Vancomycin, a glycopeptide antibiotic, is commonly prescribed as initial therapy for hospitalized patients due to its broad gram-positive coverage. Vancomycin is used for the treatment and prevention of a variety of bacterial infections ranging from streptococcal to methicillin-resistant Staphylococcus aureus (MRSA) infections.1 Notable adverse effects of intravenous vancomycin include nephrotoxicity, ototoxicity and hypersensitivity reactions. Given its pharmacokinetic profile, therapeutic drug monitoring is essential in determining the therapeutic efficacy of vancomycin as well as for avoiding nephrotoxicity.

Vancomycin, a glycopeptide antibiotic, is commonly prescribed as initial therapy for hospitalized patients due to its broad gram-positive coverage. Vancomycin is used for the treatment and prevention of a variety of bacterial infections ranging from streptococcal to methicillin-resistant Staphylococcus aureus (MRSA) infections.1 Notable adverse effects of intravenous vancomycin include nephrotoxicity, ototoxicity and hypersensitivity reactions. Given its pharmacokinetic profile, therapeutic drug monitoring is essential in determining the therapeutic efficacy of vancomycin as well as for avoiding nephrotoxicity.

The 2020 guidelines continue to enforce AUC/MIC as the preferred PK/PD parameter, but now recommend utilizing vancomycin peak and trough concentrations to target an AUC/MIC of 400-600 mg*h/L for serious MRSA infections. Although this AUC goal is not new, the 2009 consensus guidelines previously recommended trough only monitoring as a simplistic surrogate marker for attaining this AUC goal. Furthermore, the most accurate way of calculating AUC requires obtaining two steady state vancomycin serum concentrations over one dosing period. In this way, AUC guided monitoring requires more pharmacist and nursing time, the use of more hospital resources and additional cost to the patient.

As was true of the 2009 guidelines, the 2020 guidelines also leave certain questions unanswered. The paucity and conflicting data of vancomycin monitoring in patients with non-serious MRSA infections (skin and soft tissue infections, urinary tract infections, etc.), methicillin-sensitive Staphylococcus aureus (MSSA) infections and non-staphylococcal pathogen infections has left no guidance on the ideal vancomycin PK/PD targets in these patient populations. A literature search of AUC/MIC monitoring in patients with streptococcal and enterococcal infections yielded very few studies in patients with enterococcal infections and no studies in patients with streptococcal infections.

Inclusion Criteria:

• Patients hospitalized from June 2020- January 2021.
• 18 years and older
• At least 1 vancomycin trough concentration drawn at steady state
• Organism with an MIC of 2 mg/L, if vancomycin was continued and in whom a steady state trough concentration was obtained

Exclusion Criteria:

• Patients with end stage renal disease (on hemodialysis or peritoneal dialysis) or on continuous renal replacement therapy

Adult patients who received vancomycin while inpatient at MCMC with at least one corresponding vancomycin trough level taken at steady state will be included.