The Changing Face of Epidemiology of Dermatophytoses in Chinese Mainland: A 30 years Nationwide Retrospective Study from 1991 to 2020

Rapid emergence of recalcitrant dermatophytosis caused by a cluster of multidrug-resistant Trichophyton indotineae in China

We describe 14 cases of native refractory dermatophytes caused by Trichophyton indotineae diagnosed at a hospital in China since 2021, primarily diagnosed in the past 1 year and from the same province. Trichophyton indotineae isolates were resistant to multiple antifungals and harboured Phe397Leu or Leu393Ser substitutions in the squalene epoxidase enzyme. Short-term rapid emergence of multidrug-resistant T. indotineae in China poses increasing threats to public safety and warrants continued public health surveillance.

Prior selection of itraconazole in the treatment of recalcitrant Trichophyton indotineae infection: Real-world results from retrospective analysis

BACKGROUND

The number of terbinafine-resistant Trichophyton indotineae is increasing in recent years while the treatment is still a matter to discuss.

OBJECTIVES

To explore the best therapeutic approach, we present real-world treatment of T. indotineae infection by analysing publicly available data.

METHODS

We have reviewed all published articles, mainly including case reports and case series, on the drug-resistant T. mentagrophytes complex by using the key search terms to search the databases.

RESULTS

We enrolled 25 articles from 14 countries, including 203 times of treatment information for 113 patients. The cure rate of itraconazole 200 mg per day at the fourth, eighth and the twelfth week were 27.27%, 48.48% and 54.55%, respectively, which was significantly higher than terbinafine 250 mg per day (8.77%, 24.56% and 28.07%) and even 500 mg/d terbinafine. Griseofulvin 500-1000 mg for 2-6 months may be effective while fluconazole had no record of successful treatment. Voriconazole and ravuconazole had potential therapeutic efficacy. Topical therapy alone showed limited therapeutic efficacy, but the combination with oral antifungals can be alternative.

CONCLUSION

Oral itraconazole 200 mg per day for 4-8 weeks was the most effective treatment out of these commonly used antifungal drugs, and can be prior selection.

Dermatophyte infection: from fungal pathogenicity to host immune responses

Dermatophytosis is a common superficial infection caused by dermatophytes, a group of pathogenic keratinophilic fungi. Apart from invasion against skin barrier, host immune responses to dermatophytes could also lead to pathologic inflammation and tissue damage to some extent. Therefore, it is of great help to understand the pathogenesis of dermatophytes, including fungal virulence factors and anti-pathogen immune responses. This review aims to summarize the recent advances in host-fungal interactions, focusing on the mechanisms of anti-fungal immunity and the relationship between immune deficiency and chronic dermatophytosis, in order to facilitate novel diagnostic and therapeutic approaches to improve the outcomes of these patients.

The Domestic Isolation of Terbinafine- and Itraconazole-Resistant Trichophyton indotineae in Chinese Mainland

BACKGROUND

Trichophyton indotineae, a new species of dermatophytes, has become a significant concern in treating dermatophytosis due to the high level of terbinafine resistance reported in India and even worldwide.

OBJECTIVES

This study aimed to report the terbinafine- and itraconazole-resistant T. indotineae in Chinese mainland, by identifying the phylogenetic classification of the isolate strain, and detecting the drug resistance, gene mutation and expression.

PATIENTS/METHODS

The skin scales of the patient were cultured on SDA and the isolate was authenticated by DNA sequencing and MALDI-TOF MS. Antifungal susceptibility testing was performed following the M38-A2 CLSI protocol to examine the MICs values of terbinafine, itraconazole, fluconazole, etc. The strain was screened for mutations in the squalene epoxidase (SQLE) gene by Sanger sequencing and detected the expression of CYP51A and CYP51B by qRT-PCR.

RESULTS

A multi-resistant ITS genotype VIII sibling of the T. mentagrophytes complex (T. indotineae) was isolated in Chinese mainland. The strain harbored high terbinafine MIC of > 32 μg/mL and itraconazole MIC of 1.0 μg/mL, which was identified a mutation in the squalene epoxidase gene with amino acid substitution (Phe397Leu, mutation 1191C > A). In addition, overexpression of CYP51A and CYP51B was observed. With multiple relapses, the patient finally achieved clinical cure by itraconazole pulse therapy and topical clotrimazole cream for 5 weeks.

CONCLUSIONS

The first domestic strain of terbinafine- and itraconazole-resistant T. indotineae from a patient in Chinese mainland was isolated. Itraconazole pulse therapy can be an effective method for the treatment of T. indotineae.

Tinea pedis: an updated review

Background

Tinea pedis is one of the most common superficial fungal infections of the skin, with various clinical manifestations. This review aims to familiarize physicians with the clinical features, diagnosis and management of tinea pedis.

Methods

A search was conducted in April 2023 in PubMed Clinical Queries using the key terms 'tinea pedis' OR 'athlete's foot'. The search strategy included all clinical trials, observational studies and reviews published in English within the past 10 years.

Results

Tinea pedis is most often caused by Trichophyton rubrum and Trichophyton interdigitale. It is estimated that approximately 3% of the world population have tinea pedis. The prevalence is higher in adolescents and adults than in children. The peak age incidence is between 16 and 45 years of age. Tinea pedis is more common amongst males than females. Transmission amongst family members is the most common route, and transmission can also occur through indirect contact with contaminated belongings of the affected patient. Three main clinical forms of tinea pedis are recognized: interdigital, hyperkeratotic (moccasin-type) and vesiculobullous (inflammatory). The accuracy of clinical diagnosis of tinea pedis is low. A KOH wet-mount examination of skin scrapings of the active border of the lesion is recommended as a point-of-care testing. The diagnosis can be confirmed, if necessary, by fungal culture or culture-independent molecular tools of skin scrapings. Superficial or localized tinea pedis usually responds to topical antifungal therapy. Oral antifungal therapy should be reserved for severe disease, failed topical antifungal therapy, concomitant presence of onychomycosis or in immunocompromised patients.

