Combined action of semisynthetic penicillin and macrolide antibiotic on Pseudomonas aeruginosa in vitro and in vivo.

For the purpose of studying therapy for pseudomonas infection, the synergistic effect of carbenicillin and midecamycin or 9,3''-di-O-acetyl midecamycin on Pseudomonas aeruginosa were studied in vitro and in vivo. Midecamycin and 9,3''-di-O-acetyl midecamycin were effective against spheroplasts of P. aeruginosa induced by carbenicillin treatment. As a result of investigating treatment using a combination of both carbenicillin and macrolide antibiotics on mouse infection model caused by subcutaneous injection of carrageenan solution containing viable cells of P. aeruginosa, the combined treatment was demonstrated to be significantly more effective than the control's single treatment by carbenicillin or the macrolide antibiotic alone.