Term
Using the nomenclature of the A-B model for binary toxin structure, the B subunit of anthrax toxin would most closely correspond to... |
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Definition
protective antigen
(edema factor and lethal factor would be A / active subunit)
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Term
The principal polymer structure of a bacterial cell wall (peptidoglycan) acquires most of its strength at a final step in the synthesis that involves crosslinking through... |
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Definition
N glycosidic linkages
bind at penultimate AA and cleave it off to acheive strong bond
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Term
Would the involvement of an integron as a mechanism of multidrug resistance be more likely in e coli (Gram -) or in s aureus (Gram +) ? |
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Definition
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Term
True or false: In an individual animal, a positive test for antibodies against a pathogen is always indicative of an infection. |
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Definition
FALSE
infection could have already passed |
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Term
True or False: In an individual animal, disease is always a consequence of infection |
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Definition
FALSE
carriers, normal flora, etc |
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Term
Disease prevalence usually has the greatest impact on which property of testing? |
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Definition
Positive predictive value |
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Term
The Beta lactam ring found in all penicillin and cephalosporin antibiotics has the greatest structural homology with |
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Definition
Terminal alanine dipeptides in peptidoglycan (gram + peptidoglycan)
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Term
When bacteria are actively growing, their numbers increase in what fashion? |
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Definition
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Term
T/F: Prokaryotic and eukaryotic organisms can possess a cell wall |
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Definition
true
fungi are eukaryotes that have cell walls |
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Term
T/F Prokaryotic and eukaryotic organisms replicate by mitosis |
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Definition
FALSE
bacteria replicate by binary fission |
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Term
The conditions employed for destruction of endospores in an autoclave are.. |
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Definition
121 C for 15 minutes
high pressure is also used
heat is provided by steam (hot air would take much longer to sterilize)
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Term
T/F Germination of bacterial endospores is dependent on an activating factor that ends the state of dormancy and may cause slight damage to the spore coat |
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Definition
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Term
Germination of bacterial endospores is dependent on an intiating factor that causes degradation of the ______ _____ and _____, ______ of ________ and release of _____ and _______ acid. |
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Definition
spore coat and cortex, absoption of water and release of calcium and dipicolinic acid |
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Term
Peptidoglycan is associated with Gram +, Gram -, or both? |
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Definition
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Term
Teichoic acid is found in Gram |
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Definition
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Term
Gram + and - have plasmids that encode for _____ ______ |
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Definition
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Term
What does NOT limit the commercial development of lytic bacterial viruses to combat bacterial infections in animals?
a)poor immunogenicity of bacterial viruses
b) host specificity of bacterial virus
c) potential trasnfer of bacterial genes from a pathogen to a non-pathogen
d) metaboilic activity of bacterial viruses |
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Definition
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Term
The MIC (minimum inhibitory concentration) of an antimicrobial drug for a bacterium is usually expressed in which unit? |
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Definition
micrograms per milliliter |
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Term
The best choice of media for isolation of a fastidous bacterial pathogen is |
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Definition
chocolate agar
does not have chocolate!
blood that has bascially been cooked for the bacteria
not a selective medium
fastitidous = picky eater
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Term
Bacteria with storage granules (cytoplasmic inclusions) will have a ______ with methylene blue or Gram's stain |
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Definition
beaded filament appearance
uneven staining |
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Term
____ developed his ideas about germ theory of disease by inoculating animals with ATTENUATED ORGANSISMS |
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Definition
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Term
Specimen transport and storage: diagnostic specimens should be placed in ____ ______ for transport |
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Definition
two containers
(should be well sealed) |
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Term
The greatest weakness of antibody detection as a means of diagnosing bacterial disease is... |
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Definition
antibodies are indicative of antigen exposure
could be not disease or not current disease
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Term
Feature of _______ that differentiates them from insertion sequences, is a possession of terminal invert repeat sequences:
a) transposons
b)integrons
c)both
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Definition
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Term
Feature of _______ that differentiates them from insertion sequences, is the ability to readily move across some distance in a cell form one DNA molecule to another:
a)integrons
b)transposons
C)both
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Definition
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Term
Feature of _______ that differentiates them from insertion sequences, is possession of a strong generic promoter sequence:
a)integrons
b)transposons
c) both
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Definition
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Term
Feature of _______ that differentiates them from insertion sequences, is association with antibiotic resistance:
a) integrons
b)transposons
c)both
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Definition
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Term
Trace metal that is required in greatest abundance for growth of bacteria is... |
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Definition
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Term
Lingering bacterial inhibition in the body after antimicrobial drug levels disappear is.... |
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Definition
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Term
Dependency on fermentation as a means of generating energy from carbohydrate substrates is greatest among... |
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Definition
Obligately anaerobic bacteria
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Term
Methicillin resistance in Staphylococcus species is usually indicative of... |
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Definition
resistance to all beta lactams
mecA gene! |
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Term
Chronic and recurrent forms of canine pyoderma caused by Staphylococcus pseudintermedius are often complicated by... |
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Definition
hypersensitvity and immune complexes
skin barriers are weakened
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Term
Fluid and electrolyte replacement is most critical to individual patient care during |
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Definition
diarrheal disease caused by enteric infections.
