Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Laboratório de Taxonomia, Bioquímica e Bioprospecção de Fungos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
Med Mycol. 2020 Oct 1;58(7):973-986. doi: 10.1093/mmy/myz139.
The emerging opportunistic pathogens comprising the Candida haemulonii complex (C. haemulonii [Ch], C. duobushaemulonii [Cd] and C. haemulonii var. vulnera[Chv]) are notable for their intrinsic antifungal resistance. Different clinical manifestations are associated with these fungal infections; however, little is known about their biology and potential virulence attributes. Herein, we evaluated some surface properties of 12 clinical isolates of Ch (n = 5), Cd (n = 4) and Chv (n = 3) as well as their virulence on murine macrophages and Galleria mellonella larvae. Scanning electron microscopy demonstrated the presence of homogeneous populations among the species of the C. haemulonii complex, represented by oval yeasts with surface irregularities able to form aggregates. Cell surface hydrophobicity was isolate-specific, exhibiting high (16.7%), moderate (25.0%) and low (58.3%) hydrophobicity. The isolates had negative surface charge, except for one. Mannose/glucose- and N-acetylglucosamine-containing glycoconjugates were evidenced in considerable amounts in all isolates; however, the surface expression of sialic acid was poorly detected. Cd isolates presented significantly higher amounts of chitin than Ch and Chv. Membrane sterol and lipid bodies, containing neutral lipids, were quite similar among all fungi studied. All isolates adhered to inert surfaces in the order: polystyrene > poly-L-lysine-coated glass > glass. Likewise, they interacted with murine macrophages in a quite similar way. Regarding in vivo virulence, the C. haemulonii species complex were able to kill at least 80% of the larvae after 120 hours. Our results evidenced the ability of C. haemulonii complex to produce potential surface-related virulence attributes, key components that actively participate in the infection process described in Candida spp.
新兴的机会性病原体包括半知酵母属复合种（半知酵母[Ch]、双头半知酵母[Cd]和脆弱半知酵母变种[Chv]），其特点是固有抗真菌耐药性。这些真菌感染与不同的临床表现有关，但对它们的生物学和潜在毒力特性知之甚少。在此，我们评估了 12 株 Ch（n=5）、Cd（n=4）和 Chv（n=3）的临床分离株的一些表面特性及其对鼠巨噬细胞和金龟子幼虫的毒力。扫描电子显微镜显示，半知酵母属复合种的各物种之间存在同质群体，表现为表面不规则的椭圆形酵母，能够形成聚集体。细胞表面疏水性是分离株特异性的，表现为高（16.7%）、中（25.0%）和低（58.3%）疏水性。除一个外，所有分离株均带负表面电荷。所有分离株都含有相当数量的甘露糖/葡萄糖和 N-乙酰葡萄糖胺糖蛋白，但唾液酸的表面表达检测较差。Cd 分离株的壳聚糖含量明显高于 Ch 和 Chv。所有分离株都含有相当数量的甘露糖/葡萄糖和 N-乙酰葡萄糖胺糖蛋白，但唾液酸的表面表达检测较差。所有分离株都含有相当数量的甘露糖/葡萄糖和 N-乙酰葡萄糖胺糖蛋白，但唾液酸的表面表达检测较差。Cd 分离株的壳聚糖含量明显高于 Ch 和 Chv。膜甾醇和脂质体，含有中性脂质，在所有研究真菌中非常相似。所有分离株在惰性表面上的黏附顺序为：聚苯乙烯>聚-L-赖氨酸包被玻璃>玻璃。同样，它们与鼠巨噬细胞的相互作用方式也非常相似。关于体内毒力，半知酵母属复合种在 120 小时后能够杀死至少 80%的幼虫。我们的研究结果表明，半知酵母属复合种能够产生潜在的表面相关毒力特性，这些特性是积极参与念珠菌属描述的感染过程的关键组成部分。
