Canine and feline dermatophytosis due to Microsporum gypseum : A retrospective study of clinical data and therapy outcome with griseofulvin

Chemical composition of Artemisia argyi essential oil and its antifungal activity against dermatophytes by inhibiting oxidative phosphorylation and causing oxidative damage

ETHNOPHARMACOLOGICAL RELEVANCE

Dermatophytes are notorious pathogens capable of infecting various mammals skin, posing serious threats to human health and overall life quality worldwide. Artemisia argyi has been recorded and applied for over a thousand years to treat skin itching. Although it has the potential to be developed as a plant-based antifungal agent, it's antifungal activity and action mechanism of active ingredients are still unclear.

AIM OF THE STUDY

The aim of this study was to investigate the chemical composition, antifungal activity against skin fungi, and potential mechanisms of Artemisia argyi essential oil (AEO).

MATERIALS AND METHODS

The chemical composition of AEO was analyzed by gas chromatography-mass spectrometry (GC-MS) firstly. Flat growth restraint and double half dilution tests was performed to evaluate AEO antifungal activity against Microsporum gypseum, Trichophyton mentagrophytes, and Trichophyton rubrum. And then, the physiological mechanism of AEO inhibiting dermatophytes was systematically explored through scanning electron microscopy, relative conductivity, membrane leakage, ROS content, and antioxidant enzyme activity. Finally, the main pathways were screened through transcriptome sequencing, while the related genes expression levels and enzyme activity were validated.

RESULTS

Monoterpenes and sesquiterpenoids were the most highly representative class of AEO. AEO had powerful antifungal activity against M. gypseum, T. mentagrophytes, and T. rubrum, with minimum inhibitory concentration (MIC) values of 0.6, 1.2, and 1.2 μL/mL, respectively. Moreover, AEO can also damage the cell membrane integrity of T. mentagrophytes, resulting in cellular extravasation of intracellular substances. Transcriptome analysis revealed that the main target of AEO is to inhibit electron transfer and oxidative phosphorylation during respiration, ultimately leading to obstruction of normal ATP synthesis and energy metabolism in mitochondria. And a large amount of ROS will generate due to the incompletely catalysis of oxygen under mitochondrial complexes. Coupled with the decrease of antioxidant enzyme (SOD, POD) activity, excessive accumulation of ROS will cause serious oxidative damage to cells and eventually exhibiting antifungal activity against dermatophytes.

CONCLUSIONS

The present study demonstrated that Artemisia argyi was a valuable source of active compounds with antifungal activity. These findings support AEO as a potential agent to inhibit dermatophytes and prevent related dermatophytoses.

Nannizzia species causing dermatophytosis in cats and dogs: First report of Nannizzia incurvata as an etiological agent in Brazil

Dermatophytosis is a superficial cutaneous infection, most commonly caused by fungal species such as Microsporum canis, Nannizzia gypsea (Microsporum gypseum), and Trichophyton mentagrophytes in dogs and cats. The zoonotic potential of these species is concerning, as companion animals are increasingly close to their owners. Therefore, the objectives of the study were to evaluate the current prevalence of Nannizzia-causing canine and feline dermatophytosis in Curitiba and Metropolitan Region, as well as perform phenotypic and phylogenetic characterizations of these isolates. Thus, 241 skin and fur samples from 163 dogs and 78 cats were analyzed from 2020 to 2021. The samples were obtained from animals of three sources: Veterinary Hospital of the Federal University of Paraná, animal shelters, and private clinics. The diagnosis was performed through phenotypic characterization and sequencing ITS rDNA region. Among 97 positive samples for dermatophytes, Nannizzia was identified in 14 (14.4%) samples, while other dermatophyte genera were found in the remaining 83 (85.6%) samples. Among the canine samples, nine (90%) were N. gypsea, and one (10%) was N. incurvata. Whereas in feline samples, three (75%) were N. gypsea, and one (25%) was N. incurvata. It was concluded that among 97 animals infected with dermatophytes, dogs (24.4%; 10/41) were significantly more affected by Nannizzia than cats (7.1%; 4/56) (P < .05). According to molecular analyses, the ITS rDNA region provided satisfactory results for species-level identification of Nannizzia, confirming the first report of N. incurvata as an etiological agent of canine and feline dermatophytosis in Brazil.

