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Rapid immunodiagnosis of streptococci and enterococci in blood cultures Note
Author(s) -
Kristensen Brian,
Højbjerg Tove,
Schønheyder Henrik Carl
Publication year - 2001
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1034/j.1600-0463.2001.d01-121.x
Subject(s) - latex fixation test , microbiology and biotechnology , streptococcus , enterococcus , blood culture , gram positive cocci , antigen , streptococcaceae , streptococcus pneumoniae , direct agglutination test , agglutination (biology) , medicine , biology , bacteria , antibody , staphylococcus aureus , immunology , antibiotics , serology , genetics
We evaluated a procedure for rapid identification of blood culture isolates of pneumococci, enterococci and beta‐haemolytic streptococci groups A, B, C, and G. Immunological tests were applied directly to blood culture medium and included a quellung reaction for pneumococci, and latex agglutination tests (LAT) for pneumococcal antigen and Lancefield antigens A, B, C, D and G. During a one‐year trial period with approximately 12,000 blood culture sets (BacT/Alert ® , Organon‐Teknika), 208 sets showed pure growth of Gram‐positive cocci in pairs or chains by direct microscopy. Overall, a correct diagnosis was noted for 103 (63.2%, 95% CI: 55.3–70.6%) of 163 sets yielding pneumococci, beta‐haemolytic streptococci, or enterococci. A procedure excluding Lancefield antigens only A, B, and D was implemented during a one‐year follow‐up period. With this simplified procedure positive and negative predictive values, respectively, were 1.00 and 0.87 for pneumococci, 1.00 and 0.94 for beta‐haemolytic streptococci group A, 0.60 and 1.00 for beta‐haemolytic streptococci group B, and 0.91 and 0.88 for enterococci. We conclude that rapid identification of Gram‐positive cocci is feasible and may improve the information given to clinicians at the first notification of positive blood cultures.