[Comparison of various characters and antigenic structure in S. aureus strains cultivated in hospitalized patients and in healthy carriers].

A comparison has been done between various characters of 170 non epidemic strains cultivated from hospitalized patients and 29 strains originated from healthy carriers without any hospital contact and antibiotic treatment since 6 months. Following characters have been tested: M.I.C. of 13 antibiotics, heterogenous methicillin resistance, enzymatic antibiotic resistance, macrolide inducible or constitutive type resistance, mercuric chloride susceptibility; phage types; enzymes and toxins production. Antigenic structure has been studied, in particular production of protein A, A beta teichoc acid and type antigens. Significant differences have been observed between hospital and healthy carriers strains; these later strains are antibiotic susceptible, produce few toxins and enzymes, are not frequently phage typable. Their antigenic structure shows also significant differences: A beta-teichoic acid is less frequently detected; type antigens are less frequent and different. Role of these surface antigens in virulence is discussed.