Development, preparation, and evaluation of a novel non-adjuvanted polyvalent dermatophytes vaccine

Ringworm is a worldwide distributed contagious disease infecting both man and animals that constitute an economic, zoonotic, and health problem concern all over the world. During the last decade, attention has been directed to vaccination as an ideal approach to the control of such diseases. In the present study, non-adjuvanted polyvalent vaccines were prepared from locally isolated hot and virulent dermatophyte species, namely Trichophyton verrucosum (T. verrucosum), Trichophyton mentagrophytes (T. mentagrophytes), and Microsporum canis (M. canis) were immunologically evaluated. The prepared vaccine evaluation was focused on the aspects of immunogenicity and protective efficacy using guinea pigs. Both in its living or inactivated forms, the vaccine-induced significant humoral and cell-mediated immune responses and achieve proper protection of guinea pigs against challenging infections with homologous and heterologous dermatophyte strains. On the other hand, investigations on dermatophyte exo-keratinases showed that it was better produced and more expressed in a mineral-based medium containing pure keratin (3 g/L) than in the same medium with human hair supplementation (2.6 g/L). The maximum dermatophyte productivity of exo-keratinases was found to be between 18 and 21 days post-incubation. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), two fractions with molecular weights of 40 kDa (fraction I) and 28 kDa (fraction II) have been identified in the culture filtrate of the three involved dermatophyte species. Both fractions demonstrated keratinolytic activity. The specific activity of the isolated keratinases (number of Keratinase units (KU)/mg protein) was stronger in fraction I, where it reached 18.75, 15.38, and 14 KU/mg protein as compared to 12.9, 8.74, and 12 KU/mg protein in fraction II of T. verrucosum, T. mentagrophytes, and M. canis, respectively. The dermatophyte exo-keratinases proved to be immunogenic as they stimulated high keratinase-specific antibody titers and induced strong delayed skin hypersensitivity reactions in vaccinated animals. Anti-keratinase-specific IgG was detected in sera of guinea pigs immunized with the inactivated or living polyvalent dermatophyte vaccines by a homemade enzyme-linked immunosorbent assay (ELISA) using dermatophyte exo-keratinases as coating antigen. The intradermal injection of dermatophyte exo-keratinases induced specific delayed skin reactions in guinea pigs immunized with the inactivated or the living polyvalent dermatophyte vaccines. The intradermal injection of dermatophyte exo-keratinases in the control non-sensitized guinea pigs was associated with itching, swelling, and bloody scar formation, however, no skin indurations were formed. The development of those post-exo-keratinases injection reactions in the control non-sensitized apparently healthy guinea pigs group, suggests an exo-keratinases possible role in the pathogenesis of dermatophytosis.

Microsporum gypseum Isolated from Ailuropoda melanoleuca Provokes Inflammation and Triggers Th17 Adaptive Immunity Response

Microsporum gypseum causes dermatomycoses in giant pandas (Ailuropoda melanoleuca). This study aimed to investigate the immune response of M. gypseum following deep infection. The degree of damage to the heart, liver, spleen, lungs, and kidneys was evaluated using tissue fungal load, organ index, and histopathological methods. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) detected the mRNA expression of receptors and cytokines in the lung, and immunofluorescence staining and flow cytometry, were used to assess immune cells in the lung. The results indicated that conidia mainly colonized the lungs and caused serious injury with M. gypseum infection. Furthermore, dectin-1, TLR-2, and TLR-4 played a role in recognizing M. gypseum cells. Numerous inflammatory cells, mainly macrophages, dendritic cells, polymorphonuclear neutrophils, and inflammatory cytokines (TGF-β, TNF-α, IL-1β, IL-6, IL-10, IL-12, and IL-23), were activated in the early stages of infection. With the high expression of IL-22, IL-17A, and IL-17F, the Th17 pathway exerted an adaptive immune response to M. gypseum infection. These results can potentially aid in the diagnosis and treatment of diseases caused by M. gypseum in giant pandas.

Survey of Keratinophilic Fungi from Feathers of Birds in Tuscany

Although keratinophilic fungi on avian feathers have been widely described, data from European literature are quite lacking regarding Mediterranean countries. The aim of the present study was therefore to evaluate the occurrence of fungal species on feathers of different avian species in Italy. A total of 378 feather samples from both aquatic (n = 254) and terrestrial birds (n = 124), for a total of 30 bird species, were cultured for keratinophilic fungi. Fungal isolates were recognized by their macro- and micro-scopical morphology, and results were corroborated by PCR and sequencing. Keratinophilic fungi belonging to 11 different species (Scopulariopsis brevicaulis, Chrysosporium keratinophilum, Trichophyton terrestre, Microsporum gypseum, Sepedonium sp., Chrysosporium pannorum, Myriodontium sp., Chrysosporium tropicum, Chrysosporium pruinosum, Chrysosporium luteum and Aphanoascus fulvescens) were isolated from 71 animals (18.8%). The frequency of isolation of keratinophilic species from terrestrial birds was significantly higher in waterfowl. Migratory birds in Italy have been proven to carry pathogenic fungi such as dermatophytes, (A. platyrhyncos, A. crecca, E. rubecula), besides saprophytic species.

