Molecular characterization and antifungal susceptibility profile of Podospora bulbillosa keratitis: case series and review of literature

IF 2.4 4区医学 Q3 MYCOLOGY

Journal de mycologie medicale Pub Date : 2025-12-01 Epub Date: 2025-10-11 DOI:10.1016/j.mycmed.2025.101585

Sourav Das , Amrita Mohanty , Esther Sheba , Joveeta Joseph

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引用次数: 0

Abstract

Purpose

Podospora species are rarely reported as etiological agents of keratitis. This study reports a series of fungal keratitis caused by Podospora bulbillosa, detailing their clinical presentation, treatment outcomes, in vitro antifungal susceptibility and molecular characterization.

Methods

Cases of fungal keratitis caused by Podospora bulbillosa between January-March 2025, were retrospectively reviewed from the electronic medical records (EMR). Following microbiological work up, fungal identification was confirmed by large subunit 28S and internal transcribed spacer (ITS) region sequencing and molecular phylogenetic tree was constructed by Maximum Likelihood method. In vitro antifungal susceptibility testing was conducted using the Clinical & Laboratory Standards Institute (CLSI) broth microdilution method (M38-A2).

Results

Five male patients (aged 5–72 years) presented with Podospora bulbillosa keratitis, all following ocular trauma as the predisposing factor. Clinical presentation included central or paracentral pigmented plaque-like stromal infiltrates with surrounding edema and varying degrees of thinning and hypopyon in advanced cases. All patients received topical natamycin 5 % as primary therapy; while one case involved polymicrobial infection with Corynebacterium pseudodiphtheriticum. Three patients showed clinical resolution with scarring following medical management alone. All Podospora bulbillosa isolates showed low MICs (0.03–0.125 µg/mL) to natamycin, azoles, echinocandins, and amphotericin B, indicating potent in vitro activity.

Conclusion

Notably, all five P. bulbillosa isolates clustered within a single subclade, indicating close genetic relatedness. Podospora bulbillosa keratitis responds well to standard antifungal agents. Molecular tools are crucial for accurate identification of rare, non-sporulating fungal pathogens.

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球孢足孢角膜炎的分子特征和抗真菌敏感性分析：病例系列和文献综述。

目的：足孢子虫作为角膜炎的病原很少被报道。本研究报道了一系列由球泡孢子虫引起的真菌性角膜炎，详细介绍了它们的临床表现、治疗结果、体外抗真菌敏感性和分子表征。方法：回顾性分析2025年1 - 3月电子病历（EMR）中因球泡足孢子虫引起的真菌性角膜炎病例。微生物学鉴定后，采用大亚基28S和ITS区测序法对真菌进行鉴定，并采用极大似然法构建分子系统发育树。采用美国临床与实验室标准协会（CLSI）肉汤微量稀释法（M38-A2）进行体外抗真菌药敏试验。结果：5例男性患者（5 ~ 72岁）出现球囊性足孢子性角膜炎，其易感因素均为眼部外伤。临床表现为中心或中心旁色素斑块样间质浸润伴周围水肿，晚期患者不同程度的变薄和垂体功能减退。所有患者均接受5%的纳他霉素作为主要治疗；1例假性白喉棒状杆菌多微生物感染。3例患者仅在药物治疗后出现疤痕的临床消退。对纳他霉素、唑类、棘白菌素和两性霉素B的mic均较低（0.03 ~ 0.125µg/mL），表明其体外活性较强。结论：值得注意的是，所有5株球孢假单胞菌都聚集在一个亚枝内，表明遗传亲缘关系密切。球孢足孢角膜炎对标准抗真菌药物反应良好。分子工具对于准确鉴定罕见的非孢子真菌病原体至关重要。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal de mycologie medicale 医学-真菌学

CiteScore

5.10

自引率

2.80%

发文量

审稿时长

6-12 weeks

期刊介绍： The Journal de Mycologie Medicale / Journal of Medical Mycology (JMM) publishes in English works dealing with human and animal mycology. The subjects treated are focused in particular on clinical, diagnostic, epidemiological, immunological, medical, pathological, preventive or therapeutic aspects of mycoses. Also covered are basic aspects linked primarily with morphology (electronic and photonic microscopy), physiology, biochemistry, cellular and molecular biology, immunochemistry, genetics, taxonomy or phylogeny of pathogenic or opportunistic fungi and actinomycetes in humans or animals. Studies of natural products showing inhibitory activity against pathogenic fungi cannot be considered without chemical characterization and identification of the compounds responsible for the inhibitory activity. JMM publishes (guest) editorials, original articles, reviews (and minireviews), case reports, technical notes, letters to the editor and information. Only clinical cases with real originality (new species, new clinical present action, new geographical localization, etc.), and fully documented (identification methods, results, etc.), will be considered. Under no circumstances does the journal guarantee publication before the editorial board makes its final decision. The journal is indexed in the main international databases and is accessible worldwide through the ScienceDirect and ClinicalKey platforms.