Evaluation of several commercial biochemical and immunologic methods for rapid identification of gram-positive cocci directly from blood cultures.
To develop laboratory methods for the rapid identification of gram-positive cocci from blood cultures, several commercial immunological and biochemical tests for identifying staphylococci and streptococci from two different blood culture systems (Thiol/TSB, Difco Laboratories; BACTEC, Johnston Laboratories, Inc.) were evaluated and compared with conventional identification methods. A total of 44 cultures contained Staphylococcus aureus as determined by conventional methods. Commercial immunological methods (six tested) ranged in overall sensitivity from 38.6 (Staphyloslide; BBL Microbiology Systems) to 77.3% (Staphaurex; Wellcome Diagnostics). All methods tested had 100% specificity. A total of 30 isolates of group D streptococci were tested with immunological and biochemical identification systems. The overall sensitivity ranged from 14.2% (Phadebact Group D; Pharmacia Diagnostics) to 100% with Streptex (Wellcome; immunological) and Identicult A-E (Scott Laboratories, Inc.; biochemical). The results of this study suggest that some reagents can be used to provide rapid identification of gram-positive cocci from blood cultures 24 h earlier than standard methods.
Rappaport
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Department of Microbiology, Thomas Jefferson University, Philadelphia, Pennsylvania.
Sawyer
K P
KP
Nachamkin
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D002374:Catalase / Q000032:analysis; D003030:Coagulase / Q000032:analysis; D006801:Humans; D006868:Hydrolysis; D011237:Predictive Value of Tests; D011760:Pyrrolidinones / Q000378:metabolism; D018805:Sepsis / Q000175:diagnosis*; D013210:Staphylococcus / Q000201:enzymology / Q000302:isolation & purification*; D013211:Staphylococcus aureus / Q000201:enzymology / Q000302:isolation & purification; D013291:Streptococcus / Q000201:enzymology / Q000302:isolation & purification*; D013296:Streptococcus pneumoniae / Q000201:enzymology / Q000302:isolation & purification
D003030:Coagulase; D011760:Pyrrolidinones; C034099:pyrrolidonyl-beta-naphthylamide; D002374:Catalase