Antibiotic Lecture

Question 1

agents that inhibit synthesis of bacterial cell walls

Answer 1

penicillins, cephalosporins, vancomycin, bacitracin

Question 2

agents that alter cell membrane permeability

Answer 2

polymyxin B

Question 3

inhibition of bacterial protein synthesis by affecting function of 30S or 50S ribosomal subunits

Answer 3

50S – chlorampehnicol, macroslides, erythromycin, azithromycin, clarithromycin, telithromycin, clindamycin, quinupristin, linezolid

30S – amniglycosides, tetracyclines

Question 4

inhibit nucleic acid synthesis

Answer 4

inhibit DNA gyrase – fluoroquinolones

Question 5

metabolic analogs that block metabolic steps

Answer 5

trimethoprim, sulfonamides block enzymes involved in folic acid synthesis

Question 6

Minimum inhibitory concentration MIC

Answer 6

minimal concentration of an antibiotic that prevents visible growth
dilutes the antibiotic in culture broth containing a constant amount of pts bacteria

Question 7

minimum bactericidal concentration MBC

Answer 7

minimum concentration of an antibiotic needed to kill the bacteria
put MIC onto agar plate, if no growth than it is killed

Question 8

transduction

Answer 8

bacteriophage (virus that infects bacteria) has bacterial DNA in its protein coat, obtained from a previous host bacterium that contains a gene for drug resistance

Question 9

Transformation

Answer 9

DNA that is free in the environment and contains resistance genes is incorporated into the bacterial genome

Question 10

conjugation

Answer 10

genes pass from cell to cell by direct contact of the sex pilus

Question 11

transposons

Answer 11

DNA sequences that can jump from place to place

Question 12

synergism

Answer 12

fourfold or greater reduction in the MIC or MBC when a drug combination is used vs when used alone