A case of an apparent infestation by Proisotoma spp. springtails (Collembola: Isotomidae) in a cat.

This case report is presumed to be the first case of infestation of a cat by springtails which are small arthropods closely related to insects. The organisms, found by skin scrapings, were identified as Proisotoma spp. (Collembola: Isotomidae). The cat presented with dermatological lesions (itchy, furfuraceous dermatitis), and we speculate that they were due to this infestation. The pathogenic role of the Collembola was hypothesized because of the large number of organisms, the presence of eggs indicating an active reproduction cycle, the lack of other pathogens (fleas, mites or lice) and the clinical recovery accompanied by the disappearance of Collembola following treatment. The owner seemed to be affected by the infestation, because a few days after having purchased the cat, she developed a pruriginous papular dermatitis on the neck and the arms, which disappeared shortly after treatment of the kitten and a careful washing of all of its toys and other accoutrements.

Evaluation of the antifungal susceptibility of Malassezia pachydermatis to clotrimazole, miconazole and thiabendazole using a modified CLSI M27-A3 microdilution method.

BACKGROUND: In this study, we evaluated the antifungal susceptibility of Malassezia pachydermatis to clotrimazole (CTZ), miconazole (MCZ), and thiabendazole (TBD), azole derivatives employed in aural formulations labeled for treatment of canine otitis. METHODS: The procedure for in vitro testing was based on the indications of the Clinical and Laboratory Standards Institute (CLSI) M27-A3 microdilution method. A lipid-enriched medium was employed to enhance the yeast growth (Christensen's urea broth, with 0.1% Tween 80 and 0.5% Tween 40 as the lipid sources), while the inoculums size corresponded to approximately 1-5 × 10(5) yeast cells/mL. Microplates were incubated at 37°C and read 48 h after inoculation. Azole MICs inhibiting fungal growth were the lowest drug concentrations that showed an optical density of ≤ 50% of the (drug-free) growth control, as assessed by spectrophotometer (630 nm filter). RESULTS: All isolates were inhibited by the three azoles, with different minimum inhibitory concentration (MIC) values. Most isolates were inhibited by drug concentrations of 2-8 (CTZ), 1-4 (MCZ), or 16-32 (TBD) µg/mL. These results are partially in agreement with the findings of previous studies, in which substantially higher/lower MICs were occasionally reported. This is likely because of the different methodologies employed. Such discrepancies may not apply to clinical situations, where the compounds are applied topically. CONCLUSION AND CLINICAL IMPORTANCE: The concept that clinical failure is linked to increased MICs is debatable, because significantly higher concentrations (in most cases at least 1,000 × the MIC) of the antifungals that were included in our study are routinely used in formulated products.

Antifungal Resistance Regarding Malassezia pachydermatis: Where Are We Now?

Malassezia pachydermatis is a yeast inhabiting the skin and ear canals in healthy dogs. In the presence of various predisposing conditions it can cause otitis and dermatitis, which are treated with multiple antifungal agents, mainly azole derivatives. This manuscript aims to review the available evidence regarding the occurrence of resistance phenomena in this organism. Various findings support the capacity of M. pachydermatis for developing resistance. These include some reports of treatment failure in dogs, the reduced antifungal activity found against yeast isolates sampled from dogs with exposure to antifungal drugs and strains exposed to antifungal agents in vitro, and the description of resistance mechanisms. At the same time, the data reviewed may suggest that the development of resistance is a rare eventuality in canine practice. For example, only three publications describe confirmed cases of treatment failure due to antifungal resistance, and most claims of resistance made by past studies are based on interpretive breakpoints that lack sound support from the clinical perspective. However, it is possible that resistant cases are underreported in literature, perhaps due to the difficulty of obtaining a laboratory confirmation given that a standard procedure for susceptibility testing of M. pachydermatis is still unavailable. These considerations highlight the need for maintaining surveillance for the possible emergence of clinically relevant resistance, hopefully through a shared strategy put in place by the scientific community.

Methodological Issues in Antifungal Susceptibility Testing of Malassezia pachydermatis.

Reference methods for antifungal susceptibility testing of yeasts have been developed by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antibiotic Susceptibility Testing (EUCAST). These methods are intended to test the main pathogenic yeasts that cause invasive infections, namely Candida spp. and Cryptococcusneoformans, while testing other yeast species introduces several additional problems in standardization not addressed by these reference procedures. As a consequence, a number of procedures have been employed in the literature to test the antifungal susceptibility of Malassezia pachydermatis. This has resulted in conflicting results. The aim of the present study is to review the procedures and the technical parameters (growth media, inoculum preparation, temperature and length of incubation, method of reading) employed for susceptibility testing of M. pachydermatis, and when possible, to propose recommendations for or against their use. Such information may be useful for the future development of a reference assay.

Trichophyton verrucosum infection in livestock in the Chitral district of Pakistan.

INTRODUCTION: Trichophyton verrucosum belongs to the dermatophyte fungi, closely related organisms that cause skin infections in animals and humans. T. verrucosum infection has been reported in livestock and people in different countries from all continents. Human cases have been reported in different areas of Pakistan, but there is little information about the animal source of the fungus. METHODOLOGY: Dermatological specimens collected in the Chitral district of Pakistan for a study on mange in livestock were retrospectively analyzed for the presence of T. verrucosum. In total, 5,873 animals (1,087 cows, 2,033 goats, and 2,753 sheep) were screened for evidence of dermatological lesions during two surveys performed in the summer and winter seasons. Skin scrapings collected from animals with lesions were analyzed by direct microscopic examination after digestion in sodium hydroxide and a real-time polymerase chain reaction (PCR) targeting pathogenic Trichophyton species. RESULTS: At microscopy, samples from 18 cows (1.6%), 3 sheep (0.1%), and 4 goats (0.2%) were positive for fungal elements consistent with T. verrucosum. PCR confirmed the microscopy results. The prevalence was lower than that reported in other countries in intensive breeding farms. Results agree with the literature regarding factors affecting T. verrucosum diffusion, i.e., infection was more prevalent in cattle, especially in younger animals during the winter season. CONCLUSIONS: This study reports, for the first time, the presence of T. verrucosum in livestock in Pakistan. A better knowledge of the animal role in the spread of this fungus may allow the adoption of more efficient control measures and prophylaxis.