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Term
Bacillus anthracis requires ________ for capsular production. |
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Definition
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Term
________ infections are acquired within hospitals |
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Definition
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Term
The principal function of lysozyme in the mucosal lining of the GI tract is to ___________ |
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Definition
destroy bacterial cells
(breaks glycosidic bond in peptidoglycan) |
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Term
When an antibiotic drug molecule binds to the target macromolecule associate with its antibacterial action in a bacterial cell, the drug is _____________ and unavailable to bind to _________________________-. |
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Definition
irreversibly bound; other bacterial targets
(1st order rate kinetics) |
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Term
Severe intestinal disease that develops in some patients after administration of a broad-spectrum antibiotic is most likely the result of an _______________________________ |
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Definition
imbalance of the normal bacterial flora caused by the antibiotic |
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Term
T/F infectious disease is the same thing as communicable disease |
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Definition
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Term
When not causing disease, Streptococcus equi subspecies equi is likely to persist for the longest period of time in ___________________-- |
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Definition
asymptomatic animal carriers.
guttural pouch?
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Term
A positive predictive value is... |
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Definition
the likelihood that a positive test result is a true positive |
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Term
A flagellar filament is composed of...
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Definition
a polymer of a single protein subunit. |
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Term
Many strains of staphylococcus aureus express a plasminogen activator that causes dissolution of fibrin clots. This product is called |
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Definition
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Term
The _____ (organ) is most active in removing bacteria from the blood stream |
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Definition
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Term
The O antigens of Gram negative bacteria are protective against ___________. |
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Definition
complement mediated lysis |
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Term
_______________- is part of the repeated subunit structure of BOTH lipid A AND peptidoglycan. |
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Definition
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Term
Two of the most important safety concepts that should be addressed when shipping or internally transporting infectious substances are: |
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Definition
secondary containment and external package hazard communication |
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Term
When selecting a drug to use, choose the one that has the zone of inhibition______________ |
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Definition
that is the largest
larger zone diameter is more likely to be susceptible |
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Term
Intuitively, one would expect that gram ______ bacteria are preferentially more susceptible than gram______ bacteria to drugs that inhibit membrane function. |
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Definition
negative; positive
less osmotic stability in gram - |
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Term
Insertion of a________________- into a chromosomal bacterial toxin gene is most likely to result in toxin gene inactivation. |
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Definition
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Term
Once initiated, bacterial endospore production usually requires |
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Definition
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Term
The process of creating a live, relatively harmless and usually stable form of a pathogenic bacterium is called? |
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Definition
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Term
In an iron-restricted environment, pathogenic Staphylococcus sp. Are able to grow faster than less pathogenic Staphylococcus sp. Due to their ability to up-regulate genes that encode? |
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Definition
siderophores
this was multiple choice; another option not listed could be hemolysis and heme binding |
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Term
Side chain substitutions in members of a particular class of antimicrobial drugs are LEAST likely to affect…. |
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Definition
Mode of action of drug on bacteria |
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Term
The role of agar in bacterial growth is best described as… |
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Definition
Non-nutritional support matrix |
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Term
A bacterium that has a high MIC for a particular drug… (Minimum Inhibitory Concentration) |
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Definition
Is likely to be refractory to usual treatments w/ the drug during infection |
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Term
A property of the stratum corneum that enhances the antimicrobial barrier functions of skin is… |
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Definition
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Term
C3b, the cleavage product of the third component of complement, is of central importance to the host, especially against invasive infections caused by capsulated bacteria because it… |
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Definition
Enhances phagocytosis in the absence of bacteria-specific antibodies
complement is able to act without recognzing a specific antigen (it is part of
innate immunity)
recognises PAMPs (pathogen associated molecular patterns)
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Term
A chronic pyogranulomatous process involving subcutaneous tissues of the foot in birds is commonly associated w/ staphylococcus aureus infection. This condition is called… |
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Definition
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Term
Cellular stimulation through non-specific binding to T lymphocyte receptors and macrophage major histocompatibility complex proteins best describes the mode of action of… |
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Definition
Staphylocococal toxic shock syndrome toxin |
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Term
If an assay measures bacterial growth endpoints in broth as the change in visible opacity from clear to turbid, the highest (and most sensitive) final concentration of the starting bacterial inoculum that would be suitable is… |
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Definition
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Term
Global (transcriptional) regulation of many genes involved with staphylococcal disease is triggered by… |
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Definition
Staphylococcal population density
(Quorum sensing)
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Term
The best empirical drug choice for treating a severe infection caused by methicillin resistant Staphylococcus aureus would be… |
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Definition
Vancomycin (a narrow spectrum, glycopeptide antibiotic)
same mechanism as beta lactams (cell wall synthesis) but not the same chemical structure
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Term
Clavulanic acid is known primarily as a… |
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Definition
Beta lactamase inhibitor
administered along with drug
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Term
It is often recommended that the duration of antimicrobial treatment for an acute infection should be… |
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Definition
Continued for 48 hours after disappearance of symptoms
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Term
Acidic Polysaccharide polymers of glycerol or ribitol phosphate… |
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Definition
(teichoic acids)
Are major surface antigens of many Gram positive bacteria
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Term
Myeloperoxidase is an enzyme that is useful in… |
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Definition
Oxygen dependent bacterial killing in phagolysosomes
other oxygen dependent enzymes: NADPH oxidase, superoxide dismutase
oxygen independent: pH, lysozyme, cationic proteins, lactoferrin, vitamin B12 binding protein, acid hydrolases
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Term
Integrons are most frequently associated w/… |
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Definition
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Term
As commonly performed, the color of gram-positive bacteria in a Gram stain smear is |
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Definition
PURPLE
crystal violet stain
gram negative is pink/red: safranin |
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Term
Alcohol based handwashing solutions should be used… |
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Definition
BEFORE EATING
not for endospores, they will resist
it's not a replacement for sterile gloves
don't use it when hands are visibly soiled because it will not rinse away dirt and your hands will not be clean at all!
