Case 1 - Staphylococcus aureus endocarditis

Question 1

General stats - No need to memorize…

Answer 1

IV drug abuser, 30 years old
Presents with fever, malaise lasting two days Reports sharing needles with friends.
Physical exam is noted for cardiac murmur and rash
Multiple blood cultures grow Gram positive Cocci

Question 2

Without Tx endocarditis has mortality of…?

Answer 2

100%

Question 3

Since contracted via non-sterilized needle (through skin) it is probably…?

Answer 3

Staph. aureus

Question 4

Would it be MSSA or MRSA?

Answer 4

Depends on resistance patterns in the area it was contracted – in Israel MSSA is more probably, in the US probably MRSA.

Question 5

Antibiotics used for Staphylococcus aureus - 6

Answer 5

Oxacillin (Nafcillin), Cephalosporins (1st Gen = cefamezine), Vancomycin, Linezolid (Daptomycin), Trimetophrim-sulphamethoxazole, Clindamycin

Question 6

MSSA Tx options and order - 2

Answer 6

1st line antibiotic treatment – synthetic penicillin (e.g. oxacillin)
2nd line antibiotic treatment – 1st generation cephalosporin (ex. If allergic to Oxacillin)

Question 7

MSSA Tx side effects

Answer 7

o Allergicreactions (including life threatening) – if allergic reaction in one is severe do not give the other
o Some cross reactivity between the two groups (1%)
o Interstital nephritis
(Relatively safe)

Question 8

MRSA Tx options and order - 3

Answer 8

1st line is Vancomycin.

Other options for treating MRSA:

Linezolid –more and more in use, but expensive and serious SEs

Trimetophrim-sulphamethoxazole andClindamycin simpler, oral antibiotics, used for community acquired MRSA in the U.S. (where MRSA is very common) - better option than hospitalizing every kid with inf for IV Vancomycin

Question 9

MRSA Tx side effects - 1 drug, 2 effects

Answer 9

Linezolid - if used for over 2wks (neutopathy, BM damage)