Life-threatening acute generalized exanthematous pustulosis induced by two different protease inhibitors in an HIV-1-infected patient

rapidly bactericidal antimicrobial that has a similar mechanism of action to vancomycin, but also causes bacterial membrane depolarization. 2 To our knowledge, this is the first case using telavancin in mitral valve MRSA endocarditis. Current expert opinion recommends consideration of alternative therapies for bacterial isolates with a vancomycin MIC of ≥2 mg/L, as the required higher doses may lead to an increase in toxicity over efficacy. 3 For this reason, daptomycin was chosen over vancomycin. Initially, daptomycin was dosed (4 mg/kg) at 350 mg intravenously every 48 h—renally adjusted, but not at the recommended dose for endocarditis, 6 mg/kg. Over a period of 8 days, the dose was increased twice (secondary to noticed underdosing and improving renal function) to a final dose of 500 mg intravenously every 24 h. During this period the MIC for the isolate increased from 0.38 mg/L to 4 mg/L [dapto-mycin-non-susceptible S. aureus (DNSSA)]. Common reasons for daptomycin clinical failure reported in the literature include antecedent vancomycin therapy, exposure of an isolate to suboptimal concentrations of daptomycin and having a large inoculum of infection that is not or cannot be aggressively debrided. 4 Higher doses of daptomycin (10 mg/kg/ day) have been suggested for reducing the inoculum from endo-cardial vegetations, 4 though we ultimately chose against this, as the data are conflicting. 5,6 This case demonstrates the efficacy and tolerability of tela-vancin as well as the importance of proper antimicrobial dosing to prevent the unintended emergence of bacterial resistance. As noted in the literature, 4,5 prompt surgical intervention should be pursued (if warranted) to optimize clinical outcome. In conclusion, we report successful treatment of a patient with MRSA mitral valve endocarditis. While bacteraemia initially resolved with mitral valve annuloplasty, vegetation excision and linezolid monotherapy, telavancin was successful in completing this patient's treatment for left-sided endocarditis, para-spinal abscess and forearm wound despite being exposed to vancomycin and subtherapeutic doses of daptomycin that led to development of DNSSA.