Clinical outcome of cutaneous rapidly growing mycobacterial infections in cats in the south-eastern United States: A review of 10 cases (1996–2006)

Abstract

Cutaneous infection caused by rapidly growing mycobacteria is a relatively uncommon condition in cats, with variable response rates to surgical debulking and aggressive antibiotic therapy. To date, there have been very few case reports of this disease, especially in the United States. This study reviews a series of cases of cats with rapidly growing cutaneous mycobacterial infections from the south-eastern United States. A majority of the cats were spayed female domestic shorthairs. The median age at onset of clinical signs was 8 years. A majority of cats presented with characteristic lesions in multiple locations, and half of the cats had a known incidence of trauma preceding the development of clinical signs. Mycobacterium fortuitum was the most frequently cultured organism. Cats were treated with a variety of antibiotics for a median of 12 months, and half of them underwent surgical debulking of infected tissue. Five out of the 10 cats reached clinical resolution, while five did not. Those that did resolve required a median of 7 months of antibiotic treatment following diagnosis, and had been lesion-free for a median of 24 months at the time this study was completed. Those that did not resolve were treated for a median of 20 months following diagnosis, two of which were still being treated at the time this study was completed.

Infectious Diseases

“…39 These cats are also antigen negative, but viral genetic material can be detected in a small percentage of blood cells by PCR.…”

“…55 However, recommendations continue to evolve as new drugs, such as fourth-generation fluoroquinolones and tetracycline derivatives, become available. 39 Initial treatment should be with one or two oral antimicrobials chosen empirically, then adjusted based on susceptibility data. However, some cases, especially those caused by M. fortuitum in the United States remain frustrating to treat.…”

“…16,26 Many individual case reports are in the veterinary literature as well as a case series of 29 affected cats in Australia. 39,42 Infection typically starts in the inguinal fat pad, possibly after a cat-fight wound has become contaminated, 56 and it may spread to the abdominal wall, perineum, and tail base. 3 In Australia, organisms from the M. smegmatis group account for most feline cases, 53,57 while in the United States, most cases are caused by members of the M. fortuitum group.…”

“…17 Other countries with reported cases include the United States, 49 Canada, 17,74 New Zealand, 17 France, 68 Finland, 1 the Netherlands, 43 and Switzerland. 39 Many patients are initially treated for a cat fight abscess with surgical drainage and antibiotics, although the lesions do not have a fetid odor or the typical bacterial discharge. 39,42 Infection typically starts in the inguinal fat pad, possibly after a cat-fight wound has become contaminated, 56 and it may spread to the abdominal wall, perineum, and tail base.…”

“…37 Clinical signs depend upon location of infection. 12,39 In another study, 63% of 263 cats had nasal discharge, and 12.5% had A definitive diagnosis of cryptococcosis requires culturing the organism from infected tissue (Box 33-1). Dissemination has been documented ( Figure 33-2).…”