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Hobi S, Tam WYJ, Tse M, Nekouei O, Chai Y, Hill FI, Cheung E, Botes W, Saulnier-Troff F, McDermott CT, Barrs VR. Microsporum canis Causes Cutaneous and Extracutaneous Feline Dermatophytic Pseudomycetomas: Molecular Identification and Clinicopathological Characteristics. J Fungi (Basel) 2024; 10:576. [PMID: 39194901 DOI: 10.3390/jof10080576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Revised: 08/12/2024] [Accepted: 08/12/2024] [Indexed: 08/29/2024] Open
Abstract
Dermatophytic pseudomycetoma (DPM) is a rarely reported invasive fungal infection of humans and animals, especially cats. This study aimed to identify dermatophytes, breed associations, and the frequency of extracutaneous (EC) involvement in feline DPM. Electronic records and formalin-fixed paraffin-embedded tissue (FFPET) from 32 suspected DPM cases in 30 cats were retrieved from a diagnostic laboratory between 2018 and 2024. To confirm DPM and molecular identity, DNA was extracted from FFPET for ITS2 sequencing, and immunohistochemistry was performed on PCR-negative cases. All cases were confirmed as DPM. Microsporum canis was the only dermatophyte identified. The sensitivity and specificity of ITS2 sequencing for M. canis identification in FFPET were 22/32 (68.8%) and 21/22 (95.5%), respectively. Exotic (36.7%) and Persian (23.3%) but not British breeds (26.3%) were over-represented compared to feline admissions at an affiliated veterinary hospital (8.5%, p < 0.001; 3%, p < 0.001; 21.6%, p = 0.817, respectively). Five cases (16.7%) had EC lesions; two had intra-abdominal masses; two had oral cavity masses, including one which extended into the cranial vault; and one had superficial cervical lymph node invasion. Exotic and Persian breeds are over-represented for DPM and M. canis is the primary cause. EC lesions of DPM may occur more commonly than previously thought.
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Affiliation(s)
- Stefan Hobi
- Department of Veterinary Clinical Sciences, Jockey Club College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
- City University Veterinary Medical Centre, Hong Kong, China
| | - Wing Yan Jacqueline Tam
- Department of Veterinary Clinical Sciences, Jockey Club College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - May Tse
- Department of Veterinary Clinical Sciences, Jockey Club College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
- Veterinary Diagnostic Laboratory, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Omid Nekouei
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Yingfei Chai
- Department of Veterinary Clinical Sciences, Jockey Club College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Fraser I Hill
- Veterinary Diagnostic Laboratory, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Edmund Cheung
- Not for Profit Veterinary Clinic, Prince Edward, Hong Kong, China
| | | | | | - Colin T McDermott
- Department of Veterinary Clinical Sciences, Jockey Club College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
| | - Vanessa R Barrs
- Department of Veterinary Clinical Sciences, Jockey Club College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, China
- Centre for Animal Health and Welfare, City University of Hong Kong, Kowloon Tong, Hong Kong, China
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Soares FO, Rosado IR, Sousa MVC, Dumont CF, Bittar JFF, Martin I, Beletti ME, Melo RT, Alves EGL. Osteomyelitis by Microsporum canis and Staphylococcus spp. in cat (Felis catus) - case report. BMC Vet Res 2024; 20:58. [PMID: 38374006 PMCID: PMC10875912 DOI: 10.1186/s12917-024-03904-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 01/29/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND Staphylococcus spp and Microsporum canis are zoonotic microorganisms which can cause infections and systemic diseases. The bone infection is usually caused by invasion of pathogen through the hematologic route. Mixed osteomyelitis caused by bacteria and fungi is rare, and to date, there have been no reports of mixed osteomyelitis with Staphylococcus spp. and Microsporum canis. CASE PRESENTATION This essay reports an atypical presentation of mixed osteomyelitis (Staphylococcus spp. and Microsporum canis) in a domestic cat. A 15-month-old female Persian cat was presented to a veterinary service; the main complaint was the appearance of a nodule in the mandibular ventral rostral region. A radiographic exam performed on the animal showed proliferative and osteolytic bone lesions. The patient