Deep dermatophytosis caused by Trichophyton rubrum: report of two cases

Erythroderma combined with deeper dermal dermatophytosis due to Trichophyton rubrum in a patient with myasthenia gravis: first case report and literature review

BACKGROUND

Dermatophytes are the most common causative pathogens of mycoses worldwide and usually cause superficial infections. However, they can enter deep into the dermis lead to invasive dermatophytosis such as deeper dermal dermatophytosis on rare occasions. Erythroderma is a severe dermatological manifestation of various diseases resulting in generalized skin redness, but erythroderma due to fungi infections is barely reported. In this article, we reported the first case of erythroderma combined with deeper dermal dermatophytosis due to Trichophyton rubrum (T. rubrum) in a patient with myasthenia gravis.

CASE PRESENTATION

A 48-year-old man was hospitalized because of erythema with scaling and nodules covering his body for a month. The patient had a history of myasthenia gravis controlled by regularly taking prednisolone for > 10 years and accompanied by onychomycosis and tinea pedis lasting > 8 years. Based on histopathological examinations, fungal cultures, and DNA sequencing results, the patient was finally diagnosed with dermatophyte-induced erythroderma combined with deeper dermal dermatophytosis caused by T. rubrum. After 2 weeks of antifungal treatment, the patient had recovered well.

CONCLUSIONS

This case report shows that immunosuppressed patients with long histories of superficial mycoses tend to have a higher risk of developing invasive dermatophytic infections or disseminated fungal infections. Dermatologists should be alert to this condition and promptly treat the superficial dermatophytosis.

Lactobacillus plantarum strain HT-W104-B1: potential bacterium isolated from Malaysian fermented foods for control of the dermatophyte Trichophyton rubrum

The objective was to screen and evaluate the anti-fungal activity of lactic acid bacteria (LABs) isolated from Malaysian fermented foods against two Trichophyton species. A total of 66 LAB strains were screened using dual culture assays. This showed that four LAB strains were very effective in inhibiting growth of T. rubrum but not T. interdigitale. More detailed studies with Lactobacillus plantarum strain HT-W104-B1 showed that the supernatant was mainly responsible for inhibiting the growth of T. rubrum. The minimum inhibitory concentration (MIC), inhibitory concentration, the 50% growth inhibition (IC₅₀) and minimum fungicide concentration (MFC) were 20 mg/mL, 14 mg/mL and 30 mg/mL, respectively. A total of six metabolites were found in the supernatant, with the two major metabolites being L-lactic acid (19.1 mg/g cell dry weight (CDW)) and acetic acid (2.2 mg/g CDW). A comparative study on keratin agar media showed that the natural mixture in the supernatants predominantly contained L-lactic and acetic acid, and this significantly controlled the growth of T. rubrum. The pure two individual compounds were less effective. Potential exists for application of the natural mixture of compounds for the treatment of skin infection by T. rubrum.

Multiple abscesses in the lower extremities caused by Trichophyton rubrum

Background

Dermatophytes are keratinophilic fungi, that usually infect the hair, stratum corneum, and nails. However, dermatophytes occasionally invade the dermis, subcutaneous tissues, and internal organs, resulting in a condition called deep dermatophytosis. We report a case of an unusual presentation of Trichophyton rubrum infection causing multiple fungal abscesses in the lower extremities of an immunocompromised patient.

Case presentation

A 66-year-old male who had been receiving immunosuppressive drugs for 7 years developed numerous subcutaneous nodules in the lower extremities. The yellow purulent fluid obtained from the cyst was positive for T. rubrum. Topical bifonazole cream was effective for tinea pedis, but oral Sporanox 400 mg/day was discontinued after 2 months because the patient died from pneumonia after hospitalization for a lumbar fracture.

Conclusions

Although deep dermatophytosis is very rare, dermatomycosis should be considered in any examination of patients who are receiving immunosuppressive drugs. Fungi can enter the bloodstream and disseminate to distant major organs, including the lymph nodes, liver, brain, and bone, which often causes systemic infections that can be fatal.

