title: The in vitro effect of three antibiotics on alveolar macrophages.
abstract: The effects of 3 antibiotics, azlocillin, ticarcillin and tobramycin, on rat alveolar macrophage function has been examined. These antibiotics are used in the treatment of Pseudomonas aeruginosa lung infections in cystic fibrosis patients. In this study low concentrations of the antibiotics were used, similar to the low levels found in the lungs of these patients. Tobramycin, a highly active aminoglycoside, inhibited the phagocytosis of opsonized Pseudomonas aeruginosa and enhanced the binding of sheep erythrocytes sensitized with IgG2b, when pre-incubated with macrophage monolayers for 30 min. Inhibition of both phagocytosis and binding of sensitized sheep erythrocytes was observed when tobramycin was co-incubated with the macrophage monolayers and indicator cells. Azlocillin, a semi-synthetic penicillin, caused inhibition of phagocytosis of opsonized bacteria and binding of sensitized sheep erythrocytes when added with the indicator cells. However, no effect was found if the macrophages were pre-incubated with azlocillin for 30 min. Ticarcillin, a semi-synthetic penicillin which is less active in vitro as an antimicrobial agent than azlocillin, had no effect on alveolar macrophages at the concentrations used in these assays. It is postulated that if these in vitro findings with rat alveolar macrophages are reflected in the in vivo situation in humans, the effect of antibiotics on host defence may be of clinical importance.
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001390:Azlocillin / Q000494:pharmacology; D002478:Cells, Cultured; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D008297:Male; D010587:Phagocytosis / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012397:Rosette Formation; D013982:Ticarcillin / Q000494:pharmacology; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D013982:Ticarcillin; D001390:Azlocillin; D014031:Tobramycin