Safety and efficacy of quinupristin/dalfopristin for treatment of invasive Gram-positive infections in pediatric patients

Background. Antibiotic-resistant Gram-positive pathogens are an increasingly common cause of serious pediatric infections. Although quinupristin/dalfopristin demonstrates favorable activity in vitro against resistant Gram-positive pathogens (including many vancomycin-resistant E. faecium and methicillin-resistant staphylococci), published experience in the pediatric patient population is limited. Methods. We retrospectively analyzed data from the global quinupristin/dalfopristin Emergency-Use Program, which enrolled patients with serious Grampositive infections who had no further therapy options because of resistance to, failure on or intolerance to standard antibiotic treatments. Our subset included safety and efficacy data from pediatric patients (age <18 years). There were no restrictions on underlying diseases, severity of illness or prior/concomitant antimicrobial use. Results. Between May 1995 and October 1999, 127 pediatric patients with 131 infections were enrolled. Microbiologic confirmation of etiology was available in 124 patients. All patients had 1 or more concomitant conditions, including malignancy and solid organ or bone marrow transplantation. The most frequent causative pathogens were vancomycin-resistant Enterococcus faecium (80%), Enterococcus spp. (7%), methicillin-resistant Staphylococcus aureus (6%) and Staphylococcus epidermidis (4%). All but 21 patients received intravenous quinupristin/dalfopristin 7.5 mg/kg every 8 h. The favorable clinical response rate of quinupristin/dalfopristin was 86 of 124 (69%); the favorable microbiologic response rate was 97 of 124 (78%). Eleven patients (8%) had nonvenous adverse events classified as possibly or probably related to quinupristin/dalfopristin. Conclusions. Quinupristin/dalfopristin demonstrated favorable response rates and was reasonably well-tolerated in pediatric patients with serious Gram-positive infections unable to receive alternative therapy. In our opinion quinupristin/dalfopristin is a therapeutic option for the management of such infections.