a Departamento de Microbiología , Facultad de Medicina, Universidad Autónoma de Nuevo León , Monterrey , México.
b Departamento de Ciencias Básicas , Vicerrectoría de Ciencias de la Salud, Universidad de Monterrey , San Pedro Garza García , México.
Mycologia. 2019 May-Jun;111(3):395-407. doi: 10.1080/00275514.2019.1585161. Epub 2019 Apr 15.
Opportunistic mycoses by yeasts have increased considerably in the last three decades. Although is considered one of the most important causes of nosocomial infections, there is a recent shift to non- species as the most frequently isolated yeasts in particular risk groups. (formerly ) is a complex that includes four species: sensu stricto, , and , and they are estimated to represent 0.2% of all clinical isolates. In this study, we analyze nine clinical isolates of with focus on the virulence determinants and pathogenicity of the species by means of a survival model. Overall, we detected very strong aspartyl-protease and esterase activities. In contrast, both DNase and hemolysin activities were evident in only two of the isolates. None of the isolates was positive for phospholipase activity. All isolates studied were able to form biofilm after 72 h of incubation in a robust manner when compared with the strain used as control. Susceptibility testing showed minimum inhibitory concentrations (MICs) ≤1 µg/mL for amphotericin B in all isolates tested. Eight out of nine of the isolates had MICs ≤2 µg/mL for fluconazole. All isolates were resistant to both anidulafungin and caspofungin (MICs ≥1 µg/mL). We found a significant difference ( < 0.0001) amongst the survival curves for the different isolates in the survival model. Strains HPM309 and H259 produced an acute infection and exhibited the highest virulence, whereas the isolates 99-480 and DM17 proved to be the less virulent strains.
机会性真菌感染在过去三十年中显著增加。尽管 被认为是医院感染的最重要原因之一，但最近出现了一种趋势，即在特定高危人群中，非- 种酵母已成为最常分离的酵母。 （以前称为 ）是一个包含四个种的复合体： sensu stricto、、和 ，据估计，它们代表所有临床分离株的 0.2%。在这项研究中，我们分析了 9 株临床分离的 ，重点研究了该物种的毒力决定因素和致病性，方法是通过生存模型进行分析。总体而言，我们检测到非常强的天冬氨酸蛋白酶和酯酶活性。相比之下，只有 2 株分离株中检测到了 DNase 和溶血素活性。没有分离株显示出磷脂酶活性。与用作对照的 菌株相比，所有研究的分离株在 72 小时孵育后都能够以强大的方式形成生物膜。药敏试验显示，所有分离株的最低抑菌浓度（MIC）均≤1 µg/mL，对两性霉素 B 敏感。9 株分离株中有 8 株对氟康唑的 MIC≤2 µg/mL。所有分离株对安曲南和卡泊芬净均有耐药性（MIC≥1 µg/mL）。我们在生存模型中发现了不同 分离株之间生存曲线的显著差异（ < 0.0001）。菌株 HPM309 和 H259 产生急性感染，表现出最高的毒力，而 分离株 99-480 和 DM17 则被证明是毒力较弱的菌株。
