Country: United States
Date: July 2007
What is biochemical test can differentiate Enterococcus
faecium from Enterococcus faecalis?
Try this link-it has a table that shows how to distinguish gram
positive cocci in the clinical lab. Enterococci are bile esculin
positive, and grow in 6.5% salt, but E. fecalis is tellurite pos
and E. faecium is tellurite neg.
What you need to do depends on what kind of sample you're working with and
what kind of facilities you have access to use. There are many options,
although don't get your hopes up for anything simple like gram-staining.
If you have a clinical sample of some kind and are not culturing, In Situ
Hybridization might be a good way to go (J Med Microbiol 54 (2005), 937-944;
Fluorescent in situ hybridization with specific DNA probes offers adequate
detection of Enterococcus faecalis and Enterococcus faecium in clinical
samples. Karola Waar, John E Degener, Marja J van Luyn, and Hermie JM
Harmsen). Of course this requires a fluorescent microscope.
If you're able to culture, then you could use morphology (JOURNAL OF
CLINICAL MICROBIOLOGY, June 2003, p. 2644-2646. Use of Colony Morphology To
Distinguish Different Enterococcal Strains and Species in Mixed Culture from
Clinical Specimens. Shabnam Qamer, Jonathan A. T. Sandoe, and Kevin G.
Kerr), although this method uses some unusual ingredients. There are
biochemical tests (Identification of Enterococcus Species Isolated from
Human Infections by a Conventional Test Scheme, R. R. FACKLAM AND M. D.
COLLINS, JOURNAL OF CLINICAL MICROBIOLOGY, Apr. 1989, p. 731-734) as well,
although they're tedious.
I recommend you read these journal articles and decide which you're best
equipped to execute. There are many more articles that provide different
variations on these methods as well -- look them up on Google Scholar
(scholar.google.com) and decide (use the 'cited by' feature to find more
recent variations). Since this is a pretty complex subject, and you didn't
enter a grade, I am assuming you are college level or above. Virtually every
university library will have subscriptions to these, so you should have
Hope this helps,
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Update: June 2012