Preliminary report on the isolation of a dysgonic variety of Microsporum canis together with the normal variety from a cattery

A zoonotic ringworm outbreak caused by a dysgonic strain of Microsporum canis from stray cats

BACKGROUND

Cats are frequent carriers of Microsporum canis and veterinary students are at high risk of exposure and acquisition of the organism a la infección.

OBJECTIVES

An outbreak of zoonotic ringworm carried by a litter of stray cats is described. Four veterinary students, four dogs, and six cats living in five separate locations were affected. All had direct or indirect contact with the infected kitten litter. We tried to identify the causal dermatophyte.

METHODS

Conventional and mycological culture methods were used.

RESULTS

Microscopic features of scrapings and hairs treated with 20% KOH strongly suggested a M. canis etiology, and a diagnosis of ringworm was empirically supported by successful treatment of humans and animals. Nevertheless, cultures failed to show the expected morphology.

CONCLUSIONS

Culture features of our strain are compared with those described by other authors for dysgonic M. canis strains. Epidemiological features are also discussed.

Study of the ITS region in an atypical isolate and comparison with six species of Microsporum

Microsporum species are a frequent cause of cutaneous mycoses in humans. Atypical strains of Microsporum can sometimes be difficult to identify with conventional methods. Recently, we have obtained a Microsporum isolate with atypical morphology and special nutritional requirements (Microsporum CHUS-126-02). As several molecular techniques have been developed for the identification of fungi, we analysed six Microsporum species (M. canis, M. gypseum, M. gallinae, M. nanum, M. ferrugineum and M. persicolor) in order to compare them with our isolate, by using polymerase chain reaction-restriction enzyme analysis (PCR-REA). We studied the nucleotide sequence of the internal transcribed spacer regions from the nuclear DNA encoding for the ribosomal domain. Digestion with MvaI and EcoRI endonucleases obtained specific patterns for M. gypseum, M. gallinae, M. nanum and M. persicolor. Microsporum canis, M. ferrugineum and Microsporum CHUS-126-02 yielded the same patterns. Based on these results and phenotypic criteria, we classified our atypical isolate as M. canis.

Feline dermatophytosis. Recent advances and recommendations for therapy

Feline dermatophytosis is one of the most common skin diseases of cats. In the past, much of the information available on this subject stemmed from clinical observations. This article summarizes current research findings on the epidemiology, immunology, pathogenesis, and treatment of feline dermatophytosis. As a result of these studies, the authors propose new recommendations for treatment.