[Resistance profiles of the various species of the genus Staphylococcus to 15 clinically-used antimicrobials].

A total of 78 strains of 11 species of Staphylococcus genus (29 S. aureus, 48 Staphylococcus coagulase-negative and 1 S. intermedius strain,) were studied in order to determine the resistance patterns to fifteen commonly used antimicrobial agents. Out of 48 Staphylococcus coagulase-negative strains studied, 8 (4/15 S. epidermidis, 1/10 S. hominis, 1/6 S. haemolyticus, 2/3 S. xylosus) showed resistance patterns similar to that of S. aureus strains against beta-lactam antibiotics, aminoglycosides, chloramphenicol and fosfomycin, and 10 exhibit beta-lactamase-activity. Although the 7 S. saprophyticus strains assayed were beta-lactamase-negative by the chromogenic cephalosporin method after induction, the penicillin G minimal inhibitory concentration values were slightly higher than those obtained with other beta-lactamase-negative species. The susceptibilities to erythromycin and clindamycin suggested that macrolides-lincosamides-streptogramin type B (MLS) resistance was present in a large number of Staphylococcus coagulase-negative strains. In all the Staphylococcus genus, the aminoglycosides resistance seems to be mediated by the same aminoglycosides modifying-enzymes. Vancomycin was very active against the 11 species assayed. Rifampicin was effective with all Staphylococcus coagulase-negative strains. The S. aureus rifampicin-resistant were also resistant to oxacillin, and variable against aminoglycosides, chloramphenicol, fosfomycin, erythromycin and clindamycin. Only 5 strains were resistant to trimethoprim-sulfamethoxazole (TMS), 1 S. aureus oxacillin-susceptible, 1 S. aureus oxacillin-resistant, 2 S. xylosus and 1 S. warneri strains.