The prevalence of dermatophyte infection in patients infected with human immunodeficiency virus

Global Insights and Trends in Research on Dermatophytes and Dermatophytosis: A Bibliometric Analysis

BACKGROUND

Dermatophytosis, caused by dermatophytes, affects up to 25% of people globally, with higher rates observed in Africa and Asia. While these infections are usually superficial, they can become severe in immunocompromised individuals. Despite their high prevalence, scientific research on dermatophytes is limited and the epidemiological data available are insufficient. In addition, diagnostic methods are not standardised and there are challenges with resistance to antifungals.

OBJECTIVES

This study aimed to conduct a bibliometric analysis of scientific publications related to dermatophytes and dermatophytosis to assess research output and trends.

METHODS

A bibliometric analysis of publications from 2000 to 2023 in Web of Science and Scopus examined trends, citation counts, publication types, key journals, top authors and institutions and funding sources.

RESULTS

The analysis revealed a significant increase in dermatophyte-related publications, with 15,868 articles retrieved from the Web of Science and 23,189 from Scopus. Research articles dominated the output, constituting 76.2% in Web of Science and 80% in Scopus. Peak publication years were 2019, 2021 and 2022 in Web of Science, and 2020, 2021 and 2023 in Scopus, with lower output between 2000 and 2002. The United States and India were the leading contributors, followed by Brazil and China, though citation metrics varied. Although there has been a rise in the number of publications, the amount of research conducted on dermatophytes is still very limited in comparison with other types of fungal diseases.

CONCLUSIONS

Dermatophyte-related research has increased over the past 2 decades. However, research gaps remain, particularly compared with other fungal diseases. Advances in diagnostics, antifungal testing and taxonomic classification are urgently needed. The study underscores the need for continued research and global collaboration to address these issues.

The StuA Transcription Factor and Alternative Splicing Mechanisms Drive the Levels of MAPK Hog1 Transcripts in the Dermatophyte Trichophyton rubrum

Trichophyton rubrum is a human fungal pathogen that causes dermatophytosis, an infection that affects keratinized tissues. Integrated molecular signals coordinate mechanisms that control pathogenicity. Transcriptional regulation is a core regulation of relevant fungal processes. Previous RNA sequencing data revealed that the absence of the transcription factor StuA resulted in the differential expression of the MAPK-related high glycerol osmolarity gene (hog1) in T. rubrum. Here we validated the role of StuA in regulating the transcript levels of hog1. We showed through RT-qPCR that transcriptional regulation controls hog1 levels in response to glucose, keratin, and co-culture with human keratinocytes. In addition, we also detected hog1 pre-mRNA transcripts that underwent alternative splicing, presenting intron retention in a StuA-dependent mechanism. Our findings suggest that StuA and alternative splicing simultaneously, but not dependently, coordinate hog1 transcript levels in T. rubrum. As a means of preventing and treating dermatophytosis, our results contribute to the search for new potential drug therapies based on the molecular aspects of signaling pathways in T. rubrum.

Genome-wide identification and functional analysis of circRNAs in Trichophyton rubrum conidial and mycelial stages

Background

Circular RNAs (circRNAs) are a group of noncoding RNAs that participate in gene expression regulation in various pathways. The essential roles of circRNAs have been revealed in many species. However, knowledge of circRNAs in fungi is still not comprehensive.

Results

Trichophyton rubrum (T. rubrum) is considered a model organism of human pathogenic filamentous fungi and dermatophytes. In this study, we performed a genome-wide investigation of circRNAs in T. rubrum based on high-throughput sequencing and ultimately identified 4254 circRNAs. Most of these circRNAs were specific to the conidial or mycelial stage, revealing a developmental stage-specific expression pattern. In addition, 940 circRNAs were significantly differentially expressed between the conidial and mycelial stages. PCR experiments conducted on seven randomly selected differentially expressed (DE-) circRNAs confirmed the circularized structures and relative expression levels of these circRNAs. Based on their genome locations, most circRNAs originated from intergenic regions, unlike those in plants and animals. Furthermore, we constructed circRNA-miRNA-mRNA regulatory networks that included 661 DE-circRNAs targeting 140 miRNAs and further regulating 2753 mRNAs. The relative expression levels of two randomly selected circRNA-miRNA-mRNA axes were investigated by qRT-PCR, and the competing endogenous RNA (ceRNA) network theory was validated. Functional enrichment analysis of the target genes suggested that they were significantly involved in posttranscriptional processes and protein synthesis as well as some small-molecule metabolism processes. CircRNAs are relatively more conserved in closely related dermatophytes but rarely conserved in distantly related species. Tru_circ07138_001 is a highly conserved circRNA that was conserved in all ten dermatophytes analyzed in our study and three distantly related species. Its host gene TERG_07138 was also highly conserved in two of these distantly related species Gallus gallus and Caenorhabditis elegans. The specific role of this circRNA deserves further exploration.

