Comparison of three commercial rapid identification systems for the unusual gram-positive cocci Dolosigranulum pigrum, Ignavigranum ruoffiae, and Facklamia species

We evaluated three rapid identification systems-The Biomerieux rapid ID 32 STREP (ID32), the BBL Crystal rapid gram-positive identification (Crystal), and the Remel IDS RapID STR (IDS) systems-for their ability to identify 7 strains of Alloiococcus otitidis, 27 strains of Dolosigranulum pigrum, 3 st rains of Ignavigranum ruoffiae, and 18 strains of 4 different Facklamia spe cies, Since none of these six species of gram-positive cocci are included i n the identification databases for these systems, the correct identificatio n for the strains tested should be "unacceptable ID" for the ID32 and Cryst al systems or "no choice" for the IDS system. The ID32 system identified al l 27 strains of D. pigrum, 6 of 18 Facklamia species, and 2 of 3 cultures o f I. rouffiae as "unacceptable ID." The Crystal system identified 10 of 27 D. pigrum, 2 of 18 Facklamia species, and 2 of 3 I. ruoffiae strains as "un acceptable ID." The IDS system identified only 1 culture of D. pigram as "n o choice," but it also identified 2 cultures of D. pigrum as a "questionabl e microcode" and 19 cultures of D, pigrum as an "inadequate ID, E. faecalis 90%, S. intermedius 9%." A total of 2 of the 18 cultures of Facklamia and ail 3 of the I. ruoffiae cultures were correctly identified as "no choice." The most common misidentifications of Facklamia species by the ID32 and ID S systems were as various Streptococcus species and as Gemella species. In the Crystal system, the most common erroneous identification was Micrococcu s luteus, These data indicate the need for the commercial manufacturers of these products to update their databases to include newly described species of gram-positive cocci.