COMPARISON OF 5 AGGLUTINATION TESTS FOR IDENTIFICATION OF STAPHYLOCOCCUS-AUREUS

Various commercially produced agglutination kits are widely used for t he identification of Staphylococcus aureus. These kits detect the pres ence of protein A and/or clumping factor on S. aureus. The literature has shown that methicillin-resistant S. aureus (MRSA) isolates which a re deficient in both clumping factor and protein A may be misidentifie d. Two products. Slider and Staphaurex Plus, utilize specific anti-S. aureus antibodies, potentially giving them greater sensitivity compare d to products without these antibodies. We report a prospective study designed to compare the performance characteristics of Fastaph, Slider , Staphaurex, Staphaurex Plus, Staphyloslide, and the tube coagulase t est for the identification of staphylococcal isolates. All discrepant isolates were tested with the Gen-Probe AccuProbe S. aureus test and w ere identified to the species level with conventional reference bioche micals. A total of 1,193 isolates were tested, including 33 MRSA and 4 23 methicillin-sensitive S. aureus isolates. The sensitivities and spe cificities of the tests, respectively, were as follows: Fastaph, 99.1 and 98.9%; Slider, 99.6 and 96.4%; Staphaurex, 98.9 and 99.9%; Staphau rex Plus, 99.6 and 93.9%; Staphyloslide, 99.1 and 98.9%; and tube coag ulase, 99.3 and 100%, Sensitivity was excellent for all of the product s tested. The specificities of Fastaph, Staphaurex, and Staphyloslide were excellent, while Staphaurex Plus and Slider demonstrated less opt imal results.