Mode of action of the protein, SP127, which enhances the activity of macrolide antibiotics against Pseudomonas aeruginosa.

Antibiotics, the activity of which enhanced against Pseudomonas aeruginosa by SP127, were restricted to the basic macrolide antibiotics such as erythromycin, maridomycin and oleandomycin, the neutral macrolide antibiotics such as lankamycin and lankacidin C, vancomycin and enramycin. Synergistic activity of SP127 with the above antibiotics was found against Pseudomonas aeruginosa and several strains of Escherichia coli, but not against Proteus vulgaris and macrolide-resistant Staphylococcus aureus. SP127 had extremely weak proteolytic but no lytic activity. From the isotopic experiments, the action of SP127 was partially attributed to the promotion of antibiotic penetration to cells of Pseudomonas aeruginosa.