was submitted to a biopsy for histopathological evaluation, along with bacterial and fungal cultures. Results showed mixed osteomyelitis by Staphylococcus spp. and Microsporum canis. Microbial Sensitivity Test was performed to choose a more suitable treatment. Two surgical procedures were executed to resect and curette the lesion, and treatments with anti-inflammatory, antibiotic, and antifungal drugs were established, showing a positive clinical evolution. After 8 months of treatment, the patient's owner moved to a different city, and the animal was seen by other veterinarians, who followed along with the same treatment. However, due to complications and a diminishing quality of life over 4 years of diagnosis, the patient was euthanized. CONCLUSION Given the above, mixed osteomyelitis is difficult to treat and can cause losses of life quality resulting death, especially in infections where M. canis is the agent causing the disease. Bacterial osteomyelitis is more frequently reported. But the lack of investigation of microorganisms other than bacteria, such as fungal cases, may imply in underdiagnosed cases. Treatment of osteomyelitis can be difficult considering the difficulties in isolating the pathological agent, resistance to the drug used, prolonged treatment time, and cost.
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Affiliation(s)
- Fernanda O Soares
- Hospital Veterinário Uniube, Universidade de Uberaba, Uberaba, Minas Gerais, Brazil
| | - Isabel R Rosado
- Hospital Veterinário Uniube, Universidade de Uberaba, Uberaba, Minas Gerais, Brazil
| | - Marcus V C Sousa
- Laboratório de Patologia Animal - PAVET, Universidade de Uberaba, Uberaba, Minas Gerais, Brazil
| | - Carolyne F Dumont
- Laboratório de Epidemiologia Molecular - LEPIMOL, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal de Uberlândia, Av. Ceará, s/n, Bloco 2D43, Uberlândia, CC 38402-018, Brazil.
| | - Joely F F Bittar
- Hospital Veterinário Uniube, Universidade de Uberaba, Uberaba, Minas Gerais, Brazil
| | - Ian Martin
- Hospital Veterinário Uniube, Universidade de Uberaba, Uberaba, Minas Gerais, Brazil
| | - Marcelo E Beletti
- Laboratório de Epidemiologia Molecular - LEPIMOL, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Roberta T Melo
- Laboratório de Epidemiologia Molecular - LEPIMOL, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Endrigo G L Alves
- Hospital Veterinário Uniube, Universidade de Uberaba, Uberaba, Minas Gerais, Brazil
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Moriello KA, Coyner K, Paterson S, Mignon B. Diagnosis and treatment of dermatophytosis in dogs and cats.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 2017; 28:266-e68. [PMID: 28516493 DOI: 10.1111/vde.12440] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2016] [Indexed: 12/12/2022]
Abstract
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.
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Affiliation(s)
- Karen A Moriello
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive West, Madison, WI, 53706, USA
| | - Kimberly Coyner
- Dermatology Clinic for Animals, 8300 Quinault Drive NE Suite A, Lacey, WA, 98516, USA
| | - Susan Paterson
- Department of Veterinary Dermatology, Rutland House Referral Hospital, Abbotsfield Road, St Helens, WA9 4HU, UK
| | - Bernard Mignon
- Department of Infectious and Parasitic Diseases, Veterinary Mycology, FARAH (Fundamental and Applied Research for Animals & Health), Faculty of Veterinary Medicine, University of Liège, Quartier Vallée 2, Avenue de Cureghem 10, B43A, 4000, Liège, Belgium
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Intra-abdominal fungal pseudomycetoma in two cats. Rev Iberoam Micol 2017; 34:112-115. [DOI: 10.1016/j.riam.2016.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 10/04/2016] [Accepted: 10/28/2016] [Indexed: 11/18/2022] Open
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Ziglioli V, Panciera DL, LeRoith T, Wiederhold N, Sutton D. Invasive Microsporum canis causing rhinitis and stomatitis in a cat. J Small Anim Pract 2016; 57:327-331. [PMID: 27061928 DOI: 10.1111/jsap.12471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 11/17/2015] [Accepted: 02/11/2016] [Indexed: 11/29/2022]
Abstract
Microsporum canis is a pathogenic fungus that typically causes dermatophytosis in cats. This report describes a cat with a Microsporum canis infection causing invasive fungal rhinitis that extended through the hard palate, resulting in adjacent stomatitis. Treatment with itraconazole and terbinafine resolved the infection.
