The evolutionary dynamics of multiazole resistance in pathogenic Aspergillus fungi

病原曲霉菌多唑抗性的进化动态

• 批准号: NE/P000940/1
• 负责人: Bart Fraaije
• 金额: $ 8.22万
• 依托单位: Rothamsted Research
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP000940%2F1
• 关键词: evolutionary; dynamics; multiazole; resistance; pathogenic

The fungus Aspergillus fumigatus is globally ubiquitous in the environment, being present on decaying vegetation and in soils, where it performs a valuable role in nutrient recycling. The fungus is a minimal health threat to healthy individuals. However, patients that suffer from cystic fibrosis, cancer or have received organ transplants and are undergoing corticosteroid therapy, are at risk from 'invasive aspergillosis'. Current estimates indicate that over 63,000 patients develop this fungal disease annually across Europe. The primary method for controlling infections is by administering azole antifungal drugs. However, we and others have shown a sharp increase in the resistance of A. fumigatus to frontline azole antifungals, with unacceptably high mortality rates in these at-risk patient groups. The mutations that confer resistance of A. fumigatus to these drugs appear to have evolved in the environment, rather than in the patient. Azole compounds are also used as fungicides to control crop diseases. This has led to the hypothesis that the widespread use in agricultural crops of azole antifungal sprays is leading to the environmental selection for resistance in A. fumigatus, which is then resulting in decreased patient survival following infection.Our project aims to examine this hypothesis by determining the relative proportions of azole-resistant and azole-sensitive A. fumigatus in the UK by sampling environmental populations using growth media containing antifungal drugs. This environmental exposure assessment approach will target environments that have had high to low applications of crop-antifungals and will enable us to statistically examine whether there are links between the intensive use of these azole-based compounds in the environment and the occurrence of drug-resistant A. fumigatus. We will then use powerful technologies to sequence the genomes of many hundreds of A. fumigatus that are sensitive, or resistant, to azole antifungals. We already have numerous isolates pre-collected from around the world though a broad network of project partners, and we now know that there are two main azole-resistance mutations that widely occur. Our plan is to use our genome sequences and cutting-edge statistical genetic methods in order to determine when and where these mutations originated globally, use our newly isolated samples to test whether they occur within the UK environment and patient populations, whether they are spreading to invade new environments here and elsewhere, and whether novel undescribed resistance mutations exist.A. fumigatus is capable of sexual, as well as asexual, reproduction. In this case, the rate at which a newly-evolved resistance mutation can be integrated into new genetic backgrounds depends on the fertility of the A. fumigatus populations. In order to directly measure the 'sexiness' of the A. fumigatus populations, we will therefore perform sexual crosses using sequenced isolates that represent not only the range of genetic diversity that we encounter, but also the range of azole-resistance mutations. By measuring the number and fitness of progeny, we will be able to determine the rate at which resistance mutations can recombine into new genetic backgrounds, and also discover unknown drug-resistance mechanisms.By addressing these questions, we will directly measure the risk that the use of antifungal compounds has on evolving resistance in non-target fungal species, and also answer important questions on the distance that these airborne fungi are able to spread and share genes with one another. Our findings will not only be of high relevance to health care professionals, directly informing diagnostic protocols and disease management in intensive-care settings, but will also inform current debates on the costs of widespread use of antimicrobial compounds in the environment. These goals all directly feed into NERCs new strategic direction 'The Business of the Environment'.

真菌烟曲霉在全球环境中普遍存在，存在于腐烂的植被和土壤中，在营养循环中发挥着重要作用。这种真菌对健康个体的健康威胁很小。然而，患有囊性纤维化、癌症或接受过器官移植并正在接受皮质类固醇治疗的患者有患“侵袭性曲霉病”的风险。目前的估计表明，欧洲每年有超过63，000名患者患上这种真菌病。控制感染的主要方法是使用唑类抗真菌药物。然而，我们和其他人已经显示出A的抗性急剧增加。烟曲霉菌替代一线唑类抗真菌药，在这些高危患者群体中具有不可接受的高死亡率。A.烟曲霉菌对这些药物的耐受性似乎是在环境中而不是在患者体内进化而来的。唑类化合物也用作杀真菌剂以控制作物病害。这导致了一种假设，即唑类抗真菌喷雾剂在农作物中的广泛使用导致了A.我们的项目旨在通过确定唑类耐药和唑类敏感的A.通过使用含有抗真菌药物的生长培养基对环境种群进行采样，在英国对烟曲霉进行了研究。这种环境暴露评估方法将针对作物抗真菌剂施用量从高到低的环境，并使我们能够统计检查环境中这些唑类化合物的密集使用与抗药性A的发生之间是否存在联系。烟熏。然后，我们将使用强大的技术来测序数百个A的基因组。对唑类抗真菌剂敏感或耐药的烟曲霉。我们已经通过广泛的项目合作伙伴网络从世界各地预先收集了许多分离株，我们现在知道有两种主要的唑类耐药突变广泛发生。我们的计划是使用我们的基因组序列和尖端的统计遗传学方法来确定这些突变在全球范围内起源的时间和地点，使用我们新分离的样本来测试它们是否发生在英国环境和患者人群中，它们是否正在传播入侵这里和其他地方的新环境，以及是否存在新的未描述的耐药突变。烟曲霉既能有性繁殖，也能无性繁殖。在这种情况下，新进化的抗性突变整合到新的遗传背景中的速度取决于A.烟曲霉种群为了直接测量A.因此，我们将使用测序的分离株进行有性杂交，这些分离株不仅代表我们遇到的遗传多样性范围，而且还代表唑抗性突变的范围。通过测量后代的数量和适应性，我们将能够确定耐药突变重组成新的遗传背景的速率，并发现未知的耐药机制。通过解决这些问题，我们将直接测量使用抗真菌化合物对非靶真菌物种产生耐药性的风险，也回答了关于这些空气传播的真菌能够传播的距离和彼此共享基因的重要问题。我们的研究结果不仅与医疗保健专业人员高度相关，直接为重症监护环境中的诊断方案和疾病管理提供信息，而且还将为当前关于环境中广泛使用抗菌化合物的成本的辩论提供信息。这些目标都直接纳入了NERC新的战略方向“环境业务”。

项目成果

Epidemiological Studies of Pan-Azole Resistant Aspergillus fumigatus Populations Sampled during Tulip Cultivation Show Clonal Expansion with Acquisition of Multi-Fungicide Resistance as Potential Driver.

• DOI: 10.3390/microorganisms9112379
• 发表时间: 2021-11-18
• 期刊: Microorganisms
• 影响因子: 4.5
• 作者: Fraaije BA;Atkins SL;Santos RF;Hanley SJ;West JS;Lucas JA
• 通讯作者: Lucas JA

The one health problem of azole resistance in Aspergillus fumigatus: current insights and future research agenda

• DOI: 10.1016/j.fbr.2020.10.003
• 发表时间: 2020-12
• 期刊: Fungal Biology Reviews
• 影响因子: 6
• 作者: P. Verweij;J. Lucas;M. Arendrup;P. Bowyer;A. J. Brinkmann;D. Denning;P. Dyer;M. Fisher;P. Geenen;U. Gisi;D. Hermann;A. Hoogendijk;E. Kiers;K. Lagrou;W. Melchers;J. Rhodes;A. Rietveld;Sijmen E. Schoustra;K. Stenzel;B. Zwaan;B. Fraaije