Abstract
Short course of antimicrobial therapy can select resistant bacteria that persist for 4 years or longer.
We examined how a common therapy that includes clarithromycin affects normally colonizing
Staphylococcus epidermidis
. Samples from the nostrils of 5 patients receiving therapy were collected before, immediately after, 1 year after, and 4 years after treatment. From each patient and sample,
S. epidermidis
strains were isolated and analyzed for clarithromycin susceptibility and presence of the
erm
(C) gene. We show that macrolide-resistant strains of
S. epidermidis
were selected during therapy and that the same resistant strain may persist for 4 years, in the absence of further antimicrobial treatment.