Deep Cutaneous Neoscytalidium dimidiatum Infection: Successful Outcome with Amphotericin B Therapy

Pest categorisation of Neoscytalidium dimidiatum

The EFSA Plant Health Panel performed a pest categorisation of Neoscytalidium dimidiatum, a clearly defined plant pathogenic fungus of the family Botryosphaeriaceae. The pathogen affects a wide range of woody perennial crops and ornamental plants causing symptoms such as leaf spot, shoot blight, branch dieback, canker, pre- and post-harvest fruit rot, gummosis and root rot. The pathogen is present in Africa, Asia, North and South America, and Oceania. It has also been reported from Greece, Cyprus and Italy, with a restricted distribution. Nevertheless, there is a key uncertainty on the geographical distribution of N. dimidiatum worldwide and in the EU, because in the past, when molecular tools were not available, the two synanamorphs of the pathogen (Fusicoccum-like and Scytalidium-like) might have been misidentified based only on morphology and pathogenicity tests. N. dimidiatum is not included in Commission Implementing Regulation (EU) 2019/2072. Because of the wide host range of the pathogen, this pest categorisation focuses on those hosts for which there is robust evidence that the pathogen was formally identified by a combination of morphology, pathogenicity and multilocus sequence analysis. Plants for planting, fresh fruits and bark and wood of host plants as well as soil and other plant growing media are the main pathways for the further entry of the pathogen into the EU. Host availability and climate suitability factors occurring in parts of the EU are favourable for the further establishment of the pathogen. In the areas of its present distribution, including Italy, the pathogen has a direct impact on cultivated hosts. Phytosanitary measures are available to prevent the further introduction and spread of the pathogen into the EU. N. dimidiatum satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as potential Union quarantine pest.

First Isolation of Neoscytalidium dimidiatum from Human Dermatomycosis in Japan

Neoscytalidium dimidiatum is a common fungus that causes non-dermatophyte dermatomycosis in tropical regions, but there have been no reports of infection with N. dimidiatum in Japan. Here, we report the first isolation of N. dimidiatum from human dermatomycosis in Japan. A 62-year-old healthy Japanese male had been treated with oral terbinafine for tinea pedis diagnosed from a microscopic examination in 2003 with a lesion that was intractable. In 2020, re-identification by sequencing the internal transcribed spacer regions and the D1/D2 domain of the large-subunit (LSU) ribosomal RNA gene revealed that the pathogen was N. dimidiatum. Antifungal susceptibility tests showed that the minimum inhibitory concentration of the drug luliconazole (LLCZ) against the pathogen was 0.00049 µg/mL. The patient's lesions were cured by topical LLCZ. The clinical course and drug susceptibility suggest that LLCZ is a suitable first-line drug for treatment.

Phaeohyphomycosis in China

Background

Due to more attentions paid to melanized fungi over the past few decades and under the background of the global coronavirus disease 2019 pandemic (COVID-19) the fact that the virus itself and the immunosuppressive agents such as glucocorticoids can further increase the risk of infections of deep mycoses, the number of patients with phaeohyphomycosis (PHM) has a substantial increase. Their spectrum is broad and the early diagnosis and treatments are extremely sticky. This study aims to more comprehensively understand the clinical features of phaeohyphomycosis in China over 35 years and to establish a more applicable systematical classification and severity grades of lesions to guide treatments and prognosis.

Methods

We reviewed 174 cases of proven phaeohyphomycosis reported in Chinese and English language literature from 1987 to 2021 and we also made the accurate classification definitions and detailed information about the epidemiology, species of clinical dematiaceous fungi, minimum inhibitory concentration values, clinical features, treatments, and prognosis.

Results

The mortality of cerebral, disseminated and pulmonary phaeohyphomycosis are 55%, 36%, and 25%. Nearly 19% of patients had poor quality of life caused by the complications such as disability, disfigurements, and blindness. The overall misdiagnosis rate of phaeohyphomycosis was 74%. Moderate to severe rashes are accounting for 82% of subcutaneous phaeohyphomycosis. The areas of the head and face are mostly affected accounting for 16% of severe rashes. Nearly 30% of invasive infections of phaeohyphomycosis are triggered by recurrent lesions. Voriconazole, itraconazole, amphotericin B deoxycholate (AmB-DOC), and terbinafine were most commonly used but diagnosis and treatments of phaeohyphomycosis remain challenging in reality.

Conclusions

Our classifications are likely to be more practical and easier to popularize, and there are still also plenty of characteristics in these non-specific lesions. There’re no significant variations in cure rates, or death rates between three grades of lesions. But patients with severe rashes have longer courses and lower effective rates.

