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VISA/hVISA Confirmation

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Reference Details


Confirmation of vancomycin intermediate Staphylococcus aureus (VISA) or heterogeneous vancomycin intermediate Staphylococcus aureus (hVISA) by Etest.

Test Category:
Susceptibility Testing
Staphylococcus aureus
Illnesses and Diseases:
  • Necrotizing pneumonia
  • Skin and soft tissue infections

Pure culture.

Collection Method:


Specimen Processing, Storage and Shipping:

Send cultures as growth on culture medium or in transport medium. Culture vessel should be leak-proof or sealed appropriately.

Transportation of Dangerous Goods:

Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.


Patient Criteria:


Accompanying Documentation:

Completed Antimicrobial Resistance and Nosocomial Infections Requisition.


As this is not the gold standard test for determination of VISA status (PAP-AUC), this combination of tests only indicates if the organism may be a hVIS/VISA if the vancomycin MIC by standard Etest is <=2 mg/L.

Methods and Interpretation of Results:

A combination of standard vancomycin Etest MIC determination and macro & GRD Etests are used to indicate if the organism is a probable hVISA or VISA or not. 

Turnaround Time:

8 calendar days.

Phone #: (204) 789-5000
Fax: (204) 789-5020
  1. Walsh TR1, Bolmström AQwärnström AHo PWootton MHowe RAMacGowan APDiekema D. 2001. Evaluation of current methods for detection of staphylococci with reduced susceptibility to glycopeptides. J Clin Microbiol.  Jul;39(7):2439-44.
  2. Yusof A, et al. 2008. Evaluation of a New Etest Vancomycin-Teicoplanin strip for detection of glycopeptide-intermediate Staphylococcus aureus (GISA), in particular heterogeneous GISA. J Clin Microbiol 46(9) 3042-3047.
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