PCR and real-time PCR approaches to the identification of Arthroderma otae species Microsporum canis and Microsporum audouinii/Microsporum ferrugineum

Tinea corporis intrafamilial infection in pets due to Microsporum canis

Microsporum canis, one of the most widespread dermatophytes worldwide, is a zoonotic microorganism that transmits infection from reservoirs such as cats and dogs to humans. This microorganism is associated with Tinea corporis and other clinical manifestations; however, few studies have used genetic surveillance to determine and characterize the process of zoonotic transmission. In this study, we show a clear example of zoonotic transmission from a cat to an intrafamilial environment, where it caused Tinea corporis by infection with M. canis. Molecular characterization using the b-tubulin gene and Random Amplified Polymorphic DNA analysis made it possible to determine that the six isolates of M. canis obtained in this study belonged to the same genetic variant or clone responsible for reservoir-reservoir or reservoir-human transmission.

Molecular diagnosis of dermatophyte isolates from canine and feline dermatophytosis in Northeast Iran

Background

Dermatophytes are the most common causes of cutaneous fungal diseases. Dermatophytosis is a common skin disorder in dogs and cats. Species identification of these fungi is important from a therapeutic and epidemiological aspect. Conventional methods used to identify dermatophyte species are often lengthy and may be inefficient in many circumstances. Recently broad varieties of several molecular DNA‐based techniques were successfully utilised for species detection of dermatophytes.

Objectives

The aim of this study was to determine the molecular detection of dermatophyte isolates from canine and feline dermatophytosis in Mashhad, Iran.

Methods

Thirty dermatophytes isolated from dogs and cats with skin lesions and one standard strain of Microsporum canis were cultured onto Mycosel agar, and then internal transcribed spacer (ITS) region of the ribosomal DNA was amplified using the universal fungal primers ITS1 and ITS4. PCR products were subjected to sequencing and sequence analysis.

Results

Based on the sequencing of the ITS1‐5.8S‐ITS2 region on all samples, all the studied strains were M. canis and their sexual stage (teleomorph) was Arthroderma otae.

Conclusions

Microsporum canis was the only species found among dogs and cats, and its high prevalence can increase the rate of transmission to humans. In practice, ITS‐PCR, with sequence analysis, is a useful and reliable method to identify and differentiate various pathogenic species, and it can be used in clinical and epidemiological fields, even for the rapid diagnosis of dermatophyte species that are closely interrelated.

A new molecular marker for species-specific identification of Microsporum canis

Species identification of dermatophytes by conventional mycological methods based on macro- and microscopy analysis is time-consuming and has a lot of limitations such as slow fungal growth or low specificity. Thus, there is a need for the development of molecular methods that would provide reliable and prompt identification of this group of medically important fungi. The are many reports in the literature concerning PCR identification of dermatophyte species, but still, there are not many PCR assays for the separate detection of members of the genera Microsporum, especially Microsporum canis (zoophilic species) and Microsporum audouinii (anthropophilic species). The correct distinction of these species is important to determine the source of infection to implement the appropriate action to eliminate the path of infection transmission. In this paper, we present such a PCR-based method targeting velB gene that uses a set of two primers—Mc-VelB-F (5′-CTTCCCCACCCGCAACATC-3′) and Mc-VelB-R (5′-TGTGGCTGCACCTGAGAGTGG-3′). The amplified fragment is specific due to the presence of (CAGCAC)₈ microsatellite sequence only in the velB gene of M. canis. DNA from 153 fungal samples was used in PCR assay followed by electrophoretic analysis. The specificity of the designed set of primers was also confirmed using the online BLAST-Primer tool. The positive results were observed only in the case of M. canis isolates, and no positive results were obtained neither for other dermatophytes and non-dermatophyte fungi nor for other Eukaryotes, including the human genome sequence, as well as the representatives of bacterial and viral taxa. The developed PCR assay using the proposed Mc-VelB-F and Mc-velB-R primers can be included in the algorithm of M. canis detection in animals and humans.

Identification of Dermatophyte and Nondermatophyte Molds Isolated from Animal Lesions Suspected to Dermatomycoses

Background:

Dermatomycoses contain superficial fungal infections of keratinized layers of the body such as skin, hair, and nail that affect more than 20%–25% of people and animals worldwide. Some fungi can cause superficial infections in animals after accidental penetration and colonization on injured skin and can be transmitted to humans by exposure. The infection caused mainly by dermatophyte species and may also be caused rarely by yeasts and nondermatophytic molds.

Materials and Methods:

Eighty-two skin scrapings and hair samples were collected from animals (sheep, cow, cat, camel, calf, goat, horse, and dog) in three specialized pet clinics and three livestock and slaughterhouses. The isolates were identified using direct microscopy, culture, and polymerase chain reaction-sequencing of ITS1-5.8SrDNA-ITS2 region.

Results:

Thirteen mold strains out of 82 clinical samples (15.8%) were isolated from animal lesions. Acremonium exuviarum (n = 4; 30.7%), Sarocladium implicatum (n = 2; 15.4%), Arthroderma otae (n = 2; 15.4%), Chaetomium iranianum (n = 1; 7.7%), Trichothecium roseum (n = 1; 7.7%), Lichtheimia ramosa (n = 1; 7.7%), Penicillium chrysogenum (n = 1; 7.7%), and Microsporum equinum (n = 1; 7.7%) were isolated from clinical specimens.

Conclusion:

Since opportunistic fungi are increasing as etiological agents of dermatomycoses, isolation of these molds from wounds can be a warning to veterinarians, and daily cleaning of wounds with a proper disinfectant is recommended for the prevention of fungal colonization.