Quiz 3 Flashcards
Gram positive bacteria contain lipids in their membranes that specifically bind the gram stain
True / False
False
2) Bacteriostatic antibiotics, because they inhibit replication of bacteria, do not produce
resistance True / False
False
3) Plasmin exchange mechanisms of resistance development only occur in closely related strains
of bacteria True / False
False
4) Briefly explain the disk diffusion test for microbial susceptibility (2 pts)
Bacteria is grown
on agar plate with disks containing different antibiotic for 18-24 hours. You look at the bacterial growth around the disks. There will be an area of no growth around the disk the bacteria is sensitive to and smaller areas of no growth around the disks the bacteria with less sensitivity
5) Binds end of peptidoglycan strands to prevent cell wall elongation
Vancomycin
7) Antipseudomonal penicillin
Ticarcillin, Piperacillin
8) Disrupts membrane potential and blocks cell wall synthesis
Televancin, Daptomycin
9) Blinds 30 s ribosome and prevents binding of initiation tRNA
Aminoglycoside
1) Gram negative bacterial cell walls have different peptidoglycans and lipids that gram positive
bacteria. True / False
False
2) Use of broad spectrum bactericidal antibiotics is the best defense against resistance
development True / False
False
3) MIC is the amount of antibiotic required to kill bacteria. True / False
False
4) List 2 mechanisms of bacterial resistance development: (any two)
Natural selection,
altered enzymes, permeability changes, change in efflux pathways, change in affinity of
binding sites, altered metabolic pathways, , form spores, mutational changes, conjugation –
plasmid, transduction, transformation
Beta lactams with the broadest spectrum of activity
___Carbapenems_______________
9) Blocks lipid carrier that moves peptidoglycans across cell membrane
____Bacitracin_____________
1) Natural compound produced by bacteria or fungi to suppress growth of other
Microorganisms. Antibiotic / Antimicrobial
Antibiotic
2) Antibiotic agents which kills microorganisms. Bacteriostatic / Bactericidal
Bactericidal
4) The disk diffusion method is used to determine the MIC values of antibiotics.
True / False
False
3) Combined use of two broad spectrum antibiotics is always contraindicated
True / False
False
5) For an antibiotics which show concentration dependent killing, you do not need to
maintain specific therapeutic blood levels for killing to occur. True / False
True
6) Resistance due to a change in efflux pathways occurs with which of the following
antibiotics? Penicillin / Tetracycline / Sulfonamides
Tetracycline
7) Beta lactam which is the choice for Syphilis
Penicillin G
8) Penicillinase-resistant penicillin
Oxacillin, Nafcillin, Dicloxacillin
1) Synthetic compound used to suppress growth of other Microorganisms.
Antibiotic / Antimicrobial
Antimicrobial
2) Antimicrobial agents which prevent replication of microorganisms.
Bacteriostatic / Bactericidal
Bacteriostatic
3) In general narrow spectrum are preferred over broad spectrum agents because
they lead to less resistance. True / False
True
4) MBC is determined by serial dilution of bacteria with increasing concentrations of
antibiotic. MBC is the concentration at which no bacterial growth is seen in the
diluted tubes. True / False
False
5) Time dependent killing, means the antibiotic specific must be kept within specific
therapeutic blood levels for killing to occur. True / False
True
9) Suicide inhibitor of Penicillinase
Tazobactam, Sulbactam
2) Given the choice between a bactericidal and bacteriostatic antibiotic you would always
choose the bactericidal agent (1 pt) True / False
False
3) The disk diffusion test is useful in determining the MIC value. (1 pt) True / False
False
4) Explain concentration dependent killing by antibiotics. (2 pts)
Killing is dependent on the concentration not time above the MIC value, continues to kill even after blood levels fall below MIC
5) Vancomycin resistance can develop due to plasmid exchange between bacteria. (1pt)
True / False
True
6) Gram negative bacterial cell walls are made up of N-acetylmuramic acid while gram
positive bacterial cell walls are made up of N-acetylglucosamine (1pt) True / False
False
7) Penicillin V is broken down quickly by stomach acid. (1pt) True / False
False
8) Piperacillin with Tazobactam has the broadest spectrum of activity of all penicillin’s.
(1pt) True / False
True
9) Penicillin allergies are only seen in patients after multiple treatments. (1 pt)
True / False
False
1) Define antimicrobial. (1 pt)
Synthetic agents to suppress the growth of microorganisms
2) Bacteriostatic antibiotics are never first line in treating infections. (1 pt) True / False
False
3) The minimum bactericidal concentration is the concentration of antibiotic that shows no
visible growth in bacterial dilution tests. (1 pt) True / False
False
4) Define time dependent killing by antibiotics. (2 pts)
Time dependent requires antibiotic plasma levels to be above MIC values to kill bacteria,
5) Sulfonamides resistance can develop in a microorganism which increase PABA
concentration. (1pt) True / False
True
6) Gram negative bacteria have different lipids in their membranes than gram positive, that
do not bind the gram stain. (1pt) True / False
False
8) Tazobactam is combined with Piperacillin to increase its gram negative activity. (1pt)
True / False
False
9) Penicillin’s enter the renal tubule by simple filtration through the glomerulus. (1 pt)
True / False
False
3) The minimum inhibitory concentration is the concentration of antibiotic which kills all
bacteria. (1 pt) True / False
False
4) List two situations where combination therapy with antibiotics is warranted. (2 pts)
(Any two)
Treatment of life threatening infections, treatment of polymicrobial infections,
To enhance the microbial activity of another antibiotic, treatment of resistant
strains, lower dose of one to reduce toxicity, prevent resistant strains
5) Tetracycline’s are an example of an antibiotic that develops resistance by enhancing efflux pathways (1pt) True / False
True
6) Gram positive bacteria express beta-lactamases while gram negative bacteria do not.
(1pt) True / False
False
7) Penicillin V is the naturally occurring penicillin and must be given by injection. (1pt)
True / False
False
8) Sulbactam is combined with Ampicillin to extend its gram negative activity. (1pt)
True / False
False
9) Penicillin are excreted into the renal tubules by active secretion by acid/base
transporters. (1 pt) True / False
True
What agents increase gram - activity by using up penicillinase?
Piperacillin
Ticarcillin + Clavulanate
Piperacillin + Tazobactam (broadest)
How to keep penicillin in the blood longer
Give probenacid, prevents excretion
Drug class with cross-sensitivity to penicillin (allergy to both)
Cephalosporins
Orally available cephalosporins
1st generation
Cephalexin
Cephradine
Cefadroxil
2nd generation
target gram - and gram +
3rd generation
target gram -, start to lose gram +
Drug class cannot be given orally
Penems, also vancomycin (structure too big)
