxins that cause paralysis and can stop respiratory function
Critical sterilization:
-Item will be inserted into body
-Must be sterilized
Ex: IV, catheter, surgical instruments
Semi-critical sterilization:
- Item will contact mucous membrane
- Item does not have to be sterilized but must be highly disinfected
Non-critical sterilization:
- Item will contact skin
- Items must be cleaned but not highly disinfected
Bacteriostatic:
Bacteriocide:
- Causes bacteria to be static/inactive
- Kills bacteria
Sanitation:
- Reduces microbial load of inanimate object to public health levels
- Ex: Detergent in dishwasher
Degerming:
- Reduces microbial load on skin or tissue through hand washing
- Ex: Washing hands with soap
DRT (decimal reduction time):
Time to kill 90% of population
Harder to treat:
Eukaryotes such as fungus because more similar to humans
Thermal death time:
Time needed to kill ALL organisms
Autoclave:
Protocol?
- Water in chamber that gets heated and pressurized to generate steam for sterilization
- Denature endospore, vegetative cells, and viruses
- 121 C @ 15 psi for 30 minutes
Resistant to auto-claving:
Prions
Pasteurization:
Protocol?
- Reduces heat sensitive microbes that cause food spoilage, but doesn’t kill all microbes
- Does not sterilize food
- Heat at 72C for 15 seconds for normal pasteurization or 132C for 2 seconds for UHT
Refrigeration:
- Slows microbial growth, except for pyschrophiles
- Ex: Listeria
Drying/dessication:
Physically removes water
Adding salt to food:
Creates a hypertonic environment
Radiation:
Kills bacteria and destroys viruses through UV light sterilization by forming thymine dimers
Gamma-radiation:
- Stronger than XR
- Shines radiation on food as it passes by-> breaks DNA
HEPA filtration:
- Filters out allergens, dust, and garbage
- Port size= 0.3 um
Membrane filtration:
- Pore size= 0.2 um
- Reduces pathogen load level to undetectable
Phenolic compounds:
- Removes microorganisms but doesn’t sterilize
- Disinfectants found in mouthwash and throat lozenges
Triclosan:
- Banned in hand soaps by FDA in 2017
- Previously thought to be antimicrobial
Betadine:
Topical antiseptic used before surgery
Alcohols:
Bactericidal and fungacidal
-70% because anything past 70% denatures glycoproteins but 70% is just enough to let alcohol in
Quaternary ammonium salts- Quats:
- Disrupts plasma membranes
- Ex: lysol
Soaps:
How?
- Breakdown bacteria and debris by removing from surface
- Hydrophilic and hydrophobic regions bind to each other, locks, and rubbing of hands removes them
Peroxide:
Produces free radicals that binds to DNA-> mutates DNA
If you have the enzyme catalase, it converts hydrogen peroxide into:
Water and oxygen
How to test antimicrobial/abx effectiveness?
Disk diffusion method that tests the zone of inhibition of an antimicrobial/abx
In-use test:
Used in clinical settings when you store your disinfectants in bottles
In-use test steps:
- take disinfectant
- put it into sterile broth with inactivator for disinfectant-> inactivated
- place soln onto plates
- if you see growth of 5+ colonies on either plate= contamination
Why does CRE affect hospital patients?
- It’s a rampant resistant strain in hospital settings that causes nosocomial infections due to instrument/equipment being contaminated
- Patients are immune-compromised
Structure of phenolic compounds:
Benzine ring with an OH off of it
Freezing below ___ can kill microorganism?
-2C
Things that can change your decimal reduction time or thermal death time?
Concentration
Location of where it is applied
Modes of action
