Infection of the Subcutis and Skin of Cats with Rapidly Growing Mycobacteria: A Review of Microbiological and Clinical Findings

Abstract

Mycobacteria were isolated and characterised from 49 cats with extensive infections of the subcutis and skin. Cats were generally between 3 and 10 years of age, and female cats were markedly over-represented. All isolates were rapid-growers and identified as either Mycobacteria smegmatis (40 strains) or M fortuitum (nine strains). On the basis of Etest for minimum inhibitory concentration and/or disc diffusion susceptibility testing, all strains of M smegmatis were susceptible to trimethoprim while all strains of M fortuitum were resistant. M smegmatis strains were typically susceptible to doxycycline, gentamicin and fluoroquinolones but not clarithromycin. All M fortuitum strains were susceptible to fluoroquinolones, and often also susceptible to gentamicin, doxycycline and clarithromycin. Generally, M smegmatis strains were more susceptible to antimicrobial agents than M fortuitum strains. Treatment of mycobacterial panniculitis involves long courses of antimicrobial agents, typically of 3-6 months, chosen on the basis of in vitro susceptibility testing and often combined with extensive surgical debridement and wound reconstruction. These therapies will result in effective cure of the disease. One or a combination of doxycycline, ciprofloxacin/enrofloxacin or clarithromycin are the drugs of choice for long-term oral therapy.

Strategies for potentiation of ethionamide and folate antagonists againstMycobacterium tuberculosis

“…Therefore, it remains unknown why trimethoprim does not work against M. tuberculosis [71]. MICs of trimethoprim required to inhibit M. tuberculosis exceed 128 μg ml -1 , at least 100-fold higher than the MICs of M. smegmatis [77,78]. It is possible that M. tuberculosis is not entirely dependent on DHFR for the reduction of dihydrofolate to tetrahydrofolate.…”

Preliminary Study of Effects of Multiple Oral Dosing of Clarithromycin on the Pharmacokinetics of Cyclosporine in Dogs

“…In healthy beagles, 10 mg/kg PO of CLM produced serum concentrations of approximately 3 µ g/m l , although steady-state studies have not been performed in dogs [20]. Serum concentrations greater than 2 µ g/m l are likely to be effective for conventional bacteria [15]. In this study, we used therapeutic doses of CLM 10 mg/kg PO twice daily.…”

Infectious Diseases

“…The most common presentation is localized infection in healthy cats, most typically chronic panniculitis 72 ; there have been occasional reports of pneumonia caused by RGM. 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.…”

“…of noneffusive FIP include cutaneous lesions, such as intradermal papules 57. of noneffusive FIP include cutaneous lesions, such as intradermal papules 57.…”