Malassezia dermatitis in dogs and cats.

Malassezia are members of the mycobiome of dogs and cats. In the presence of an underlying disease, these yeasts can proliferate, attach to the skin or mucosa to induce a secondary Malassezia dermatitis, otitis externa or paronychia. Since allergic dermatitis is one of the most common underlying causes, diagnostic investigation for allergy is often indicated. Cats may suffer from various other underlying problems, especially where Malassezia dermatitis is generalised. Malassezia dermatitis in dogs and cats is chronic, relapsing and pruritic. Direct cytology from dermatological lesions and the ear canal, showing "peanut-shaped" budding yeasts, facilitates a rapid and reliable diagnosis. Topical treatment includes antiseptic and antifungal azole-based products. Systemic treatment with oral antifungals is indicated only in severe or refractory disease. Identification and treatment of the underlying cause is essential for an optimal response. In this evidence-based narrative review, we discuss the clinical presentation of Malassezia dermatitis in dogs and cats, underlying comorbidities, and diagnostic considerations. Treatment is discussed in light of emerging evidence of antifungal resistance and the authors' clinical experience.

Identification of Familial Infections Using Multilocus Microsatellite Typing in Tinea Corporis due to Microsporum canis.

Microsporum canis is a type of dermatophyte that causes zoonotic dermatophytosis in cats and dogs. We report three cases of tinea corporis due to M. canis from a single household with a domestic cat as a pet. The cases included a woman in her thirties (mother), a girl in her teens (older sister), and a girl in her teens (younger sister). Following sudden hair loss in the domestic cat, annular erythema with pruritus and scales appeared on the face, neck, and limbs of the older sister, younger sister, and mother, sequentially; they subsequently visited our hospital. Potassium hydroxide direct microscopy revealed filamentous fungi on all three women. In addition, short-haired colonies with a white to yellowish-white color and extending in a radial manner were found in cultures using a flat plate agar medium. A slide culture with the same medium indicated pointed spindle-shaped macroconidia with 7-8 septa. Therefore, the cases were diagnosed as tinea corporis due to M. canis. Genetic analysis of the cells of the cat and the mother, older sister, and younger sister using multilocus microsatellite typing (MLMT) indicated that all cases were classified into the same genotype, suggesting that the transmission route of these cases was familial. Here, we show that MLMT is useful in identifying the infection route in cases of tinea corporis due to M. canis.

Deep cutaneous mycoses in kidney transplant recipients: Diagnostic and therapeutic challenges.

Deep cutaneous mycoses (DCMs) are rare infections that extend throughout the dermis and subcutis, often occurring after inoculation with pathogenic fungi. Trends toward a growing incidence have been observed that may be partially related to an increasing population of solid organ transplant patients. The aim of this study is to describe the diagnostics and the outcomes of DCM among kidney transplant recipients so as to optimize their management. We performed a retrospective review of cases of DCM occurring among kidney transplant recipients in our institution over 12 years. Twenty cases were included. Lesions were only located on the limbs and presented mainly as single (10/20, 50%) nodular lesions (15/20, 75%), with a mean size of 3 cm. Direct mycological examination was positive for 17 patients (17/20, 85%) and the cultures were consistently positive. Thirteen different fungal species were observed, including phaehyphomycetes (n = 8), hyalohyphomycetes (n = 3), dermatophytes (n = 1), and mucorale (n = 1). The (1-3) beta-D-glucan antigen (BDG) was also consistently detected in the serum (20/20, 100%). Systematic imaging did not reveal any distant infectious lesions, but locoregional extension was present in 11 patients (11/14, 79%). Nineteen patients received antifungal treatment (19/20, 95%) for a median duration of 3 months, with surgery for 10 (10/20, 50%). There is a great diversity of fungal species responsible for DCMs in kidney transplant recipients. The mycological documentation is necessary to adapt the antifungal treatment according to the sensitivity of the species. Serum BDG positivity is a potentially reliable and useful tool for diagnosis and follow-up.

Comparing the diagnostic accuracy of PCR-reverse blot hybridization assay and conventional fungus study in superficial fungal infection of the skin: A systematic review.