In vitro activities of 8 antifungal agents against geophilic dermatophyte isolates

BACKGROUND

Members of the Nannizzia gypsea complex are globally the most common geophilic dermatophytes which cause infection in animals and human. Although the susceptibility patterns of anthropophilic or zoophilic dermatophyte species to antifungal agents are well documented, the effectiveness of such drugs against geophilic species have rarely been explored.

OBJECTIVES

This study was aimed to evaluate the in vitro antifungal activity of common and new antifungals against a set of environmental and clinical geophilic dermatophyte isolates.

METHODS

108 soil and clinical geophilic isolates from two genera Nannizzia (N. fulva n = 59; N. gypsea n = 43) and Arthroderma (A. quadrifidum n = 4; A. gertleri n = 1; A. tuberculatum n = 1) were included in the study. The in vitro antifungal susceptibility patterns of eight common and new antifungals against the isolates were determined according to broth microdilution method and by CLSI M38-A3 (3rd edition) protocol.

RESULTS

MIC values across all isolates from five species ranged as: luliconazole: 0.0002-0.002 µg/ml, terbinafine: 0.008-0.125 µg/ml, efinaconazole: 0.008-0.125 µg/ml, ciclopirox olamine: 0.03-0.5 µg/ml, itraconazole: 0.125-1 µg/ml, amorolfine hydrochloride: 0.125-4 µg/ml, griseofulvin: 0.25-2 µg/ml and tavaborole: 1-8 µg/ml, respectively.

CONCLUSION

Luliconazole, terbinafine and efinaconazole exhibited the highest in vitro efficacy, regardless of the dermatophyte species. Further surveillance studies are recommended to confirm the implication of such in vitro data for the clinical recovery rate of dermatophytosis with geophilic species following antifungal therapy.

Survey on the Presence of Bacterial, Fungal and Helminthic Agents in Off-Leash Dog Parks Located in Urban Areas in Central-Italy

Simple Summary

Off-leash dog parks are designated, generally fenced, public spaces where dogs can move freely under the supervision of their owners. These areas, allowing animals to socialize and run free, play a fundamental role in dogs’ welfare. However, such environments may be a source of different pathogens, even zoonotic, excreted by the attending animals. The present study evaluated the occurrence of bacterial, fungal, and parasitic pathogens in off-leash dog parks located in Florence (central Italy). Yersinia spp., Listeria innocua, Toxocara canis eggs and Ancylostoma caninum/Uncinaria stenocephala eggs were found in canine feces. Keratinophilic geophilic fungi (mostly Microsporum gypseum/A. incurvatum, Microsporum canis in a single case) were recovered from soil. Trichosporon sp. and Geotrichum candidum were isolated from two water samples. The obtained results suggest that, despite the not negligible canine fecal contamination of selected areas (feces were found in 88.5% of the parks), attending dogs did not act as important carriers for the investigated pathogens, although examined off-leash dog parks may represent a risk for the spreading of some dermatophytoses to both pets and their owners. Thus, in a One-Health perspective, periodical examinations to detect the main bacteriological, parasitological and mycological pathogens in different samples collected in off-leash dog parks are recommended.

Abstract

Off-leash dog parks are designated public spaces where dogs can move freely, under their owners’ supervision. These areas, allowing animals to socialize and move freely, are fundamental for dogs’ welfare. However, different pathogens, even zoonotic, may be excreted by the attending animals and contaminate the environment. The aim of the present study was to verify the occurrence of bacterial, fungal and parasitic pathogens in off-leash dog parks located in Florence (central Italy). Between March and May 2019, 83 fecal samples, 43 soil samples and 23 water samples (from fountains and puddles) collected from 26 off-leash fenced areas were examined. Fecal samples scored positive for Yersinia spp. (n = 7), Listeria innocua (n = 4), Toxocara canis eggs (n = 2) and Ancylostoma caninum/Uncinaria stenocephala eggs (n = 1). Keratinophilic geophilic fungi (mostly Microsporum gypseum /A. incurvatum) were recovered from 43 soil samples belonging to 23 out of 26 parks, along with Microsporum canis in a single case. Prototheca spp. was never isolated from water samples, while Trichosporon sp. was cultured in two cases, alone and in association with Geotrichum candidum. These results show that dogs did not act as important carriers for the investigated bacterial and parasitic pathogens, although examined areas may represent a risk for the spreading of some dermatophytoses to both pets and their owners. Periodical examinations to assess the main bacteriological, parasitological and mycological pathogens in different samples collected in off-leash dog parks should be carried out in a One-Health perspective.

