A genetically modified nasopharyngeal commensal as a platform for human bacteriotherapy

我们的长期目标是发明一种由活细菌组成的新型药物，这种药物将作为滴鼻剂服用(类似于商业上可获得的、由肠道疾病患者口服的Yacult饮料)。我们最近发表了一项研究，在参与者的鼻子里接种了一种小剂量的“友好细菌”--内氏内氏杆菌，发现6个月后这种细菌仍然存在于他们的喉咙里，并且没有引起任何不良反应。此外，友好的细菌阻止了参与者感染可能导致脑膜炎的相关细菌。作为一种治疗细菌感染的方法，“细菌疗法”的概念正在迅速得到人们的信任--例如，我们现在用从捐赠者粪便中提取的细菌来治疗艰难梭菌腹泻，而且效果非常好。我们已经发现了一种方法，可以用来自非常广泛的生物的基因来转化乳酸奈瑟氏菌，这意味着我们有可能开发一系列含有在接受者身上发挥特定预期效果的基因的细菌药物。例如，我们可以制造一种细菌药物，它可以制造杀死有害细菌或病毒的物质，或者只是在竞争中击败它们。我们的想法存在的一个问题是，当我们给学生接种内瑟氏菌时，我们发现其中65%的人被定植，但如果我们将研究限制在不吸烟的人中，这一比例只有35%。这不是一种非常可靠的细菌疗法，如果这种方法要有任何用处，我们需要增加殖民的可能性。因此，在这项拟议的研究中，我们将使用我们的技术来制造一种内毒素奈瑟氏菌，它可以产生两种通常被其他细菌用来粘着细胞的蛋白质。为此，我们将使用两种蛋白质，通常是由相关的脑膜炎奈瑟菌脑膜炎奈瑟菌所产生的，当它定植于人类时，它会粘在鼻子的内表面上。我们将展示这种新的转基因菌株具有我们预期的所有特征，包括在实验室中更好地附着在细胞上的能力，而且释放到社区是安全的(因为它对免疫系统或抗生素没有更强的抵抗力，也没有增加逐渐转变为更危险的东西的能力)。然后，我们将向适当的监管机构申请许可，允许我们对人类志愿者重复我们的研究，看看我们产生的转基因菌株是否比衍生它的野生型细菌能够更好地定居。这将是后续研究的主题--如果研究成功，我们设计的这一策略将是一种未来的治疗方法，适用于任何涉及鼻咽定植的疾病过程，例如肺炎、慢性支气管炎、鼻窦炎、耳朵感染、脑膜炎或MRSA定植和疾病。

Our long term objective is to invent a new type of medicine which consists of living bacteria which would be given as nose drops (akin to the Yacult drink that is commercially available and taken by mouth by people with bowel problems). We have recently published work in which we inoculated a small dose of a `friendly bacterium` - Neisseria lactamica - into the noses of participants and found that the bacterium was still present in their throats 6 months later, and caused no ill effects. Furthermore, the friendly bacterium stopped the paticipants from being infected with a related bacterium which can cause meningitis. This concept of `bacteriotherapy` is rapidly gaining credence as a way to treat bacterial infections - for example we now treat Clostridium difficile diarrhoea with bacteria derived from the stools of donors, and it works very well. We have discovered a way to genetically transform Neisseria lactamica with genes from a very wide range of living things, which means that we could potentially develop a range of bacterial medicines containing genes which exert specific desired effects in the recipients. For example, we could make a bacterial medicine which makes substances which kill harmful bacteria or viruses or which simply out-competes them. One of the problems with our idea is that when we inoculated students with the Neisseria lactamica, we found that 65% of them became colonised, but this was only 35% if we restricted the study to non-smokers. This would not be a very reliable bacteriotherapy and we would need to increase the likelihood of colonisation if this approach is to be of any use. So, in the proposed study, we will use our technology to make a strain of Neisseria lactamica which makes two proteins that are normally used by other bacteria to stick to cells. We will use for this purpose two proteins that are normally made by the related meningitis bacterium Neisseria meningitidis, to stick to stick to the inner surface of the nose when it colonises humans. We will show that the new genetically modified strain has all of the characteristics we expect including the ability to stick better to cells in the laboratory, and that is safe to release into the community (because it is not more resistant to the immune system, or to antibiotics, and does not have increased capacity to gradually change into something more dangerous). We will then apply to the appropriate regulators for permission to repeat our studies with human volunteers to see if the genetically modified strain that we have generated manages to colonise better than the wild type bacterium from which it is derived. This would be the subject of a follow-on study - if that were to be successful this strategy that we have devised would be a future therapy of relevance to any disease process involving colonisation of the nasopharynx, eg pneumonia, Chronic Bronchitis, sinusitis, ear infection, meningitis or MRSA colonisation and disease.