Staphylococcus epidermidis with intermediate resistance to vancomycin: elusive phenotype or laboratory artifact?

The recent and troubling isolation of Staphylococcus aureus and coagulase-negative staphylococci that have increased resistance to glycopeptide antibiotics has prompted the use of aggressive surveillance measures in the clinical microbiology laboratory to aid in the recognition of these strains. Despite increasing awareness, the confirmation of glycopeptide resistance among staphylococci can be problematic; we present a case of catheter-associated peritonitis caused by Staphylococcus epidermidis to illustrate the dilemma.