Invasive fungal infection of the brain caused by Neoscytalidium dimidiatum in a post-renal transplant patient: A case report

Neoscytalidium is a phytopathogen that is often found in plants and soil. It mostly leads to skin and nail infections, and invasive diseases of the sinuses, lung, and brain have been described mostly in immunocompromised patients. We report a case of a post-renal transplant patient who received anti-thymocyte globulin for induction immunosuppression. A month after her transplant, she presented with fever and new-onset seizures, and computed tomography revealed a brain abscess with mass effects and herniation. The patient underwent abscess drainage and craniectomy. The pathological findings showed filamentous septate hyphae. The surgical culture rapidly grew wool-like colonies with a black reverse on Sabouraud agar. Lactophenol cotton blue staining showing septate branched hyphae with one to two arthroconidia cells with flattened ends. The patient was given a combination of amphotericin B and voriconazole but unfortunately died ten days after the diagnosis. This case highlights Neoscytalidium as a cause of invasive fungal disease in immunocompromised patients that is difficult to treat and is often fatal, even when combined surgical and medical therapies are used as treatment modalities.

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Neoscytalidium spp. is a rare human pathogenic fungal disease that most likely leads to superficial infection.

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Immunocompromised host is at particularly higher risk of invasive disease.

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This is the fifth case in the literature describing cerebral invasive disease caused by Neoscytalidium spp.

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The present case further confirms the aggressiveness of the disease and refractoriness to antifungal therapy.

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The diagnoses need to be entertained, especially in an immunocompromised patient and who have history of exposure to agricultural areas.

Genotyping and In Vitro Antifungal Susceptibility Profile of Neoscytalidium Species Isolates from Respiratory Tract

The fungus genus Neoscytalidium is mainly distributed in (sub) tropical regions of the world and has been essentially considered as a phytopathogen. There are however several reports of human infection caused by Neoscytalidium spp. through direct or indirect contact with contaminated plants or soil. Reliable and accurate identification to species level is critical for implementing proper therapeutic strategies. In the present study we investigated the genotypes and in vitro antifungal susceptibility patterns of Neoscytalidium species identified from respiratory tracts of patients with various underlying diseases. The identity and diversity of the isolates were done using PCR and sequencing of five different loci (the ITS region, D1/D2 domains of 28S rRNA gene, and part of the beta tubulin, elongation factor 1α and chitin synthase genes). The in-vitro antifungal susceptibility was also performed using the Clinical and Laboratory Standards Institute (CLSI) M38-Ed3-2017 guidelines. Overall, 13 isolates were identified as Neoscytalidium species (eight N. dimidiatum and five N. novaehollandiae). Two sequence types (STs) were identified by the alignment of 1846 combined base pairs among 13 clinical isolates. All isolates classified as N. dimidiatum were clustered in ST6 (61.5%) and those of N. novaehollandiae were in ST7 (38.5%). Luliconazole was the most active antifungal in vitro against species. This is the first report of N. novaehollandiae isolation from respiratory tracts samples. Further study from other regions of the world with a larger set of clinical specimens is required to provide additional insight into diversity of Neoscytalidium species.

ITS rDNA Gene Analysis Versus MALDI-TOF MS For Identification of Neoscytalidium dimidiatum Isolated from Onychomycosis and Dermatomycosis Cases in Medellin (Colombia)

Within the Neoscytalidium genus, N. dimidiatum, N. oculus, N. orchidacearum, and N. novaehollandiae have been recognized. Although these species are frequently found in soil, N. dimidiatum has been identified as an etiologic agent of onychomycosis or dermatomycosis, and N. oculus has been identified as an etiologic agent of an ocular lesion. All these species can be cultured in vitro, but their morphological identification by macroscopic and microscopic traits is difficult and imprecise due to their similarity. In this study, 34 isolates of Neoscytalidium spp. from 32 onychomycosis and two dermatomycosis cases in Medellin (Colombia) were identified at the species level using sequencing of the ITS1+5.8S+ITS2 nuclear rDNA region and MALDI-TOF mass spectrometry (MS). Neoscytalidium dimidiatum strain MUM 17.21 was used to construct the reference spectrum in the in-house library to identify the clinical isolates by MALDI-TOF MS. Additionally, N. dimidiatum PPC-216 and PLAB-055 strains were used to validate the in-house constructed reference spectra. Although four groups were observed in the dendrogram obtained from the proteins of each isolate profile, MALDI-TOF MS and sequencing results are in accordance, since all isolates were identified as N. dimidiatum.