quiz 2-25-15 Flashcards
what is the study of how a specific infectious agent survives and spreads through a community
epidemiology
what is the actual way the infectious agent is spread?
Disease transmission
what is the entrance way through which a specific microbe is able to invade a host
portal of entry
what are the 2 most common portals of entry
respiratory tract and GI tract
person to person form of transferring microbes is known as
direct transmission
any object living or non-living that allows a microbe to grow , reproduce and maintain its ability to remain infective is
reservoir of infection
a non-living object capable o allowing a microbe to survive but not reproduce is known as a
fomite
an inanimate object that can serve as vehicle for the spread of disease
fomite
what can control fomite transmission?
hand washing
what is the single most important method of controlling microbes in a clinical setting
hand washing
what is the goal of isolating bacteria?
to obtain a pure culture
what are pure cultures used forq
to carry out biochemical testing to determine abt sensitivity to develop vaccines determining the nutritional requirements study organisms that cause disease
agar is a substance derived from
seaweed
agar melts at what degrees
100 degrees C
agar solidifies at
42 degrees C
agar remains liquid at
45 degrees C
what is the solid surface to grow isolated colonies of bacteria
agar
what is a colony
a clump of bacteria growing on a solid surface
true or false
every cell in the colony is genetically identical
true
what are the usual temperatures used in a laboratory propagation?
it falls between 20C and 40C
a container of medium, that grows only a single known species or type of microorganism is called
a pure culture
what is frequently used to allow the precise examination and control of one microorganism by itself
a pure culture ( axenis )
a water based solution that do not solidify at temperatures above freezing and that tend to flow freely when the container is tilted is what kind of media
liquid media that comes in broth, milk or infusion.
what form of media exhibits a clot like consistency, used to determine the motility of bacteria
semi-solid media
what type of media provides a firm surface on which cells can form discrete colonies and are advantages for isolating and culturing bacteria and fungi
solid media
what type of media can viruses grow
none. viruses can only be cultivated in live host cells not media
what are the two types of solid media
liquefiable solid media and non-liquefiable solid media
name a general purpose media type
tryptic soy
tryptic soy broth
brain heart infusion
what are bacteria that require growth factors and complex nutrients are termed
fastidious
how is media made
powder is mixed with distilled water, the media liquid is dispensed into tubes or bottles and its then autoclaved to be sterilized
an autoclave reaches what tempurature
121 degrees C
an autoclave reaches what PSI
15 pounds of PSI
how long is media placed in the autoclave?
20 minutes kills all bacteria, fungi, spores and viruses
what machine is use that holds a constant temperature to grow bacterial cultures
incubator
a device used to sterilize inoculating tools
incinerator
tools used to transfer bacteria from a culture to a sterile media are called
inoculating loop or inoculating needle
what technique is used when handling bacteria
aseptic technique
what are the steps to performing aseptic technique when transferring the bacteria to your media in a tube
flame the loop remove the caps flame the tubes move the bacteria with the instrument flame the tubes replace the caps flame the loop
when do you flame the inoculating tools in the incinerator
at the start and end of every transfer
when do you flame the tubes
before and after every transfer
what is the goal of the streak plate
to isolate and thin out the number of bacteria on a plate to get isolated colonies
are members of a colony on a streak plate genetically identical
yes. they all arouse from a single bacterial cell
what is the method of handling microbes and materials in a way that minimizes contamination
aseptic technique
the process of transferring a microbe from one media to the next
inoculation
the sample being transferred
inoculum
what tool is used to transfer an inoculum
inoculating loop
what instrument is used for techniques that require stabbing into the agar
inoculating needle
what metal alloy that heats up very quickly, is used to make the inoculating loop and needle
Nichrome
how do you sterilize the inoculating instruments in the lab
using a bunsen burner or micro incinerator
where do you store the inoculating loop while not in use
the test tube rack
to cool the loop after sterilization what should you not do
wave the loop to cool it
blow on the loop
touch the loop to see if its hot
place the loop on the bench top
when you remove the caps from the test tubes what fingers do you use
pinky and ring finger of the hand that holds the inoculating loop
how long do you flame the tubes in the incinerator
5 seconds
when opening the lid of the agar plate how do you hold the lid
at a 45 degree angle to minimize the air born bacteria from entering
before using your media what do you look for
contamination
contamination of a broth media that looks uniformly cloudy is called
turbidity
flecks or chunks of bacterial growth scattered throughout the tube is known as
flocculent
growth that settled onto the bottom is known as
sediment
film of bacteria covering the surface of the media is what kind of contamination
pellicle
growth contamination found on media is known as
a ring
widely used method to separate individual bacteria from mixtures is called an
isolation streak plate
what technique is used to isolate individual bacteria from the mixture as a result of having fewer and fewer bacteria as you continue around the surface of the streak plate is known as
streaking pattern
a single bacteria that is coming off of the surface of the streak plate is known as
isolated colonies
this arises from a single bacterium that divides repeatedly over time to form a mass of millions of cells
colony
what is the technique called that is used to inoculate the streak plate
quadrant technique
1 in every ______ bacteria can cause disease?
50,000
pathogens that may have been acquired from another person or may have already been in or on that individual
opportunistic pathogens
microbes that are on the skin, that are harmless and some are beneficail, and are difficult to remove are known as what?
normal biota
these are found on the skin for short periods of time but do not grow there, they are acquired by contact with contaminated surfaces and are usually easily removed, some can cause disease, and are easily transferred from person to person
transient organsims
during the gram staining procedure, this type of bacteria stains purple
gram +
during the gram staining procedure this type of bacteria are stained red
Gram - bacteria
what color are acid fast bacteria after the acid fast stain
pink
what color are the non acid fast bacteria after the acid fast stain
blue
what is the staining procedure called that is similar to the acid fast stain but it uses heat to force the dye into the resistant cells
endospore stain
this stain is designed to distinguish between spores and a vegetative cells that make them
endospore stain
what stain is used to emphasize special cell parts such as capsules, endospores, and flagella that are not revealed by conventional staining methods
structural stain
what is the best practice that can limit the transmission of pathogens from one human to another
handwashing
to be most effective hand washing should include what 3 components
soap/detergent
friction
antiseptic
what is the name of the process in which soap is produced
saponification- this involves treating a fat with an alkali (base) in the presence of heat.
what emulsifies skin oils in which bacteria is trapped in the deep dermal ridges of the hands, lifts microbes from dermal ridges, bursts and kills cells
soap / detergent
what can disrupt the lipid protion of the cell membrane
a surfactant
what physically removes the emulsified skin oil with the trapped bacteria
friction
a chemical that kills microbes without damaging the skin is known as
an antiseptic
when washing your hands with soap or detergents, what microorganisms are removed
transient microorganisms are removed but your normal biota is usually not completely removed.
