Week 2 Intensive Flashcards
Destruction of all forms of life including bacterial spore
Sterilization
Destruction of some forms of life except bacterial spores
Disinfection
Applied to skin; cannot be used as disinfectants
Antiseptic
Applied to inanimate objects
Disinfectant
Enumerate the 8 factors affecting degree of microbial killing
- Types of organisms
- Microbial load
- Concentration of disinfecting agent
- Presence of organic material
- Nature of surface to be disinfected
- Contact time
- Temperature
- pH
Fill in the Blank; The _____ presents variability to withstand chemical and physical treatment
Type of Organisms
Most resistant to least resistant type of organism; P - BS - M - NV - F - B - LV
Prions - Bacterial Spores - Mycobacteria - Nonlipid Viruses - Fungi - Bacteria - Lipid Viruses
Most likely composed of organisms with varying degrees of susceptibility to killing agents
Microbial load
True or False? Not all the organisms die at the same time (considering the microbial load)
TRUE
Fill in the blank; The _____ numbers of organism, the _____ the exposure time
higher; longer
True or False? The amount of disinfectant needed to destroy microorganisms varies with the different agents
TRUE
True or False? Organic material such as blood, mucus, and pus affects killing activity by inactivating the disinfecting agent
TRUE
True or False? Bleach is easily inactivated by organic material
TRUE
True or False? The amount of time of a disinfectant or sterilant is important when considering the factors affecting the degree of microbial killing
TRUE
2 methods of disinfection and sterilization are ____ and _____ method
Physical and Chemical Method
True or False? Some advantage of using heat as disinfection and sterilization are it’s reliable effects, ease of use, shorter time and cost effectivity
TRUE
Most common methods of heat disinfection and sterilization
Heat under steam, pressure, and autoclave
Fill in the blank; steam under ___ atm of pressure, or ___ psi, ___ C for ___ minutes
1 atm, 15 psi, 121 degree celcius, 15 minutes
True or False? All microorganisms can be eliminated using heat except for prions
TRUE
Sterilization method of choice for heat-stable object?
Heat
Sterilization method for heat-stable substances that are not penetrated by moist heat
Dry heat
True or False? Dry heat has longer exposure times and requires higher temperature
TRUE
Sterilization method for glass wares
Dry heat
True or False? Boiling and pasteurization are considered as a disinfection method but not sterilization
TRUE
Fill in the blank; For pasteurization to occur, the heat should be at ___
63 degree celsius or 72 degree celsius
True or False? Boiling kill most microorganism in approximately 10 minutes
TRUE
Eliminates food-borne pathogens & organisms; responsible for food spoilage
Pasteurization
Method: Autoclave (Moist Heat), Temp: ? , Duration: ?, Application: ?
121 degree celsius, 15 min at 15 psi, Sterilizes
Method: Oven (Dry Heat), Temp: ? , Duration: ?, Application: ?
160-180 degree celsius, 1.5-3 hours, Sterilizes
Method: Boiling (Steam), Temp: ? , Duration: ?, Application: ?
100 degree celsius, 15 miuntes, Disinfects
Method: Pasteurization (Flash Method), Temp: ? , Duration: ?, Application: ?
72 degree celsius, 15 sec, Disinfects
Method: Pasteurization (Batch Method), Temp: ? , Duration: ?, Application: ?
63 degree celsius; 30 mins, Disinfects
Requires thin membrane filters composed of plastic polymers or cellulose esters containing pores
Liquid filtration
Pore sizes needed for liquid filtration of bacteria, yeasts, and molds
0.45 and 0.8 micrometer
Pore size for critical sterilizing
0.22 micrometer
Pore size for small viruses
0.01 micrometer
Sterilization method for heat-sensitive solutions
Liquid filtration
Method of filtration that requires HEPA filters
Air filtration
What does “HEPA” stands for in HEPA filters
“high-efficiency particulate air” filter
True or False? Air filtration removes microorganisms larger than 0.3 micrometer
TRUE
Type of filtration used in laboratory hoods and in air systems
Air filtration
Fill in the blank; Disinfection/Sterilization using Radiation (Ionizing) uses ___
Gamma rays or electron beam
Fill in the blank; Disinfection/Sterilization using Radiation (Non-ionizing) uses ___
UV rays
True or False? Gamma rays or electric beam has shorter wavelegth hence higher energy
TRUE
True or False? UV rays has longer wavelegth hence lower energy
TRUE
Sterilization method for disposable supplies
Ionizing radiation
Disinfection method for surfaces
Non-ionizing radiation
Chemical agents that may be used to sterilize
Chemosterilizers
Fill in the blank; ___ percent ethyl or isopropyl alcohol may be used to disinfect or sterilized
60-90
Disadvantage of using alcohol
Inactivated by organic materials
Principle behind using alcohol
Inactivate microorganism by denaturing protein
Two aldehydes used for disinfection and sterilization
Formaldehyde and Glutaraldehyde