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Affiliation(s)
- V Ziglioli
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA 24061, USA
| | - D L Panciera
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA 24061, USA
| | - T LeRoith
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA 24061, USA
| | - N Wiederhold
- Department of Pathology, Fungus Testing Laboratory, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - D Sutton
- Department of Pathology, Fungus Testing Laboratory, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Sun PL, Peng PC, Wu PH, Chiang YL, Ju YM, Chang CC, Wang PC. Canine eumycetoma caused byCladophialophora bantianain a Maltese: case report and literature review. Mycoses 2013; 56:376-81. [DOI: 10.1111/myc.12033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Walker L, Bianchi M, Maiolo E, Arechavala A, Santiso G, Messina F, Lehmann E, Schtirbu R, Negroni R. [Clinical problems in medical mycology: problem number 44]. Rev Iberoam Micol 2011; 29:181-3. [PMID: 21872674 DOI: 10.1016/j.riam.2011.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 07/19/2011] [Indexed: 10/17/2022] Open
Affiliation(s)
- Laura Walker
- Unidad Micología, Hospital de Infecciosas Francisco J. Muñiz, Buenos Aires, Argentina
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Sakai MR, May ER, Imerman PM, Felz C, Day TA, Carlson SA, Noxon JO. Terbinafine pharmacokinetics after single dose oral administration in the dog. Vet Dermatol 2011; 22:528-34. [PMID: 21599768 DOI: 10.1111/j.1365-3164.2011.00985.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Terbinafine is an allylamine antifungal prescribed for the treatment of mycoses in humans. It is increasingly being used in veterinary patients. The purpose of this study was to evaluate the pharmacokinetic properties of terbinafine in dogs after a single oral dose. Ten healthy adult dogs were included in the study. A single dose of terbinafine (30-35 mg/kg) was administered orally, and blood samples were periodically collected over a 24 h period during which dogs were monitored for adverse effects. Two of 10 dogs developed transient ocular changes. A high-performance liquid chromatography assay was developed and used to determine plasma terbinafine concentrations. Pharmacokinetic analysis was performed using PK Solutions(®) computer software. Area under the curve (AUC) from time 0 to 24 h was 15.4 μg·h/mL (range 5-27), maximal plasma concentration (C(max) ) was 3.5 μg/mL (range 3-4.9 μg/mL) and time to C(max) (T(max) ) was 3.6 h (range 2-6 h). The time above minimal inhibitory concentration (T > MIC) as well as AUC/MIC was calculated for important invasive fungal pathogens and dermatophytes. The T > MIC was 17-18 h for Blastomyces dermatitidis, Histoplasma capsulatum and dermatophytes (Microsporum spp. and Trichophyton mentagrophytes), while the MIC for Sporothrix schenckii and Coccidioides immitis was exceeded for 9.5-11 h. The AUC/MIC values ranged from 9 to 13 μg h/mL for these fungi. Our results provide evidence supporting the use of terbinafine as an oral therapeutic agent for treating systemic and subcutaneous mycoses in dogs.
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Affiliation(s)
- Mary R Sakai
- Department of Veterinary Clinical Sciences, Iowa State University, Ames, IA 50011, USA.
