Chapter 11 notes Flashcards
Microbes are _______
ubiquitous
Are most environments sterile or not sterile
not sterile
Define fomite
any inanimate object that, when contaminated with or exposed to infectious agents, can transfer disease to a new host
What can be found in drinking water
numerous diseases are from pathogens found in drinking water
What is the process of boiling water for disinfection
exposure of materials to 30+ minutes in boiling water will kill most non-spore forming pathogens
What is the mode of action for boiling water for disinfection
denature proteins and alter cell membranes
Will boiling water sterlize?
NO just disinfect
What can survive boiling water
Endospores
Will a fridge filter remove pathogens from…
Euk
Pro
Virus
most
most
no
What is the process of filtration
strain fluid or air through a porous membrane to physically remove microbes
What is the mode of action of filtration
physical separation, not destroying the microbe
Filtration is used to sterilize heat sensitive ______ and ________ in hospital isolation units
liquids; air
Filtration is used in water ____
purification
Define contaminant
microbes present that are undesirable or unwanted
What 3 things influence how clean is clean
- object of interest
- application for object
- potential pathogens that may infect the item, their level of resistance to control methods
What are the physical methods of microbial control
heat
filtration
desiccation
radiation
cold
What are the two types of chemical methods of microbial control
chemo/drugs
biocides
What 2 microbes are highest level of resistance
prions
bacterial endospores
Define prions
protein infectious particles
What are the microbes in the moderate resistance level
protozoan cysts
naked viruses
bacteria with no endospore but resistant walls (staphyloccocus)
What are the microbes in the least resistant level
most bacterial vegetative cells
fungal spores and hyphae
protozoan trophozoite
enveloped viruses
yeast
Define anthrax spores
a protective layer called endospore by which it can remain inactive for many years and under suitable environmental condition it can revive and become infectious
No microbial adaptation or cellular structure can compare to the resiliency of the _______ ________ (or _____ _____)
bacterial endospore; simple spore
Is an endospore considered “dead”
metabolically inert but can become vegetative cell
Define sterilization
process that destroys all viable endospores
Define microbial death
loss of reproductive capacity
What is the microbial death curve
describes the process, often plotted as semilog function
death continues in a log manner as time of exposure increases
The amount of time it takes for a specific protocol to produce a one order of magnitude decrease in the number of organisms or dealth of 90% of the population is called
decimal reduction time or D-value
Define microbial load
the size of the microbial population, also can be thought of as the total number of microbes at the beginning of a disinfection treatment
Define filtration
separation process the removes larger molecules or cells from air or liquids
Define incineration
the destruction of microbes by burning or turning to ash
Define germination
the process of something becoming metabolically active again (e.g. endospore becoming a vegetative cell)
these chemical control agents can be used in antisepsis products and consist of a small organic compound containing an OH group
alcohols
Hydrogen peroxide is an example of this
peroxygens
What is sepsis
growth of microbes in human blood and other tissues
What is microbicide
agent aimed at killing or destroying microbes; general term to include all microbes
What is an autoclave
a piece of equipment that uses high temperatures, steam, and pressure to control microbial growth
examples of this include cl2, NaOCl, and I2
halogens
What is the surfactant used in a variety of washing and cleaning products
soap
What is the process of making something free from microbes, viruses, and endospores, destroying any possibility of viability in the process
sterilization
What is a vegetative cell
endospore revitalized when favorable conditions arise, they break dormancy and become this
What is the permanent loss of reproductive capacity for a microbe, even under optimal growth conditions called
microbial death
Formalin is an example of this and is commonly used to preserve biological specimens
aldehydes
What are agents that halt microbial growth without killing the cells, growth may resume if the control agents are removed
microbistatic
What is the method of microbial control originally developed by louis pasteur
pasteurization
What is the use of a physical process or chemical agent to destroy most microbes called
disinfection
These are widely used chemical control agents, chemical features include a benzene ring with an OH group
phenolics
What is the cleansing technique that removes debris, soil, microbes, and toxins and in this way reduces the potential for infection and spoilage, this technique may not directly target the microbe but still can result in control of its growth
sanitization
This is a dormant, tough, and non-reproductive structure produced by some bacteria to withstand extreme or harsh environmental conditions
Endospore
What is the use of edible chemicals to prevent microbial growth in food called
preservatives
What is the agents that kill microbes and explode the cells in the process
Microbilytic
WHat is the emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization called
radiation
What is the goal in disinfection
to destroy vegetative pathogens but not bacterial endospores
Disinfection usually occurs on __________ things
non-living things
Define antisepsis
use of chemicals on skin or human tissues to inhibit or eliminate microbial growth but not equal to sterilization
Germicides are agents that kill pathogenic microbes and can be on ______ living and non living things
can
For temperature control:
temps below the minimum growth temperature is ____________
microbistatic
For temperature control:
temps exceeding the maximum growth temperature is _____________
microbicidal
Is moist heat or dry heat more effective
moist heat
Is boiling water for disinfection sporicidal
no
Is pasteurization sporicidal
no
What is the mode of action for pateurization
denatures proteins and alters cell membrane
