Improved identification of Staphylococcus aureus using a new agglutination test. Results of an international study.

A new reagent for the identification of Staphylococcus aureus, SLIDEX STAPH-KIT, operates on the principle of a latex and red blood cell combination agglutination: red blood cells are coated with fibrinogen for the detection of clumping factor, and latex particles are sensitized with anti-S. aureus serotype 18 monoclonal antibody for the detection of protein A and antigen 18. French strains belonging to serotype 18 are methicillin-resistant. The performance of this reagent was compared with STAPHYSLIDE and STAPHAUREX in Europe (France, Germany, Italy), in the United States and in Japan using 548 methicillin-resistant S. aureus strains, 392 methicillin-sensitive S. aureus strains, and 441 non-aureus staphylococci. The specificity of the three reagents was equivalent (98.8% for SLIDEX STAPH-KIT, 99.1% for STAPHYSLIDE, 98.1% for STAPHAUREX). SLIDEX STAPH-KIT (97.3%) was more sensitive than STAPHYSLIDE (93.5%) and STAPHAUREX (89.7%) for all S. aureus strains due to a higher rate of identified methicillin-resistant S. aureus strains.