Ramos Lívia S, Parra-Giraldo Claudia M, Branquinha Marta H, Santos André L S
Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes (LEAMER), Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-902, Brazil.
Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá 110231, Colombia.
Trop Med Infect Dis. 2023 Jul 27;8(8):382. doi: 10.3390/tropicalmed8080382.
The opportunistic fungal pathogens belonging to the complex and the phylogenetically related species are well-known for causing infections that are difficult to treat due to their multidrug-resistance profiles. is even more worrisome due to its ability to cause outbreaks in healthcare settings. These emerging yeasts produce a wide range of virulence factors that facilitate the development of the infectious process. In recent years, the aggregative phenotype has been receiving attention, as it is mainly associated with defects in cellular division and its possible involvement in helping the fungus to escape from the host immune responses. In the present study, we initially investigated the aggregation ability of 18 clinical isolates belonging to the species complex (, , and var. ) and . Subsequently, we evaluated the effects of physicochemical factors on fungal aggregation competence. The results demonstrated that cell-to-cell aggregation was a typically time-dependent event, in which almost all studied fungal isolates of both the species complex and exhibited high aggregation after 2 h of incubation at 37 °C. Interestingly, the fungal cells forming the aggregates remained viable. The aggregation of all isolates was not impacted by pH, temperature, β-mercaptoethanol (a protein-denaturing agent), or EDTA (a chelator agent). Conversely, proteinase K, trypsin, and sodium dodecyl sulfate (SDS) significantly diminished the fungal aggregation. Collectively, our results demonstrated that the aggregation ability of these opportunistic yeast pathogens is time-dependent, and surface proteins and hydrophobic interactions seem to mediate cell aggregation since the presence of proteases and anionic detergents affected the aggregation capability. However, further studies are necessary to better elucidate the molecular aspects of this intriguing phenomenon.
属于该复合体以及系统发育相关物种的机会性真菌病原体，因其多重耐药性而导致难以治疗的感染而闻名。由于其在医疗机构中引发暴发的能力，情况甚至更令人担忧。这些新兴酵母产生多种毒力因子，促进感染过程的发展。近年来，聚集表型受到关注，因为它主要与细胞分裂缺陷有关，并且可能参与帮助真菌逃避宿主免疫反应。在本研究中，我们首先调查了属于该物种复合体（、和变种）以及的18株临床分离株的聚集能力。随后，我们评估了物理化学因素对真菌聚集能力的影响。结果表明，细胞间聚集是一个典型的时间依赖性事件，其中在37℃孵育2小时后，几乎所有研究的该物种复合体和的真菌分离株都表现出高聚集性。有趣的是，形成聚集体的真菌细胞仍然存活。所有分离株的聚集不受pH、温度、β-巯基乙醇（一种蛋白质变性剂）或EDTA（一种螯合剂）的影响。相反，蛋白酶K、胰蛋白酶和十二烷基硫酸钠（SDS）显著降低了真菌聚集。总体而言，我们的结果表明，这些机会性酵母病原体的聚集能力是时间依赖性的，表面蛋白和疏水相互作用似乎介导细胞聚集，因为蛋白酶和阴离子洗涤剂的存在影响聚集能力。然而，需要进一步研究以更好地阐明这一有趣现象的分子方面。