Comparison of subclinical dermatophyte infection in short- and long-haired cats

Background and Aim

Long-haired cats may have an increased risk of dermatophytosis due to insufficient grooming and their thick hair coat trapping fungal spores. The prevalence of subclinical dermatophytosis in long-haired cats was evaluated using fungal culture and Wood's lamp test. Hematology and blood chemistry results were compared between cats negative and positive for dermatophytosis.

Materials and Methods

A total of 127 cats (median age, 3 years [range, 10 months-10 years]) without feline leukemia virus or feline immunodeficiency virus infection were classified into short-haired (n=64) and long-haired (n=63) groups. Hair samples were cultured on a fungal culture medium (dermatophyte test medium, enhanced sporulation agar, and Sabouraud agar).

Results

The prevalence of dermatophytosis in short-haired and long-haired cats was 6.25% (95% confidence interval [CI], 2.15-12.28) and 34.92% (95% CI, 22.94-46.90), respectively. The odds of long-haired cats having dermatophytosis were 8.05 (95% CI, 2.44-33.97) times greater than that in short-haired cats. The number of positive dermatophytosis found in domestic short-haired cats (2/50, 4.0%) was significantly lower than that in Persian cats (17/47, 36.17%; p<0.001) and long-haired mixed breed cats (3/7, 42.86%; p=0.011). The overall sensitivity and specificity of the Wood's lamp test for diagnosing Microsporum canis infection were 37.5% (95% CI, 21.2-57.3%) and 96.1% (95% CI, 90.4-98.5%), respectively. Cats with dermatophytosis had significantly lower hematocrit and serum albumin levels than cats without dermatophytosis.

Conclusion

Subclinical dermatophytosis was more common in long-haired cats; therefore, dermatophyte examinations should be performed routinely.

Trichophyton species and Microsporum gypseum infection and fomite carriage in cats from three animal shelters: a retrospective case series

OBJECTIVES

The goal of this retrospective case series was to report on the clinical aspects of confirmed Trichophyton species and Microsporum gypseum infections in cats from three animal shelters.

METHODS

This was an observational retrospective study. Fungal culture and treatment data from three animal shelters was retrospectively reviewed to identify cats with dermatophytosis caused by Trichophyton species or M gypseum.

RESULTS

Among the three shelters only four cats were diagnosed with M gypseum dermatophytosis. With respect to Trichophyton species infections, there were six cases identified and treated in a 1 year period in one shelter, 13 cases over 13 years in the second shelter and 27 cases over 5 years in the third shelter. Four cases of M gypseum dermatophytosis were treated in the third shelter. Young cats were most commonly infected and the disease was most commonly diagnosed in the fall and winter months. Lesions were inflammatory and found predominantly on the head and neck. There was a rapid response to treatment in all cases; mean (n = 20) and median (n = 17) days to mycological cure were calculated from available data. Fungal culture data revealed fomite carriage without clinical evidence of infection for Trichophyton species (n = 43) cats and M gypseum (n = 37) cats.

CONCLUSIONS AND RELEVANCE

There is a paucity of clinical information about non-Microsporum canis dermatophytosis in shelter cats. This study data shows that Trichophyton species and M gypseum infections do occur but are uncommon. Based upon the rapid response to conventional treatment, these infections do not represent a treatment challenge, as most cats reached mycological cure within 3 weeks.

Comparison of two inoculation methods for Microsporum canis culture using the toothbrush sampling technique

BACKGROUND

The fungal culture toothbrush method is a common method for obtaining material for fungal cultures to diagnose dermatophytosis. The optimal technique for inoculation onto the agar surface has not been studied.

HYPOTHESIS/OBJECTIVES

To compare two inoculation techniques; the first involved pressing the toothbrush onto the plate surface (Procedure A) and the second involved pressing the toothbrush onto the agar, as well as transferring hairs and scales entrapped in the bristles. (Procedure B). The hypothesis was that transferring hairs onto the plate would increase the likelihood of obtaining positive cultures.

ANIMALS

Twenty-six cattery-housed cats were sampled using the toothbrush technique. Two toothbrush samples were obtained from each cat.

METHODS AND MATERIALS

The two toothbrush samples from each cat were randomized to Procedure A or B, and the investigator was blinded to inoculation technique. Cultures were performed on a medium specific for dermatophytes. The number of positive plates, and the presence and abundance of colonies of dermatophytes and contaminant moulds were compared between the two techniques.