Conclusions

Our study is the first to provide a global profile of circRNAs in T. rubrum as well as dermatophytes. These results could serve as valuable resources for research on circRNA regulatory mechanisms in fungi and reveal new insights for further investigation of the physical characteristics of these significant human fungal pathogens.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08184-y.

Alternative Splicing in Heat Shock Protein Transcripts as a Mechanism of Cell Adaptation in Trichophyton rubrum

Heat shock proteins (HSPs) are involved in critical processes like host tissue invasion, resistance, and pathogenicity in dermatophytes. RNA-Seq analysis of Trichophyton rubrum exposed to undecanoic acid (UDA) revealed intron retention events in HSP transcripts. Because HSPs are modulated in response to various stimuli and as alternative splicing (AS) can result in a broad diversity in the proteome of eukaryotic cells, our objective was to confirm the aforementioned retention events, investigating their consequences and extent. Furthermore, we aimed to determine: (1) the expression profile of HSP genes in an infection-like scenario and (2) the importance of Hsp90 for the keratinolytic potential of T. rubrum. RT and qPCR analyses comparing the exposure to UDA and terbinafine (TRB) confirmed the presence of two mRNA isoforms of the hsp7-like gene, with distinct expression patterns in response to UDA and TRB. The HSP expression profile revealed two upregulated, three downregulated, and four unmodulated transcripts; Hsp90 inhibition by 17-AAG resulted in a significant decrease in keratinolytic potential at 37 °C. Altogether, these results broaden the current knowledge on the importance of HSP-mediated pathways for cell adaptation and other aspects of dermatophyte biology, indicating that HSP network proteins can be potential targets for antifungal therapy.

Subclinical Onychomycosis: Not Present in HIV-Positive Population?

Background

Onychomycosis is one of the most common nail diseases and constitutes up to 50% of all nail conditions. It is a chronic fungal nail infection common in the HIV-infected population. Few studies have found fungal organisms in the nail without clinical evidence, and thus, termed subclinical onychomycosis.

Objectives

We analyzed the nails of the HIV population in our hospital, searching for subclinical onychomycosis.

Method

A distal nail clipping was stained with PAS and observed by a trained dermatopathologist.

Results

All of our samples (n = 48) turned out to be negative for fungal structures.

Conclusions

The epidemiology of onychomycosis is changing, treatment options are much better now, and diagnosis and infection detection are being done earlier. Therefore, we will continue to further study this disease in other patient populations so that we can compare our results and see whether the incidence of onychomycosis in the HIV population is now similar to that in those without HIV infection of the same age.

Dual RNA-Seq Analysis of Trichophyton rubrum and HaCat Keratinocyte Co-Culture Highlights Important Genes for Fungal-Host Interaction

The dermatophyte Trichophyton rubrum is the major fungal pathogen of skin, hair, and nails that uses keratinized substrates as the primary nutrients during infection. Few strategies are available that permit a better understanding of the molecular mechanisms involved in the interaction of T. rubrum with the host because of the limitations of models mimicking this interaction. Dual RNA-seq is a powerful tool to unravel this complex interaction since it enables simultaneous evaluation of the transcriptome of two organisms. Using this technology in an in vitro model of co-culture, this study evaluated the transcriptional profile of genes involved in fungus-host interactions in 24 h. Our data demonstrated the induction of glyoxylate cycle genes, ERG6 and TERG_00916, which encodes a carboxylic acid transporter that may improve the assimilation of nutrients and fungal survival in the host. Furthermore, genes encoding keratinolytic proteases were also induced. In human keratinocytes (HaCat) cells, the SLC11A1, RNASE7, and CSF2 genes were induced and the products of these genes are known to have antimicrobial activity. In addition, the FLG and KRT1 genes involved in the epithelial barrier integrity were inhibited. This analysis showed the modulation of important genes involved in T. rubrum–host interaction, which could represent potential antifungal targets for the treatment of dermatophytoses.

