Gram Positive organisms

Question 1

Gram positive cocci in chains?

Answer 1

Streptococci

Question 2

Gram positive cocci in clusters?

Answer 2

Staphylococcus aureus

Staphylococcus epidermis

Question 3

Gram positive cocci that have gamma haemolysis?

Answer 3

Enterococcus faecalis

Enterococcus faecium

Question 4

Gram positive bacilli?

Answer 4

Listeria monocytogenes
C.diff
C.perfringens
Corynebacterium - diphtheroids

Question 5

What penicillins are included in the beta lactams drug class?

Answer 5

Penicillin
Flucloxacillin
Amoxicillin
Cephalosporins 
Piperacillin/tazobactam
Carbapenems

Question 6

What route of antibiotics does sepsis require?

Answer 6

IV

Question 7

Why is penicillin given 4 -6 times a day?

Answer 7

Has to be above the minimum inhibitor concentration

Excreted quickly via the kidneys

Question 8

Why are aminoglycosides (gentamicin and streptomycin) and quinolones (levofloxacin, ciprofloxacin) given once a day?

Answer 8

High dose to get the drug over the minimum inhibitor concentration then excreted slowly over the day

Question 9

Where is it difficult for the drug to enter?

Answer 9

Tight junctions
CNS
Eyes
Prostate

Question 10

Where do biofilms commonly form?

Answer 10

CF
Bronchiectasis
Prosthetic material

Question 11

Describe the classification of streptococcal species?

Answer 11

Gram positive
Chains or pairs 
Catalase positive 
Facultative anaerobes
Haemolysis on blood agar

Question 12

Describe haemolysis

Answer 12

Alpha - partial, green color
Beta - complete, golden colour, clear zone
Gamma - non-haemolytic

Question 13

What is group A strep (beta haemolysis)?

Answer 13

Streptococcus pyogenes

Question 14

What is group B strep (beta haemolysis)?

Answer 14

Streptococcus agalactiae

Question 15

What needs to be done if streptococcus bovis/gallollyticus is found in endocarditis?

Answer 15

Colonoscopy - high association with colon cancer

Question 16

What can strep pneumoniae cause?

Answer 16

Otitis media
Pneumonia
Meningitis

Question 17

How does penicillin work against strep pneumoniae?

Answer 17

Binds to enzymes to prevent synthesis of the peptidoglycan wall

Question 18

What are the different mechanisms of antibiotic resistance?

Answer 18

Active efflux 
Target replication 
Modified drug target 
Decreased permeability 
Drugs inactivating enzymes

Question 19

Where can enterococcus be found and what can it cause?

Answer 19

GI tract

UTI, endocarditis, bactaeaemia

Question 20

How is enterococcus treated?

Answer 20

Amoxicillin IV
Then
Amoxicillin or co-trimoxazole PO

Question 21

What can be used to treat vancomycin resistant enterococcus?

Answer 21

Linezolid
Daptomycin
Tigecycline

Question 22

What can be used to treat amoxicillin resistant enterococcus?

Answer 22

Vancomycin

Question 23

What is the mean inhibitor concentration?

Answer 23

Concentration of drug required to kill 99.% of organisms during 18-24 hours
Useful guidance for endocarditis and meningitis

Question 24

What is used for staphylococcus aureus?

Answer 24

Flucloxacillin IV

Vancomycin IV in allergy or MRSA

Question 25

What is pharmacodynamics?

Answer 25

Relationship between infection outcome and drug outcome

Question 26

What is pharmacokinetics?

Answer 26

Effect of the body’s processes on the drug

Question 27

What gram positive bacillus should I know?

Answer 27

Listeria
Bacillus cereus
C.diff

Question 28

How is the severity of c.diff calculated?

Answer 28

ONE or more:
Temp over 38
Ileus, colonic dilation, toxic megacolon and/or pseudomembranous colitis
WBC >15
Acute rising serum creatinine 1.5x baseline

Question 29

What is the treatment for non-severe c.diff?

Answer 29

PO metronidazole

Question 30

What is the treatment of severe c.diff?

Answer 30

PO vancomycin +/- IV metrondiazole