Endocarditis due to Streptococcus faecalis with high-level resistance to gentamicin.

Recently, reports of Streptococcus faecalis with resistance to high levels of gentamicin have appeared in the literature, although there have been no previous reports of endocarditis due to such organisms. In this article, two cases of endocarditis--both due to Streptococcus faecalis with high-level gentamicin resistance and both presenting in an atypical manner--are described. The data suggest that a high level of suspicion regarding a diagnosis of endocarditis must be maintained in such cases and that, once a case is diagnosed, careful evaluation in the microbiology laboratory is helpful in determining the optimal antimicrobial regimen.