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Published on: March 29, 2020
Localised Mycobacterium ulcerans infection in a cat in Australia
Lisa Elsner1, Julie Wayne, Carolyn R O'Brien
1Longford Veterinary Centre, Sale, Victoria, Australia.
Insights
This study reports the first known case of Mycobacterium ulcerans infection in a domestic cat. The cat was successfully treated with clarithromycin, showing no recurrence of the infection.
Area of Science:
- Veterinary Medicine
- Infectious Diseases
- Microbiology
Background:
- Mycobacterium ulcerans causes Buruli ulcer in humans and has been identified in various mammal species.
- Subcutaneous masses and pyogranulomatous inflammation are clinical signs that can indicate mycobacterial infections.
Purpose of the Study:
- To document the first case of Mycobacterium ulcerans infection in a domestic cat.
- To describe the clinical presentation, diagnosis, and treatment of this novel feline infection.
Main Methods:
- Surgical excision of a nasal subcutaneous mass.
- Cytological and histological examination of the lesion.
- Ziehl-Neelsen staining for acid-fast bacilli.
- Molecular identification of Mycobacterium ulcerans.
- Treatment with oral clarithromycin.
Main Results:
- A subcutaneous mass on the nasal bridge of a cat was diagnosed as Mycobacterium ulcerans infection.
- Histopathology revealed pyogranulomatous inflammation and acid-fast bacilli.
- The cat responded well to a 3.5-month course of clarithromycin.
- No recurrence was observed one year post-treatment.
Conclusions:
- This is the first reported case of Mycobacterium ulcerans infection in a domestic cat.
- Clarithromycin appears to be an effective treatment for feline M. ulcerans infection.
- Further surveillance for M. ulcerans in feline populations may be warranted.
Abstract:
A 10-year-old castrated male domestic cat domiciled in eastern Victoria (Australia) was presented for a subcutaneous mass on its nasal bridge in November 2006. Cytological examination of an aspirate demonstrated pyogranulomatous inflammation. At surgery, the lesion consisted of an encapsulated mass containing viscid fluid. Histological examination of the resected lesion revealed pyogranulomatous inflammation surrounding a central zone of necrosis. Sections stained with the Ziehl-Neelsen method revealed numerous acid-fast bacilli, intracellularly within macrophages and extracellularly. Molecular studies established the infection was caused by Mycobacterium ulcerans. As histology demonstrated that the infection extended to the margin of the excised tissues, the cat was treated subsequently with clarithromycin (62.5mg orally once daily for 7 days, then twice daily for 3 months). The surgical wound healed unremarkably. The infection has not recurred at the time of writing, 1 year following discontinuation of treatment. Although M ulcerans infections have been recorded in variety of mammals, this is the first known case in a cat.
