Clinico-mycological study of onychomycosis and in vitro antifungal susceptibility of Trichophyton rubrum.

Onychomycosis, a fungal nail infection, is primarily caused by dermatophytes, yeasts, and non-dermatophyte moulds (NDMs). The incidence of this disease and the predominance of specific pathogens vary across different regions and evolve. This study aimed to elucidate the epidemiology of onychomycosis and the pattern of causative pathogens in Beijing, and to ascertain the in vitro antifungal susceptibility profiles of Trichophyton rubrum against itraconazole (ITR), terbinafine (TER), and fluconazole (FLU). Involving 245 patients of onychomycosis with positive fungal culture results, the study implemented internal transcribed spacer (ITS) sequencing of ribosomal DNA (rDNA) on all collected samples. The mean age of the participants was 37.93 ± 13.73 years, with a male-to-female ratio of 1.53:1. The prevalence of toenail infections was significantly higher than that of fingernails. Distal and lateral subungual onychomycosis (DLSO) were the most frequent clinical classifications. PCR results indicated that dermatophytes were the most prevalent pathogens, followed by yeasts and NDMs, among which T. rubrum was the most dominant dermatophyte. TER demonstrated high sensitivity to T. rubrum. However, in clinical settings, some patients with onychomycosis exhibit a poor response to TER treatment. The relationship between in vitro antifungal sensitivity and clinical effectiveness is complex, and understanding the link between in vitro MIC values and clinical efficacy requires further investigation.

Simplicillium sinense sp. nov., a novel potential pathogen of tinea faciei.

Simplicillium species are widely distributed with a broad spectrum of hosts and substrates. Generally, these species are entomopathogenic or mycoparasitic. Notably, some isolates of Simplicillium lanosoniveum and Simplicillium obclavatum were obtained from human tissues. In this study, two fungi were isolated from the annular itchy patch of infected skin of a 46-year-old man with diabetes mellitus. Based on a combination of morphological characteristics and phylogenetic analysis, a novel species, Simplicillium sinense, was introduced herein. It morphologically differs from the remaining Simplicillium in the size of phialides and conidia. Additionally, it grows slowly on YPD at 37°C. Antimicrobial susceptibility testing presented that this fungus is resistant to most azole antifungals. Therefore, the diagnosis of tinea faciei was made, and after 2 weeks of being treated with oral terbinafine (250 mg, once a day) and topical terbinafine cream for 1 month, the rash was mainly resolved and no recurrence happened after 6 months of follow-up. Herein, Simplicillium sinense was introduced as a new fungal taxon. Meanwhile, a case of superficial infection caused by S. sinense was reported. So far, it is the third Simplicillium species obtained from human tissue. Meanwhile, terbinafine is recommended as the first-line antifungal treatment against Simplicillium infection.

The first suspected disseminated Hormographiella aspergillata infection in China, diagnosed using metagenomic next-generation sequencing: a case report and literature review.

Hormographiella aspergillata is a rare and emerging cause of invasive mould infections in patients with haematological malignancies, with a mortality rate of approximately 70%. Here, we present the first reported case of suspected disseminated H. aspergillata infection in China. The patient experienced a second relapse of acute myeloid leukaemia and developed neutropenia, fever, discrepant blood pressure between limbs, and cutaneous lesions limited to the left upper extremity. Since lung tissue biopsy was not feasible, metagenomic next-generation sequencing (mNGS) and panfungal polymerase chain reaction (PCR) analysis of bronchoalveolar lavage fluid and blood samples were performed, which indicated probable H. aspergillata pulmonary infection. Histopathology of cutaneous lesions revealed numerous fungal hyphae within dermal blood vessels. mNGS of a skin biopsy sample identified H. aspergillata sequences, and the fungi was subsequently recovered from fungal culture, proving cutaneous H. aspergillata infection. Despite combined antifungal therapy, the patient died owing to disease progression. Additionally, 22 previously reported cases of invasive H. aspergillata infection were reviewed in patients with haematological malignancies. Thus, mNGS is a powerful diagnostic tool for the early and effective detection of invasive H. aspergillata infections, with the advantage of sequencing all potential pathogens, and providing results within 24 h.