Dermatophytes and dermatophytosis in the eastern and southern parts of Africa

Dermatophytosis is currently a disease of global importance and a public health burden. It is caused by dermatophytes, which attack and grow on dead animal keratin. Dermatophytes belong to three genera, namely, Epidermophyton, Microsporum, and Trichophyton. The predominant clinical forms and causative agents vary from one region of the world to another. Poor socioeconomic status, high population densities, and poor sanitary conditions are some of the factors responsible for the high prevalence of dermatophytosis in many developing countries, which include countries in southern and eastern Africa, the focus of this review. To the best of our knowledge, there is currently no review article on published findings on dermatophytosis in the eastern and southern parts of Africa. This information will be of interest to the medical and research community since the world has become a global village. This review covers published research findings in eastern and southern regions of Africa until this date. The countries covered in the current review include Kenya, Ethiopia, Tanzania, South Africa, Mozambique, Madagascar, Malawi, Rwanda, Burundi, Uganda, Zambia, Zimbabwe, and Botswana. T. violaceum is the most common human etiological agent in all the countries under review with prevalence ranging from 56.7% to 95%, except for Madagascar (M. langeronii, reclassified as M. audouinii), Uganda (M. gypseum) and Malawi (M. audouinii). Tinea capitis was the most clinical type, followed by tinea corporis. Etiological agents of animal dermatophytoses were variable in the countries where they were reported. Major risk factors for dermatophytoses are age, climatic, and socioeconomic factors.

Majocchi's granuloma: current perspectives

Majocchi’s granuloma (MG) is a rare fungal infection of the dermis that is mainly caused by dermatophytes (in ≥95% of cases); the most frequently identified cause is anthropophilic Trichophyton rubrum. In the rest of the cases, the causes are non-dermatophytic fungi such as Aspergillus species. This review aimed to provide information about the current perspectives on MG regarding its clinical characteristics, predisposing factors, laboratory diagnosis, and treatment strategies. Although the lower extremities were reported to be the most common site of infection, facial involvement has been predominant in the past 5 years. Our literature research showed that the most common predisposing factor (55%) is the use of topical steroid creams without potassium hydroxide examination during treatment of erythematous squamous dermatoses. A reliable diagnosis of MG is based on histopathological examination, including fungal culture and molecular analyses. MG should be treated not only with topical agents but also with systemic antifungal agents that are continued until the lesions are completely resolved. In systemic treatment, the most preferred drug is terbinafine, because of its efficacy, side effects, and safety.

Study of prevalence of dermatophytes among human immunodeficiency virus/AIDS patients in Shadan Institute of Medical Sciences and Teaching Hospital and Research Centre, Hyderabad, Telangana, India

Introduction:

The objective of the study was to evaluate the prevalence of dermatophytoses in human immunodeficiency virus (HIV) patients as well as to analyze the influence of CD4+ T-cell level in the Dermatology and STD Outpatient Department of Shadan Institute of Medical Sciences Teaching Hospital and Research Centre, Himayat sagar road, Hyderabad (Telangana state). The patients were tested for dermatophytic infections, as well as for the CD4+ T-cell counts. A total of 120 HIV-seropositive patients were included in this study, among which 38 were diagnosed of dermatophytosis. A majority of patients were in the 21–30 years’ age group. Tinea cruris was seen in majority of the cases, with Trichophyton rubrum being the most common culprit.

Background:

Cutaneous fungal infections have been reported worldwide as being one of the most common human infectious diseases in clinical practice. Dermatophytoses in individuals with HIV infection seem to manifest with atypical, multiple, or extensive lesions more frequently.

Aims:

The aim of this study was to determine the prevalence of dermatophytic infections among HIV-seropositive patients and their relation with CD4 count.

Materials and Methods:

This single-center prospective study was conducted in all HIV-seropositive patients (by double ELISA methods) who attended the Dermatology and STD Outpatient Department of Shadan Institute of Medical Sciences Teaching Hospital and Research Centre, Himayat sagar road, Hyderabad (Telangana state), from March 2015 to September 2016. They were screened for cutaneous fungal infections and those who tested positive were recruited for this study.

Results:

A total of 120 HIV-seropositive patients were included in this study, among which 38 were diagnosed of dermatophytosis. Most patients were in the 21–30 years’ age group. Tinea cruris was the most common variant, and T. rubrum was the most common offending pathogen. It was also found that the CD4+ T-cell count does not influence the occurrence of dermatophytoses.

Conclusion:

Superficial fungal infections are a common yet significant problem in HIV infection. They are characterized by the diversity of clinical aspects; the lesions are mostly caused by T. rubrum. It is essential that optimum treatment should be administered.

Immune reconstitution inflammatory syndrome associated with dermatophytoses in two HIV-1 positive patients in rural Tanzania: a case report

Background

Immune reconstitution inflammatory syndrome associated with dermatophytoses (tinea-IRIS) may cause considerable morbidity. Yet, it has been scarcely reported and is rarely considered in the differential diagnosis of HIV associated cutaneous lesions in Africa. If identified, it responds well to antifungals combined with steroids. We present two cases of suspected tinea-immune reconstitution inflammatory syndrome from a large HIV clinic in rural Tanzania.

