Evaluation of a biochemical test scheme for identifying clinical isolates of Enterococcus faecalis and Enterococcus faecium.
OBJECTIVE
To evaluate the full test scheme of Facklam and Sahm (1995) for the identification of clinical enterococcal isolates to genus and species level.


RESULTS
Fifty-nine clinical isolates, previously provisionally classed as enterococci on the basis of just four biochemical tests of Facklam and Sahm and one other test, were subjected to genus and species identification using the full identification scheme of Facklam and Sahm; 98% of these strains were confirmed to be enterococci and of these, 69% were identified as Enterococcus faecalis and 31% as Enterococcus faecium. Six tests in the scheme (out of 24) gave anomalous or unreliable results for some strains, and two gave unexpected results for the majority of strains presumptively identified as Ent. faecium.


CONCLUSIONS
Nine (out of 12) genus tests and nine (out of 12) species tests from the Facklam and Sahm scheme were reliable. Testing for the presence of the Lancefield antigen D was also useful. The majority of presumptive Ent. faecium strains gave different results for the sorbitol and raffinose tests from that expected.


CONCLUSIONS
This study indicates the level of reliability for each of the tests in a current enterococcal identification scheme for differentiating clinical isolates, and showed that two tests gave consistently different test results from those expected for Ent. faecium.
Day
A M
AM
Division of Microbiology, School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
Sandoe
J A
JA
Cove
J H
JH
Phillips-Jones
M K
MK
D015373:Bacterial Typing Techniques / Q000379:methods*; D013293:Enterococcus faecalis / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D016984:Enterococcus faecium / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D015203:Reproducibility of Results; D013045:Species Specificity