Component used in formaldehyde for disinfection and sterilization
Formalin
Fill in the blanks; Formaldehyde uses ___ or ___
37 percent aqueous solution; Formaldehyde gas
Principle behind using formaldehyde
Reaction with the thiol (–SH) groups of enzyme
Disadvantage of using formaldehyde
Carcinogenic agent
True or False? Formaldehyde is not recommended (in any form) be used as a disinfectant or sterilant on a routine basis
TRUE
Disinfection method for biosafety cabinets
Formaldehyde
Principle behind using glutaraldehyde
Inactivation of DNA and RNA through alkylation of sulfhydryl and amino groups
Advantage of using glutaraldehyde
Rapid killing action
Disadvantage of using glutaraldehyde
Extremely susceptible to pH
Disinfectant or Sterilant? 2% solution of glutaraldehyde for 10mins
Disinfectant
Disinfectant or Sterilant? 2% solution of glutaraldehyde for 3-10hrs
Sterilant
Sterilization method for heat labile medical equipment and materials that cant be sterilized with gas
Glutaraldehyde
True or False? Aldehydes are active at alkaline
TRUE
Principle behind using Halogens (Iodophors)
Degrades microbial cell walls and cytoplasm, denatures enzymes, and coagulates chromosomal material
Advantage of using Halogens (Iodophors)
Less irritating, nonstaining, and more stab
Iodine (5-10%) + neutral polymer =
Can be used as antiseptic (Iodophor)
True or False? Iodine can be used in two forms as antiseptic
TRUE
Contact time for Halogens (Iodophors)
> 30 seconds
Fill in the blanks; ___ + ___ = tincture
alcohols; iodine
Fill in the blanks; ___ + ___ = iodophor
iodine (5-10%) + neutral polymer carrier
Most common iodophor
Polyvidone or povidone
Two forms of hypochlorite (chlorine and chlorine compounds)
liquid sodium hypochlorite and solid calcium hypochlorit
Principle behind using Chlorine and Chlorine Compounds (Hypochlorite)
Oxidative effects of hypochloro
Disadvantage of using Chlorine and Chlorine Compounds (Hypochlorite)
long exposure time required for sporicidal action; inactivated by organic materials
0.5% to 1% sodium hypochlorite =
Can be used as disinfectant
Contact time for Chlorine and Chlorine Compounds (Hypochlorite)
Atleast 3 mins
Recommendation of CDC for blood spills
1 : 10 dilution of a 5.25% concentration of sodium hypochlrite
Disinfection method for water
Chlorine and Chlorine Compounds (Hypochlorite)
Principle behind using Detergents (Quaternary Ammonium Compound)
Reducing the surface tension of molecules in a liquid; disruption of the cellular membrane, resulting in leakage of cell contents
Disadvantage of using Detergents (Quaternary Ammonium Compound)
Effectiveness is reduced by hard water & soap; Inactivated by organic materials
Disinfection method for noncritical surfaces (benchtops and floors)
Detergents (Quaternary Ammonium Compound)
Commonly found as ingredients of germicidal soaps
Phenolics
Disinfection method for surfaces in hospitals and household environments
Phenolics
Principle behind using Phenolics
Disruption of cell walls leading to precipitation of proteins
Lower concentration of phenolics = ?
Distruption of enzyme systems
Topical antiseptic
Chlorhexidine Gluconate (0.5% to 4%)
Principle behind using Chlorhexidine Gluconate (0.5% to 4%)
Disrupts the microbial cell membrane and precipitates cellular contents
Advantage of using Chlorhexidine Gluconate (0.5% to 4%)
Strong affinity to the skin and mucous membranes; not significantly affected by organic mater
Disadvantage of using Chlorhexidine Gluconate (0.5% to 4%)
Affected by pH
Disinfection method for hands of surgical personnel and body of patients undergoing surgery
Chlorhexidine Gluconate (0.5% to 4%)
Effective against gram-positive bacteria (3% for 15-30 seconds)
Hexachlorophene
Principle behind using Hexachlorophene
Interrupts bacterial electron transport
Principle behind using Hexachlorophene at low concentration
Inhibits membrane-bound enzymes
Principle behind using Hexachlorophene at high concentration
Ruptures bacterial membranes
Disadvantage of using Hexachlorophene
With severe toxic effects
Principle behind using Chloroxylenol (0.5% to 4%)
Microbial cell wall disruption and enzyme inactivation
Advantage of using Chloroxylenol (0.5% to 4%)
Unaffected by organic materials
Disadvantage of using Chloroxylenol (0.5% to 4%)
Neutralized by nonionic surfactants and polyethylene glycol
Common example for Chloroxylenol (O.5% to 4%)
Parachlorometaxylenol [PCMX])
Disinfection method for health care personnel handwash and also acts as surgical hand scrub
Chloroxylenol (O.5% to 4%)
Principle behind using Triclosan
Disrupts the cell wall
Chemical used for disinfection and sterilization that is commonly found in consumer and proffesional health care products
Triclosan
Advantage of using Triclosan
Not significantly affected by organic ma
Disadvantage of using Triclosan
Affected by pH, surfactants and emollients; Formulation significantly affects activity; Absorbed through intact skin
Triclosan - Good activity: ?
