Introduction: The clinical practicability of DNA microarray chip in detecting the presence of mycobacterial species/isolates directly in the skin tissues has not been evaluated, nor the efficacy of DNA microarray chip as a novel diagnostic tool for the early diagnosis of cutaneous mycobacterial infections is known.Methods: The present study analyzed the incidence of cutaneous mycobacterial infections in Shanghai and explored the efficacy of a novel DNA microarray chip assay for the clinical diagnosis of the disease from skin tissue specimens compared to traditional detection methods. A total of 60 participants fulfilling the defined diagnostic criteria and confirmed positive for cutaneous mycobacterial infections from 2019 to 2021 were enrolled in the study. Subsequent to recording the participants’ medical history and clinical characteristics, the skin tissue specimens were collected for analyses. The specimens underwent histopathological analyses, skin tissue culture, and DNA microarray chip assay.Results: Increased incidence of cutaneous mycobacterial infection was detected from 2019 to 2021. The most common infecting pathogen was M. marinum followed by M. abscessus. The sensitivity, specificity and accuracy of the skin tissue culture method were 70%, 100% and 76.62%, respectively, while that of the DNA microarray chip assay were 91.67%, 100% and 93.51%, respectively. The sensitivity and accuracy of the DNA microarray chip assay were significantly higher than those of the skin tissue culture method. The positive likelihood and diagnostic odds ratio were >10 and >1, respectively for both the methods. The negative likelihood ratio was significantly higher (30% vs 8.33%) and the Youden’s index was significantly lower (70.00% vs 91.67%) in the skin culture method compared to that of the DNA microarray chip assay. There was a significant association of false negative results with a history of antibiotic use in the skin tissue culture method.Discussion: Given the increasing incidence of cutaneous mycobacterial infections, early diagnosis remains a prime clinical focus. The DNA microarray chip assay provides a simple, rapid, high-throughput, and reliable method for the diagnosis of cutaneous mycobacterial infections with potential for clinical application.

Background: Trichophyton benhamiae is a zoophilic dermatophyte that can cause tinea in humans and animals. Lesions caused by T. benhamiae tend to be highly inflammatory, and patients are often infected by animals or other patients infected with T. benhamiae. In this paper, we report the first case of tinea faciei caused by T. benhamiae in a Chinese girl who might be transmitted from a fox. Case presentation: A 4-year-old girl from HaiNing city developed an itchy, erythematous, and annular plaque on her right face for the past 2 months. Before the lesion appeared, she was in close contact with the fur of a fox for almost 1 week. Septate hyaline hyphae were detected by direct mycological examination of the scales. Cultures grew on Sabouraud’s dextrose agar (SDA) at 26 °C for 2 weeks revealed the presence of T. mentagrophytes. A molecular sequencing test confirmed that the isolate was consistent with reference strains to T. benhamiae. Then, the diagnosis of tinea faciei due to T. benhamiae was made. Treatment with terbinafine (oral 125 mg/d) and sertaconazole nitrate cream (topical, twice daily) for 4 weeks was initiated and achieved significant improvement of the skin lesions. Conclusions: This rare dermatophytosis case highlights the importance of ITS sequencing in helping to recognize rare pathogenic fungi that can be easily misdiagnosed with a conventional morphological diagnosis.

Atopic dermatitis (AD) is a common chronic relapsing inflammatory disease. There is substantial evidence suggesting that noncoding RNAs have indispensable roles in the pathogenesis of AD. Exosomal transfer RNA‑derived fragments (tRFs) have been identified as potential biomarkers for various disorders. However, the role of tRFs in AD has remained to be elucidated, which was thus the aim of the present study. Plasma samples from 23 pediatric patients with AD and 23 healthy controls were collected. Exosomes were successfully isolated from plasma according to the manufacturer's protocol. Small RNA sequencing was performed in 3 patients with AD and 3 controls, and 135 significantly differentially expressed plasma exosomal tRFs were identified, including 36 upregulated and 99 downregulated tRFs. Using the miRanda and RNAhybrid databases, 58,227 target genes of these 135 differentially expressed tRFs were predicted. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that these target genes of tRFs are involved in multiple functions and pathways associated with AD. Downregulation of tRF‑28‑QSZ34KRQ590K and tRF‑33‑Q99P9P9NH57SD3 were validated in 20 patients with AD and 20 controls by reverse transcription‑quantitative PCR and tRF‑28‑QSZ34KRQ590K exhibited significance in the receiver operating characteristic curve analysis. The present study was the first to provide a tRF profile in AD and implied that plasma exosomal tRF‑28‑QSZ34KRQ590K may be a potential biomarker for pediatric patients with AD. The present study enhanced the understanding of the pathogenesis of AD and provided a novel marker for the diagnosis and targeted treatment of AD.