Vancomycin is the primary antimicrobial choice for MRSA HAP worldwide. Vancomycin is relatively inexpensive in per-dose pricing, generally effective and has a favorable safety profile. However, staph aureus isolates which are incompletely sensitive or even resistant to vancomycin have been reported8. These vancomycin-intermediately sensitive staph aureus (VISA) and vancomycin-resistant staph aureus (VRSA) isolates are rare but increasing in prevalence9. Since the first report of VISA in the United States in 1999, other reports have documented the existence of staph aureus isolates with incomplete sensitivity to vancomycin, termed as vancomycin "heteroresistance"9.