What options are available for treatment of S aureus IE caused by isolates that are not susceptible to vancomycin?
No standard therapies exist for the treatment of S aureus IE caused by isolates that are not susceptible to vancomycin. Classification of these isolates has become complex and includes designations of reduced susceptibility (hVISA), intermediate resistance (VISA), and high-level resistance (VRSA). To date, the limited number of patients reported to have IE caused by these isolates precludes specific treatment recommendations. Thus, these infections should be managed in conjunction with an infectious diseases consultant. Although Markowitz et al165 showed that trimethoprim- sulfamethoxazole was inferior to vancomycin in the treatment of invasive S aureus infections, it is sometimes used in salvage situations.