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首页> 外文期刊>Infection and immunity >Plasmid-mediated susceptibility to intestinal microbial antagonisms in Escherichia coli.
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Plasmid-mediated susceptibility to intestinal microbial antagonisms in Escherichia coli.

机译：质粒介导的大肠杆菌对肠道微生物拮抗作用的敏感性。

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Self-transferable plasmid pIP1100 confers to Escherichia coli an unusually high level of resistance (1 to 2 mg/ml) to erythromycin by production of an erythromycin esterase. The effect of pIP1100 on the destiny of E. coli strains in the intestines of gnotobiotic mice was studied. In germfree mice, pIP1100 was efficiently transferred to a plasmid-free E. coli recipient. Intestinal counts of the donor, the recipient, and the transconjugants were greater than 8.5 log CFU/g of feces. When erythromycin was added to the diet of the mice, counts of the plasmid-bearing strains were only slightly lowered and partial inactivation of erythromycin was observed in the feces. Transfer of pIP1100 also occurred in human-flora-associated mice. In this model all the E. coli strains were subject to microbial antagonisms caused by the anaerobic components of the flora. However, strains harboring pIP1100 were strongly inhibited (less than 2.5 log CFU/g of feces), whereas their plasmid-free counterparts persisted at much higher population levels (greater than 5.2 log CFU/g of feces). The ecological disadvantage conferred by pIP1100 to E. coli when a complex human flora was concomitantly present in the intestine of the mice persisted during erythromycin administration. These results provide an explanation for the low incidence of isolation of highly erythromycin-resistant E. coli strains despite the extensive use of the antibiotic.
机译：可自我转移的质粒pIP1100通过产生红霉素酯酶，赋予大肠杆菌以异常高的水平对红霉素的抗性（1至2 mg / ml）。研究了pIP1100对致生性小鼠肠道中大肠杆菌菌株命运的影响。在无菌小鼠中，pIP1100被有效转移到无质粒的大肠杆菌受体中。供体，受体和转导结合体的肠道计数均大于8.5 log CFU / g粪便。当将红霉素添加到小鼠的饮食中时，带有质粒的菌株的计数仅稍微降低，并且在粪便中观察到红霉素的部分失活。 pIP1100的转移也发生在与人类植物区系相关的小鼠中。在该模型中，所有大肠杆菌菌株均受到菌群厌氧成分引起的微生物拮抗作用。但是，带有pIP1100的菌株被强烈抑制（小于2.5 log CFU / g粪便），而它们的无质粒对应物则以更高的种群水平持续存在（大于5.2 log CFU / g粪便）。当在小鼠肠道内同时存在复杂的人类菌群时，pIP1100赋予大肠杆菌以生态上的不利影响。这些结果说明了尽管广泛使用抗生素，但对高红霉素抗性大肠杆菌菌株的分离率低。

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