Intro + SSTIs

Question 1

Disease =

Answer 1

pathogen load + virulence / host immunity

Question 2

acute, community acquire meningitis is typically?

Answer 2

bacterial or viral, use CSF to distinguish between them

Question 3

Vancomycin

Answer 3

• cell wall synthesis inhibitor, non-B-lactam drug
• blocks the x-linking of PDG synthesis by binding the substate
• rapidly bactericidal, can enter CNS
• SLOW IV administration
• **narrow spectrum: gram (+), mainly MRSA

Question 4

Penicillin

Answer 4

B-lactam Abx: inhibit PBPs to block x-linking

• bactericidal, do CNS penetration
• **narrow specturm: gram (+) aerobes and some gram (-)

Question 5

Amoxicillin

Answer 5

extended-spectrum penicillin, aminopenicillin

**non-lactamase gram (-) bacilli like e.coli, H.influ, salmonella and shigella

Question 6

Most SSTI, esp CA, are caused by: (2)

Answer 6

1) staph aureus

2) s. pyogenes (GAS)

Question 7

(T/F) if an SSTI is chronically inflamed, that suggests a lymphatic route of spread and intra-cellular organisms.

Answer 7

first half = false, suggests a hematogenous route

second half = true, intra-cellular

Question 8

(3) principles of SSTI treatement

Answer 8

1) local hygienic care
2) I & D
3) abx coverage for organism if SYSTEMIC SIGNS or Special population pt.

Question 9

Important pearls about S. aureus

Answer 9

Gram (+) cocci in clusters
catalase and coag (+)
forms abscesses, PMN = pus!
*skin, blood, heart and bone
*toxins: TSS and SSS

Question 10

Important pearls about S. pyogenes

Answer 10

-rapidly spreading rash, cellulitis, lymphagitis, adenopathy
-Gram (+) cocci in chains
catalase (-) b-hemolytic
-abx of choice = penicillin
-Complications: scarlet fever, acute rheumatic fever, glomerulonephritis

Question 11

16 yo otherwise health male

• steps on nail, penetrates skin through tennis shoe
• not able to put pressure on the foot
• gram stain = GNR, oxidase (+)

organisms?
treatment?

Answer 11

P. aeruginosa

treat with extended spectrum penicillin (amox)

Question 12

Hospitalized patient with infection at IV site,

ddx?

Answer 12

coag neg. staph
staph. aureus
GNR

Question 13

How does the IV affect the ID 50 (the dose of an infectious organism required to produce infection in 50% of subjects)?

Answer 13

it decreases the ID 50 by > 100x (REALLY BAD :( )