美国波士顿儿童医院Gregory P. Priebe和Thomas J. Sandora以及以色列海法理工大学Roy Kishony研究组合作，发现了细菌从益生菌荚膜向重症监护病房（ICU）患者血液传播的基因组学和流行病学证据。该成果2019年11月7日在线发表在《自然—医学》上。

研究报道，益生菌治疗的ICU患者与未经治疗者相比，患有乳酸菌菌血症的风险明显更高。研究提供了基因组学数据，支持将益生菌直接克隆传播至血液的观点。基于全基因组的系统发生研究表明，从治疗患者血液中分离出的乳酸杆菌，与从相关益生菌产品中分离出的乳酸杆菌，在系统发生上是不可分离的。实际上，血液分离物中的微小遗传多样性，大多反映了在益生菌产品中发现的先前存在的遗传异质性。一些血液分离株还包含从头突变，包括一个患者的非同义SNP赋予抗生素耐药性。他们的发现支持益生菌菌株可以直接引起菌血症，并在ICU患者体内适应性进化。

据介绍，益生菌常用于住院病人的许多潜在适应症，但其副作用可能超过其潜在益处。令人震惊的是，益生菌菌株可引起菌血症，但缺乏血液分离物和常用益生菌之间血缘关系的直接证据。

附：英文原文

Title: Genomic and epidemiological evidence of bacterial transmission from probiotic capsule to blood in ICU patients

Author: Idan Yelin, Kelly B. Flett, Christina Merakou, Preeti Mehrotra, Jason Stam, Erik Snesrud, Mary Hinkle, Emil Lesho, Patrick McGann, Alexander J. McAdam, Thomas J. Sandora, Roy Kishony, Gregory P. Priebe

Issue&Volume: 2019-11-07

Abstract: Probiotics are routinely administered to hospitalized patients for many potential indications1 but have been associated with adverse effects that may outweigh their potential benefits27. It is particularly alarming that probiotic strains can cause bacteremia8,9, yet direct evidence for an ancestral link between blood isolates and administered probiotics is lacking. Here we report a markedly higher risk of Lactobacillus bacteremia for intensive care unit (ICU) patients treated with probiotics compared to those not treated, and provide genomics data that support the idea of direct clonal transmission of probiotics to the bloodstream. Whole-genome-based phylogeny showed that Lactobacilli isolated from treated patients blood were phylogenetically inseparable from Lactobacilli isolated from the associated probiotic product. Indeed, the minute genetic diversity among the blood isolates mostly mirrored pre-existing genetic heterogeneity found in the probiotic product. Some blood isolates also contained de novo mutations, including a non-synonymous SNP conferring antibiotic resistance in one patient. Our findings support that probiotic strains can directly cause bacteremia and adaptively evolve within ICU patients. Patients in intensive care units administered a bacterial probiotic had an elevated risk of bloodstream infection due to the probiotic strain.

DOI: 10.1038/s41591-019-0626-9

Source:https://www.nature.com/articles/s41591-019-0626-9