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49 Cards in this Set

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What is the diff between antiseptic / disinfectant?
antiseptic = body
disinfectant = inanimate objects
Define MIC
minimum inhibitory conc.
= min. conc of bacteriostatic antibiotics required to stop growth
Can bacteria grow in presence of bactericidals when conc falls below MIC?
no
Can bacteria grow in presence of bacteriostatics when conc falls below MIC?
yes
What common featre do the beta-lactams have?
the 4-membered beta-lactam ring
Which bacteria usually more sensitive to antibiotics? Gram-(+) or (-)?
Gram-(+)
What are the optimal attributes of a chemotherapeutic agent?
solubility
low MIC
broad spectrum
low freq of resistance
low rate of breakdown
low toxicity
non-allergenic
How do beta-lactams inhibit growth?
interfere with cell-wall synthesis during PDG synthesis
What do polymyxins do?
destabilize cell wall
What do erythromycin, tetracyclines, and oxazolidinones do? Are they bacteriocidal or static?
bind to ribosome and inhibit function. Bacteriostatic.
What does nalidic acid, and ciprofloxacin do?
intereferes with DNA gyrase activity (involved in unwinding during chromosome replication)
What drugs interefere with protein synthesis via ribosome binding?
erythromycin, tetracyclines, oxazolidinones
What drugs interfere with DNA grase activity?
nalidic acid, and ciprofloxacin
What does rifampin do?
interferes with DNA-directed RNA polymerase activity, inhibits transcription
What do sulfonamides and trimethoprim do?
interfere with folic acid metabolism
Define antibiotic resistance
acquired ability to resist effects of antibiotic, to which it is normally resistant
Define efflux
active transport to pump out unwanted substances
Why are mycoplasmas (causative agent of pneumonia) resistant to penicillin?
lack PDG
Why are antibiotic-producing organisms a worry?
they often have resistance genes as well, which can be passed on via horizontal xfer to other organisms
What are the four types of horizontal gene transfer?
conjugation
transduction
transformation
transposition
Define transduction
the transfer of DNA (viral or bacterial) from one cell to another via bacteriophage
Define transformation
the genetic alteration of a cell resulting from the introduction of foreign DNA
Define conjugation
transmission of DNA without fusion of gametes
Define transposition
a mutation in which a chromosomal segment is transferred to a new position on the same or another chromosome
Mutation and selection is ___ gene transfer
vertical
What are the main contributors to the antibiotic resistance problem?
agriculture industry (use 50% of antibiotics produced, 90% of which are growth-promoting agents)

over-prescription (20%/80%)

failure to complete prescription cycle

availability in developing countries of antibiotics without prescription
What are four superbugs prevalent today?
MRSA: methicillin-resistant Staphylococcus aureus
VRE: vancomycin-resistant Enterococcus
imipenem resistant Pseudomonas aeruginosa
penicillin resistant Streptococcus pneumoniae
Define cocci
microorganisms that are spherical
What is the most common multi-drug resistant bacteria in hospitals?
MRSA
What is vancomycin? What does it do?
a glycoprotein that interferes with synthesis of bacterial cell wall
What is the cost of treating TB? Antibiotic resistant TB?
$1200 vs $400,000
Describe Linezolid
an oxazolidinone
inhibits initiation of prot synthesis
bacteriostatic
limited spectrum
used for infections of blood, lungs, skin
Describe Daptomycin
a cyclic lipopeptide
causes depolarization of cell membrane potential
used for skin infections
What are the four materials used in vaccines?
killed bacteria
avirulent mutants of bacteria
components of bacteria
toxoids (detoxified toxins)
Define active immunization
injecting human with vaccine to induce antibody or cellular immune response
Define passive immunization
injecting pre-formed antibodies
Give an example of passive immunization treatment
hyperimmune gamma globulin used for botulism toxin
Do vaccines lower the case fatility rate?
no
Do vaccines lower the mortality rate? The incidence rate?
yes, yes
M. tuberculosis is often an infection of the ___
lungs
M. tuberculosis survives and replicates in ___ after inducing an inflammatory reaction in lungs and being engulfed by phagocytic cells
macrophages
Does M. tuberculosis induce cell-mediated immunity? Is it effective?
yes, not completely
How is M. tuberculosis similar to HIV?
They both tend to lie dormant than suddenly spring into action for poorly understood reasons
M. tuberculosis is responsible for __% of all deaths in developing countries
5%
M. tuberculosis kills ___ people worldwide every year
3 million
More than ___ people are infected in the US with M. tuberculosis
30,000
M. tuberculosis is especially prevalent in ___
poor people and AIDS patients in large american cities (ie New York)
Describe the antibiotic treatment for M. tuberculosis
therapy for 9-12 months with multiple antibiotics
Describe the vaccine for M. tuberculosis
live strain of Mycobacterium bovis, resulting in cell-mediated immune response