The first succinylome profile of Trichophyton rubrum reveals lysine succinylation on proteins involved in various key cellular processes.

BACKGROUND: Dermatophytes, the most common cause of fungal infections, affect millions of individuals worldwide. They pose a major threat to public health because of the severity and longevity of infections caused by dermatophytes and their refractivity to therapy. Trichophyton rubrum (T. rubrum), the most common dermatophyte species, is a promising model organism for dermatophyte research. Post-translational modifications (PTMs) have been shown to be essential for many biological processes, particularly in the regulation of key cellular processes that contribute to pathogenicity. Although PTMs have important roles, little is known about their roles in T. rubrum and other dermatophytes. Succinylation is a new PTM that has recently been identified. In this study, we assessed the proteome-wide succinylation profile of T. rubrum. This study sought to systematically identify the succinylated sites and proteins in T. rubrum and to reveal the roles of succinylated proteins in various cellular processes as well as the differences in the succinylation profiles in different growth stages of the T. rubrum life cycle. RESULTS: A total of 569 succinylated lysine sites were identified in 284 proteins. These succinylated proteins are involved in various cellular processes, such as metabolism, translation and epigenetic regulation. Additionally, 24 proteins related to pathogenicity were found to be succinylated. Comparison of the succinylome at the conidia and mycelia stages revealed that most of the succinylated proteins and sites were growth-stage specific. In addition, the succinylation modifications on histone and ribosomal proteins were significantly different between these two growth stages. Moreover, the sequence features surrounding the succinylated sites were different in the two stages, thus indicating the specific recognition of succinyltransferases in each growth phase. CONCLUSIONS: In this study, we explored the first T. rubrum succinylome, which is also the first PTM analysis of dermatophytes reported to date. These results revealed the major roles of the succinylated proteins involved in T. rubrum and the differences in the succinylomes between the two major growth stages. These findings should improve understanding of the physiological and pathogenic properties of dermatophytes and facilitate future development of novel drugs and therapeutics for treating superficial fungal infections.

Identification of the causative dermatophyte of tinea capitis in children attending Mbarara Regional Referral Hospital in Uganda by PCR-ELISA and comparison with conventional mycological diagnostic methods.

Tinea capitis is a dermatophyte infection common among prepubertal children in sub-Saharan Africa and mainly caused by Trichophyton and Microsporum species. Accurate identification is challenging as conventional methods like culture and microscopy are slow and mostly based on morphological characteristics, which make them less sensitive and specific. Modern molecular methods, like polymerase chain reaction (PCR) assays, are gaining acceptance and are quick as well as accurate. The aim of this study was to investigate the clinical patterns of tinea capitis and to accurately identify the most common causative dermatophytes affecting the scalps of children aged 1 to 16 years attending the Skin Clinic at Mbarara University of Science and Technology (MUST), Mbarara, Uganda, East Africa, using both conventional mycological methods and PCR-ELISA for detection of dermatophyte DNA. One hundred fifteen clinical samples from children from Western Uganda attending the MUST Skin Clinic with a clinical diagnosis of tinea capitis were analyzed. T. violaceum was identified as the most common causative agent, followed by M. audouinii, T. soudanense, and T. rubrum. The early identification of the causative agent of tinea capitis is a prerequisite for the effective management of the disease, the identification of probable source and the prevention of spreading. Children with tinea capitis in Western Uganda should be treated by systemic therapy rather than topical preparations to ensure high cure rates as the most common causative dermatophytes T. violaceum exhibits an endothrix rather than ectothrix invasion of the hair follicle.

Tiña del cuerpo de rápida evolución / Rapidly evolving tinea corporis

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A 9-Month-Old Girl from Iran with Extensive Erythematous Plaques Due to Trichophyton simii, a Zoophilic Dermatophyte.