Inherited CARD9 Deficiency: Invasive Disease Caused by Ascomycete Fungi in Previously Healthy Children and Adults

Autosomal recessive CARD9 deficiency underlies life-threatening, invasive fungal infections in otherwise healthy individuals normally resistant to other infectious agents. In less than 10 years, 58 patients from 39 kindreds have been reported in 14 countries from four continents. The patients are homozygous (n = 49; 31 kindreds) or compound heterozygous (n = 9; 8 kindreds) for 22 different CARD9 mutations. Six mutations are recurrent, probably due to founder effects. Paradoxically, none of the mutant alleles has been experimentally demonstrated to be loss-of-function. CARD9 is expressed principally in myeloid cells, downstream from C-type lectin receptors that can recognize fungal components. Patients with CARD9 deficiency present impaired cytokine and chemokine production by macrophages, dendritic cells, and peripheral blood mononuclear cells and defective killing of some fungi by neutrophils in vitro. Neutrophil recruitment to sites of infection is impaired in vivo. The proportion of Th17 cells is low in most, but not all, patients tested. Up to 52 patients suffering from invasive fungal diseases (IFD) have been reported, with ages at onset of 3.5 to 52 years. Twenty of these patients also displayed superficial fungal infections. Six patients had only mucocutaneous candidiasis or superficial dermatophytosis at their last follow-up visit, at the age of 19 to 50 years. Remarkably, for 50 of the 52 patients with IFD, a single fungus was involved; only two patients had IFDs due to two different fungi. IFD recurred in 44 of 45 patients who responded to treatment, and a different fungal infection occurred in the remaining patient. Ten patients died from IFD, between the ages of 12 and 39 years, whereas another patient died at the age of 91 years, from an unrelated cause. At the most recent scheduled follow-up visit, 81% of the patients were still alive and aged from 6.5 to 75 years. Strikingly, all the causal fungi belonged to the phylum Ascomycota: commensal Candida and saprophytic Trychophyton, Aspergillus, Phialophora, Exophiala, Corynesprora, Aureobasidium, and Ochroconis. Human CARD9 is essential for protective systemic immunity to a subset of fungi from this phylum but seems to be otherwise redundant. Previously healthy patients with unexplained invasive fungal infection, at any age, should be tested for inherited CARD9 deficiency.

KEY POINTS

• Inherited CARD9 deficiency (OMIM #212050) is an AR PID due to mutations that may be present in a homozygous or compound heterozygous state. • CARD9 is expressed principally in myeloid cells and transduces signals downstream from CLR activation by fungal ligands. • Endogenous mutant CARD9 levels differ between alleles (from full-length normal protein to an absence of normal protein). • The functional impacts of CARD9 mutations involve impaired cytokine production in response to fungal ligands, impaired neutrophil killing and/or recruitment to infection sites, and defects of Th17 immunity. • The key clinical manifestations in patients are fungal infections, including CMC, invasive (in the CNS in particular) Candida infections, extensive/deep dermatophytosis, subcutaneous and invasive phaeohyphomycosis, and extrapulmonary aspergillosis. • The clinical penetrance of CARD9 deficiency is complete, but penetrance is incomplete for each of the fungi concerned. • Age at onset is highly heterogeneous, ranging from childhood to adulthood for the same fungal disease. • All patients with unexplained IFD should be tested for CARD9 mutations. Familial screening and genetic counseling should be proposed. • The treatment of patients with CARD9 mutations is empirical and based on antifungal therapies and the surgical removal of fungal masses. Patients with persistent/relapsing Candida infections of the CNS could be considered for adjuvant GM-CSF/G-CSF therapy. The potential value of HSCT for CARD9-deficient patients remains unclear.

A Giant Dermatophyte Abscess Caused by Trichophyton rubrum in an Immunocompromised Patient

A 73-year-old male who had been receiving immunosuppressive drugs for 15 years developed a nodule on the left buttock region. The nodule slowly grew into a 15-cm fluctuant multilocular subcutaneous cyst. Serum beta-D-glucan levels were high, and the yellow purulent fluid obtained from the cyst was positive for Trichophyton rubrum. Granuloma formation in the cyst wall and large abscesses in the central cystic area were found, and septated hyphae were observed in both tissues. The cyst was surgically removed, and followed by itraconazole treatment. Notably, the clinical manifestations closely resembled those of a huge atheroma.

A Unique Clinicopathological Manifestation of Fungal Infection: A Case Series of Deep Dermatophytosis in Immunosuppressed Patients

BACKGROUND

Dermatophytes are the most common cause of superficial fungal infections in humans. Deep dermatophytosis, however, is rare, described to date only in isolated case reports, usually in the setting of systemic immunosuppression.

OBJECTIVE

To present the 15-year experience of a tertiary dermato-mycology clinic with the diagnosis and treatment of deep dermatophytosis.

METHODS

Patients were identified by database search. Clinical, mycological, histological, and treatment data were collected from the medical files.

