title: Vancomycin Minimum Inhibitory Concentration for Methicillin-Resistant Staphylococcus aureus Infections; Is There Difference in Mortality Between Patients?
abstract: BACKGROUND
  New data indicates that vancomycin may be less effective against methicillin-resistant Staphylococcus aureus (MRSA) infections with minimum inhibition concentration (MIC) within a sensitive range.
  
  
  OBJECTIVE
  The aim of this study was to determine the distribution of the vancomycin MIC between MRSA strains and observe the difference in mortality between patients, while the influence of changes in MIC on the efficacy of vancomycin was also examined.
  
  
  METHODS
  A routine date-based study was conducted on 41 MRSA isolates in a hospital in Tehran, Iran. The isolates were assessed for MIC by using the E-test method, and results were categorized into three groups: A (MIC < 1.5 μg/mL), B (1.5 ≤ MIC < 2 μg/mL) and C (MIC ≥ 2 μg/mL) MRSA.
  
  
  RESULTS
  Group A was the most common group, followed by groups C and B. Although there was no statistically significant difference between patients' mortality with the MIC group, the mortality rate of group A was higher than C and B.
  
  
  CONCLUSIONS
  Regarding Clinical and Laboratory Standards Institute (CLSI) definition for vancomycin susceptibility (MIC < 2 μg/mL), it seems that vancomycin may not be considered as the best antibiotic in order to treat heteroresistant vancomycin intermediate S. aureus (hVISA) and vancomycin sensitive S. aureus (VSSA) infections, and a new breakpoint for vancomycin and alternative antibiotics should be considered.
authors: Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran ; University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia.
authors: Zohreh
authors: Z
authors: Aminzadeh
authors: Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors: Davood
authors: D
authors: Yadegarynia
authors: Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors: Alireza
authors: A
authors: Fatemi
authors: Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors: Elham
authors: E
authors: Tahmasebian Dehkordi
authors: Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors: Saeed
authors: S
authors: Azad Armaki
keywords: Methicillin Resistant; Minimum Inhibitory Concentration; Mortality; Staphylococcus aureus; Vancomycin
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