The incidence of dermatophytosis due to Trichophyton simii is generally considered to be limited to endemic areas, particularly one area of India. However, the high similarity between the morphological features of atypical T. simii isolates and those of other dermatophytes such as Trichophyton interdigitale and Arthroderma benhamiae may lead to misidentification of the cause of dermatophytosis in many instances. We investigated a rare case of tinea corporis in a 9-month-old female with extensive erythematous lesions. Morphological features of the recovered isolate from the culture resulted in the identification of Trichophyton interdigitale. For accurate identification, the internal transcribed spacer regions (ITS1 and ITS2) of the ribosomal DNA (rDNA) gene were sequenced and the isolate was ultimately identified as T. simii. In conclusion, T. simii, which has been formerly known to be restricted to specific endemic regions, appears to be not infrequent in non-endemic areas but instead simply less well-known and consequently underestimated. To determine its actual prevalence of infection, the application of DNA-based molecular methodologies is required.

Silicon phthalocyanine 4 phototoxicity in Trichophyton rubrum.

Trichophyton rubrum is the leading pathogen that causes long-lasting skin and nail dermatophyte infections. Currently, topical treatment consists of terbinafine for the skin and ciclopirox for the nails, whereas systemic agents, such as oral terbinafine and itraconazole, are also prescribed. These systemic drugs have severe side effects, including liver toxicity. Topical therapies, however, are sometimes ineffective. This led us to investigate alternative treatment options, such as photodynamic therapy (PDT). Although PDT is traditionally recognized as a therapeutic option for treating a wide range of medical conditions, including age-related macular degeneration and malignant cancers, its antimicrobial properties have also received considerable attention. However, the mechanism(s) underlying the susceptibility of dermatophytic fungi to PDT is relatively unknown. As a noninvasive treatment, PDT uses a photosensitizing drug and light, which, in the presence of oxygen, results in cellular destruction. In this study, we investigated the mechanism of cytotoxicity of PDT in vitro using the silicon phthalocyanine (Pc) 4 [SiPc(OSi(CH3)2(CH2)3N(CH3)2)(OH)] in T. rubrum. Confocal microscopy revealed that Pc 4 binds to cytoplasmic organelles, and upon irradiation, reactive oxygen species (ROS) are generated. The impairment of fungal metabolic activities as measured by an XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt) assay indicated that 1.0 µM Pc 4 followed by 670 to 675 nm light at 2.0 J/cm(2) reduced the overall cell survival rate, which was substantiated by a dry weight assay. In addition, we found that this therapeutic approach is effective against terbinafine-sensitive (24602) and terbinafine-resistant (MRL666) strains. These data suggest that Pc 4-PDT may have utility as a treatment for dermatophytosis.

Is Trichophyton simii endemic to the Indian subcontinent?

Trichophyton simii is considered to be prevalent only in the Indian subcontinent where it was isolated from soil, as well as from infections of humans and animals. We have investigated a case of onychomycosis caused by this exotic dermatophyte, not traceable to endemic areas. This case, as in others due to this fungus in man or animals, that have been previously and sporadically reported worldwide, suggests infections caused by T. simii might be underestimated, especially outside its primary geographic areas. Indeed, there are isolates that do not show species-specific morphology, as in our case isolate, and as a result may be misidentified by classical methods. By checking the identity of some strains preserved in the collection BCCM/IHEM, we found several that proved to be T. simii, originating from non-endemic areas (Belgium, France and Ivory Coast). Therefore, the natural distribution of T. simii is probably not as restricted as has previously been proposed.

Laser treatment of onychomycosis: an in vitro pilot study.