RESULTS

Ten patients were identified: nine after solid-organ transplantation and one undergoing chemotherapy, all diagnosed within 3 years after beginning immunosuppression (average 7.5 months). The infective agent in nine cases was Trichophyton rubrum. All patients presented with concurrent superficial fungal infections. Complete resolution was noted in response to systemic antifungal agents. There was no histological evidence of hair-follicle involvement.

LIMITATIONS

The limitations of the study were the retrospective design and the small cohort size.

CONCLUSION

This case-series study suggests that deep dermatophytosis is a separate entity, distinct from Majocchi's granuloma. It occurs only in immunocompromised patients and is characterized by discrete nodules, an indolent course, the absence of follicular invasion, and proximity to a superficial dermatophyte infection. Systemic antifungal treatment leads to complete resolution. The urgent need for the treatment of superficial fungal infections in immunocompromised patients is emphasized.

Trichophyton rubrum Infection Characterized by Majocchi's Granuloma and Deeper Dermatophytosis: Case Report and Review of Published Literature

Infections caused by Trichophyton rubrum are very common in dermatological disease. It most often appears as superficial cutaneous mycosis, such as tinea manuum, tinea pedis, and tinea corporis. However, deep infection caused by T. rubrum was rarely reported. We describe a case of mixed type of deep infection caused by T. rubrum in a 45-year-old man with no significant immunodeficiency. This patient had a history of onychomycosis on the toenails without regular treatment for nearly 6 years. And, he had erythema, papule, and nodules on the submandibular area, neck, and chest for almost 1 year. After treated with intravenous infusion of cefotiam for 2 weeks, the lesion aggravated. The fungal direct microscopic examination of pyogenic fluid was positive, and the fungal cultures that produced reddish-brown and yellow pigment showed cottony, wooly, and white colony. After the DNA sequencing, it was identified as T. rubrum. We gave the patient oral terbinafine 250 mg per day and bifonazole cream for external use. Six months later, the patient's skin lesion was disappeared, and healthy nail growth was seen in two-thirds of nail bed. The terbinafine is effective against deep infection caused by T. rubrum.

Determination of minimum inhibitory concentrations of itraconazole, terbinafine and ketoconazole against dermatophyte species by broth microdilution method

PURPOSE

Various antifungal agents both topical and systemic have been introduced into clinical practice for effectively treating dermatophytic conditions. Dermatophytosis is the infection of keratinised tissues caused by fungal species of genera Trichophyton, Epidermophyton and Microsporum, commonly known as dermatophytes affecting 20-25% of the world's population. The present study aims at determining the susceptibility patterns of dermatophyte species recovered from superficial mycoses of human patients in Himachal Pradesh to antifungal agents; itraconazole, terbinafine and ketoconazole. The study also aims at determining the minimum inhibitory concentrations (MICs) of these agents following the recommended protocol of Clinical and Laboratory Standards Institute (CLSI) (M38-A2).

METHODOLOGY

A total of 53 isolates of dermatophytes (T. mentagrophyte-34 in no., T. rubrum-18 and M. gypseum-1) recovered from the superficial mycoses were examined. Broth microdilution method M38-A2 approved protocol of CLSI (2008) for filamentous fungi was followed for determining the susceptibility of dermatophyte species.

RESULTS

T. mentagrophyte isolates were found more susceptible to both itraconazole and ketoconazole as compared to terbinafine (MIC50: 0.125 µg/ml for itraconazole, 0.0625 µg/ml for ketoconazole and 0.5 µg/ml for terbinafine). Three isolates of T. mentagrophytes (VBS-5, VBSo-3 and VBSo-73) and one isolate of T. rubrum (VBPo-9) had higher MIC values of itraconazole (1 µg/ml). Similarly, the higher MIC values of ketoconazole were observed in case of only three isolates of T. mentagrophyte (VBSo-30 = 2 µg/ml; VBSo-44, VBM-2 = 1 µg/ml). The comparative analysis of the three antifungal drugs based on t-test revealed that 'itraconazole and terbinafine' and 'terbinafine and ketoconazole' were found independent based on the P < 0.005 in case of T. mentagrophyte isolates. In case of T. rubrum, the similarity existed between MIC values of 'itraconazole and ketoconazole' and 'terbinafine and ketoconazole'.

CONCLUSION

The MIC values observed in the present study based on standard protocol M38-A2 of CLSI 2008 might serve as reference for further studies covering large number of isolates from different geographic regions of the state. Such studies might reflect on the acquisition of drug resistance among isolates of dermatophyte species based on MIC values.

