[Resistance to streptogramin antibiotics in "Staphylococcus aureus" (author's transl)].

Pristinamycin and virginiamycin, two antibiotics belonging to the streptogramin group, are widely used in France against staphylococcal infections. They are mixtures of two different active compounds, pristinamycin I and II, virginiamycine S and M. The present study describes five clinical isolates of Staphylococcus aureus with unusual resistance to these antibiotics. This resistance, whose level is variable according to the strains, concerns both compounds of these antibiotics. It is lost at high frequency spontaneoulsy or after treatment by curing agents, suggesting that the resistance is plasmid mediated. The drug inactivation by the resistant strains supports the hypothesis of an enzymatic mechanism of resistance. Furthermore, this new resistance seems to be linked, in some strains, to either of the two aminoglycoside resistance patterns recently described in S. aureus.