BACKGROUND: Laser treatment of onychomycosis is the object of considerable interest. Laser therapy could be a safe and cost-effective treatment modality without the disadvantages of drugs. Some studies have described the inhibitory effects of lasers on the growth of fungal colonies. We therefore examined the effects of various laser wavelengths, which have previously shown inhibitory potential, on the fungal isolate Trichophyton rubrum. PATIENTS AND METHODS: Isolates of fungal colonies were placed clockwise on culture plates. Each culture plate was irradiated on one half with one of the following treatment regimens: 1064 nm-Q-switched Nd:YAG laser at 4 J/cm(2) and 8 J/cm(2) ; 532 nm-Q-switched Nd:YAG laser at 8 J/cm(2) ; 1064 nm-long-pulsed Nd:YAG laser at 45 J/cm(2) or 100 J/cm(2) . The other half remained untreated. Standardized photographs were taken and areas of treated and untreated colonies were compared for growth inhibition. RESULTS: There was no inhibition of fungal growth in any of the treated plates. Differences in size between treated and untreated colonies were not significant (p > 0.10). CONCLUSIONS: In this in vitro study Nd:YAG laser treatment of Trichophyton rubrum colonies failed to inhibit fungal growth. Nevertheless there might be an effectiveness in vivo which has to be clarified by clinical studies.

Trichophyton Rubrum with the 'raubitschekii' morphotype: the first report from Turkey.

In modern taxonomy, Trichophyton rubrum with the 'raubitschekii' morphotype differs from the common strains of T. rubrum morphologically, physiologically, and clinically, despite genetic homogeneity. In this paper, we report the first autochthonous Turkish cases in a 24-year-old woman and her 26-year-old fiancé with tinea cruris and tinea manuum, respectively. The isolates were proven to be T. rubrum with the 'raubitschekii' morphotype by their morphological and physiological characteristics including the following: (1) granular colony surface, (2) profuse macroconidia and microconidia, (3) strongly positive urease activity after 3 days, (4) non-perforating hair, (5) restricted growth and producing no alkaline reaction on bromocresol purple-milk solids-glucose agar, and (6) restricted growth and producing no conidia on 3-9% NaCl-supplemented Sabouraud agar. The internal transcribed spacer (ITS) regions of both isolates were sequenced, and the assembled DNA sequences were examined using the Basic BLAST (nucleotide-nucleotide) software of the National Center for Biotechnology Information web database. Actually, the lack of epidemiological data on this variety is notable, and the actual prevalence is unknown. Otherwise, routine methods misidentified the strains as T. rubrum or unrecognized cases were underreported.

Quantitative analysis of the effects of antimycotic agents on the hyphal growth of Trichophyton rubrum: a preliminary study.

The thallus diameter is commonly used as a quantitative parameter to evaluate hyphal growth. However, a different parameter is required to evaluate hyphal growth more precisely. The hyphal growth of Trichophyton rubrum in the presence of antimycotic agents was evaluated using the number of hyphal crossings as a quantitative parameter. Continuous video images of hyphal growth were taken for 48 h. Culture medium contained 0.4 µg ml(-1) of terbinafine (TBF) and itraconazole (ITCZ). Image analyses were performed every 6 h using a 50 µm square grid. The mean density of the hyphal crossings in each sampling frame was used as a parameter of hyphal growth. The mean ratio of hyphal crossings on distressed hyphae to total hyphal crossings was used as a parameter representing the antimycotic effects of TBF and ITCZ. The mean density of total hyphal crossings in the TBF group was significantly lower than in the control and ITCZ groups. The ratio of distressed hyphae significantly increased during the 48-h time course in the TBF group, but not in the ITCZ group. Counting the number of hyphal crossings provides a new method for assessing hyphal growth and antimycotic activity quantitatively.

Clinical, mycological and histological aspects of white onychomycosis.