BACKGROUND: In superficial fungal infections, prompt diagnosis and treatment are essential to prevent the spread of infection and minimise the impact on patients' quality of life. Traditional diagnostic methods, such as KOH smear and fungal culture, have limitations in terms of sensitivity and turnaround time. Recently, the PCR-reverse blot hybridization assay (PCR-REBA) has been developed for the direct detection of dermatophyte DNA. However, there is a lack of information assessing the diagnostic accuracy of PCR-REBA. OBJECTIVES: This systematic review aimed to evaluate the diagnostic accuracy of PCR-REBA in superficial fungal infections compared to conventional and molecular methods. METHODS: The comprehensive search containing Ovid MEDLINE and Embase databases was conducted on 7 August 2022. Two reviewers independently reviewed the included articles. Quality assessment was performed using the Newcastle-Ottawa Scale tool. RESULTS: The included studies were conducted in Korea (five studies) and the Netherlands (two studies), all of which were conducted in a single institution. The quality assessment of these studies indicated low risk of bias. When compared to the potassium hydroxide (KOH) smear and fungus culture, the sensitivity of PCR-REBA ranged from 85% to 100%, and the positive predictive values ranged from 58.9% to 100%. When compared to the RT-PCR, the sensitivity of PCR-REBA ranged from 93.3% to 100%, and the positive and negative predictive values were 91.6%-99.6% and 81.0%-89.1%, respectively. CONCLUSIONS: The PCR-REBA shows promise as a valuable diagnostic tool for dermatophytosis, offering practical and cost-effective benefits.

Cutaneous Fungal Infections in Older Adults.

The population of older adults continues to increase in the United States, leading to a concomitant increase in cutaneous disease. Fungal disease, specifically, commonly affects this population but often goes undiagnosed for too long. It is therefore important that providers be aware of common fungal pathogens, recognizable symptoms of disease, and treatment options. This article discusses 3 groups of pathogens: dermatophytes, Candida species, and Pityrosporum species, all of which cause a host of conditions that can be debilitating for older adults.

PCR-based methods in detection and identification of dermatophytes in dogs and cats with suspected dermatophytosis in 2021 in Poland.

Dermatophytes from Microsporum, Trichophyton and Epidermophyton genera are divided into geophilic, zoophilic and anthropophilic species which cause skin infection in humans and wide group of animals, mainly mammals. Main species causing dermatophytosis in dogs and cats are Microsporum and Trichophyton. Conventional mycological diagnostic technique includes Saburaud Dextrose Agar (SAD) and others medium cultures, 10% KOH mount and direct microscopy of hairs and scraping. Molecular diagnostic become more frequent in veterinary practice due to shortening of waiting time. In this study we based on two PCR methods. The nested PCR amplified CHS1 gene for dermatophytes detection, and multiplex PCR coding ITS1 and ITS2 fragments for species identification of detected derpatophytes. Most frequently detected species was Microsporum canis, mainly in young cats. Geophilic Microsporum gypseum and anthropophilic Trichophyton rubrum was found primarily in dogs. Molecular methods in dermatophytosis identification are rapid in contrast to routinely, long lasting culture.

Invasive Malassezia Infections.

The Malassezia species are dimorphic fungi that require lipids such as olive oil for their growth. They are constituents of the normal human skin microbiota and can affix to the host or other surfaces through the establishment of biofilms. Malassezia species are accountable for superficial mycoses like folliculitis. Additionally, they are capable of causing invasive infections, such as of the bloodstream, in neonates and immunocompromised patients, albeit infrequently. Catheter-associated bloodstream infections in neonates are the most commonly reported invasive cases. Remarkably, unlike other invasive fungal infections, neutropenia and the use of broad-spectrum antibiotics do not seem to contribute to the risk of invasive Malassezia infections. Nosocomial outbreaks of Malassezia infections have been reported. While most cases of invasive Malassezia infection are fungemia, they seldom give rise to disseminated lesions in various organs. The diagnosis can be confirmed by the visualization of characteristic yeasts through histologic or cytologic examination of a biopsy or needle aspiration specimen, or via positive culture results from sterile sites. The prognosis for invasive Malassezia infection is generally favorable, with few reports of treatment failure. Nevertheless, due to the limited number of cases, evidence-based treatment recommendations are wanting. Management of invasive Malassezia infections linked to central venous catheters includes removal of the catheter, cessation of intravenous lipid emulsion, and intravenous administration of appropriate antifungal agents.

Subcutaneous mycoses: Endemic but neglected among the Neglected Tropical Diseases in Ethiopia.

