Editing Vancomycin-resistant Staphylococcus aureus (section)

==Diagnosis==
The diagnosis of vancomycin-resistant ''Staphylococcus aureus'' (VRSA) is performed by performing susceptibility testing on a single ''S. aureus'' isolate to vancomycin. This is accomplished by first assessing the isolate's [[Minimum inhibitory concentration|minimum inhibitory concentration (MIC)]] using standard laboratory methods, including [[Disk diffusion test|disc diffusion]], [[Etest|gradient strip diffusion]], and [[antibiotic sensitivity testing|automated antimicrobial susceptibility testing systems]].<ref name="vre">{{cite journal|last1=Loomba|first1=Poonam Sood|last2=Taneja|first2=Juhi|last3=Mishra|first3=Bibhabati|date=2010-01-01|title=Methicillin and Vancomycin Resistant S. aureus in Hospitalized Patients|journal=Journal of Global Infectious Diseases|volume=2|issue=3|pages=275–283|doi=10.4103/0974-777X.68535|issn=0974-777X|pmid=20927290|pmc=2946685 |doi-access=free }}</ref> Once the MIC is known, resistance is determined by comparing the MIC with established breakpoints.<ref>{{cite report
 | author      = CLSI
 | date        = 2023
 | title       = M100 Performance Standards for Antimicrobial Susceptibility Standards
 | publisher   = Clinical and Laboratory Standards Institute
 | edition     =33
 | location    =Wayne PA
 | page        =8
}}</ref>

Resistant or "R" designations are assigned based on agreed upon values called breakpoints. Breakpoints are published by [[Standards organization|standards development organizations]] such as the U.S. [[Clinical and Laboratory Standards Institute]], the [[British Society for Antimicrobial Chemotherapy]] and the [[European Committee on Antimicrobial Susceptibility Testing]].