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.

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.

For additional guidance on the transport of infectious substances in other languages, please click on the link below.


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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