What is the process of pasteurizaiton
use of elevated heat for prolonged time to reduce microbial load and destroy pathogens, followed by rapid cooling to minimize damage to food or liquid
The change in environments disrupts what in regards to protein denaturing
protein shape and function
What is the mode of action of autoclaves
denature proteins and alter cell membrane
What is the process of incineration
use of a flame or electric heating coil to ignite and reduces microbes to ashes and gas
What is the mode of action of incineration
destroy by burning
inoculation loop through a flame is an example of incineration (T/F)
T
What is the process of ovens
heath to 180 C for 2 to 4 hours
What is the mode of action of ovens
dehydration, denatures proteins, and alters membranes
Is incineration sporicidal
yes
are ovens sporicidal
yes at prolonged time
Define food poisoning
disease caused by injecting contaminated food
What is the type of food poisoning for exoproduct produced by microbes causes diesase
food intoxication
What is the type of food poisoning for microbe itself cause disease
food infection
Can the following be microbes that are food-borne pathogens
bacteria
protozoa
viruses
algae
yes
yes
yes
usually no
What are the 4 good practices to reduce incorporation of potentially pathogenic microbes into food
clean
separate
cook
chill
What is the mode of action of cold
inhibits metabolism (slows or arrests cell division)–freezing may lyse cells
What is the process of desiccation
dry out the sample
What is the mode of action of desiccation
water is essential for metabolism and survival
Is desiccation effective
not really
Define radiation
energy emitted from atomic particles and dispersed at high velocity through matter or space
Define ionizing radiation
consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or a molecule by detaching electrons from them
What are examples of ionizing radiation
nuclear radiation, gamma rays, x-rays
What is the process of ionizing radiation
shine radiation source on sample or expose sample to EM waves
What is the mode of action of ionizing radiation
strong enough to pass into the cell where it alters molecular structure and damages cell component (double stranded breaks in DNA)
Ionizing radiation has ____________ power
high penetrating
Is ionizing radiation sporicidal
yes
What are examples of non ionizing radiation
UV light or sunlight
What is the mode of action of non ionizing radiation
introduces thymine dimers leading to DNA mutation
Non ionizing radiation has ___________ power
low penetrating
is non ionizing radiation sporicidal
yes
What is an example of non ionizing a liquid
UV water treatment
What is the target microbes for chlorine
sporicidal (slowly)
What is the level of germicidal activity for chlorine
intermediate
What is the level of toxicity for chlorine
gas is highly toxic; solution irritates skin
what is chlorine inactivated by and when is it unstable
inactivated by organics; unstable in sunlight
What is the target microbes for iodine
sporicidal (slowly)
What is the level of germicidal activity for iodine
Intermediate
What is the toxicity for iodine
can irritate tissue; toxic if ingested
What is the target microbe of phenolics
some bacteria, viruses, fungi
What is the level of germicidal activity of phenolics
low to intermediate
What is the toxicity of phenolics
can be absorbed by skin; can cause CNS damage
What is the target microbes of alcohols
most bacteria, viruses, fungi
What is the level of germicidal activity of alcohols
intermediate
What is the toxicity of alcohols
toxic if ingested; a mild irritant; dries skin
What is the target microbes of hydrogen peroxide
sporicidal
What is the level of germicidal activity of hydrogen peroxide
high (sterilant)
What is the toxicity of hydrogen peroxide
toxic to eyes; toxic if ingested
What is the target microbe soaps
certain very sensitive species
What is the level of germicidal activity of soaps
very low
What is the toxicity of soaps
nontoxic; few if any toxic effects
What is the target microbe of ethylene oxide gas
sporicidal
What is the level of germicidal activity of soaps
high (sterilant)
What is the toxicity of ethylene oxide gas
very dangerous to eyes, lungs, carcinogenic
What is the mode of action of halogens
oxidation and breaks down proteins, damages DNA, RNA, and fatty acids
What is the mode of alcohols
work by rapidly denaturing proteins (which inhibits cell metabolism) and by disrupting membranes (which leads to cell lysis)
What is the mode of aldehydes
kill by alkylating proteins and DNA
What is the mode of action of peroxygens
produce highly reactive hydroxyl-free radicals that damage protein and DNA while also decomposing to O2 gas–toxic to anaerobes
What is the mode of action of gases (ethylene oxide)
alkylating DNA, RNA, and protein
What is the mode of action of soaps and detergents
surfactants insert in the lipids bilayer and disrupt it to create abnormal channels that alter permeability and cause leakages
Would surfactants be more disruptive against enveloped or unenveloped viruses
enveloped
What chemicals could be added to soaps to make them “germicidal”
phenolics
What is the mode of action of preservatives
often weak acids that disrupt membrane functions, also solutes like salt and sugar produce conditions of high osmolarity
What do antibiotics, antivirals, and antifungals do
they are toxic or inhibits growth to a very specific and selective group of microbes
Antibiotics, antivirals, and antifungals are usually __________ products
natural
What do antibiotics, antivirals, and antifungals target
target the processes of DNA replication, transcription, and translation
How would we sterlize room air
filtration
How would we sterilize heat sensitive drugs
radiation
How would we sterilize a pot of soil
gamma radiation
How would we sterilize a pot of soil
gamma radiation
How would we sterlize cloth dressings
radiation
How would we sterilize a glass bottle with media
autoclave
How would we sterilize fruit juice
pasteurization
Spores are _____________ to disinfectants because the spore coat and cortex act as a barrier
resistant
What makes bacteria more resistant to antimicrobials than the same bacteria
biofilms
Mycobacteria have a ______ cell wall that prevents disinfectant entry
waxy
more time means it can be __________ effective
more
