MICROBIO W1-DAY2_ALN Flashcards
most effective method of sterilization
autoclave
autoclaving of media and instruments is set at:
121C, 15 psi for 15 mins
autoclaving of infectious medical waste
132C (270F) for 30-60 mns
QC for autoclave
Bacillus stearothermophilus
sterilizer used in tyndallization
Arnold’s sterilizer
Tyndallization = flowing steam set at:
100C for 30 mns for 3 successive days
In tyndallization, flowing steam is set for 3 consecutive days. Indicate the purpose of each day.
1: killing of vegetative cells
2: germinating spores
3: remaining spores and vegetative cells
“thickening through evaporation”
Inspissation
Inspissation is set at:
75-80C for 2 hours, 3 consecutive days
used to sterilize inoculating loops and needles
Flame
Killing principle/mechanism of dry heat
via oxidation
Usage of oven for sterilization is set at:
160-180 for 1.5-3 hrs
Biological indicator for QC of ovens
Bacillus subtilis
this is the most common method of treating infectious waste
Incineration
Incineration temp
870-980C
Safest method to ensure that no infective materials remain in samples or containers upon disposal
Incineration
Methods of culture media sterilization
Autoclave
Membrane filtration
T/F:
Evacuated tubes should be sterilized via autoclave and ethylene oxide gas
FALSE
This can alter pressure inside the tubes
The most effective filter used for sterilization via filtration
Asbestos - Sietz (98% effective)
Millipore size that equates to 100% bacterial sterility
0.22 um
Sterilization method of choice for antibiotic solutions, toxic chemicals, radioisotopes, vaccines, and carbohydrates
Filtration
Pertained to as filtrable agents of infection
Viruses
Filter: 0.22 um
Virus size: 0.01-0.03 um
In filtration, filtration of liquids is accomplished by pulling the solution through ___________ membrane with a vacuum
cellulose acetate
cellulose nitrate
Used to filter air
High-efficiency particulate air (HEPA) filter
removes organisms >0.3 um
Sterilization method of choice for syringes, catheter, gloves, and evacuated tubes
Ionizing radiation
Sterilization method involving high energy gamma rays
Ionizing radiation
Most common chemical sterilant
Ethylene oxide
Ethylene oxide biological indicator for QC
Bacillus subtilis
“cold sterilization”
ethylene oxide
glutaraldehyde
peracetic acid
This sterilization method kills spores in 3-10 hrs and is used for medical equipment (e.g., bronchoscopes) because it does not corrode lenses, metal, or rubber
glutaraldehyde
Sterilization method effective in the presence of organic material
Peracetic acid
The process that destroys pathogenic organisms, but not necessarily all microorganisms or spores
Disinfecition
Sterilization via boiling is set at what temp & duration
100C for 15 mns
This sterilization method is used mostly in food industry to prevent food spoilage
Pasteurization
Two methods by which pasteurization may be done
Batch method (Low-temp holding)
Flash method (High temp, short-time)
Batch method is set at:
63C for 30 mns
Flash method is set at:
72C for 15 secs
An example of this sterilization method is the use of mercury lamps (long wavelength, low energy)
Non-ionizing radiation
Disinfectants used on living tissue are termed:
Antiseptics
This destroys vegetative forms on inanimate objects (microbicidal)
Disinfectants
Alcohol concentration for disinfection
70%
increased water conc = for protein denaturation
Conc. of formaldehyde as disinfectant
8%
Conc. of glutaraldehyde as disinfectant
2%
Examples of halogens used as disinfectant
Iodine
Chloride
How long must iodine be applied to skin
60 secs
Iodine + detergent = ?
Iodophor
Used to neutralize chlorine (e.g., in pools)
Sodium thiosulfate
Bleach is also known as:
Sodium hypochlorite
How long before halogens inactive HBV?
10 mns
How long before halogens inactivate HIV?
2 mns
Common bleach dilution
1:10
1 part NaOCl, 9 parts H2O
Metal that is known as algicide
COpper
Eye drop solution containing ________ is used to prevent Opthalmia neonatorium
1% AgNO3
use of QUATS should be avoided in labs handling what type of microorganism?
MTB
Prior to culture of MTB specimens, ________ is used for decontamination to remove normal flora
QUATS