USA Pharm Exam 5 – Review Questions & Answers |
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Terms in this set (176)
MIC -minimum inhibitory concentration--lowest conc of
antibacterial agent that inhibits growth of standard
inoculum of specific organism
MBC -minimum bactericidal concentration--lowest conc of
an antibacterial agent that produces a 1000-fold
reduction in organisms from an original inoculum
concentration dependence -conc--rate and extent of bactericidal activity inc w/
drug conc; inc efficacy and dec selection of resistant
bacteria
time dependence -bactericidal activity does not inc w/ increased
concentrations above MBC
-agent is bactericidal as long as conc > MBC
postantibiotic effect (PAE) -persistent suppression of bacterial growth after
limited exposure to an antibacterial agent; most likely
represents an extension of the lag phase of bacterial
growth
other aspects of PAE in addition to -postantibiotic leukocyte enhancement (PALE) due
suppression of bacterial growth to inc bacterial susceptibility to actions of neutrophils
-subinhibitory drug conc result in altered bacterial
morphology and dec growth rate
ABX synergy -combination of 2 agents produces a dec in colony
counts that is 100-fold lower than when either agent
used alone
,ABX antagonism -effect of combination is less than the added effects
from the 2 individual drugs
ABX definitive therapy -use of narrowest-spectrum, least expensive drug to
which the organism is susceptible
3 major sign/symptoms of microbial 1.fever
infection 2.elevated WBC count
3.pain and inflammation
typical alterations of WBC count in -elevated granulocyte counts (neutrophils, basophils)
bacterial infection -inc bands in peripheral blood smear (left-shift)
typical alterations of WBC count in Relative lymphocytosis, even with normal or slightly
viral and fungal infection elevated total WBC counts, is generally associated
with viral or fungal infections
3 reasons for using combination Combinations of antimicrobials are generally used to
antimicrobial drug therapy broaden the spectrum of coverage for empiric
therapy, achieve synergistic activity against the
infecting organism, and prevent the emergence of
resistance
2 major disadvantages of combination -combination can be antagonistic
therapy -inc toxicity
Describe the clinical situations in -often necessary in mixed infections
which increased spectrum of activity -nosocomial infections
using combination therapy is
necessary
Describe the clinical situations in -has been successful in cases of TB and HIV
which use of combinations prevents
emergence of resistance
, Identify the major reasons for failure -Failures caused by drug selection--malabsorption of
of antimicrobial therapy drug due to GI dz or drug interaction; accelerated
drug elimination; inactivation of antimicrobial agents
by other drugs; poor penetration into the site of
infection
-failures caused by host factors--immunosuppressed
pts may respond poorly; necessity for abscess
drainage and removal of FO and necrotic tissue
-failure caused by microorganisms--development of
drug resistance during tx
Explain why bactericidal and inhibition of bactericidal activity by static agents:
bacteriostatic agents should not be i. inhibition of bacterial growth by the static agent
used for the same infection prevents the presence of actively dividing bacteria
required for activity of some bactericidal agents
ii. inhibition of active uptake of some bactericidal
agents
State the basis for selective toxicity for eukaryotic cells lack a cell wall
all of all of the following antibacterial
agents: cell wall synthesis inhibitors
State the basis for selective toxicity for selective toxicity: differences in ribosomal
all of all of the following antibacterial composition and size
agents: bacterial protein synthesis i. bacterial ribosome is termed 70S; bacterial
inhibitors ribosomal subunits are designated as 30S and 50S
ii. mammalian ribosome is termed 80S; mammalian
ribosomal subunits are 40S and 60S
State the basis for selective toxicity for i. sulfonamides are structural analogues of para-
all of all of the following antibacterial aminobenzoic acid (PABA) which is required in the
agents: sulfonamides bacterial
cell for synthesis of folic acid; folic acid is involved in
DNA synthesis and cell growth
ii. selective toxicity: mammalian cells utilize
preformed folic acid and have specialized transport
mechanisms for its absorption; bacterial cells do not
have these transport mechanisms and must
