intro to chemotherapy

Question 1

selective toxicity

Answer 1

greater toxicity to parasite than host

Question 2

chemotherapy selects for what strains of bacteria

Answer 2

resistant strains

Question 3

purpose of chemotherapy

Answer 3

lowers the microorganism load so that the host defense system can rid the body of foreign organisms

Question 4

is maintenance of constant blood levels more important with bacteriostatic or bactericidal agents

Answer 4

bacteriostatic

Question 5

what is vertical antimicrobial resistance

Answer 5

resistance to a drug is acquired by a mutation and passed vertically by selection to daughter cells

Question 6

what are the three types of horizontal transfer of antimicrobial resistance

Answer 6

transduction, transformation, conjugation

Question 7

transduction

Answer 7

DNA is transferred from one bacterium to another by a virus (bacteriophage)

Question 8

transformation

Answer 8

bacteria undergo lysis all of the time and release DNA into environment. DNA is picked up by neighboring bacteria and incorporated into DNA

Question 9

conjugation

Answer 9

required cell to cell contact; need sex pilus to join two cells together

Question 10

list the drugs that are hepatotoxic

Answer 10

• tetracyclines
• isoniazid
• erythromycin estolate
• clindamycin
• sulfonamides
• amphotericin B

Question 11

list the drugs that are renal toxic

Answer 11

• cephalosporins
• vancomycin
• aminoglycosides
• sulfonamides
• amphotericin B

Question 12

which drugs have ototoxicity

Answer 12

• aminoglycosides
• vancomycin
• minocycline (vestibular only)

Question 13

which drugs have visual toxicity

Answer 13

• ethambutol
• isoniazid

Question 14

which drugs have photosensitivity

Answer 14

• tetracyclines
• fluoroquinolones
• sulfonamides

Question 15

what is empirical antimicrobial therapy

Answer 15

diagnosis and choice of antimicrobial agent is based on clinical judgment and experience

Question 16

bacteriocidal

Answer 16

cell death

Question 17

bacteriostatic

Answer 17

growth inhibition

Question 18

MIC vs MBC

Answer 18

• MIC: minimum inhibitory concentration
• MBC: minimum bactericidal concentration

Question 19

concentration dependent killing

Answer 19

rate and extent of killing dependent upon drug concentrations

Question 20

time dependent killing

Answer 20

killing is not increased with increasing concentrations above MBC, but is dependent on the time of exposure to the Abx

Question 21

postantibiotic effect

Answer 21

persistant suppression of bacterial growth after limited exposure to an antimicrobial agent

Question 22

abx synergism

Answer 22

when the inhibitory or killing effects of two or more antimicrobials used together are significantly greater than expected from thier effects when used inidividually

Question 23

superinfections are most frequently observed with what type of Abx

Answer 23

broad spectrum antibiotics

Question 24

what is the most common superinfection

Answer 24

intestinal candidiasis

• can be treated with oral nystatin or amphotericin B

Question 25

staphylococcal enterocolitis is a superinfection that is life-threatening and should be treated how?

Answer 25

• discontinue abx therapy
• treat staph infection with oral vancomycin

Question 26

pseudomembranous colitis is caused by what organism?

Answer 26

• clostridium difficile