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Nobre MDO, Negri Mueller E, Teixeira Tillmann M, da Silva Rosa C, Normanton Guim T, Vives P, Fernandes M, Martins Madrid I, Gevehr Fernandes C, Araújo Meireles MC. Disease progression of dermatophytic pseudomycetoma in a Persian cat. Rev Iberoam Micol 2010; 27:98-100. [DOI: 10.1016/j.riam.2009.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 12/23/2009] [Indexed: 10/19/2022] Open
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Thian A, Woodgyer AJ, Holloway SA. Dysgonic strain ofMicrosporum canispseudomycetoma in a Domestic Long-hair cat. Aust Vet J 2008; 86:324-8. [PMID: 18673475 DOI: 10.1111/j.1751-0813.2008.00328.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- A Thian
- University of Melbourne Veterinary Clinic and Hospital, 250 Princes Highway, Werribee, Victoria 3030, Australia.
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12
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Dermatophytoses in Animals. Mycopathologia 2008; 166:385-405. [PMID: 18478363 DOI: 10.1007/s11046-008-9102-7] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 01/15/2008] [Accepted: 01/30/2008] [Indexed: 10/22/2022]
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STANLEY SKYEW, FISCHETTI ANTHONYJ, JENSEN HENRIKE. IMAGING DIAGNOSIS—SUBLUMBAR PSEUDOMYCETOMA IN A PERSIAN CAT. Vet Radiol Ultrasound 2008; 49:176-8. [DOI: 10.1111/j.1740-8261.2008.00346.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Nardoni S, Franceschi A, Mancianti F. Identification of Microsporum canis from dermatophytic pseudomycetoma in paraffin-embedded veterinary specimens using a common PCR protocol. Mycoses 2007; 50:215-7. [PMID: 17472620 DOI: 10.1111/j.1439-0507.2007.01368.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effectiveness of a simple PCR protocol performed on paraffin-embedded tissues, obtained from histopathologically and culturally diagnosed cases of dermatophytic pseudomycetoma DPM was tested. The specimens were investigated using previously described primers (DH1L and DH1R) targeting the 18S rDNA gene and amplifying a 183-bp fragment. Microsporum canis was identified from all samples. The PCR protocol described in the present work demonstrated a 100% concordant result comparing the molecular characterisation with phenotypic characterisation of dermatophytes. Molecular biology could represent a valid identification tool in dermatophytic deep infections, when diagnosis cannot be achieved by cultural methods.
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Affiliation(s)
- Simona Nardoni
- Dipartimento di Patologia Animale, Profilassi ed Igiene degli Alimenti, Università di Pisa, Pisa, Italy.
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Berg JC, Hamacher KL, Roberts GD. Pseudomycetoma caused by Microsporum canis in an immunosuppressed patient: a case report and review of the literature. J Cutan Pathol 2007; 34:431-4. [PMID: 17448202 DOI: 10.1111/j.1600-0560.2006.00628.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND A 65-year-old woman with a history of liver and kidney transplantation presented with a pruritic and tender rash of 2-year duration on her left knee. METHODS The patient had a physical examination, and multiple skin biopsies were performed. RESULTS Examination showed a cluster of dome-shaped, violaceous papules. A skin biopsy specimen showed multiple granules containing basophilic material within the superficial to mid dermis. The grains were embedded in an eosinophilic substance and surrounded by granulomatous inflammation. A Gomori methenamine silver stain showed abundant septate hyphae, and cultures grew colonies of Microsporum canis. A diagnosis of dermatophytic granuloma, or pseudomycetoma, was made. After considering the patient's immune status, a prolonged course of fluconazole was initiated. CONCLUSION Microsporum canis, a frequently encountered zoophilic dermatophyte associated with tinea capitis and tinea corporis, is rarely associated with a mycetoma-like presentation, grain formation, or systemic infection. The medical literature describes only six cases of M. canis causing mycetoma-like formations in immunocompromised and immunocompetent patients. This case report describes an unusual presentation of a common dermatophyte infection, and the literature review summarizes the importance of recognizing atypical presentations of dermatophyte infections. Such infections may warrant more aggressive treatment in immunocompromised patients.
