Home Products Most Popular Contact
No items in your cart.
The page below is a sample from the LabCE course Multi-drug Resistant Organisms: MRSA, VRE, and Clostridium difficile. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Multi-drug Resistant Organisms: MRSA, VRE, and Clostridium difficile (online CE course) »
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 106 CE courses, most popular
$95 Add to cart
Pick Your Courses
Up to 8 CE hours
$50 Add to cart
Individual course$20 Add to cart

Detecting Vancomycin Resistance

Interpretive standards for Enterococcus species against vancomycin
Disk diffusion
> 17 mm
15-16 mm
< 14 mm
Broth dilution
< 4 µg/mL 8-16 µg/mL
> 32 µg/mL
Screening methodologies
BHI agar with 6 µg/mL vancomycin can be employed as a screen for vancomycin resistance. 1-10 µL of a 0.5 McFarland standard suspension is spotted onto the agar surface and incubated at 35 + 2° C for a full 24 hours. The presence of >1 colony equates to presumptive vancomycin resistance; these isolates would require species identification and a vancomycin MIC.
A motility test and documentation of the presence or absence of a yellow pigment can distinguish between the species with intrinsic (VanC) resistance (E. gallinarum and E. casseliflavus) and those with acquired (VanA and VanB) resistance (E. faecium and E. faecalis).