Druzhinina Irina S, Komoń-Zelazowska Monika, Kredics László, Hatvani Lóránt, Antal Zsuzsanna, Belayneh Temesgen, Kubicek Christian P
Research Area of Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9/1665, A-1060 Vienna, Austria.
Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
Microbiology (Reading). 2008 Nov;154(Pt 11):3447-3459. doi: 10.1099/mic.0.2008/021196-0.
The common soil fungus Trichoderma (teleomorph Hypocrea, Ascomycota) shows increasing medical importance as an opportunistic human pathogen, particularly in immunocompromised and immunosuppressed patients. Regardless of the disease type and the therapy used, the prognosis for Trichoderma infection is usually poor. Trichoderma longibrachiatum has been identified as the causal agent in the majority of reported Trichoderma mycoses. As T. longibrachiatum is very common in environmental samples from all over the world, the relationship between its clinical and wild strains remains unclear. Here we performed a multilocus (ITS1 and 2, tef1, cal1 and chit18-5) phylogenetic analysis of all available clinical isolates (15) and 36 wild-type strains of the fungus including several cultures of its putative teleomorph Hypocrea orientalis. The concordance of gene genealogies recognized T. longibrachiatum and H. orientalis to be different phylogenetic species, which are reproductively isolated from each other. The majority of clinical strains (12) were attributed to T. longibrachiatum but three isolates belonged to H. orientalis, which broadens the phylogenetic span of human opportunists in the genus. Despite their genetic isolation, T. longibrachiatum and H. orientalis were shown to be cosmopolitan sympatric species with no bias towards certain geographical locations. The analysis of haplotype association, incongruence of tree topologies and the split decomposition method supported the conclusion that H. orientalis is sexually recombining whereas strict clonality prevails in T. longibrachiatum. This is a rare case of occurrence of sexual reproduction in opportunistic pathogenic fungi. The discovery of the different reproduction strategies in these two closely related species is medically relevant because it is likely that they would also differ in virulence and/or drug resistance. Genetic identity of environmental and clinical isolates of T. longibrachiatum and H. orientalis suggests the danger of nosocomial infections by Hypocrea/Trichoderma and highlights the need for ecological studies of spore dispersal as source of invasive human mycoses.
常见的土壤真菌木霉属（有性型为肉座菌属，子囊菌门）作为一种机会性人类病原体，在医学上的重要性日益凸显，尤其在免疫功能低下和免疫抑制的患者中。无论疾病类型和所采用的治疗方法如何，木霉感染的预后通常都很差。长枝木霉已被确定为大多数已报道的木霉病的病原体。由于长枝木霉在世界各地的环境样本中非常常见，其临床菌株与野生菌株之间的关系仍不清楚。在此，我们对所有可用的临床分离株（15株）和36株该真菌的野生型菌株进行了多位点（ITS1和2、tef1、cal1和chit18 - 5）系统发育分析，其中包括其假定有性型东方肉座菌的几种培养物。基因谱系的一致性表明长枝木霉和东方肉座菌是不同的系统发育物种，它们在生殖上相互隔离。大多数临床菌株（12株）属于长枝木霉，但有三株分离株属于东方肉座菌，这拓宽了该属人类机会性病原体的系统发育范围。尽管它们在基因上相互隔离，但长枝木霉和东方肉座菌被证明是世界性的同域物种，对某些地理位置没有偏向性。单倍型关联分析、树形拓扑不一致性分析和分裂分解法支持了以下结论：东方肉座菌进行有性重组，而长枝木霉以严格的克隆性为主。这是机会性致病真菌中罕见的有性繁殖实例。在这两个密切相关的物种中发现不同的繁殖策略在医学上具有相关性，因为它们在毒力和/或耐药性方面可能也存在差异。长枝木霉和东方肉座菌环境分离株与临床分离株的基因一致性表明了肉座菌属/木霉属医院感染的危险性，并突出了对作为侵袭性人类真菌病来源的孢子传播进行生态学研究的必要性。