washing and rinsing is actually more effective than alcohol or other chemicals if there is solid matter present b/c they can't penetrate the dirt/poop/whatever.
it's the same on inanimate objects like cages |
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Term
Tissue necrosis seen in gangrenous forms of mastitis caused by Staphylococcus aureus is attributed to staphylococcal… |
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Definition
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Term
The minimum inhibitory concentration (MIC) of an organism for a particular drug is equivalent to its minimum bactericidal concentration (MBC) for the same drug |
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Definition
No. The MIC is how much to inhibit growth, not to kill the bacteria (MBC). there might still be viable bacteria in the solution at MIC. |
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Term
If an abscess is not drained, live bacteria contained within the pus will escape into the surrounding tissues and blood stream |
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Definition
Not necessarily true, in the case of a long standing absess, usually the area is walled off by fibrin from surrounding tissue. Pus is an accumulation of dead leukocytes and thus is drained out of the body |
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Term
Isolation of numerous microorganisms from a normally sterile body site without the presence of inflammatory cells should be viewed with suspicion. |
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Definition
True, microorganisms that should not be present should trigger an immune response, if they do not, test that isolated them should be examined |
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Term
Plasmids are transferred between bacteria via bacteriophage
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Definition
This is not true, some plasmids can transfer themselves, bacteriophages can transfer information by packaging some of DNA from a host cell and injecting it (generally or specifically) into a 2nd bacteria
(plasmids can be conjugative, mobilizing or non mobilizing - not all transfer themselves but none are transferred by bacteriophage)
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Term
A bacterial isolate that grows in the absence of oxygen is classified as an anaerobe. |
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Definition
This is not necessarily true, there are also facultative anaerobes which can tolerate oxygen and can also grow without. It is not strictly just an anaerobe. |
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Term
Bacteria can be visualized by bright-field microscopy using 100x oil-immersion objective. |
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Definition
Not true, to see bacteria following staining one should use a 1000x magnification as bright field only shows bacteria up to .2 um in size. |
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Term
Disease is not an inevitable consequence of infection. |
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Definition
True, infection can be carried by a chronic patient and shed into the environment w/out the carrier actually being sick. Also bacteria can live in a state of lysogeny w/ bacteriophages and not be “sick” until lysogeny ends. |
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Term
Fimbriae (pilli) have specialized function in bacterial gene transfer. |
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Definition
True - sex pilli are formed from a donor cell and 1 strand of DNA is transferred, at which time another complementary strand is synthesized. |
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Term
Give one example of an activity that supports the philosophy of “prudent use of antimicrobials” in order to control population wide antimicrobial resistance |
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Definition
Working to improve compliance in affected patients, if someone does not finish a route of antimicrobials, they have chance of illness again because the disease could come back and be more resistant after mutation
(education)
(prudent use of drug)
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Term
In a laboratory bacterial killing assay, Penicillin G at a concentration of .3 micrograms/ml caused a 99.9% reduction in bacterial numbers. However, in the same assay with the same inoculum, penicillin G at a concentration of 300 micrograms/ml caused only 10% reduction in bacterial numbers. Bacteria that survived the drug treatments, when retested, were susceptible to penicillin G and were indistinguishable from the original bacterial population.
• What is the principal mode of action of penicillin G on bacteria?
• How could the bactericidal action of penicillin G be negated by increasing concentrations of the drug, without changing the inherent properties of the bacterium?
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Definition
1: Disrupts the cell wall by not allowing cross-linking of peptidoglycan (correct) more info - this only happens during development; not to fully grown bacteria
2: Pharmokinetics follows 1st rate order kinetics, meaning 1 molecule of drug is consumed for every 1 receptor, all receptors could be bound with drug, yielding no response when penicillin concentration elevates.(partial credit)
real answer: penicillin only works on actively growing populations! if you've killed off the majority of the growing bacteria quickly, then the population is not actively growing. thus a higher concentration of the drug is actually less effective in killing bacteria
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