Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
Institute for Infectious Diseases, University of Bern, Bern, Switzerland; Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland.
J Glob Antimicrob Resist. 2020 Sep;22:664-671. doi: 10.1016/j.jgar.2020.05.018. Epub 2020 Jun 23.
We investigated the use of bacteriophages as a strategy to decolonize intestinal carriers of multidrug-resistant Escherichia coli.
A fermentor was used as a continuous culture system for 48h. Two different pools of faeces (studies I and II) obtained from volunteers were spiked with a CTX-M-15-producing ST131 E. coli (strain 4901.28) susceptible to bacteriophages and challenged with three doses of INTESTI Bacteriophage cocktail administered at 2, 6 and 10h after the inoculum. Bacterial typing was performed by implementing microdilution panels, spot test, rep-PCR and whole-genome sequencing (including cgMLST and single-nucleotide variant analysis) obtained using Nanopore and Illumina platforms.
In study I, bacteriophages decreased the numbers of 4901.28 dramatically (≤10CFU/mL after 6h). In contrast, during study II, a phage-resistant mutant of 4901.28 persisted in the continuous culture (10CFU/mL at 48h). Whole-genome sequencing revealed the presence of two additional plasmids in the mutant as well as 11 single-nucleotide variants, including one chromosomal in a glycosyltransferase family 2 protein that is responsible for the transfer of sugars to polysaccharides and lipids. In both studies, the commensal E. coli population remained unchanged by the phage treatment maintaining itself at 10CFU/mL.
Our data indicates that bacteriophage cocktails may be implemented to decolonize some intestinal carriers. However, the individual microbiota composition may have an impact on the development of phage resistance. Mechanisms underlying this phenomenon are likely to be various and complex. Further in vivo studies and protein expression experiments are needed to confirm our observations and hypotheses.
我们研究了利用噬菌体作为一种策略来消除产多药耐药性大肠杆菌的肠道携带者。
使用发酵罐作为连续培养系统进行 48 小时。从志愿者中获得的两个不同粪便池（研究 I 和 II）被添加了对噬菌体敏感的产 CTX-M-15 的 ST131 大肠杆菌（菌株 4901.28），并在接种后 2、6 和 10 小时用 INTESTI 噬菌体鸡尾酒进行了三次剂量挑战。通过实施微稀释板、点测试、rep-PCR 和全基因组测序（包括 cgMLST 和单核苷酸变异分析）进行细菌分型，这些测序是使用 Nanopore 和 Illumina 平台获得的。
在研究 I 中，噬菌体在 6 小时后大大降低了 4901.28 的数量（≤10CFU/mL）。相比之下，在研究 II 中，4901.28 的噬菌体抗性突变体在连续培养中持续存在（48 小时时为 10CFU/mL）。全基因组测序显示，突变体中存在两个额外的质粒以及 11 个单核苷酸变异，包括一个在糖基转移酶家族 2 蛋白中的染色体，该蛋白负责将糖转移到多糖和脂质上。在这两项研究中，噬菌体处理对共生大肠杆菌种群没有影响，使其保持在 10CFU/mL。
我们的数据表明，噬菌体鸡尾酒可以用于消除一些肠道携带者。然而，个体微生物群落组成可能会影响噬菌体耐药性的发展。这种现象的潜在机制可能是多种多样和复杂的。需要进一步的体内研究和蛋白质表达实验来证实我们的观察和假设。
