Quinupristin / dalfopristin (Q / D) is given together in a fixed 30/70 combination; this combination has synergistic bactericidal activity against the following: Streptococci and staphylococci, including strains resistant to other antibiotic classes Some gram-negative anaerobic bacilli Clostridium perfringens Peptostreptococcus species Atypical respiratory pathogens (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila) Q / D inhibits Enterococcus faecium, including vancomycin - resistant strains.