Point: Vancomycin Is Not Obsolete for the Treatment of Infection Caused by Methicillin-Resistant Staphylococcus aureus

Abstract

Since the discovery, development, and US Food and Drug Administration approval of vancomycin in the 1950s, this agent has remained a mainstay for the treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA). However, because of the development of new antistaphylococcal antibiotics and reports of vancomycin failures, the utility of vancomycin has recently been questioned. Although vancomycin did not undergo the strict US Food and Drug Administration approval process that is in place today to demonstrate efficacy, there is considerable information available that sheds light on the role vancomycin has in infectious diseases pharmacotherapy today. In addition, although we look to in vitro susceptibility testing to assess vancomycin activity against S. aureus, we have come to appreciate that resistance of S. aureus to vancomycin can be a continuous--rather than a categorical--phenomenon. This has resulted in clinical microbiology laboratories having difficulty identifying S. aureus that may not respond to conventional doses of vancomycin. A better understanding is needed of the pharmacodynamic relationship between vancomycin and MRSA as relates to optimal dosing strategies, including consideration for loading doses, and development of rational categorical breakpoints for susceptibility based on clinical outcomes. By better understanding these critical issues, it may be possible to optimize the use of vancomycin, resulting in a cost-effective treatment option for many patients infected with MRSA.

Multicenter Evaluation of Vancomycin Dosing: Emphasis on Obesity

“…21 A Monte Carlo simulation utilizing these pharmacokinetic data demonstrated that the high dose regimen had a 20% higher probability of achieving the pharmacodynamic target for MRSA isolates with a vancomycin MIC of 1 µg/ml, while pharmacodynamic target attainment rates for higher or lower MIC values were not significantly affected by dosing strategy. 22 Optimizing vancomycin dosing is important as 70% of MRSA isolates in a recent study had a vancomycin MIC of 1 µg/ml. 23 These data are not specific to obese patients, but the pharmacodynamic principles should transcend BMI classes.…”

Treatment options for methicillin-resistant Staphylococcus aureus (MRSA) infection: Where are we now?

“…Controversy still exists over the current, non-methoddependent breakpoint of 2 mg/L, appreciating that if this were to be lowered further the majority of isolates would be deemed resistant [7]. A growing body of data showing significant variability both in minimum inhibitory concentration (MIC) measurements and accuracy of MIC determination demonstrates the importance of the method of susceptibility testing [8,9].…”

Bacterial pericarditis and antimicrobial resistance at the Tehran Heart Center, Iran

“…Therapeutic alternatives exist, as S. aureus remains highly susceptible to vancomycin, teicoplanin, linezolid, and quinupristin/dalfopristin [23]. Mohr and Murray also asserted that vancomycin is as a safe drug and alternative agent for MRSA infections, as it has no drug-drug interactions, can be administered fairly infrequently through a peripheral vein, and is inexpensive [24]. Another study recommended that penicillin should be used for infrequent penicillinsusceptible isolates, that oxacillin and nafcillin are to be considered the major option for penicillin-resistant staphylococci, and that glycopeptides are the drugs of choice for infections caused by MRSA or MRSE.…”