Sweeney N J, Laux D C, Cohen P S
Department of Biochemistry, Microbiology, and Molecular Genetics, University of Rhode Island, Kingston 02881, USA.
Infect Immun. 1996 Sep;64(9):3504-11. doi: 10.1128/iai.64.9.3504-3511.1996.
The Escherichia coli human fecal isolates F-18 and K-12 are excellent colonizers of the streptomycin-treated mouse intestine. E. coli F-18 and E. coli K-12 eda mutants (unable to utilize glucuronate, galacturonate, and gluconate) were constructed by insertional mutagenesis. Neither the E. coli F-18 eda nor the E. coli K-12 eda mutant was able to colonize the streptomycin-treated mouse intestine, whether they were fed to mice together with their respective parental strains or alone. Complementation of the eda mutants with pTC190 (containing a functional E. coli K-12 eda gene) completely restored the colonization ability of both eda mutants. Relative to their parental strains, the E. coli F-18 eda mutant and the E. coli K-12 eda mutant grew poorly in cecal mucus isolated from mice fed either normal mouse chow or a synthetic diet containing sucrose as the sole carbon source, yet the mutants and parental strains demonstrated identical growth rates in minimal medium with glucose as the carbon source. E. coli F-18 edd eda and E. coli K-12 edd eda double mutants colonized the streptomycin-treated intestine when fed to mice alone; however, when fed simultaneously with their respective parental strains, they were poor colonizers. Since the edd gene is involved only in gluconate metabolism via the Entner-Doudoroff pathway, these results implicate the utilization of gluconate and the Entner-Doudoroff pathway as important elements in E. coli colonization of the streptomycin-treated mouse large intestine.
从人类粪便中分离出的大肠杆菌菌株F - 18和K - 12是经链霉素处理的小鼠肠道的优良定植菌。通过插入诱变构建了大肠杆菌F - 18和大肠杆菌K - 12的eda突变体（无法利用葡萄糖醛酸、半乳糖醛酸和葡萄糖酸）。无论是将大肠杆菌F - 18 eda突变体还是大肠杆菌K - 12 eda突变体与各自的亲本菌株一起喂给小鼠，还是单独喂给小鼠，它们都无法在经链霉素处理的小鼠肠道中定植。用pTC190（含有功能性大肠杆菌K - 12 eda基因）对eda突变体进行互补，完全恢复了两个eda突变体的定植能力。相对于它们的亲本菌株，大肠杆菌F - 18 eda突变体和大肠杆菌K - 12 eda突变体在从喂食正常小鼠饲料或含有蔗糖作为唯一碳源的合成饲料的小鼠中分离出的盲肠黏液中生长较差，但这些突变体和亲本菌株在以葡萄糖作为碳源的基本培养基中显示出相同的生长速率。当单独喂给小鼠时，大肠杆菌F - 18 edd eda和大肠杆菌K - 12 edd eda双突变体能在经链霉素处理的肠道中定植；然而，当与各自的亲本菌株同时喂食时，它们的定植能力较差。由于edd基因仅通过恩特纳-杜德洛夫途径参与葡萄糖酸代谢，这些结果表明葡萄糖酸的利用和恩特纳-杜德洛夫途径是大肠杆菌在经链霉素处理的小鼠大肠中定植的重要因素。