Cases presentation

A first case was a 33 years-old female newly diagnosed HIV patient with CD4 count of 4 cells/μL (0 %), normal complete blood count, liver and renal function tests was started on co-formulated tenofovir/emtricitabine/efavirenz and prophylactic cotrimoxazole. Two weeks later she presented with exaggerated inflammatory hyperpigmented skin plaques with central desquamation, active borders and scratch lesions on the face, trunk and lower limbs. Tinea-IRIS was suspected and fluconazole (150 mg daily) and prednisolone (1 mg/Kg/day tapered down after 1 week) were given. Her symptoms subsided completely after 8 weeks of treatment, and her next CD4 counts had increased to 134 cells/μL (11 %). The second case was a 35 years-old female newly diagnosed with HIV. She had 1 CD4 cell/μL (0 %), haemoglobin 9.8 g/dl, and normal renal and liver function tests. Esophageal candidiasis and normocytic-normochromic anaemia were diagnosed. She received fluconazole, prophylactic cotrimoxazole and tenofovir/emtricitabine/efavirenz. Seven weeks later she presented with inflammatory skin plaques with elevated margins and central hyperpigmentation on the trunk, face and limbs in the frame of a good general recovery and increased CD4 counts (188 cells/μL, 6 %). Tinea-IRIS was suspected and treated with griseofulvin 500 mg daily and prednisolone 1 mg/Kg tapered down after 1 week, with total resolution of symptoms in 2 weeks.

Conclusion

The two cases had advanced immunosuppression and developed de-novo exaggerated manifestation of inflammatory lesions compatible with tinea corporis and tinea facies in temporal association with antiretroviral treatment initiation and good immunological response. This is compatible with unmasking tinea-IRIS, and reminds African clinicians about the importance of considering this entity in the differential diagnosis of patients with skin lesions developing after antiretroviral treatment initiation.

Dermatophytosis in patients with human immunodeficiency virus infection: clinical aspects and etiologic agents

Dermatophytosis in individuals with human immunodeficiency virus infection seems to manifest with atypical, multiple, or extensive lesions more frequently. In addition, there are reports of presentations with little inflammation, called anergics. Less common etiologic agents have been isolated in these individuals, such as Microsporum species. To describe clinical aspects and etiologic agents of dermatophytosis in individuals with human immunodeficiency virus (HIV) infection. Patients with clinical diagnosis of dermatophytosis underwent scarification for mycological diagnosis through direct microscopic examination and fungal isolation in culture on Sabouraud dextrose agar. Sixty individuals had a clinical hypothesis of dermatophytosis. In 20 (33.3%) of the 60 patients, dermatophytosis was confirmed through a mycological study. Tinea corporis, diagnosed in 14 patients, was the most frequent clinical form, followed by tinea unguium in 7, tinea cruris in 5, and tinea pedis in 1 patient. Most of the lesions of tinea corporis were anergic. Five patients with tinea unguium had involvement of multiple nails, with onychodystrophy as the predominant subtype. Multiple cutaneous lesions occurred in 3 patients and extensive cutaneous lesions in 4. Regarding the agent, Trichophyton rubrum was the most commonly isolated. The high occurrence of anergic skin lesions and involvement of multiple nails, especially as onychodystrophy, corroborates the hypothesis that atypical, disseminated, and more severe presentations are common in individuals with HIV infection. However, no Microsporum species was isolated even in atypical, extensive, or disseminated cases, in disagreement with previous reports. Therefore, the approach of squamous lesions in HIV-positive patients must include a mycological study, in view of the possibility of anergic dermatophytosis, to promote the introduction of a suitable therapeutic agent.

Dermatophytosis and immunovirological status of HIV-infected and AIDS patients from Sao Paulo city, Brazil

Over the past decades, more people became infected with human immunodeficiency virus (HIV) and developed acquired immunodeficiency syndrome (AIDS). Because of that the incidence of fungal infections rose dramatically. It happened because this virus can modify the course of fungal diseases, leading to altered clinical pictures. The aim of this study was to evaluate epidemiological and biological aspects of dermatophytosis in HIV-positive and AIDS patients living in the city of São Paulo, Brazil. A total of 84 (44 HIV-positive and 40 AIDS) patients were enrolled in this study. The patients were tested for dermatophyte infections, as well as for the CD4(+) /CD8(+) and HIV viral load counts. Tinea unguium was most frequently observed in AIDS patients, whereas Tinea pedis was mostly observed in HIV-positive patients. The most frequent dermatophyte species was Trichophyton rubrum. CD4(+) counts and CD4(+) /CD8(+) ratios were not associated with a higher risk for dermatophytosis. On the other hand, viral load higher than 100 000 copies/ml was associated with a higher frequency of dermatophytosis. The results suggest to that although dermatophytosis is common in HIV-positive and AIDS patients, the degree of immunosuppression does not seems to correlate with increased risk of this fungal infection. In addition, high viral load as a predictive risk factor for dermatophyte infection should be subject of further evaluations.

