Comment on: Successful treatment of methicillin-resistant Staphylococcus aureus mitral valve endocarditis with sequential linezolid and telavancin monotherapy following daptomycin failure

Sir, Joson et al. recently published a report using telavancin to complete treatment of endocarditis due to methicillin-resistant Staphylococcus aureus. While in agreement with their discussion and informative thoughts, some other points should also be considered. While the authors correctly point out the initial underdosing of daptomycin and its potential contribution to the subsequent emergence of daptomycin-non-susceptible isolates, they did not comment on the vancomycin dose (which was also underdosed initially). This may also contribute to future issues with reduced antimicrobial susceptibilities. Persistent bacteraemia should prompt consideration of a search for an undrained focus of infection. While paraspinal fluid collections were found and drained under CT guidance, the report does not mention any follow-up imaging performed to assess the adequacy of drainage. Transoesophageal echocardiography, if performed earlier in the hospital course, might have demonstrated the mitral valve vegetation and have led to more expeditious surgery. Blood cultures appear to have cleared with linezolid and surgery. Linezolid has been previously used as therapy for staphylococcal endocarditis. In the reported case, thrombocytopenia, which developed after an 3 week course of linezolid, led to the use of telavancin. While not disagreeing with the use of telavancin or discounting its role in the successful treatment of the patient, difficulty exists in quantifying the contribution of telavancin to the clinical success. The removal of the foci of infection and lengthy course of antimicrobials prior to the telavancin probably played a more significant role than telavancin in achieving cure. We are appreciative of the authors’ sharing of their case and of the Journal for publishing it. Clinical circumstances often lead to the need for unlabelled use of antimicrobials and communication about this serves the medical community well in the care of our patients.