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Affiliation(s)
- Jena C Berg
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
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Abstract
The diagnosis of fungal disease is a challenge that requires diligent attention to history and clinical signs as well as an astute ability to interpret laboratory data. Because fungal disease can mimic other infectious and neoplastic diseases in clinical presentation, the clinician has to be aware of fungal diseases common locally as well as in other regions of the country. A global approach to the diagnosis of fungal disease that correlates clinical signs as well as physical examination, clinical pathology, and histopathology findings with serology, culture, and the newer immunohistochemical and molecular techniques, where available, is the best approach to optimize the identification of the underlying agent.
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Affiliation(s)
- Sharon M Dial
- Department of Veterinary Science and Microbiology, Arizona Veterinary Diagnostic Laboratory, University of Arizona, 2831 North Freeway, Tucson, AZ 85705, USA.
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Martorell J, Gallifa N, Fondevila D, Rabanal RM. Bacterial pseudomycetoma in dwarf hamster, Phodopus sungorus. Vet Dermatol 2006; 17:449-52. [PMID: 17083578 DOI: 10.1111/j.1365-3164.2006.00554.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A case of a dwarf hamster with two progressively growing nodules on the right fore limb is described. These were excised following ineffective medical treatment and were submitted for histopathological examination, which revealed bacterial pseudomycetoma in both nodules. To the authors' knowledge this is the first reported case of bacterial pseudomycetoma in a dwarf hamster.
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Affiliation(s)
- Jaime Martorell
- Department of Animal Medicine and Surgery, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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Abstract
We describe mycetoma caused by Microsporum canis occurring in a 9-year-old African-American girl. Pathologic evaluation showed a granulomatous dermatitis with numerous large fungal grains containing septate hyphae that were Fontana-Masson positive. Two cultures of pure grains grew M. canis. Mycetoma due to dermatophytes is very uncommon. The few instances reported have been pseudomycetoma (grains in the absence of sinus tracts). Our patient developed sinus tracts (true mycetoma). No prior reports were found of M. canis staining Fontana positive. Differentiation of dermatophyte-induced mycetoma from kerion is important because mycetomas require a combined approach including surgical debridement in addition to oral antifungal therapy.
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Affiliation(s)
- Sasha C Kramer
- Department of Dermatology, Geisinger Medical Center, Danville, Pennsylvania 17822, USA
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Abstract
A 1-year-old spayed female Persian cat with alopecia and weight loss had numerous variably ulcerated dermal nodules. Cytologic examination of an aspirate of one of the nodules revealed pyogranulomatous inflammation along with septate hyphae and basophilic round bodies, 0.5-1.0 microm in diameter, surrounded by a thin clear halo (arthrospores). The cytologic diagnosis was dermatophytic pseudomycetoma. Histologically, there were dermal granulomas containing poorly staining, septate hyphae with bulbous spores embedded within abundant amorphous eosinophilic material (Splendore-Hoeppli reaction), and the histologic diagnosis was pseudomycetoma-associated chronic multifocal severe granulomatous dermatitis with lymphocytic perifolliculitis and furunculosis. Microsporum canis was cultured from the lesion. Pseudomycetomas are distinguished from fungal mycetomas, or eumycotic mycetomas, by the findings of multiple lesions, lack of a history of skin trauma, an association with dermatophytes, most commonly Microsporum canis, and, histologically, lack of true cement material and a more abundant Splendore-Hoeppli reaction in pseudomycetomas. Additionally, pseudomycetomas differ from dermatophytosis, in which lesions are restricted to epidermal structures. Persian cats have a high incidence of pseudomycetoma formation, suggesting a heritable predisposition. The prognosis is fair with systemic antifungal therapy. When examining cytologic specimens from Persian cats with single or multiple dermal nodules, especially if pyogranulomatous inflammation is present, a diagnosis of pseudomycetoma should be suspected and is warranted if arthrospores and refractile septate hyphae are present.
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Affiliation(s)
- Kurt Zimmerman
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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