quinupristin-dalfopristin and Heart-Valve-Diseases

Methicillin-resistant S. aureus (MRSA) with low susceptibility to glycopeptides is uncommon.. The case of a 50-year-old non-drug addict patient presenting with tricuspid valve infective endocarditis (IE) by MRSA resistant to vancomycin and linezolid is presented. There was response only to quinupristin/dalfopristin. He had a motorcycling accident four years before undergoing right above-the-knee amputation and orthopaedic fixation of the left limb. There were multiple episodes of left MRSA-osteomyelitis controlled after surgery and vancomycin therapy. MRSA isolated from the blood at the time of IE presented with the same profile than the isolated four years earlier. Sequential treatment with teicoplanin-cotrimoxazole and Linezolid associated to vancomycin--rifampicin--cotrimoxazole had no improvement. Infection was controlled after 28 days of therapy with quinupristin/dalfopristin.. The literature presents only a few cases of MRSA IE not susceptible to glycopeptides in not drug addicted patients. This case shows the comparison of a highly-resistant MRSA after previous S. aureus osteomyelitis treated with glycopeptides. This is the first description of successful treatment of resistant-MRSA IE of the tricuspid valve complicated by multiple pulmonary septic infarction with quinupristin/dalfopristin.

Topics: Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Endocarditis, Bacterial; Heart Valve Diseases; Humans; Male; Methicillin Resistance; Middle Aged; Osteomyelitis; Radiography; Staphylococcal Infections; Staphylococcus aureus; Substance-Related Disorders; Tricuspid Valve; Ultrasonography; Virginiamycin

The activity of RP 59500 against methicillin-resistant Staphylococcus aureus was studied in vitro and in a rabbit model of aortic valve endocarditis. Three strains, 67-O, 529, and Du, ranging from relatively resistant to susceptible to RP 59500 in vitro (mean agar dilution MICs of 0.65, 0.21, and 0.12 mg/L respectively) were used to establish endocarditis, which was treated either with RP 59500, 20 mg/kg im four times a day for four days or with vancomycin, 25 mg/kg iv twice a day for four days. RP 59500 was ineffective for the most resistant strain, 67-O. RP 59500 was effective for the intermediately susceptible strain 529, but vancomycin was more effective. RP 59500 was slightly more effective than vancomycin against the most susceptible strain, Du, but the difference was not statistically significant. These results suggest that strains inhibited by RP 59500 at a concentration of greater than or equal to 0.5 mg/L should probably be considered resistant in this model of infection. RP 59500 was effective in vivo against the two susceptible strains, but overall, vancomycin was the more active drug.

Topics: Animals; Aortic Valve; Drug Combinations; Drug Resistance, Microbial; Endocarditis, Bacterial; Heart Valve Diseases; In Vitro Techniques; Methicillin; Microbial Sensitivity Tests; Rabbits; Staphylococcal Infections; Staphylococcus aureus; Vancomycin; Virginiamycin