Localised Mycobacterium ulcerans infection in a cat in Australia

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.

Ulcerated and Nonulcerated Nontuberculous Cutaneous Mycobacterial Granulomas in Cats and Dogs

“…25 Two cases have been observed in alpacas (Carolyn O'Brien, personal communication). Recently, M. ulcerans has been diagnosed in a cat, 26 two horses, 27 more than five dogs ( Figure 5) 28 and numerous brush-tailed and ring-tailed possums. 25 Polymerase chain reaction is exceedingly helpful for rapid diagnosis, although the organism grows slowly on synthetic media.…”

Mycobacterium ulcerans Disease (Buruli Ulcer): Potential Reservoirs and Vectors

“…In contrast, strains of the classical lineage are typically isolated from human BU patients, but can also infect other endotherms [10, 11•, 15•]. In southeastern Australia infections by M. ulcerans strains belonging to the classical lineage were reported in a wide range of terrestrial mammals [16][17][18][19][20], in particular in possums, small arboreal marsupials [15•, 21]. In areas known to be endemic for human BU, significant numbers of possums were shown to have clinical M. ulcerans infections, implying their potential as reservoirs for the pathogen [4••, 15•].…”

“…Classical M. ulcerans strains-defined as lineage 3-were represented by human isolates from Africa as well as human and animal isolates from Australia. In areas of south-eastern Australia known to be endemic for human BU, M. ulcerans infections have not only been described in different wild possum species [42], but also in other native wildlife and domestic mammals, including koalas [43], horses [17], dogs [18], alpacas [20], and a cat [16]. However, possums appear to be particularly susceptible to M. ulcerans.…”

Epidemiology and disease burden of Buruli ulcer: a review

“…27,34 A detailed analysis of M. ulcerans human isolates of diverse geographical origin based on comparative genomic hybridization analysis revealed extensive large sequence polymorphisms, enabling a differentiation of M. ulcerans clinical isolates into two principal lineages. These lineages were designated "ancestral" in reference to M. ulcerans strains from Asia (People's Republic of China and Japan) and the Americas (Mexico, French Guiana, and Suriname) being closely related to M. marinum, and "classical", with most BU [35][36][37][38][39] and ectotherms, the different lineages appear to have adapted to distinct niche environments and may be considered as ecovars.…”