DNA relatedness, phenotypic characteristics, and antimicrobial susceptibilities of Globicatella sanguinis strains

DNA-DNA reassociation was performed on 15 strains of Globicatella sanguinis to compare their taxonomic status with phenotypic characterization. All 15 strains selected for DNA-DNA reassociation readily met the criteria for sp ecies relatedness. The relative binding ratio was 81% or greater at the opt imal temperature and 76% or greater at the stringent temperature, and the d ivergence was less than 3% for all strains hybridized with the type strain. These strains included nine strains from the Centers for Disease Control S treptococcus Laboratory culture collection that were previously included in comparative 16S rRNA gene sequencing studies as well as six additional phe notypically variant isolates. DNA-DNA relatedness was less than 18% at the optimal reassociation temperature to Aerococcus viridans, Enterococcus aviu m, and Streptococcus uberis, which are phenotypically similar to G. sanguin is. This study confirms these Globicatella strains were previously misident ified as S. uberis or S. uberis-like strains based on biochemical character istics. The biochemical data from 28 strains was compiled to further define the phenotypic criteria for identification of this species. A revised desc ription of the species should be variable reaction for pyrrolidonylarylamid ase production (75% positive), positive reaction for the bile esculin test (100%), growth at 45 C (96%), variable reaction for acid production from ar abinose (45% positive), and negative starch hydrolysis (0% positive). We al so evaluated four rapid identification systems, the Biomerieux rapid ID32 S TREP (ID32), the Crystal rapid gram-positive identification (Cry4), the BBL Crystal gram-positive identification (Cry24), and the Remel IDS RapID STR (IDS) systems for their ability to identify these strains.