The Effect of the acetone extract of Arctotis arctotoides (Asteraceae) on the growth and ultrastructure of some opportunistic fungi associated with HIV/AIDS

In this study, the effect of the acetone extract of Arctotis arctotoides (L.f.) O. Hoffm. (Asteraceae) on the growth and ultrastructure of some opportunistic fungi associated with HIV/AIDS was analyzed by means of scanning electron microscope (SEM). Remarkable morphological alterations in the fungal mycelia which were attributed to the loss of cell wall strength ranged from loss of turgidity and uniformity, collapse of entire hyphae to evident destruction of the hyphae. The elements responsible for giving the fungi their characteristic virulence were detected and quantified by energy dispersive X-ray microanalysis techniques. X-ray microanalysis showed the specific spectra of sodium, potassium and sulfur as the principal intersection of the four pathogenic fungi studied. Since these ions have the potential of fostering fungal invasion by altering the permeability of hosts' membranes, their presence was considered inherent to the pathogenicity of the opportunistic fungi. Hence, these findings indicate the potential of the crude extract of A. arctotoides in preventing fungal invasion and subsequent infection of host's membranes.

Dermatophytes: host-pathogen interaction and antifungal resistance

Cutaneous mycoses are among the most common infections in humans and have become an important public health issue because they cause invasive infections in immunocompromised patients. During the infectious process, dermatophyte-host interactions trigger specific metabolic adaptations that allow the pathogen to adhere to and penetrate the host tissue, scavenge nutrients, and overcome the host defense mechanisms. This metabolic shift and the interplay between metabolism, morphogenesis and stress response are important factors that have been extensively studied in several pathogens. Host cells also respond to the pathogen stimuli by activating intracellular signaling pathways that trigger the immune response against the infectious agent. The comprehension of the molecular aspects of these responses may help to establish new therapeutical strategies. In this review, different aspects of the biology of dermatophytes are addressed, with emphasis on the dermatophyte-host interaction and the mechanisms of antifungal resistance.

Dermatophyte virulence factors: identifying and analyzing genes that may contribute to chronic or acute skin infections

Dermatophytes are prevalent causes of cutaneous mycoses and, unlike many other fungal pathogens, are able to cause disease in immunocompetent individuals. They infect keratinized tissue such as skin, hair, and nails, resulting in tinea infections, including ringworm. Little is known about the molecular mechanisms that underlie the ability of these organisms to establish and maintain infection. The recent availability of genome sequence information and improved genetic manipulation have enabled researchers to begin to identify and study the role of virulence factors of dermatophytes. This paper will summarize our current understanding of dermatophyte virulence factors and discuss future directions for identifying and testing virulence factors.

Avaliação clínica e micológica de onicomicose em pacientes brasileiros com HIV/AIDS

INTRODUÇÃO: Onicomicoses são comuns em pacientes imunocomprometidos embora espécies emergentes tenham sido verificadas, modificado o perfil epidemiológico desta micose. Assim, o objetivo desta pesquisa é avaliar o perfil clínico e micológico da onicomicose em pacientes com infecção pelo HIV/AIDS. MÉTODOS: Amostras clínicas foram coletadas, processados para exame direto e a cultura mantida a temperatura de 30°C e 37ºC durante 15 dias. RESULTADOS: Dos 100 pacientes, 32 apresentavam onicomicose. Os agentes isolados foram Candida albicans, C. parapsilosis, C. tropicalis, C. guilliermondii, Trichophyton rubrum, T. mentagrophytes, Fusarium solani, Scytalidium hialinum, S. japonicum, Aspergillus niger, Cylindrocarpon destructans e Phialophora reptans. CONCLUSÕES: Onicomicoses em HIV/AIDS apresentam variadas manifestações clínicas e podem ser causadas por fungos emergentes. As peculiaridades apresentadas pelos diferentes agentes de origem fúngica justificam a necessidade de identificação ao nível da espécie, com a finalidade de orientar uma melhor abordagem terapêutica e minimizar a exposição desses pacientes a condições de risco de uma infecção disseminada.