Fungal leuconychia defines the clinical manifestations of white changes in onychomycosis. This uncommon clinical aspect is mostly seen, although not exclusively, in immunosuppressed patients. The principal isolated organism is Trichophyton spp. but the entity can also be caused by non-dermatophyte moulds. The mechanism of infection is unclear; it could be acquired through the proximal nail fold, or, as more recently proposed, may be secondary to lymphatic or vascular dissemination. To analyse the clinical, mycological and histopathological features of fungal leuconychia, we included 10 patients with the clinical diagnosis of fungal leuconychia. Direct examination of culture and nail plate biopsy were performed. Nine patients had confirmed fungal leuconychia. Four had a positive culture and all had positive haematoxylin-eosin (H&E) and Periodic Acid Schiff (PAS) stains for fungal elements with varying degrees of nail plate invasion. Seven of our patients were immunosuppressed and the isolated aetiological agents are the same as previously reported. The direct examination is reliable, fast and inexpensive to establish the diagnosis. The correlation of onychomycosis with histology, stained with H&E and PAS was 100%. We think that the site of nail plate invasion provides more information to support the theory that the infection reaches the ungual apparatus through systemic dissemination.

Evaluation of extracts of Jatropha curcas and Moringa oleifera in culture media for selective inhibition of saprophytic fungal contaminants.

Most fungi occur in nature and utilize simple sources of carbohydrates and nitrogen for growth. Sabouraud's dextrose agar has been an ideal medium for primary isolation of fungi from clinical specimens, but for specimens from nonsterile sites or heavily contaminated ones, it has been necessary to include inhibitory substances such as antibiotics like chloramphenicol (antibacterial) and cycloheximide (antifungal). The problems we have in the our laboratory owing to frequent contamination of cultures and the delays in the procurement of cycloheximide have stimulated a search for alternatives in our local environment to enhance effective laboratory diagnoses of fungal infections. Purified extracts of the leaves and bark of Jatropha curcas and Moringa oleifera (common plants in our locality) were tested against clinical isolates of fungi at various concentrations to determine the minimum inhibitory concentration at which common fungal contaminants are inhibited, without affecting the growth of the pathogenic fungi sought for. At a concentration of 0.75 mg ml(-1) contaminants were totally inhibited by the leaf extracts. The bark extracts did not inhibit any fungus even at higher concentrations. From the results it was evident that the leaf extracts of both plants have potentials for use as inhibitory substances in culture media against contaminant fungi including Aspergillus spp., Penicillium spp., etc. J. curcas and M. oleifera are very common plants in our locality. They can be obtained at almost no cost and at any time needed. The benefits of these findings to mycology laboratories in a developing country are enormous.

Effects of a thiosemicarbazide camphene derivative on Trichophyton mentagrophytes.

Thiosemicarbazides are compounds known for their biological activity, particularly their antimicrobial properties, which include activity against fungi. The difficulty of treating fungal diseases induced us to assess the antifungal properties of some novel thiosemicarbazide compounds. We selected the natural products limonene and camphene as sources for the preparation of these new thiosemicarbazide derivatives. The compound N(4)-[2,2-dimethyl-3-methylnorbornane]-thiosemicarbazide (TIO C) showed an antifungal effect on Trichophyton mentagrophytes, with values of MIC = 55 mmol L(-1) and MFC = 110 micromol L(-1). Scanning-electron microscopy showed a decrease in mycelium development and morphological alterations of T. mentagrophytes cultured on nail fragments and treated with TIO C. In an attempt to discover its mode of action, we noted that ergosterol is apparently not a target of TIO C activity. An effect of TIO C on T. mentagrophytes cell walls and dividing cross-walls was shown by observed impairment of the fluorescence of tissues stained with calcofluor white, a specific marker for fungal chitin, suggesting that the compound can affect and damage the cell-wall structure or may interfere with its formation, during cell division, growth, and morphogenesis. This approach to the synthesis of new derivatives might provide interesting compounds with greater biological activity in pharmacological research.

Majocchi's granuloma in a liver transplant recipient caused by a Trichophyton spp., phenotypically consistent with Trichophyton rubrum var. raubitschekii.

