Infectious Diseases in Critical Care Medicine

Table 8 Vancomycin Delayed Resolution/Failure in Treating MSSA/MRSA Bacteremias and ABE

Failure Rates Duration of Bacteremia References

.MSSA bacteremia Nafcillin: 4% Nafcillin: 2 days Hackbarth
Vancomycin: 20% Vancomycin: 7 days
(20%>3 days)
(12%>7 days)
.MSSA ABE Nafcillin 1.4%–26% Nafcillin: 2 days Gentry
Vancomycin: 37%–50% Vancomycin: 5 days Geraci
Chang
Small
.MRSA ABE Nafcillin: Not applicable
Vancomycin:>7 days

Abbreviations: ABE, acute bacterial endocarditis; MRSA, methicillin-resistantS. aureus; MSSA, methicillin-
sensitiveS. aureus.
Source: Adapted from Ref. 56.

Table 9 Suboptimal Combination Therapy for MSSA and MRSA ABE

Antibiotic Combinations Comments References

.MSSA ABE
Nafcillinþgentamicin Outcomes samegentamicin Lee
Vancomycinþgentamicin
.MRSA ABE
Vancomycin Duration of bacteremia: 7 days Levine
Vancomycinþrifampin Duration of bacteremia: 9 days (antagonistic;not
synergistic)

Shelburne

Abbreviations: ABE, acute bacterial endocarditis; MRSA, methicillin-resistantS. aureus; MSSA, methicillin-
sensitiveS. aureus.
Source: Adapted from Ref. 56.

Table 10 Antibiotic Therapy of MSSA and MRSA Bacteremias

Antibiotics/
Pathogens Attribute Disadvantages

S. aureus(MSSA)
Nafcillin l Most activeanti-MSSA antibiotic
l The only anti-MSSA penicillin with a
enterohepatic circulation
l Inexpensive
l Long experience
l No dosing modification in CRF
l Low resistance potential
l NoC. difficilepotential

l Short t½requires frequent dosing (q4h)

l Drug fevers (common)

l Interstitial nephritis (rare)

(avoid oral anti-MSSA PCNs that are

notwell absorbed instead use oral first-

generation cephalosporin, cephalexin)

Cefazolin l Most activeanti-MSSAcephalosporin

clinical effectiveness/outcomes nafcillin

l Long experience

l Inexpensive

l Low resistance potential

l HighC. difficilepotential

l Drug fevers (common)

l Avoid in patients withanaphylactic reac-

tionsto PCN

l No oral formulation (use oral first-

generation cephalosporin, cephalexin)

Ceftriaxone l Less anti-MSSA activitythan nafcillin or

cefazolin

l Low resistance potential

l LowC. difficilepotential

l No oral formulation (use oral first-

generation cephalosporin, cephalexin)

l Non-C. difficilediarrhea (common)

l Pseudobiliary lithiasis

Intravenous Central Line Infections in Critical Care 213