Antimicrobials

Question 1

Antibiotics is either bactericidal or bacteriostatic define this

Answer 1

Bactericidal : kill the organism

Bacteriostatic : slow the growth of organism

Question 2

Diagram about antimicrobials

Answer 2

1- inhibit cell wall synthesis
A- B-lactams
B- Glycopeptides

2- inhibit nucleic acid synthesis
A- sulphonamides & Trimethoprim indirectly inhibit DNA synthesis
B- Quinolones directly inhibi DNA- gyrase
C - Nitrofurantoin bind to bacterial ribosome and inhibit protein synthesis
D- Rifampicin inhibit DNA dependent RNA polymerase

Question 3

Mention the antimicrobials groups that their targets is transpeptidase

Answer 3

1- penicillin
2- Cephalosporin
3- Monobactems
4- Carbapenem

Question 4

Is penicillin bactericidal or bacteriostatic

Answer 4

Bactericidal

Question 5

What are the main side effects of pencillins

Answer 5

• hypersensitivity reaction
• anaphylactic reaction
• hemolytic anemia
• thrombocytopenia
• neurotoxicity ( w/ increase dose)
• pruritus
• urticarial reaction
• skin eruptions ( maculopapular rash )

Question 6

What example of beta- lactamase resistant pencilins which has narrow spectrum acts only against gram -

Answer 6

Temocillin

Question 7

Example of penicillin active against pseudomonas

Answer 7

Piperacillin

Question 8

Which penicillin has broader spectrum more than benzyl penicillin

Answer 8

6-aminopenicillanic acid

Question 9

Which B lactams is less active against enterococci

Answer 9

Cephalosporins

Question 10

What cephalosporin is anti-pesudomonal

Answer 10

“ceftazidime” which is from 3rd generation of cephalosporin

Question 11

Cephepime

Answer 11

Is a 4th generation of cephalosporin + is anti-gram including enterobacteriacae and pseudomonas

Question 12

Main side effects of cephalosporin

Answer 12

Hypersensitivity reaction
Thrombophlebitis
Hepatotoxicity
Thrombocytopenia
GI disturbance
Pseudomembranous colitis

Question 13

Mention antimicrobials in monobactems group ( one of B lactams)

Answer 13

Aztreonam ( narrow spectrum gram - )

Question 14

Carbapenem is isolated from streptomyce’s and is one of B lactams mention antimicrobials of this group

Answer 14

Imipenem(not stable combined with cilastatin)

2- Meropenem ( stable ) + side effects of it is seizures + transient changes in liver enzymes

Question 15

Where Glycopeptides act

Answer 15

Act on cell wall synthesis at a stage prior to B lactams

Question 16

Glycopeptides?

Answer 16

Another one that inhibit cell wall synthesis

• has two antimicrobials 1- vancomycin 2- Teicoplanin ( less nephrotoxic)
• has narrow spectrum only against gram +
• used against MRSA + those allergic to penicillin or cephalosporin with staph or strepto infection

Question 17

Which antimicrobials reduce nitro group to amine under low redox potential + active against anaerobes and helicobacter + Protozoa

Answer 17

Metronidazole

Question 18

What antimicrobials inhibit DNA replication by inhibit DNA gyrase ( topoisomerase)

Answer 18

1- Quinolones ( Naladixic acid )

2- Fluoroquinolones ( Ciprofloxacin)

Question 19

What antimicrobials used for UTI

Answer 19

Nitrofurantoin

Trimethoprim

Question 20

What antimicrobials inhibit dna synthesis indirectly and inhibit “ early” stages of folic acid synthesis

Answer 20

Sulphonamides

Question 21

What antimicrobials inhibit dna synthesis indirectly and inhibit “Later” stages of folic acid synthesis

Answer 21

Trimethooprim

Question 22

What work in synergy w/beta lactams and inhibit of protein synthesis 30s subunit

Answer 22

Aminoglycosides ( ex. Gentamycin or Amikacin)

Question 23

Macrolides?

Answer 23

-inhibit of protein synthesis 50s subunit
- used for resp infec + sexually transmitted disease esp azithromycin
- macrolides either 1- 14 ring ( Erthromycin)
2- 15 ring ( azithromycin) 3- 16 ring. ( josamycin)

Question 24

What inhibit 50 s subunit and has clostridium difficile associated diarrhea as side effects

Answer 24

Clindamycin

Question 25

What antimicrobials prevents binding to aminoacyl-tRNA and has photosensitivity and permanent brown discoloration as side effect + its bacteriostatic

Answer 25

Tetracycline

Question 26

What antimicrobials act on peptidyl transferase and used in eye drops and has irreversible bone marrow aplasia as side effect

Answer 26

Chloramphenicol

Question 27

What antimicrobials does not directly bind to ribosome and has narrow spectrum anti-staphylococci only and its not used alone bec resistance will develop

Answer 27

Fusidic acid

Question 28

What antimicrobials act on LPS ( anti-endotoxins) and bactericidal with narrow spectrum active against gram - aerobic bacilli

Answer 28

Colistin

Question 29

Linezolid?

Answer 29

• inhibit invitation process of protein synthesis
• inhibit virulence factor expression
• active against gram positive +
• active against resistant MRSA , VRE

Question 30

What antimicrobials is not recommended for pregnant women or children <8 years

Answer 30

Tigecycline ( like tetracycline)

Question 31

What antimicrobials contraindicated in children bec it cuz damage of cartilage

Answer 31

Quinolone