Infection 101

Question 1

what type of cell wall has lipoteichoic acid?

what about LPS?

what are the porins in the second plasma membrane important for drug delivery?

Answer 1

see image

Question 2

Tell me the big bad bugs on CSF Gram stain

GP cocci

CP bacilli

G neg cocci

G neg bacilli

Answer 2

This is important for treatment of meningitis

1. Gram pos cocci is steph pneumoniae
2. Gram pos bacilli is Listeria

Gram neg cocci is neisseria

Gram neg bacilli is H. influ

Question 3

what is a problem with the legionella urinary antigen?

Answer 3

this is a problem because it only detects the L. pneumophilia 1,

the MO legionella longbeacheae is also common in QLD

Question 4

what does galactomannan test for?

what about beta-D-glucan?

Answer 4

the first one is assoc with aspergillus

the second is other fungal, but not cryptococcus

Question 5

which stages of syphilis are associated with positive serology, and which with negative?

Answer 5

primary syphilis (painless ulcer) is often sero neg

secondary and tertiary are usually sero pos

Question 6

what is the most common pathogen with acute IE

what are some other causes of acute IE?

Answer 6

s. aureus is the main pathogen
s. pyogenes also important

Question 7

what are the common pathogens associated with a subacute presentation of IE?

Answer 7

Strep viridans is a big deal

Enterococci

HACEK bugs

(Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella)

Question 8

what are the risks of IE when the following come up as pos blood cultures?

1. s. mutans
2. s bovis
3. s gallolyticus
4. s. gallolyticus pasteurianus
5. e. faecalis
6. s pyogenes

Answer 8

1. s. mutans is extremely likely to be IE. 14:1 (14 IE cases for each non-IE)
2. s. bovis biotype 1 = 6:1

also very strongly associated with colon CA/adenoma

3. s. gallolyticus is the new name for s bovis (see above
4. s. gallolyticus pasteurianus is 1:1
   - strongly assoc with CRC
5. e. faecalis = 1:1
6. s. pyogenes is 1:32! (much more likely to be from skin)

Question 9

what is the most common pathogen in IE in IVDU

what is the most common in prosthetic valve IE?

Answer 9

in IVDU, number 1, 2 and 3 are s. aureus

in prosthetic valve:

1. coag- neg staph
2. s. aureus
3. streptococci
4. gram-negs

Question 10

what are the more common causes of culture negative endocarditis?

Answer 10

see pic