Gram (+) & (-) bacteria & virus
Triclosan - Fair activity: ?
M. tuberculosis
Triclosan - Poor activity: ?
Fungi
4 chemicals used for sterilizing and disinfection under phenolics
Chlorhexidine Gluconate (0.5% to 4%); Hexachlorophene; Chloroxylenol (0.5% to 4%); Triclosan
Disadvantage of using Heavy metals
Has toxic effects
Rarely used in clinical application and is slowly bactericcidal
Heavy metals
Used as preservatives for paint
Mercuric chloride
Prophylactic treatment to prevent gonococcal (Neisseria gonorrhoeae) conjunctivitis in newborns
Silver nitrate (1% eye drop solution)
3 chemicals used for sterilizing and disinfection under gases
Ethylene Oxide; Hydrogen peroxide; Periacetic acid (gaseous form)
Fill in the blanks; ___ of ethylene oxide per liter of chamber space at ___ for ___
450-700 mg; 55-60° C; 2 hours
Relative humidity of 30% ethylene oxide act as?
Sporicidal
Principle behind using Ethylene Oxide
Alkylation of nucleic acids in spore and vegetative cell
Sterilization method for materials that cannot withstand steam sterilization
Ethylene Oxide
True or False? Etylene oxide must be mixed with nitrogen or carbon dioxide before use
TRUE
Sterilant in the pharmaceutical and medical device manufacturing industries
Hydrogen peroxide and Periacetic acid (gaseous form)
Type of containment barrier that protects the worker from the aerosolized transmission of organisms
Biological Safety Cabinets (BCS)
True or false? Any procedure that has the ability to create aerosols should be performed in a BSC
TRUE
What level of biosafety does it corresponds to? Minimal threat to laboratory personnel and environment
Biosafety level 1
What level of biosafety does it corresponds to? Agents that are well classified and are not known to cause disease
Biosafety level 1
What level of biosafety does it corresponds to? Bacillus subtilis
Biosafety level 1
What level of biosafety does it corresponds to? Most common type of BSC used in a microbiology laboratory
Biosafety level 2
What level of biosafety does it corresponds to? Agents that pose a moderate potential hazard for the employees and environment
Biosafety level 2
What level of biosafety does it coresponds to? HBV, HIV, Salmonella spp., and Toxoplasma spp.
Biosafety level 2
What level of biosafety does it corresponds to? For infectious agents that are either indigenous/exotic or highly infectious
Biosafety level 3
What level of biosafety does it coresponds to? Potential for aerosol transmission
Biosafety level 3
What level of biosafety does it corresponds to? Diseases with these agents may have serious lethal
Biosafety level 3
What level of biosafety does it corresponds to? M. tuberculosis, St. Louis encephalitis virus
Biosafety level 3
What level of biosafety does it corresponds to? For agents that are dangerous and exotic
Biosafety level 4
What level of biosafety does it corresponds to? High risk of causing life-threatening infections, can be transmitted by aerosols, or have an unknown risk of transmission
Biosafety level 4
What level of biosafety does it corresponds to? For agents that are dangerous and exotic
Biosafety level 4
What level of biosafety does it corresponds to? Located in a separate building or is in an isolated zone within a building
Biosafety level 4
What level of biosafety does it corresponds to? Types: cabinet and suit
Biosafety level 4
What level of biosafety does it corresponds to? Marburg and Congo-Crimean; Hemorrhagic fever
Biosafety level 4
Fill in the blank? Phenol Coefficient Test is also known as ___
Disinfectant test
Evaluate effectiveness of disinfectants
Phenol Coefficient Test
Fill in the blank? Phenol Coefficient Test utilizes ___ or ___ for the test
Staphylococcus aureus; Salmonella typhi
Fill in the blank? Based on the dilution of phenol and experimental disinfectant are inoculated with the bacteria and incubated at ___.
20-37 deg C for 2-3 days
2 methods for phenol coeeficient test
Rideal Walker Test; Chick Martin Test
True or false? Considering the Bartlett’s Grading System, Scores of 0 or less indicate lack of iinflammation or presence of saliva
TRUE
Used for check effectiveness of sterilizers
Bacillus subtilis var. niger
Used for biologic indicator for sterilizers
Bacillus subtilis var. globigii
Used for biologic indicator for ionizing radiation sterilizer
Bacillus pumilus
Used for moist heat
Bacillus stearothermophilus