The authors report a case of Majocchi's granuloma and onychomycosis in a liver transplant recipient caused by a Trichophyton spp., phenotypically consistent with Trichophyton rubrum var. raubitschekii. A 48-year-old female patient who had undergone liver transplantation nine months earlier, presented with red papules and nodular lesions on her back, buttock and thigh of two months duration. She also had onychomycosis of toe nails for a few years, which worsened post transplant. Two fungal isolates were derived from her infected toe nails and nodular tissue. Physical, pathological and mycological examination, including KOH preparation, fungal culture and DNA sequencing of the internal transcribed spacer(ITS) of rRNA were performed. The clinical diagnosis was Majocchi's granuloma and onychomycosis caused by the Trichophyton rubrum var. raubitschekii. This is the first case report of this organism from China.

Diagnostic value of morphological, physiological and biochemical tests in distinguishing Trichophyton rubrum from Trichophyton mentagrophytes complex.

The two most frequently encountered dermatophyte etiologic agents of glabrous skin and nail dermatophytoses are Trichophyton rubrum and T. mentagrophytes. This study was aimed to discuss the efficacy of morphological, physiological and biochemical diagnostic tests commonly used in the identification of T. rubrum and members of the T. mentagrophytes complex. In this study, we evaluated; hydrolysis of urea in broth and on urea agar slants and Petri plates incubated at 22 degrees C, 28 degrees C and 37 degrees C, in vitro hair perforation (blond child, sheep and goat hair), pigment production on cornmeal dextrose agar (CMDA) and bromcresol purple-milk solids-glucose agar (BCP-MS-G), Tween opacity, sorbitol assimilation, and salt tolerance. Additionally, the production of micro- and macroconidia was investigated by using brain heart infusion agar (BHIA), Christensen's urea agar in Petri plates (UPA), CMDA, Lowenstein-Jensen agar (LJA), malt extract agar, oatmeal agar, Oxoid chromogenic Candida agar, and potato dextrose agar. All cultures were incubated at 28 degrees C, and conidial production was compared on days 5, 10 and 15. It was found that the urea hydrolysis test yielded more rapid and significant results when urea medium was prepared in Petri plates and incubated at 28 degrees C (P<0.01). LJA supported the highest production of microconidia after 15 days (P<0.001). Additionally, it was found that T. rubrum strains produced red pigment on CMDA (P<0.01) and BCP-MS-G, while strains of the T. mentagrophytes species complex did not. A special algorithm containing the various test procedures employed in these studies is presented which was found to be useful in the differentiation of T. rubrum strains from T. mentagrophytes complex. Our results revealed that UPA, CMDA, BCP-MS-G, LJA, and BHIA may be used as common mycological agars in routine practice.

Infection stages of the dermatophyte pathogen Trichophyton: microscopic characterization and proteolytic enzymes.

Dermatophytes are pathogenic fungi that infect human skin, nails and hair and cause dermatophytosis. Trichophyton mentagrophytes is one of the most widespread species that belong to this group. Infection of the skin tissues include several stages, i.e., adhesion to the surface of the skin, invasion into the sublayers by the penetration of fungal elements and secretion of enzymes that degrade the skin components. In this study we have followed the morphology of the fungal elements, such as arthroconidia and hyphae, during the adhesion and invasion stages. Skin explants were inoculated with the dermatophyte and observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Skin explants were also inoculated with a transgenic isolate of T. mentagrophytes expressing the green fluorescent protein (GFP). The infected sublayers were investigated by confocal scanning laser microscopy (CSLM). As an adaptation to the tissue environment, the dermatophyte produced long fibrils when it is on the open surface of the stratum corneum, while short and thin fibrils are produced inside the dense sublayers. The short and long projections might have a role in adhesion. Invasion may be produced by mechanical and biochemical means. Invasion of the tissue showed hyphal branching and growth in multiple directions. The proteolytic profile was assayed by substrate gel and proteolytic activity. Two serine proteases of similar molecular weight were secreted during growth on the epidermal matrix components keratin and elastin. The dermatophyte may use the proteolytic enzymes to invade the surface and also the deep layer of the skin in immunocompromised patients. Dermatophytes, which are well adapted infectious agents, seem to use their mechanical and biochemical capabilities to invade the skin tissue effectively.