Vancomycin Resistant Enterococcus

What ingredients make BEAA selective (outside of Ab)?

1) Bile salts which inhibit other GP organisms 2) Sodium Azide which inhibits GN organsism

E. faecium and faecalis have _________ vancomycin resistance

Acquired

In surveillance of VRE which agar plates are used?

Bile Esculin Azide agar (BEAA) with 6 ug/Ml and Brilliance VRE

E. faecium and E. faecalis VRE are intrinsically resistant to _________

Cephalosporins, Aminoglycosides, Clindamycin, and SXT

High level aminoglycoside Resistance

Detection of synergy between ampicillin and aminoglycoside through disk diffusion

This organism has a yellow pigement, who is it and is it of concern?

E. casselflavus, no

On brilliance VRE this organism appears as Blue

E. faecalis

This organism has phosphatase and alpha-galactosidase enzymes that is used in Brilliance VRE

E. faecium

This organism organism is arabinose positive, MGP negative, and Xylose negative.

E. faecium

What are the two VRE of clinical interest?

E. faecium and E. faecalis

These two VREs are not of clinical interest:

E. gallinarum and casseliflavus

This organism is the only to show susceptibility to ampicillin

E.faecalis

This organism only has a phosphatase enzyme that is used in brilliance VRE.

E.faecalis

On brilliance VRE this organism appears as Pink

E.faecium

When do you know you are dealing with an isolate that is an Enterococcus?

GPC pairs and chains, PYR positive, PathoDextra Group D (optional)

VRE of clinical significance will show _______ on vancomycin screen and ________ on SIM media

Growth, No-motiliy

TTC is added to SIM media for what purpose?

If the organism grows it will show up red, this give a better view of motility.

E. gallinarum and casseliflavus have _________ vancomycin resistance

Intrinsic

Is esculin considered a selective agent in BEAA?

No, it is used for its colour properties

When would you start speciation?

Once you see it is a VRE of clinical significance

van A resides on ________ and vanB resides on _________

Plasmids, chromosomes

What is the use for Brilliance VRE

To differentiate between E. faecium and faecalis

In BEAA if growth of black or grey colonies are seen:

We assume that the organism is bile esculin positive and vancomycin resistant

When would you do a vancomycin screen test?

When you know it is an enterococcus of infection control concern. (Basically if Xylose fermentation negative)

Which tube test will first differentiate between VRE of no interest with VRE of interest?

Xylose fermentation

What colour is a positive for Xylose, arabinose, and MGP fermentation?

Yellow

E. faecium and faecalis are known to have these VRE genes

van A and van B

Which genes are responsible for acquired vancomycin resistance?

vanA and vanB

What is the gene responsible for intrinsic resistance to vancomycin?

vanC (It is not transferable b/w bacteria)