Antimicrobials

Question 1

Gram stain results and meaning

Answer 1

o Positive is PURPLE- one cell membrane with peptidoglycan outer layer
o Negative is NAGENTA- 2 cell membrane with peptidoglycan in-between and lipposacchurides on outside

Question 2

Gram positive Cocci

Answer 2

Staph- coagulase +- aureus, - epidermis and strep

Question 3

Gram Negative Bacilli

Answer 3

A	Actinomyces (branching)
B	Bacillus (cereus, athracis)
C	Clostridium (difficile, perfringens, botulinum, tetani)
D	Diphtheriae (Corynebacterium diphtheriae) 
L	Listeria

Question 4

Broad Spectrum Meds

Answer 4

These Meds Can Cover
T	Tazocin (Piperacillin/Tazobactam)
M	Meropenem
C	Co-amoxiclav
C	Ciprofloxacin

Question 5

Resistant mechanisms to antibiotics

Answer 5

Bypass
Enzymes (beta-lactamases)
Accumulation impaired (tetracyclines)
Target modified (MRSA)

Question 6

Which antibiotics inhibit cell wall synthesis

Answer 6

Penicillin
Cephalosporins
Carbapenems
Glycopeptides

Question 7

Which antibiotics interrupt protein synthesis

Answer 7

Chloramphenicols
Oxazolidnones
Aminoglycosides
Tetracyclines
Macroloides

Question 8

Which AB inhibit DNA synthesis

Answer 8

Fluoroquinilones

Nitroimidazoles

Question 9

Which AB inhibit RNA synthesis

Answer 9

Rifamycin

Question 10

Which AB inhibit folate synthesis

Answer 10

Sulfonamides

Diaminopyrimidines

Question 11

What types of microbes are b lactase effective against

Answer 11

Penicillin- +
Cephs- as generation increases more negative
Carbs- wide spectrum

Question 12

What types of microbes are vancomycin effective against

Answer 12

MRSA, C diff

Question 13

What types of microbes are aminoglycosides effective against

Answer 13

Gram - sepsis

Question 14

What types of microbes are tetracyclines effective against

Answer 14

Intracellular- chlamydia

Question 15

What types of microbes are macrolides effective against

Answer 15

Gram + usually PCN allergy

Question 16

What types of microbes are chloramphenicols effective against

Answer 16

Bacterial Conjunctivitis

Question 17

What types of microbes are fluoroquinilones effective against

Answer 17

Negative

Question 18

What types of microbes are Nitroimidazoles effective against

Answer 18

Anaerobes and protozoa

Question 19

What types of microbes are rifamycin effective against

Answer 19

Mycobacteria

Question 20

What is used for cellulitis

Answer 20

Flucloaxcillin

Question 21

What Is used for pharyngitis

Answer 21

Benzylpenicillin

Question 22

What is used for CAP

Answer 22

Mild- amoxicillin

Servere- Co-amox and clarithromycin (for atypical)

Question 23

What is used for HAP

Answer 23

Non servere- Coamox/doxy
Servere- Piptazobactam/Cef+gent

MRSA- Vanc
Pseudo- Piptazobactam / Tazocin

Question 24

What is used for bacterial meningitis

Answer 24

Ceftriaxone

Question 25

What is used for community and nosocomial UTI

Answer 25

Com- Trimethoprim/Nitro | Noso- Co amox

Question 26

What is used for C diff

Answer 26

Metronidazole | If fail- vanc

Question 27

What is used in sepsis

Answer 27

Tazocin/cef or Met+ Gent

Question 28

What is the MIC

Answer 28

Minimum inhibitory concentration | o This is the minimum drug concentration that is required to inhibit the growth of the organism in a culture

Question 29

Type 1 antimicrobial pattern of activity

Answer 29

o Peak above the MIC (Cmax) is the MOST IMPORTANT factor (these drugs have concentration-dependent effects) o Therefore, aminoglycosides are given as one big dose once a day, to try and get the Cmax as high as possible o The higher the Cmax the better the clinical outcome for infections treated with aminoglycosides

Question 30

Type 2 antimicrobial pattern of activity

Answer 30

These are time-dependent, so you want to maximise the time above the MIC e.g penicillin

Question 31

Type 3 antimicrobial pattern of activity

Answer 31

o Sort of a combination of Type I and Type II o The AUC (area under curve) above the MIC is the MOST IMPORTANT factor (both concentration and time-dependent effects) o Infusions can maintain an AUC above the MIC e.g vancomycin

Question 32

What is the eagle effect

Answer 32

Penicillin works by inhibiting cell wall synthesis, but cell wall synthesis only occurs when the bacteria are dividing o In cases of extremely high bacterial burden, bacteria may be in the stationary phase of growth - hence penicillin will have little effect

Question 33

What antibiotics commonly cause c diff

Answer 33

Cephalosporins Cirpro (quinilone) Clindamycin