Conclusion

Topical antifungal therapy (once to twice daily for 1-6 weeks) is the mainstay of treatment for superficial or localized tinea pedis. Examples of topical antifungal agents include allylamines (e.g. terbinafine), azoles (e.g. ketoconazole), benzylamine, ciclopirox, tolnaftate and amorolfine. Oral antifungal agents used for the treatment of tinea pedis include terbinafine, itraconazole and fluconazole. Combined therapy with topical and oral antifungals may increase the cure rate. The prognosis is good with appropriate antifungal treatment. Untreated, the lesions may persist and progress.

Cutaneous Fungal Infections Caused by Dermatophytes and Non-Dermatophytes: An Updated Comprehensive Review of Epidemiology, Clinical Presentations, and Diagnostic Testing

Cutaneous fungal infection of the skin and nails poses a significant global public health challenge. Dermatophyte infection, mainly caused by Trichophyton spp., is the primary pathogenic agent responsible for skin, hair, and nail infections worldwide. The epidemiology of these infections varies depending on the geographic location and specific population. However, epidemiological pattern changes have occurred over the past decade. The widespread availability of antimicrobials has led to an increased risk of promoting resistant strains through inappropriate treatment. The escalating prevalence of resistant Trichophyton spp. infections in the past decade has raised serious healthcare concerns on a global scale. Non-dermatophyte infections, on the other hand, present even greater challenges in terms of treatment due to the high failure rate of antifungal therapy. These organisms primarily target the nails, feet, and hands. The diagnosis of cutaneous fungal infections relies on clinical presentation, laboratory investigations, and other ancillary tools available in an outpatient care setting. This review aims to present an updated and comprehensive analysis of the epidemiology, clinical manifestations, and diagnostic testing methods for cutaneous fungal infections caused by dermatophytes and non-dermatophytes. An accurate diagnosis is crucial for effective management and minimizing the risk of antifungal resistance.

Epidemiology of Onychomycosis in Chinese Mainland: A 30-year Retrospective Study

BACKGROUND

Onychomycosis was a common nail disease caused by dermatophytes, yeasts or molds. The prevalence of onychomycosis varied in different counties and it was necessary to understand the epidemiology in China.

OBJECTIVES

This study was conducted to investigate the epidemiology of onychomycosis in Chinese mainland in the past 30 years.

METHODS

A 30-year systemic review was carried out by searching publications investigating the prevalence of onychomycosis in Chinese mainland from 1991 to 2020.

RESULTS

A total of 90 articles involving more than 40,000 onychomycosis patients were enrolled in this study. The ratio of males to females was 1:1.32. Fingernail onychomycosis was found in 36.12% cases, toenail onychomycosis in 48.31%, and both fingernail and toenail onychomycosis in 15.57%. The most common clinical type of onychomycosis was distal lateral subungual onychomycosis (60.99%), followed by total dystrophic onychomycosis (18.91%), proximal subungual onychomycosis (10.19%) and superficial white onychomycosis (9.92%). Dermatophytes (60.59%) were the most frequently isolated pathogens, followed by yeasts (30.09%), molds (7.91%) and mixed infection (1.41%). The primary pathogens in dermatophytes, yeasts and molds were Trichophyton rubrum (49.93%), Candida albicans (10.99%) and Aspergillus (3.11%), respectively. Additionally, dermatophytes were more commonly affected males than females (63.69% vs. 51.57%), and mostly involved in toenail onychomycosis (75.63%). The infection of yeasts was higher in females than males (40.97% vs. 29.52%), often causing onychomycosis in fingernail than toenail (41.03% vs. 17.08%), and it was more common in warm and humid southern regions than northern area (34.07% vs. 24.41%).

CONCLUSION

The proportion of the causative agents changed over time, dermatophytes, especially T. rubrum had always been the predominant pathogen, followed by yeasts and molds. The distribution of fungal pathogens varied among clinical types, gender, infection sites and geography gender.

Frontier of Rural Revitalization in China: A Spatial Analysis of National Rural Tourist Towns

As the national economic situation improves, concerns about rural issues in China, a large agricultural country, are gradually increasing. Hence, rural tourism has been thrust into the limelight. This research is based on the National Rural Tourist Towns of China (NRTTC). It aims to analyze the spatial structure, influencing factors and their relevance to rural tourism development. Initially, this research examines the spatial distribution pattern in terms of kernel density. Subsequently, the imbalance index and Lorenz curve are used to distinguish the differences in spatial distribution. The Gini coefficient is used to explore the clustered regional distribution. The results indicate the following: (1) the number of NRTTC in each province is relatively even; and (2) the spatial distribution is highly uneven. The degree of aggregation is bounded by the Hu Huanyong boundary, with more in the southeast and less in the northwest. The capital circle is the core density area. Additionally, those NRTTC in the eastern and southeastern regions have a large distribution density and a more comprehensive radiation range. This study additionally analyzed the factors influencing the spatial distribution characteristics of NRTTC, and found four crucial aspects, namely, the national development strategy, the social environment, the geographical environment, and historical development. This research can provide a reference for the construction of rural tourist towns in different countries and regions.