RESULTS

Twenty-one cats were culture-positive for Microsporum canis. Procedure A resulted in a significantly higher number (P < 0.01) of positive plates (20 of 21; 95%) compared with Procedure B (seven of 21; 33%). These results were due mainly to higher plate invasion by contaminant moulds, using Procedure B.

CONCLUSIONS AND CLINICAL IMPORTANCE

Based upon the findings of this study, the optimum inoculation technique is to press toothbrush bristles onto agar plates to maximize growth of M. canis and minimize introduction of contaminant inoculation.

Activity of Salvia dolomitica and Salvia somalensis Essential Oils against Bacteria, Molds and Yeasts

Essential oils (EOs) from Salvia dolomitica and Salvia somalensis, widely employed in the cosmetic and perfume industry, were analyzed for composition and tested against bacterial and fungal pathogens isolated from clinical and environmental specimens. The analyses were carried out against Staphylococcus aureus, Staphylococcus pseudointermedius, Pseudomonas aeruginosa, Escherichia coli, Streptococcus canis, Streptococcus pyogenes, Klebsiella pneumoniae, Proteus mirabilis, Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes, Aspergillus niger, Aspergillus flavus, Candida albicans, Candida krusei, Mucor sp. and Trichothecium roseum. Both EOs showed similar percentages of total monoterpenes and sesquiterpene hydrocarbons. The main constituents were 1,8-cineole and β-caryophyllene in S. dolomitica and bornyl acetate and camphor in S. somalensis. The selected EOs have no relevant antifungal or antibacterial activities if compared to conventional drugs.

Diagnosis and treatment of dermatophytosis in dogs and cats.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

Dermatophytosis is a superficial fungal skin disease of cats and dogs. The most common pathogens of small animals belong to the genera Microsporum and Trichophyton. It is an important skin disease because it is contagious, infectious and can be transmitted to people.

OBJECTIVES

The objective of this document is to review the existing literature and provide consensus recommendations for veterinary clinicians and lay people on the diagnosis and treatment of dermatophytosis in cats and dogs.

METHODS

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to September 2016. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) provided guidance and oversight for this process. A draft of the document was presented at the 8th World Congress of Veterinary Dermatology (May 2016) and was then made available via the World Wide Web to the member organizations of the WAVD for a period of three months. Comments were solicited and posted to the GP electronically. Responses were incorporated by the GP into the final document.

CONCLUSIONS

No one diagnostic test was identified as the gold standard. Successful treatment requires concurrent use of systemic oral antifungals and topical disinfection of the hair coat. Wood's lamp and direct examinations have good positive and negative predictability, systemic antifungal drugs have a wide margin of safety and physical cleaning is most important for decontamination of the exposed environments. Finally, serious complications of animal-human transmission are exceedingly rare.

Dermatophytosis in donkeys (Equus asinus) due to Microsporum racemosum, an unusual geophilic agent

Reports about ringworm in donkeys are scanty and refer to zoonotic agents such as Trichophyton mentagrophytes and Trichophyton verrucosum. Seventeen Asino Amiatina donkeys semi-extensively farmed in paddocks showed alopecic nummular, scaling areas mainly on head and neck. Microsporum racemosum cultivated from the lesions was identified by morphology and PCR. Affected animals healed spontaneously. The present record reports for the first time the occurrence of ringworm due to M. racemosum in naturally infected animals.

Feline dermatophytosis: steps for investigation of a suspected shelter outbreak

PRACTICAL RELEVANCE

Dermatophytosis (ringworm) is the most important infectious and contagious skin disease of cats in shelters. Its importance relates to the fact that it can affect all cats, but tends to affect those which would otherwise have good chances for adoption. Although many diseases in shelters fit this description, dermatophytosis is of particular significance because of associated public health concerns.

CLINICAL CHALLENGES

Disease management in animal shelters is challenging because new animals are frequently entering the population, numerous animals are often housed together, and resources are almost always limited. GLOBAL RELEVANCE: Outbreaks of dermatophytosis occur worldwide and no animal shelter is completely shielded from possible introduction of the disease into the population.

AUDIENCE

This article offers a flexible stepwise approach to dealing with a known or suspected outbreak of dermatophytosis in an animal shelter. It is based on the authors' experiences spanning more than a decade of responses and/or consultations. While primarily aimed at veterinarians involved in shelter medicine, the principles largely apply to other group-housing situations, such as catteries and breeding establishments.

AIMS

The goals in dealing with a potential dermatophytosis outbreak are to ascertain if the 'outbreak' is actually an outbreak, to develop a shelter-specific outbreak management plan and to implement a long-term plan to prevent recurrences.