Chapter 13 Microbiology UTA Tholen
Main goal to controlling microbial growth - *answers *reduce microbial load and reduce
infection/contamination
Sterilization - *answers *removal and killing of ALL microbes from fomite (inanimate
object)/organism
Disinfection - *answers *inactivation/kill of microbes on fomites
Sanitization - *answers *decrease of microbial load (amt. of microbes)
Biological Safety Level - *answers *Levels of cleanliness assigned to labs; CDC, NIH,
WHO established 4 levels
BSL-1 - *answers *microbes aren't known to cause disease in healthy host and pose
minimal risk to workers and the environment
-sink for handwashing, door to close off lab (ex. freshman bio labs)
-ex. non-pathogenic strains of Escherichia coli
BSL-2 - *answers *microbes are typically indigenous and are associated with diseases
of varying severity; they pose moderate risk to workers and the environment
-BSL-1 and PPE, self-closing doors, eyewash station, autoclave, or sterilization method
(ex. Micro labs)
-ex. Staphylococcus aureus
BSL-3 - *answers *microbes are indigenous/exotic and cause lethal diseases thru
respiratory transmission
-BSL-2 and respirator, bio safety cabinets, hands-free wash sink, two sets of doors (ex.
none at UTA)
-ex. Mycobacterium tuberculosis
BSL-4 - *answers *- Microbes are dangerous & exotic, posing a
high risk of aerosol‐transmitted infections, which are frequently fatal w/o treatment or
vaccines. Few labs are at this level
-BSL-3 and full biohazard suit, shower on exit, lab must have own air supply (only 13 in
USA)
-ex. Ebola and Marburg viruses
Levels of Clean in the Clinic: Critical - *answers *must be sterile; items contact sterile
tissue (i.e. blood)
Levels of Clean in the Clinic: Semicritical - *answers *do not require high level
sterilization; items might contact sterile tissue (i.e. gut)
Levels of Clean in the Clinic: Noncritical - *answers *don't require sterilization, items
don't penetrate tissue (i.e. stethoscopes on skin)
, Chapter 13 Microbiology UTA Tholen
Sterilization method - *answers *heat, pressure, filtration, chemical (sterilants)
aseptic technique - *answers *used to prevent sterile environment from becoming
contaminated
Antiseptic - *answers *kills microbes but not host organism/tissue
Disinfection method does not kill - *answers *endospores
Examples of disinfectants - *answers *hydrogen peroxide and rubbing alcohol
Sanitization method - *answers *mechanical- washing hands, wiping with paper towel,
etc; may be used in combination with disinfectant to maximize microbial reduction
-cides - *answers *kill; ex. bacteriocidal, viricidal, fungicidal
-static - *answers *stop growth; ex. bacteriostatic, viristatic, fungistatic
Microbial death curve - *answers *measure of percentage of kill
Decimal Reduction Time (DRT) - *answers *how much time it takes to kill 90% (1 log
reduction) of pop.
Factors of success of control - *answers *length of control, concentration of agent, pop.
level
Physical means of control is: - *answers *mostly applied to non-living
Heat Sterilization - *answers *oldest and most common; alters membranes and
denatures proteins
Thermal Death Point - *answers *lowest temp. that will kill in 10 mins
Thermal Death Time - *answers *length of time to kill at a certain temp.
Dry heat - *answers *aka incineration; direct application of high heat (>250C); ex.
bunsen burner
Moist heat - *answers *application of high temp. liquid/vapor; beneficial because it
penetrates cells better than dry heat; ex. autoclave
Autoclave - *answers *raises the temp. of water above boiling point (~121C) by raising
pressure to 15 psi; kills viruses and endospores
Pasteurization - *answers *semisterilizes food but doesn't ruin food quality; many
methods rely on "flash" heating foods to kill most microbes
Main goal to controlling microbial growth - *answers *reduce microbial load and reduce
infection/contamination
Sterilization - *answers *removal and killing of ALL microbes from fomite (inanimate
object)/organism
Disinfection - *answers *inactivation/kill of microbes on fomites
Sanitization - *answers *decrease of microbial load (amt. of microbes)
Biological Safety Level - *answers *Levels of cleanliness assigned to labs; CDC, NIH,
WHO established 4 levels
BSL-1 - *answers *microbes aren't known to cause disease in healthy host and pose
minimal risk to workers and the environment
-sink for handwashing, door to close off lab (ex. freshman bio labs)
-ex. non-pathogenic strains of Escherichia coli
BSL-2 - *answers *microbes are typically indigenous and are associated with diseases
of varying severity; they pose moderate risk to workers and the environment
-BSL-1 and PPE, self-closing doors, eyewash station, autoclave, or sterilization method
(ex. Micro labs)
-ex. Staphylococcus aureus
BSL-3 - *answers *microbes are indigenous/exotic and cause lethal diseases thru
respiratory transmission
-BSL-2 and respirator, bio safety cabinets, hands-free wash sink, two sets of doors (ex.
none at UTA)
-ex. Mycobacterium tuberculosis
BSL-4 - *answers *- Microbes are dangerous & exotic, posing a
high risk of aerosol‐transmitted infections, which are frequently fatal w/o treatment or
vaccines. Few labs are at this level
-BSL-3 and full biohazard suit, shower on exit, lab must have own air supply (only 13 in
USA)
-ex. Ebola and Marburg viruses
Levels of Clean in the Clinic: Critical - *answers *must be sterile; items contact sterile
tissue (i.e. blood)
Levels of Clean in the Clinic: Semicritical - *answers *do not require high level
sterilization; items might contact sterile tissue (i.e. gut)
Levels of Clean in the Clinic: Noncritical - *answers *don't require sterilization, items
don't penetrate tissue (i.e. stethoscopes on skin)
, Chapter 13 Microbiology UTA Tholen
Sterilization method - *answers *heat, pressure, filtration, chemical (sterilants)
aseptic technique - *answers *used to prevent sterile environment from becoming
contaminated
Antiseptic - *answers *kills microbes but not host organism/tissue
Disinfection method does not kill - *answers *endospores
Examples of disinfectants - *answers *hydrogen peroxide and rubbing alcohol
Sanitization method - *answers *mechanical- washing hands, wiping with paper towel,
etc; may be used in combination with disinfectant to maximize microbial reduction
-cides - *answers *kill; ex. bacteriocidal, viricidal, fungicidal
-static - *answers *stop growth; ex. bacteriostatic, viristatic, fungistatic
Microbial death curve - *answers *measure of percentage of kill
Decimal Reduction Time (DRT) - *answers *how much time it takes to kill 90% (1 log
reduction) of pop.
Factors of success of control - *answers *length of control, concentration of agent, pop.
level
Physical means of control is: - *answers *mostly applied to non-living
Heat Sterilization - *answers *oldest and most common; alters membranes and
denatures proteins
Thermal Death Point - *answers *lowest temp. that will kill in 10 mins
Thermal Death Time - *answers *length of time to kill at a certain temp.
Dry heat - *answers *aka incineration; direct application of high heat (>250C); ex.
bunsen burner
Moist heat - *answers *application of high temp. liquid/vapor; beneficial because it
penetrates cells better than dry heat; ex. autoclave
Autoclave - *answers *raises the temp. of water above boiling point (~121C) by raising
pressure to 15 psi; kills viruses and endospores
Pasteurization - *answers *semisterilizes food but doesn't ruin food quality; many
methods rely on "flash" heating foods to kill most microbes
