Gram +ves

Question 1

describe the process of start smart

Answer 1

take history and begin appropriate antibiotic

then focus and clinical review after 48 hours and potentially switch antibiotic/route/dosage etc or stop the antibiotic

Question 2

name a coagulase negative staph

Answer 2

staph epidermidis

Question 3

name 3 types of enterococci

Answer 3

E. faecalis
E. feacium
vancomycin resistant enterococcus

Question 4

3 types of bacilli?

Answer 4

listeria monocytogenes
clostridia (C. diff, C. perfringens - wound infections)
corynebacterium (diptheroids - not the same as diphtheria)

Question 5

6 examples of Beta lactam antibiotics?

Answer 5

penicillin
flucloxacillin
amoxicillin
cephlasporins
piperacillin/tazobactam
carbepenems

Question 6

what is the significance of the Beta lactam antibiotics?

Answer 6

if you are allergic to one, probably allergic to the others

- allergy is due to a degredation product of the beta lactas

Question 7

general rule for sepsis antibiotics?

Answer 7

always IV apart from C. Diff

Question 8

structure of penicillin?

Answer 8

beta lactam ring is like a garage on the side of a thiazolidine ring which is like a house with a roof

Question 9

what can deactiviate beta lactam antibiotics?

Answer 9

beta lactamase

Question 10

what is bioavailability?

Answer 10

the proportion of a drug or other substance which enters the circulation when introduced into the body and so is able to have an active effect.

Question 11

what is the importance of bioavailability?

Answer 11

different routes of delivery result in different bioavailability due to absorption
therefore different routes are used depending on severity of infection (i.e sepsis is usually IV while mild infections can usually be treated orally)

Question 12

why are Beta lactam antibiotics needed to be given several times a day?

Answer 12

mode of action depends on amount of time you spend above the minimum inhibitory concentration (concentration required to inhibit the organism)

Question 13

why does gentamicin only need to be given once per day?

Answer 13

concentration dependant killing

Question 14

what drugs act via concentration dependant killing?

Answer 14

aminoglycosides (gentamicin)

quinolones (….floxacins)

Question 15

how can the structure of a target site affect antibiotic action?

Answer 15

more difficult for antibiotics to get into areas with tight junctions (CNS, eyes, prostate)

Question 16

are members of same class all the same?

Answer 16

no

can have different spectrum and site penetration

Question 17

describe characteristics of strep?

Answer 17

gram +ve cocci in chains
catalase positive
nutritional fastidious, require complex media, preferably supplemented with blood

Question 18

strep are facultative anaerobes, what does this mean?

Answer 18

grow aerobically and anaerobically - technically though they do not use oxygen in metabolism, some are capnophilic (grow well in high CO2), some prefer anaerobic conditions for growth

Question 19

alpha vs beta vs gamma haemolysis?

Answer 19

alpha = partial = green
beta = complete = clear/yellow 
gamme = none = no colour change

Question 20

what is the lancefield antigen/classification?

Answer 20

classification of strep via differences in carbohydrate but not useful for all strep

Question 21

group A beta haemolytic strep?

Answer 21

strep pyogenes

• pharyngitis, skin
• immunologic sequelae

Question 22

group B beta haemolytic strep?

Answer 22

strep agalactaiae

- pregnancy and neonates

Question 23

what type of strep is strep pneumonia?

Answer 23

alpha haemolysis

Question 24

strep bovis renamed to what?

Answer 24

strep gallollyticus

- typical endocarditis pathogen

Question 25

additional investigation in strep gallollyticus and why?

Answer 25

colonoscopy as associated with carcinoma

Question 26

what can strep pneumonia cause?

Answer 26

otitis media
pneumonia
meningitis

Question 27

what is the general antibiotic for strep pneumonia and when is this not the case?

Answer 27

penicillin (works by binding enzymes needed to synthesise peptidoglycan)
not after travel to certain countries due to resistant strains which exist

Question 28

what is penicillin G?

Answer 28

benzylpenicillin AKA IV penicillin

Question 29

what is oral penicillin known as?

Answer 29

phenoxymethylpenicillin

Question 30

where do enterococci live int he body?

Answer 30

Gut
- i.e can occur from perforation, biliary etc
can also occur in the heart causing endocarditis

Question 31

what is the main antibiotic for enterococcus?

Answer 31

amoxicillin IV

step down = amoxicillin or co-trimoxazole oral

Question 32

what is used for enterococcus if penicillin resistant?

Answer 32

vancomycin

Question 33

drug of choice in sepsis for staph aureus?

Answer 33

flucloxacillin

Question 34

what drug is used for staph aureus sepsis if penicillin allergic or MRSA?

Answer 34

vancomycin IV

Question 35

what other drugs can be used for staph aureus not causing sepsis?

Answer 35

oral doxycycline
cotrimoxazole
clindamycin

Question 36

describe staph epidermidis?

Answer 36

coagulase negative
less virulent than staph aureus
most are flucloxacillin resistant
only a likely cause of endocarditis in specific stories (i.e pacemaker, prosthetic valve, present in all cultures)

Question 37

relevant gram +ve bacilli?

Answer 37

listeria (gastroenteritis)
bacillus (reheated rice)
clostridium (C. Diff)

Question 38

why is oral vancomycin used instead of IV in C. Diff?

Answer 38

so it acts directly on bacteria in stomach (topical treatment)