Multiplicity of the genes and plasmids conferring resistance to pristinamycin in staphylococci selected in an Algerian hospital.

In an Algerian hospital where pristinamycin (Pt) was extensively used for the treatment of chronic osteomyelitis and for prophylaxis in bone surgery, the prevalence of pristinamycin-resistant (PtR) staphylococci during a five-month period (20%) was higher than that among staphylococci isolated elsewhere in Algeria (4.5%). Analysis of 13 PtR staphylococci isolated in this hospital revealed a diversity of plasmids and genes conferring resistance to Pt and to related antibiotics. Most of the PtR staphylococci were unrelated: they belonged to either different taxa or types. Nevertheless, some of the unrelated staphylococci harboured structurally related plasmids carrying streptogramin resistance genes. Thus, these plasmids may have contributed to the dispersion of these genes.