Severe Dermatophytosis and Acquired or Innate Immunodeficiency: A Review

Dermatophytes are keratinophilic fungi responsible for benign and common forms of infection worldwide. However, they can lead to rare and severe diseases in immunocompromised patients. Severe forms include extensive and/or invasive dermatophytosis, i.e., deep dermatophytosis and Majocchi’s granuloma. They are reported in immunocompromised hosts with primary (autosomal recessive CARD9 deficiency) or acquired (solid organ transplantation, autoimmune diseases requiring immunosuppressive treatments, HIV infection) immunodeficiencies. The clinical manifestations of the infection are not specific. Lymph node and organ involvement may also occur. Diagnosis requires both mycological and histological findings. There is no consensus on treatment. Systemic antifungal agents such as terbinafine and azoles (itraconazole or posaconazole) are effective. However, long-term outcome and treatment management depend on the site and extent of the infection and the nature of the underlying immunodeficiency.

Heat Shock Protein 90 (Hsp90) as a Molecular Target for the Development of Novel Drugs Against the Dermatophyte Trichophyton rubrum

Treatment of fungal infections is difficult due to several reasons, such as side effects of drugs, emergence of resistant strains, and limited number of molecular targets for the drug compounds. In fungi, heat shock proteins (Hsps) have been implicated in several processes with the conserved molecular chaperone Hsp90 emerging as a potential target for antifungal therapy. It plays key cellular roles by eliciting molecular response to environmental changes, morphogenesis, antifungal resistance, and fungal pathogenicity. Here, we evaluated the transcription profiles of hsp genes of the most prevalent dermatophyte Trichophyton rubrum in response to different environmental challenges including nutrient availability, interaction with cells and molecules of the host tissue, and drug exposure. The results suggest that each Hsp responds to a specific stress condition and that the cohort of Hsps facilitates fungal survival under various environmental challenges. Chemical inhibition of Hsp90 resulted in increased susceptibility of the fungus to itraconazole and micafungin, and decreased its growth in human nails in vitro. Moreover, some hsp and related genes were modulated by Hsp90 at the transcriptional level. We are suggesting a role of Hsp90 in the pathogenicity and drug susceptibility of T. rubrum as well as the regulation of other Hsps. The synergism observed between the inhibition of Hsp90 and the effect of itraconazole or micafungin in reducing the fungal growth is of great interest as a novel and potential strategy to treat dermatophytoses.

Trichophyton rubrum osteomyelitis after calcaneus external fixation pin stabilization of a pilon fracture

Fungal organisms are an uncommon cause of osteomyelitis, and no dermatophyte osteomyelitis infections have been reported in published studies. We present the case of Trichophyton rubrum osteomyelitis of the calcaneus. Our patient initially presented with a pilon fracture requiring temporary external fixation while awaiting definitive fixation. From our review of the published data, the present case is the first of this type of fungal osteomyelitis to be reported. The patient was evaluated for a left neck mass during his hospitalization that was later found to be consistent with salivary duct carcinoma of the tail of the parotid gland. A left neck dissection and superficial excision of the parotid gland was performed after fixation of his pilon fracture. Subsequently, he developed an increasing lucency in the calcaneus and symptoms of pain and erythema months after the calcaneus pin had been removed. The osteomyelitis was treated with surgical debridement and 3 months of itraconazole once cultures had definitively grown T. rubrum.

Majocchi's granuloma: a symptom complex caused by fungal pathogens

Majocchi's granuloma (MG) is a well-recognized but uncommon infection of dermal and subcutaneous tissues that is caused by mold fungi. Although primarily caused by keratinophilic dermatophytes such as anthropophilic Trichophyton rubrum, species from the Aspergillus and Phoma genera have been occasionally detected as etiologic agents of MG. In both healthy individuals and immunocompromised hosts, MG often presents as nodules, plaques, and papules on areas that are prone to trauma. Although MG generally appears on the upper and lower extremities (forearms, hands, legs, or ankles), it occasionally appears on the scalp and face. The clinical, mycologic, and/or cytologic diagnosis should be confirmed by the demonstration of perifollicular granulomatous inflammation by histologic examination. This review focuses on the clinical presentation, pathogenesis, laboratory diagnostic methods (including the Tzanck smear test), etiologic agents, histopathologic characteristics, and therapeutic approaches to the treatment of MG.

