Vancomycin-resistant Enterococcus faecium (VREF) is an opportunistic pathogen, which causes
infections among severely ill, hospitalized patients, in whom it is likely to increase the risk of progressive local or systemic disease and to worsen the prognosis. Because these organisms are often highly resistant to
penicillin,
ampicillin and many other antimicrobials including the
glycopeptides, there are few proven therapeutic alternatives for the treatment of
infection caused by VREF.
Quinupristin/dalfopristin is highly active against VREF in vitro. A prolonged post-
antibiotic effect, good polymorphonuclear leucocyte/macrophage penetration and slow release, and active metabolites allow this agent to be used with an 8 or 12 h dosing interval. The combined results from a Phase III non-comparative study and an emergency-use study of
quinupristin/dalfopristin for the treatment of VREF
infection produced a clinical response rate (cure or improvement) in 142 (73.6%) of 193 clinically evaluable patients. The baseline pathogen was eradicated or presumed eradicated from 110 of 156 (70.5%) bacteriologically evaluable patients. Fifty-two per cent of the severely ill patients in these two studies died, but no death was attributed to
quinupristin/dalfopristin therapy. The most common adverse event was
arthralgia (9.1%).
Quinupristin/dalfopristin has demonstrated efficacy for the treatment of serious VREF
infections, including those that have failed conventional
therapy.