Stiefel Usha, Nerandzic Michelle M, Koski Pertti, Donskey Curtis J
Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
J Antimicrob Chemother. 2008 Nov;62(5):1105-8. doi: 10.1093/jac/dkn298. Epub 2008 Aug 7.
Antibiotics that are excreted into the intestinal tract and that disrupt the indigenous microbiota may promote infection by Clostridium difficile. We previously demonstrated that oral administration of a proteolysis-resistant, recombinant class A beta-lactamase inactivates ampicillin or piperacillin excreted into the small intestine during parenteral treatment. We hypothesized that oral administration of this beta-lactamase in conjunction with parenteral ampicillin or piperacillin would preserve the colonic microbiota, thus preventing the overgrowth of and toxin production by C. difficile in mice.
Subcutaneous ampicillin, subcutaneous piperacillin or either of these plus oral beta-lactamase or either of these plus tazobactam-inactivated oral beta-lactamase were administered to mice 24 and 12 h prior to harvest of caecal contents. Contents were inoculated with one of four strains of C. difficile, and growth and toxin production were assessed after 24 h of incubation under anaerobic conditions. To assess changes in stool microbiota, denaturing gradient gel electrophoresis (DGGE) of PCR-amplified ribosomal RNA genes was performed.
Mice treated with ampicillin, piperacillin or either of these plus tazobactam-inactivated oral beta-lactamase developed high-density colonization with C. difficile, whereas those treated with ampicillin or piperacillin plus the beta-lactamase did not. DGGE demonstrated that antibiotic treatment resulted in significant alteration of the indigenous stool microbiota, whereas antibiotic plus beta-lactamase treatment did not.
Administration of oral recombinant beta-lactamase preserved the colonic microbiota of mice during parenteral beta-lactam antibiotic treatment and prevented the overgrowth of and toxin production by C. difficile in caecal contents. Oral beta-lactamase therapy may represent a novel approach towards preventing C. difficile infections in healthcare settings.
排泄至肠道并破坏原生微生物群的抗生素可能会促进艰难梭菌感染。我们之前证明，口服一种抗蛋白水解的重组A类β-内酰胺酶可使在肠胃外治疗期间排泄至小肠的氨苄西林或哌拉西林失活。我们推测，口服这种β-内酰胺酶并联合肠胃外使用氨苄西林或哌拉西林可保护结肠微生物群，从而防止小鼠体内艰难梭菌过度生长及产生毒素。
在采集盲肠内容物前24小时和12小时，给小鼠皮下注射氨苄西林、皮下注射哌拉西林，或二者之一加口服β-内酰胺酶，或二者之一加他唑巴坦灭活的口服β-内酰胺酶。将盲肠内容物接种四种艰难梭菌菌株之一，在厌氧条件下孵育24小时后评估生长及毒素产生情况。为评估粪便微生物群的变化，对聚合酶链反应扩增的核糖体RNA基因进行变性梯度凝胶电泳（DGGE）分析。
用氨苄西林、哌拉西林或二者之一加他唑巴坦灭活的口服β-内酰胺酶治疗的小鼠出现了艰难梭菌的高密度定植，而用氨苄西林或哌拉西林加β-内酰胺酶治疗的小鼠则未出现。DGGE分析表明，抗生素治疗导致原生粪便微生物群发生显著改变，而抗生素加β-内酰胺酶治疗则未导致这种改变。
在肠胃外使用β-内酰胺类抗生素治疗期间，口服重组β-内酰胺酶可保护小鼠的结肠微生物群，并防止盲肠内容物中艰难梭菌过度生长及产生毒素。口服β-内酰胺酶疗法可能是预防医疗机构中艰难梭菌感染的一种新方法。
