Detection of agents that alter the bacterial cell surface.
Proteus mirabilis is not killed by polymyxin B, normal serum, or sodium deoxycholate. Exposure to polymyxin B renders the cells susceptible to killing by the latter two agents. The data suggest that this synergism is due to polymyxin B-induced surface changes. The results point out an inadequacy of existing methods of screening for antibiotics; they fail to detect agents which, while showing no in vitro effect on growth, may alter a resistant organism so that it becomes more susceptible to other antimicrobials or host defense mechanisms. A method is described which can be used to detect such cell surface-modifying agents.
D000900:Anti-Bacterial Agents / Q000032:analysis / Q000494:pharmacology*; D001770:Blood Bactericidal Activity; D003840:Deoxycholic Acid / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004357:Drug Synergism; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011113:Polymyxins / Q000032:analysis / Q000494:pharmacology; D011513:Proteus mirabilis / Q000187:drug effects; D013499:Surface Properties
D000900:Anti-Bacterial Agents; D011113:Polymyxins; D003840:Deoxycholic Acid