BACKGROUND: Subcutaneous (deep) mycoses are a chronic infectious disease of the skin and underlying structures endemic in tropical countries. The disease has serious medical and socioeconomic consequences for patients, communities and health services in endemic areas. The inclusion of mycetoma and other subcutaneous mycoses in the list of Neglected Tropical Diseases by WHO highlights the need to assess the burden of these diseases and establish control programs where necessary. In Ethiopia no strategies can be devised because of a lack of epidemiologic information. To address this evidence gap, we performed a national rapid assessment of the geographic distribution of subcutaneous mycoses. METHODOLOGY: We conducted a rapid retrospective assessment using hospital records to identify all suspected and confirmed cases of subcutaneous mycoses in 13 referral hospitals across the country between 2015 and 2022. In each hospital the logbooks were reviewed for diagnoses of subcutaneous mycosess, as diagnosed per routine practice. Descriptive analysis was done. RESULT: From 13 hospitals we extracted 143 cases of subcutaneous mycoses, registered from July 2018 to September 2022. 118 (82.5%) patients were diagnosed as mycetoma, 21 (14.7%) as chromoblastomycosis and the remaining 4 (2.8%) as sporotrichosis. The mean age of patients was 35.8 years (SD = 14.5). 101 (70.6%) patients were male and 96 (67.1%) patients were farmers. 64 (44.8%) cases were from the Tigray regional state. 56 (65.9%) patients had information on diagnostic microscopic evaluation: for mycetoma histopathologic evaluation and fine needle aspiration cytology had a higher positivity rate while for chromoblastomycosis potassium hydroxide (KOH) staining had a better yield. The main clinical presentations were nodules, sinuses and infiltrative plaques on the skin. Radiologic findings of bone involvement was present in some. CONCLUSIONS: Mycetoma and other subcutaneous mycoses are endemic in Ethiopia, with cases reported from almost all regions with the highest cases numbers reported from the northern part of the country. A routine program and systems should be developed to identify and document the burden of subcutaneous fungal infections in the country. Diagnosis and treatment guidelines should be developed.

Comparative analysis in diagnosis by real-time polymerase chain reaction versus direct microscopy, culture, and histology in fungal infections of the nails, scalp, and skin.

BACKGROUND: The diagnosis of superficial fungal infections is the subject of intensive research in many countries around the world. The diagnostic methods used are diverse, including both conventional and innovative techniques. METHODS: This study evaluates the sensitivity, specificity, and efficacy of the real-time polymerase chain reaction (PCR) methodology and compares them with those of the conventional methods - direct microscopic, cultural, and histological examinations of materials from hair, skin, and nails - in order to demonstrate the benefits and significance of real-time PCR for the diagnosis of dermatophytic infections. RESULTS: The values obtained for the sensitivity, specificity, and efficacy of direct microscopic, cultural, histological, and real-time PCR studies are as follows: 63.71, 88.89, and 72.96% (P < 0.001); 58.06, 100, and 73.47% (P < 0.001); 85.96, 100, and 90.70% (P < 0.001); 88.52, 100, and 92.63% (P < 0.001). CONCLUSION: The use of real-time PCR in the diagnosis of dermatophytic infections is a relatively new approach in mycology and is subject to testing and experience from its use. The results are promising, but the method has not yet established itself as a new gold standard in the diagnosis of superficial fungal infections caused by dermatophytes, though its application would be very useful in identifying isolates without conidiogenesis or absence of growth.

Dermatopathology and the Diagnosis of Fungal Infections.

Diagnosis of superficial/cutaneous fungal infections from skin, hair and nail samples is generally achieved using microscopy and culture in a microbiology laboratory, however, any presentation that is unusual or subcutaneous is sampled by taking a biopsy. Using histological techniques a tissue biopsy enables a pathologist to perform a full examination of the skin structure, detect any inflammatory processes or the presence of an infectious agent or foreign body. Histopathological examination can give a presumptive diagnosis while a culture result is pending, and may provide valuable diagnostic information if culture fails. This review demonstrates how histopathology contributes to the diagnosis of fungal infections from the superficial to the life threatening.

Diagnostic capacity for cutaneous fungal diseases in the African continent.

BACKGROUND: Cutaneous fungal infections are very common, especially in poorer communities and with intercurrent HIV infection. Determining the fungal pathogen in skin-related fungal neglected tropical diseases (NTDs) determines optimal therapy. We undertook a country survey across many African countries to determine the diagnostic capacity for skin fungal diseases. METHODS: A detailed questionnaire was delivered to country contacts to collect data on availability, frequency, and location of testing for key diagnostic procedures and followed up with 2 rounds of validation by video call and by confirmation of individual country data confirmation by email. RESULTS: Of 47 countries with data, seven (15%) and 21 (45%) do not offer skin biopsy in the public or private sector, respectively, but 22 (46%) countries do it regularly, mostly in university hospitals. Direct microscopy is often performed in 20 of 48 (42%) countries in the public sector and not done in 10 (21%). Fungal cultures are often performed in 21 of 48 (44%) countries in the public sector but not done in nine (20%) or 21 (44%) in either public or private facilities. Histopathological examination of tissue is frequently used in 19 of 48 (40%) countries but not in nine (20%) countries in the public sector. The cost of diagnostics to patients was a major limiting factor in usage. CONCLUSION: Major improvements in the availability and use of diagnostic tests for skin, hair, and nail fungal disease are urgently needed across Africa.

