COMPARATIVE PERFORMANCES OF 6 AGGLUTINATION KITS ASSESSED BY USING TYPICAL AND ATYPICAL STRAINS OF STAPHYLOCOCCUS-AUREUS

Six commercial agglutination tests designed for the identification of Staphylococcus aureus were compared by using a strain collection which included 512 staphylococci representing 33 species (318 isolates of S taphylococcus aureus [including 144 oxacillin resistant], 46 S. epider midis isolates, 15 S. haemolyticus isolates, 12 S. saprophyticus isola tes, 29 S. schleiferi isolates, 30 S. lugdunensis isolates, and 62 oth er coagulase-negative staphylococci). This group also included a propo rtion of strains with unusual phenotypes (e.g., 19 coagulase-negative S. aureus isolates, 26 clumping factor-negative S. aureus isolates, an d 4 S. aureas isolates each with a double deficiency). The overall sen sitivity for identification of typical and atypical S. aureus was high with the Staphaurex Plus test (Murex Biotech) (99.7%), the Pastorex S taph Plus test (Sanofi Diagnostics Pasteur) (99.7%), and the Slider St aph Plus test (bioMerieux) (100%). The overall rate of specificity was affected by the unusual inclusion in this study of a high proportion of non-S. aureus species, such as S. lugdunensis and S. schleiferi, wh ich express a clumping factor and therefore produce a positive result with the agglutination tests.