title: Evaluation of rapid identification of gram-positive cocci in positive blood cultures by use of the AutoMicrobic system Gram-Positive Identification Card.
abstract: Because rapid identification of gram-positive organisms from blood cultures may provide valuable information for patient care and because the AutoMicrobic system Gram-Positive Identification (AMS-GPI) Card (Vitek Systems, Inc., Hazelwood, Mo.) is designed for the identification of these organisms in 4 to 13 h, we designed this study to evaluate the performance of the AMS-GPI Card in the direct identification of gram-positive organisms upon detection of growth in blood culture bottles. We compared direct identification by the AMS-GPI Card with the final AMS-GPI Card identification and with our standard identification methods. We evaluated 51 gram-positive organisms from clinical blood cultures as well as 49 simulated blood cultures. The isolates included Streptococcus pneumoniae (17), Streptococcus pyogenes (13), group D enterococci (12), Streptococcus agalactiae (11), viridans streptococci (10), coagulase-negative staphylococci (21), Staphylococcus aureus (15), and Listeria monocytogenes (1). The AMS-GPI Card identified all of the group D enterococci, viridans streptococci, and coagulase-negative staphylococci and all but one each of the Streptococcus pyogenes and Streptococcus agalactiae isolates. L. monocytogenes was also correctly identified. However, the AMS-GPI Card identified only 12 of 17 Streptococcus pneumoniae and 9 of 15 Staphylococcus aureus isolates by direct inoculation. We therefore conclude that the results of direct identification of gram-positive organisms by the AMS-GPI Card may be used cautiously for rapid direct identification of gram-positive organisms from positive blood cultures.
mesh_terms: D001431:Bacteriological Techniques; D001769:Blood / Q000382:microbiology*; D005069:Evaluation Studies as Topic; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification; D011933:Reagent Kits, Diagnostic; D018805:Sepsis / Q000175:diagnosis; D013203:Staphylococcal Infections / Q000175:diagnosis; D013210:Staphylococcus / Q000145:classification*; D013211:Staphylococcus aureus / Q000145:classification; D013212:Staphylococcus epidermidis / Q000145:classification; D013290:Streptococcal Infections / Q000175:diagnosis; D013291:Streptococcus / Q000145:classification*; D013292:Streptococcus agalactiae / Q000145:classification; D013296:Streptococcus pneumoniae / Q000145:classification; D013297:Streptococcus pyogenes / Q000145:classification
chemical_list: D011933:Reagent Kits, Diagnostic