The nutritional variant group of gram-positive bacteria has been described as satelliting, pyridoxal-dependent, vitamin B 6-dependent, cell wall-deficient (L-form), and finally nutritionally variant streptococci (NVS) before being reclassified as Streptococcus adjacens and Streptococcus defectivus (19). Kawamura et al. demonstrated that the two NVS species were phylogenetically distant from the streptococci and proposed that they be given new genus status, Abiotrophia adjacens and Abiotrophia defectivus (75). Recently, three new species have been added to the Abiotrophia genus, A. elegans (98), A. balaenopterae (89), and A. para-adiacens (74). Collins and Lawson further proposed that some of the Abiotrophia species were phylogenetically distinct from each other and proposed the establishment of the genus Granulicatella to include G. adiacens, G. balaenopterae, and G. elegans in this new genus while A. defectiva remains in the Abiotrophia genus (35). Note the corrected epithets. Table 5 includes all the species of "NVS" and an identification scheme based on the published reports (35, 74, 75, 89, 100) and our own results examining 100 strains of NVS taken from the CDC stock culture collection (26). Our results indicate that of 101 isolates from 97 patients (58 with endocarditis), 55 were G. adiacens, 43 were A. defectiva, and 3 were G. elegans. Other authors using slightly different species identification criteria found 15 G. adiacens, 13 G. para-adiacens, 9 A. defectiva, and 8 G. elegans strains among 45 endocarditis patients (74). NVS overall is reported to cause approximately 5% of all cases of endocarditis (22). These reports indicate that all the species except G. balaenopterae have been isolated from human infections. Patients with endocarditis due to NVS are more difficult to treat than those infected with viridans streptococci. As many as 41% of patients may fail to respond to antimicrobial therapy, and combination therapy is often recommended.

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