Fungal Skin Disease Classification Using the Convolutional Neural Network.

Skin is the outer cover of our body, which protects vital organs from harm. This important body part is often affected by a series of infections caused by fungus, bacteria, viruses, allergies, and dust. Millions of people suffer from skin diseases. It is one of the common causes of infection in sub-Saharan Africa. Skin disease can also be the cause of stigma and discrimination. Early and accurate diagnosis of skin disease can be vital for effective treatment. Laser and photonics-based technologies are used for the diagnosis of skin disease. These technologies are expensive and not affordable, especially for resource-limited countries like Ethiopia. Hence, image-based methods can be effective in reducing cost and time. There are previous studies on image-based diagnosis for skin disease. However, there are few scientific studies on tinea pedis and tinea corporis. In this study, the convolution neural network (CNN) has been used to classify fungal skin disease. The classification was carried out on the four most common fungal skin diseases: tinea pedis, tinea capitis, tinea corporis, and tinea unguium. The dataset consisted of a total of 407 fungal skin lesions collected from Dr. Gerbi Medium Clinic, Jimma, Ethiopia. Normalization of image size, conversion of RGB to grayscale, and balancing the intensity of the image have been carried out. Images were normalized to three sizes: 120 × 120, 150 × 150, and 224 × 224. Then, augmentation was applied. The developed model classified the four common fungal skin diseases with 93.3% accuracy. Comparisons were made with similar CNN architectures: MobileNetV2 and ResNet 50, and the proposed model was superior to both. This study may be an important addition to the very limited work on the detection of fungal skin disease. It can be used to build an automated image-based screening system for dermatology at an initial stage.

Molecular detection and species identification of dermatophytes by SYBR-Green real-time PCR in-house methodology using hair samples obtained from dogs and cats.

The classical dermatophytes diagnosis is based on mycological culture and microscopy observation both human and animal hair, skin, and nail samples. The aim of this work was to develop the new in-house real-time PCR with pan-dematophyte reaction for detection and identification of the main dermatophytes directly from hair samples, providing a simple and rapid diagnosis of dermatophytosis in dogs and cats. An in-house SYBR-Green real-time PCR was designed and used for detecting a DNA fragment encoding chitin synthase 1 (CHS1). A total of 287 samples were processed by culture, microscopic examination with KOH 10%, and real-time PCR (qPCR) analysis. Melting curve analysis of the CHS1 fragment revealed to be reproducible, showing a single distinct peak for each species of dermatophyte, namely Trichophyton mentagrophytes, T. verrucosum, Microsporum canis, and Nannizzia gypsea (formerly M. gypseum). Then, out of the 287 clinically suspected cases of dermatophytosis, 50% were positive for dermatophytes by qPCR, 44% by mycological culture, and 25% by microscopic examination. Microsporum canis was identified in 117 samples tested by culture and 134 samples tested by qPCR, followed by N. gypsea in 5 samples (either tested by culture or qPCR) and T. mentagrophytes detected in 4 and 5 samples when tested by culture or qPCR, respectively. Overall, qPCR allowed the diagnosis of dermatophytosis in clinical samples. The results suggest this newly proposed in-house real-time PCR assay can be used as alternative diagnosis and rapid identification of dermatophytes frequently associated to clinical hair samples of dogs and cats.

The aim of this work was to develop a molecular detection strategy for dermatophytes by SYBR-Green real-time PCR of hair samples from animals. The melting curve analysis of the CHS1 fragment revealed to be reproducible, showing a single distinct peak for distinct dermatophyte species and allowed the diagnosis of dermatophytosis in dogs and cats caused mainly by Trichophyton mentagrophytes, Microsporum sp., and Nannizzia gypsea).

Position statement: Recommendations on the diagnosis and treatment of Malassezia folliculitis.

Malassezia is a lipophilic yeast that is a part of the human mycobiome. Malassezia folliculitis appears when the benign colonization of the hair follicles, by the Malassezia yeasts, becomes symptomatic with pruritic papules and pustules. Although Malassezia folliculitis is common in hospital departments, diagnosing and treating it varies among dermatologists and countries. The European Academy of Dermatology and Venereology Mycology Task Force Malassezia folliculitis working group has, therefore, sought to develop these recommendations for the diagnosis and management of Malassezia folliculitis. Recommendations comprise methods for diagnosing Malassezia folliculitis, required positive findings before starting therapies and specific treatment algorithms for individuals who are immunocompetent, immunocompromised or who have compromised liver function. In conclusion, this study provides a clinical strategy for diagnosing and managing Malassezia folliculitis.