Evaluation of three slide agglutination tests for rapid identification of Staphylococcus aureus

Three slide agglutination tests for identification of Staphylococcus aureus were compared. The agglutination tests used for evaluation were Staphaurex (Wellcome Diagnostics), Staphyslide-Test (BioMerieux), and ANI S. aureus TEST (Ani Biotech Oy). A total of 347 isolates were analyzed, including 288 strains of S. aureus, 49 of S. epidermis, 11 of S. intermedius, 12 strains of other staphylococci and 14 non-staphylococcal strains. One hundred of the S. aureus strains were isolates from cases of food poisoning, 129 from mastitis and 59 from other clinical cases. The sensitivities of the tests were also compared using diluted suspensions of S. aureus strains and with purified Protein A dilutions. The results showed that the sensitivities of the tests were 98.6%, 97.9% and 99.0% for Staphaurex, Staphyslide-test and ANI S. aureus TEST, respectively. The specificities were 100% for the Staphyslide test and 98.8% for both the ANI S. aureus TEST and the Staphaurex test. The sensitivities measured with diluted S. aureus strain suspensions and Protein A solutions were equal with the Staphaurex and ANI S. aureus TEST. All the agglutination tests studied proved to be practical, easy to use and accurate for the rapid identification of S. aureus strains from culture isolates.