title: Augmentation of serum bactericidal activity by paldimycin.
abstract: At concentrations below the MIC, paldimycin induced changes in Staphylococcus aureus 502A (UC 9116, ATCC 28417) which increased its sensitivity to serum. The enhanced sensitivity to serum was concentration dependent with the maximal sensitivity found when bacteria were grown in approximately 1/10 MIC of paldimycin. Within an 1-hour incubation, S. aureus 502A typically grew 1.5-2-fold in serum. Following exposure to paldimycin, however, approximately 30-50% of the bacteria were killed in serum. The paldimycin treated bacteria were not more susceptible to phagocytosis and killing by polymorphonuclear leukocytes. At the concentrations utilized, the Staphylococci were enlarged and had thickened cell walls. The organisms were still viable and replicating, but irregularities in cell division were observed in transmission electron micrographs.
authors.affiliation: Research Laboratories, Upjohn Company, Kalamazoo, MI 49001.
authors.forename: J I
authors.initials: JI
authors.lastname: Cialdella
authors.forename: R G
authors.initials: RG
authors.lastname: Ulrich
authors.forename: V P
authors.initials: VP
authors.lastname: Marshall
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001770:Blood Bactericidal Activity / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects; D002981:Clindamycin / Q000494:pharmacology; D004187:Disaccharides; D006020:Glycopeptides / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D009504:Neutrophils / Q000276:immunology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D004187:Disaccharides; D006020:Glycopeptides; D002981:Clindamycin; C050461:paldimycin; D000111:Acetylcysteine