quinupristin-dalfopristin and Pneumonia--Bacterial

The proliferation of multidrug-resistant gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium (VREF), has created a pressing need for effective alternative antibiotics. Quinupristin/dalfopristin is a new combination streptogramin product with a selective spectrum of antibacterial activity, mainly against gram-positive aerobic bacteria. It has been assessed primarily in emergency-use protocols, in hospitalized patients with skin and skin-structure infections, and in patients with VREF bacteremia.. The objectives of this review were to summarize important results of in vitro microbiologic studies; to provide information on relevant pharmacokinetic parameters, drug interactions, and Y-site compatibility; and to assess efficacy and safety data from clinical studies of quinupristin/dalfopristin.. Articles included in this review were identified by a MEDLINE search of the literature published between 1966 and September 2000 using the terms Synercid, quinupristin, and dalfopristin. Additional articles were retrieved from the reference lists of articles identified in the MEDLINE search.. In vitro analysis of the spectrum of activity of quinupristin/dalfopristin has confirmed its relatively selective coverage of gram-positive aerobic bacteria. Both quinupristin and dalfopristin undergo hepatic metabolism and are extensively excreted in the feces. Combination quinupristin/dalfopristin inhibits the cytochrome P450 3A4 pathway, and caution is warranted with concomitant use of other medications eliminated via this pathway. In trials in patients with VREF infections, treatment success with quinupristin/dalfopristin varied depending on the site of infection, ranging from 51.9% in bacteremia of unknown origin to 88.9% in urinary tract infections. The results of comparative clinical trials suggest that quinupristin/dalfopristin has similar efficacy to that of commonly used antibiotics, including cefazolin, oxacillin, and vancomycin, in patients with skin and skin-structure infections or nosocomial pneumonia. The most frequently reported adverse effects with administration of quinupristin/dalfopristin were infusion-site inflammation, pain, and edema; other infusion-site reactions; and thrombophlebitis. Arthralgia, myalgia, nausea, diarrhea, vomiting, and rash occurred in 2.5% to 4.6% of patients and were the most frequently reported systemic adverse events.. Outcomes data from clinical trials indicate that quinupristin/dalfopristin has the potential to play an important role in the treatment of bacteremia, complicated skin and skin-structure infections, and nosocomial pneumonia caused by VREF. Issues of bacterial resistance to quinupristin/dalfopristin and other appropriate uses of this combination agent remain to be elucidated.

Topics: Anti-Bacterial Agents; Bacteremia; Cross Infection; Drug Interactions; Drug Therapy, Combination; Enterococcus faecium; Gram-Positive Bacterial Infections; Humans; Microbial Sensitivity Tests; Pneumonia, Bacterial; Skin Diseases, Bacterial; Vancomycin Resistance; Virginiamycin

Quinupristin/dalfopristin (Synercid) is an i.v. antibiotic active against serious Gram-positive infections. Its unique dual mode of action means that the potential for resistance development is expected to be low. To determine the incidence of in vitro emerging resistance in worldwide clinical studies, susceptibility to quinupristin/dalfopristin was measured for baseline pathogens and corresponding on- or post-study isolates from 880 evaluable patients. In comparative studies of community-acquired pneumonia, complicated skin and skin structure infections, and nosocomial pneumonia, the incidence of emerging resistance was low (1 of 453; 0.22%; 95% CI: 0. 01-1.4%). Resistance development occurred in only one pathogen (methicillin-resistant Staphylococcus aureus). In noncomparative studies, six instances (1.8% of 338 evaluable cases; 95% CI: 0.7 to 4.0%) of emerging resistance (all vancomycin-resistant Enterococcus faecium) were confirmed, accompanied by therapeutic failure in four cases. Molecular typing did not confirm the identity of one pair of strains. Overall, the incidence of emerging resistance to quinupristin/dalfopristin was low.

Topics: Anti-Bacterial Agents; Community-Acquired Infections; Drug Resistance, Microbial; Drug Therapy, Combination; Enterococcus faecium; Global Health; Humans; International Cooperation; Pneumonia, Bacterial; Pneumonia, Staphylococcal; Skin Diseases, Bacterial; Staphylococcal Skin Infections; Staphylococcus aureus; Virginiamycin