Enterococcus

Clinically important: enterococcus faecalis and enterococcus faecium

Used be group D

Characteristics/Epidemiology

Normal faecal flora

Also colonise oral mucous membranes and skin

Highly resistent to chemical/environmental agents

C-carbohydrate reacts with group D antisera -> used to be group D.

Now in its own group due to DNA analysis.

Clinical significance

In normal healthy adults -> does not cause disease

In post-surgical/instrumentation etc. -> can cause:

• UTI
• bacteremia/sepsis
• subacute endocarditis
• biliary infection
• intra-abdominal abscesses

Laboratory identification

Ability to survive in presence of bile

Hydrolyse the polysaccharide esculin

Grow in 6.5% NaCl

Yield positive pyrazin amidase (PYR) test.

All of the above distinguishes enterococcus with other non-D group strep.

Treatment

Naturally resistant to beta-lactam antibiotics AND aminoglycosides.

But sensitive to synergistic action of these combined.

Acquired immunity to combination drugs are rising.

E. faecium more likely to be vancomycin or multiple resistant than E. faecalis

First line: ampicillin PLUS gentamicin

Second line: vancomycin

Other (vancomycin-resistant): linezolid OR [quinupristin PLUS dalfopristin]

Prevention/immunity

No vaccine.

No lasting immunity.

 

 

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Things to revise/add later:

Bibliography: LWW microbiology

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