antibioticsbooks

96 PART 2 Antibacterial Drugs
as beta-lactams do. Does your patient have
MSSA? Use nafcillin or cefazolin instead.
• Recently, a phenomenon described as “MIC
creep” has been seen with staphylococci and
vancomycin. MICs have been rising to vancomycin
in many institutions, and while they
have not yet reached the level of resistance,
they are increasing within the range labeled
as susceptible, that is, # 2 mcg/ml. However,
patients receiving vancomycin for serious
infections caused by staphylococci with an
MIC 5 2 mcg/ml to vancomycin have been shown
to have worse outcomes than those with lower
MICs. This issue warrants careful attention.
• Telavancin is more rapidly bactericidal than
vancomycin. This activity may be an advantage
in the treatment of some infections, but
clinical evidence that shows a benefit is lacking
at this point.
What They’re Good For
Vancomycin is a drug of choice for MRSA infections
and for empiric use when MRSA is a concern, such
as for nosocomial pneumonia. It is also useful in
other Gram-positive infections when the patient
has a severe beta-lactam allergy. Telavancin is
indicated only for skin and skin structure infections
at this time (in the United States). It has activity
against organisms with decreased vancomycin
susceptibility, but its role is still being defined. In
Europe, it is approved for only MRSA hospitalacquired
pneumonia.
Don’t Forget!
Are you sure that vancomycin trough concentration
was drawn correctly?