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63 Cards in this Set
- Front
- Back
What is a broad spectrum antibiotic?
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one that is effective against a variety of Gram-positive and Gram-negative bacteria.
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Three modes of action of antibiotics,
and an example of each |
cell wall formation, inhibition of protein synthesis and interference with DNA replication. penicillin, the second type is erythromycin, and the third type is ciprofloxacin.
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What is a zone of inhibition?
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a clear halo found around an antibiotic disc on aa plate of Mueller-Hinton agar swabbed with a single bacterial culture and incubated for 18 hours at 35 C.
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What is significant of PPNG and MRSA?
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These organisms break open the beta-lactam ring in the penicillin molecule and destroy the effectiveness of the antibiotic.
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List three risks associated with aminoglycoside antibiotics
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Aminoglycoside antibiotics are nephrotoxic, ototoxic, and neurotoxic.
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What is a broad spectrum antibiotic?
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one that is effective against a variety of Gram-positive and Gram-negative bacteria.
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Three modes of action of antibiotics,
and an example of each |
cell wall formation, inhibition of protein synthesis and interference with DNA replication. penicillin, the second type is erythromycin, and the third type is ciprofloxacin.
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What is a zone of inhibition?
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a clear halo found around an antibiotic disc on aa plate of Mueller-Hinton agar swabbed with a single bacterial culture and incubated for 18 hours at 35 C.
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What is significant of PPNG and MRSA?
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These organisms break open the beta-lactam ring in the penicillin molecule and destroy the effectiveness of the antibiotic.
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List three risks associated with aminoglycoside antibiotics
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Aminoglycoside antibiotics are nephrotoxic, ototoxic, and neurotoxic.
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Define resistant colony
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small colonies found in the zone of inhibition around an antibiotic disk
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What are the three results possible form an antibiotic reacting with a microbe?
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Intermediate
Sensitive Resistant |
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penicillins are lethal to microbes because they
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block cell wall formations
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mycoplasmas are resistant to the antibiotic
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penicillin because they lack a cell wall
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An example of a macrolide antibiotic
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erythromycin
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Quinolones interfere with
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DNA synthesis
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Chlamydiae infections are treated by
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tetracyclines
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Are Dividing or Non-Dividing cells sensitive to penicillin
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dividing cells are sensitive
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What antibiotic would you use against staph and strep?
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penicillin
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What are two examples of broad spectrum antibiotics?
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cephalosporins and tetracyclies
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Name the significant ingredients in the Snyder Test medium
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The important ingredients in Snyder Test medium are glucose and the pH indicator bromcresol green.
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What are the major microbes responsible for dental caries?
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streptococcus mutans and lactobacilli
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What is plaque
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dextrins + bacteria
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What procedures increase the risk of bacteremia and endocarditis
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oral surgery and tooth extraction
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What antibiotics are used to prevent bacteremia and endocarditis?
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penicillin and erythromycin
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The dextran covering surrounding bacteria on the teeth is called a
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glycocalyx
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What is the final pH of Snyder Test agar?
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the final pH is 4.8
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Does acid in snyder test medium incubated with saliva is indicated by a change from blue green to yellow color
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yes
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T/F change in color of saliva inoculated and incubated in Snyder Test agar medium after 48 hours indicates a marked risk of dental caries
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false, a change in color after 48 hours indicates a moderate risk
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Where is periodontal disease?
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Caused by bacterial colonization and inflammation that occur in response to gingival damage
Plaque becomes mineralized (calcified) with calcium and phosphate crystals |
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What is in saliva that inhibits bacterial growth?
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lysozyme
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cephalosporins
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activity against gram positive and gram negative
broad spectrum |
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tetracyclines
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broad spectrum bacteriostatic antibiotics
effective against gram positive and gram negative |
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macrolide
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inhibits protein synthesis
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aminoglycoside
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effective against gram neative
nephrotoxic, neurotoxic and ototoxic |
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quinolones
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new category of antibiotic
interfere with DNA replication UTIs and Respiratory tract infections |
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polymixins
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antibiotics that are topical ointments
effective against gram negative interfere with selective permeability |
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empiric decision vs. differential decision
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empiric- prior experience
differential- antibiotic sensitivity test |
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antibiotics
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antimicrobial agents that are produced by living organisms
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penicillins
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bactericidal since they block formation of the cell wall
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alpha-hemolytic reaction
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streptococci release an enzyme that partly destroys the red blood cell membrane and the hemoglobin so that a green halo appears in the blood agar
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beta-hemolysis
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small white colonies surrounded by clear zones
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fomite
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non-living surface
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What are upper respiratory tract infections caused by?
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streptococcus pyogenes
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What are lower respiratory tract infections caused by
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streptococcus pneumoniae gram +
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A throat culture is done to detect the presence of?
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Group A streptococci
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What is resident bacteria on the skin?
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S. epidermis and P. acnes
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What is the major cause of infection on the skin?
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Staph aureus
coagulase production and the fermentation of mannitol |
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Is UV radiation penetrating?
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it is non-penetrating
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Process of photoreactiviation refers to light repairing dimerized bases---
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True
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3. The wavelength of light most strongly absorbed by DNA is 160 nm-------
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False, 260
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disinfectant
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control growth of microorganisms on environmental surfaces
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antiseptics
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control growth of microorganisms on skin and mucous membranes
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Bacteriostatic vs bacteriocidal
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static- the population becomes stationary, no new bacteria
cidal- kills the bacteria |
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4 types of antimicrobials
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phenols, halogens, alcohols, and quaternary ammonium compounds
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The size of the zone of inhibition IS/ISN'T a direct measure of the effectiveness of any microbial agent, since some effective chemicals may diffuse slowly in agar
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IS NOT
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Does zone of inhibition discriminate between bacteriostatic and bacteriocidal?
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no!
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the aerobic breakdown (oxidation) of sugar that produces ATP and pyruvic acid
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glycolysis
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oxidation and reduction of organic compounds in which no added electron acceptor is present
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fermentation
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fermentation that produces primarily lactic acid from pyruvic acid
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homolactic
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fermentation that produces lactic acid, ethanol and CO2 from pyruvic acid
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heterolactic
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Voges-Proskauer Test
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measures the production of neutral end products
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phenol red broth
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measure the production of acidic end products
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