Majocchi's granuloma

We report the case of a man of 45 with superficial dermatophytosis longtime inadvertently treated with antibiotics and corticosteroids with subsequent progression to the deep form, known as granuloma Majocchi. Treatment with orally terbinafine was successful.

Dermatophyte identification using matrix-assisted laser desorption ionization-time of flight mass spectrometry

The performance of the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometer (MS) for the identification of dermatophytes from clinical cultures was compared to that of dermatophyte identification using 28S rRNA gene sequencing. The MALDI Biotyper library (MBL; version 3.0) was used alone and in combination with a supplemented library containing an additional 20 dermatophyte spectra (S-MBL). Acquired spectra were interpreted using both the manufacturer-recommended scores (genus, ≥1.7; species, ≥2.0) and adjusted cutoff values established by this study (genus, ≥1.5; species, ≥1.7); identifications required a minimum 10% difference in scores between the top two different organisms to be considered correct. One hundred well-characterized, archived dermatophyte isolates and 71 fresh dermatophyte cultures were evaluated using both libraries and both sets of cutoff criteria. Collectively, the S-MBL significantly outperformed the MBL at both the genus (93% versus 37.4%; P < 0,0001) and species (59.6% versus 20.5%; P < 0.0001) levels when using the adjusted score criteria. Importantly, application of the lowered cutoff values significantly improved genus (P = 0.005)- and species (P < 0.0001)-level identification for the S-MBL, without leading to an increase in misidentifications. MALDI-TOF MS is a cost-effective and rapid alternative to traditional or molecular methods for dermatophyte identification, provided that the reference library is supplemented to sufficiently encompass clinically relevant, intraspecies strain diversity.

Pathogenesis of dermatophytoses

Dermatophytes can survive solely on outer cornified layers of the skin. The ability of certain fungi to adhere to particular host arises from numerous mechanisms and host factors, including the ability to adapt to the human body. Natural infection is acquired by the deposition of viable arthrospores or hyphae on the surface of the susceptible individual. After the inoculation in the host skin, suitable conditions favor the infection to progress through the stages of adherence and penetration. Development of host response is mostly by a T-cell mediated response of delayed-type hypersensitivity. Antibody formation does not seem to be protective. Natural defenses against dermatophytes depend on both immunological and nonimmunological mechanisms.

Transcriptional profiles of Trichophyton rubrum in response to itraconazole

Trichophyton rubrum is the predominant causative agent for superficial dermatomycosis. In order to understand how triazole antifungal agents interact with dermatophytes, the gene expression response of T. rubrum to itraconazole was studied by large-scale gene expression profiling. A total of 670 genes were found to be responsive to itraconazole, including 305 that were up-regulated and 365 down-regulated. Most genes involved in lipid metabolism and especially in ergosterol biosynthesis were up-regulated in response to itraconazole, including ERG6, ERG7, ERG11, ERG24, ERG25 and ERG26. In addition, transcription of some genes involved in cell stress response, drug efflux, and small molecule transport was also affected by itraconazole. Differential expression of selected genes was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR). This is the first microarray hybridization analysis of T. rubrum exposed to a triazole antifungal agent.

Identification of dermatophyte species causing onychomycosis and tinea pedis by MALDI-TOF mass spectrometry

Identification of dermatophytes is currently performed based on morphological criteria and is increasingly supported by genomic sequence comparison. The present study evaluates an alternative based on the analysis of clinical fungal isolates by mass spectrometry. Samples originating from skin and nail were characterized morphologically and by sequencing the internal transcribed spacer 1 (ITS1), ITS2 and the 5.8S rDNA regions of the rDNA clusters. In a blind comparative study, samples were analyzed by matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF MS). The mass spectra were compared to a database comprising of the spectral data of reference strains by applying the saramis software package. All fungal isolates belonging to the taxa Trichophyton rubrum, T. interdigitale, T. tonsurans, Arthroderma benhamiae and Microsporum canis were correctly identified, irrespective of host origin and pathology. To test the robustness of the approach, four isolates were grown on five different media and analyzed. Although the resulting mass spectra varied in detail, a sufficient number of signals were conserved resulting in data sets exploitable for unequivocal species identification. Taken together, the usually widespread dermatophytes can be identified rapidly and reliably by mass spectrometry. Starting from pure cultures, MALDI-TOF MS analysis uses very simple sample preparation procedures, and a single analysis is performed within minutes. Costs for consumables as well as preparation time are considerably lower than for PCR analysis.