Mrsa

Front 1

Per CID 2008, the most common cause of infective endocarditis in most developed regions is...

Back 1

S. aureus and increasingly MRSA

Front 2

What proportion of patients with S. aureus bacteremia will develop metastatic complications resulting either from hematogenous seeding of a distant site or from local extension of infection?

Back 2

1/3

Front 3

What defines "complicated" S. aureus bacteremia?

Back 3

At least 1 of the following factors:

1) attributable mortality
2) Metastatic infection at time of initial hospitalization
3) Embolic stroke
4) Recurrent infection <12 weeks after f/u

Front 4

The strongest indicator of clinical complication of S. aureus bacteremia per Arch Intern Med 2003; 163: 2066–72.

Back 4

(+)ve blood culture at 48-96 hours AFTER initial (+)ve blood culture

Other independent RFs:
- Community acquired infection
- Skin examination suggesting acute systemic infection
- persistent fever @72 hours after the first positive blood cx

Patients with any of these findings should be managed aggressively by ensuring both that all metastatic foci are identified and that therapy is given for an appropriate duration

Front 5

Is TEE or TTE better to detect S. aureus endocaridits?

Back 5

Many experts recommend that patients with S. aureus bac- teremia undergo transesophageal echocardiography, on the basis of several investigations that demonstrated the superior sensitivity of this diagnostic test for the detection of endocarditis among patients with S. aureus bacteremia.

In addition, transesophageal echocardiography is more sensitive than transthoracic echocardiography in identifying complications of endocarditis, such as intracardiac abscess and valvular perforation, processes that occur commonly in endocarditis due to S. aureus.

Transesophageal echocardiography has 2 major purposes in the management of S. aureus bacteremia: (1) the detection of significant cardiac complications associated with S. aureus bacteremia and infective endocarditis in high-risk settings, such as for patients with prosthetic valves, permanent cardiac devices, prolonged bacteremia or fever, or cardiac conduction abnormalities, and (2) the intracardiac assessment of patients at low risk for endocarditis, in whom short courses of therapy are desired. In this latter setting, a transesophageal echocardiography of native valves that does not identify any findings of endocarditis makes the diagnosis of endocarditis unlikely, although other cri- teria, such as the absence of other metastatic foci, must be met before the decision is made to give a short course of therapy.

Front 6

T/F = Pts with Left Sided S. aureus endocarditis are likely to benefit from early surgical intervention

Back 6

TRUE

Front 7

When should 14 days of therapy be considered for S. aureus bacteremia that is catheter associated?

Back 7

If a 14-day course of therapy is considered for catheter-associated S. aureus bacteremia, we believe that the patient must have the implicated catheter removed and then must meet the following clinical characteristics:

(1) endocarditis should be excluded with trans- esophageal echocardiography,

(2) the patient should have no implanted prostheses (e.g., prosthetic valves, cardiac devices, or arthroplasties),

(3) “follow-up” cultures of blood specimens drawn 2–4 days after the initial blood cultures were obtained must be negative for S. aureus,

(4) the patient should defervesce within 72 h after initiation of effective antistaphylococcal therapy, and

(5) the patient should have no localizing signs or symptoms of metastatic staphylococcal infection.

CID 2008:46 (Suppl 5) • Cosgrove and Fowler

Front 8

Vancomycin MICs of ???? mg/mL are associated with sporadic clinical failure and worse clinical outcomes

Back 8

vancomycin MICs of 2 mg/mL are associated with sporadic clinical failure and worse clinical outcomes

Front 9

When should rifampin be used for treatment of S. aureus bacteremia?

Back 9

if rifampin is used for the treatment of S. aureus bacteremia or endocarditis, waiting until cultures of the patient’s blood have cleared S. aureus before addition of rifampin, to minimize the risk of development of resistance .

CID 2008:46 (Suppl 5)

Front 10

When should gentamycin be used in patients with S. aureus bacteremia?

Back 10

When there is prosthetic valve endocarditis - susceptibility testing should be done, since many MRSA isolates are resistant to gentamicin

Be cautious of nephrotoxicity - extreme caution in patients with renal impairment and in elderly patients.

Front 11

A concentration-dependent, bactericidal cyclic lipopeptide that was approved by the US Food and Drug Administration (FDA) in 2006 for the treatment of S. aureus bacteremia and right-sided endocarditis

Back 11

Daptomycin

daptomycin at a dosage of 6 mg/kg daily was found to be as effective as standard therapy, consisting of initial low-dose gentamicin plus either vancomycin or an antistaphylococcal penicillin

Front 12

A bacteriostatic oxazolidinone with activity against MRSA

Can cause lactic acidosis or myelosuppression

Back 12

Linezolid