synthesize folic acid intracellularly
Accurate Solutions
Save
Terms in this set (176)
MIC -minimum inhibitory concentration--lowest conc of
antibacterial agent that inhibits growth of standard
inoculum of specific organism
MBC -minimum bactericidal concentration--lowest conc of
an antibacterial agent that produces a 1000-fold
reduction in organisms from an original inoculum
concentration dependence -conc--rate and extent of bactericidal activity inc w/
drug conc; inc efficacy and dec selection of resistant
bacteria
time dependence -bactericidal activity does not inc w/ increased
concentrations above MBC
-agent is bactericidal as long as conc > MBC
postantibiotic effect (PAE) -persistent suppression of bacterial growth after
limited exposure to an antibacterial agent; most likely
represents an extension of the lag phase of bacterial
growth
other aspects of PAE in addition to -postantibiotic leukocyte enhancement (PALE) due
suppression of bacterial growth to inc bacterial susceptibility to actions of neutrophils
-subinhibitory drug conc result in altered bacterial
morphology and dec growth rate
ABX synergy -combination of 2 agents produces a dec in colony
counts that is 100-fold lower than when either agent
used alone
,ABX antagonism -effect of combination is less than the added effects
from the 2 individual drugs
ABX definitive therapy -use of narrowest-spectrum, least expensive drug to
which the organism is susceptible
3 major sign/symptoms of microbial 1.fever
infection 2.elevated WBC count
3.pain and inflammation
typical alterations of WBC count in -elevated granulocyte counts (neutrophils, basophils)
bacterial infection -inc bands in peripheral blood smear (left-shift)
typical alterations of WBC count in Relative lymphocytosis, even with normal or slightly
viral and fungal infection elevated total WBC counts, is generally associated
with viral or fungal infections
3 reasons for using combination Combinations of antimicrobials are generally used to
antimicrobial drug therapy broaden the spectrum of coverage for empiric
therapy, achieve synergistic activity against the
infecting organism, and prevent the emergence of
resistance
2 major disadvantages of combination -combination can be antagonistic
therapy -inc toxicity
Describe the clinical situations in -often necessary in mixed infections
which increased spectrum of activity -nosocomial infections
using combination therapy is
necessary
Describe the clinical situations in -has been successful in cases of TB and HIV
which use of combinations prevents
emergence of resistance
, Identify the major reasons for failure -Failures caused by drug selection--malabsorption of
of antimicrobial therapy drug due to GI dz or drug interaction; accelerated
drug elimination; inactivation of antimicrobial agents
by other drugs; poor penetration into the site of
infection
-failures caused by host factors--immunosuppressed
pts may respond poorly; necessity for abscess
drainage and removal of FO and necrotic tissue
-failure caused by microorganisms--development of
drug resistance during tx
Explain why bactericidal and inhibition of bactericidal activity by static agents:
bacteriostatic agents should not be i. inhibition of bacterial growth by the static agent
used for the same infection prevents the presence of actively dividing bacteria
required for activity of some bactericidal agents
ii. inhibition of active uptake of some bactericidal
agents
State the basis for selective toxicity for eukaryotic cells lack a cell wall
all of all of the following antibacterial
agents: cell wall synthesis inhibitors
State the basis for selective toxicity for selective toxicity: differences in ribosomal
all of all of the following antibacterial composition and size
agents: bacterial protein synthesis i. bacterial ribosome is termed 70S; bacterial
inhibitors ribosomal subunits are designated as 30S and 50S
ii. mammalian ribosome is termed 80S; mammalian
ribosomal subunits are 40S and 60S
State the basis for selective toxicity for i. sulfonamides are structural analogues of para-
all of all of the following antibacterial aminobenzoic acid (PABA) which is required in the
agents: sulfonamides bacterial
cell for synthesis of folic acid; folic acid is involved in
DNA synthesis and cell growth
ii. selective toxicity: mammalian cells utilize
preformed folic acid and have specialized transport
mechanisms for its absorption; bacterial cells do not
have these transport mechanisms and must
synthesize folic acid intracellularly
