Actinomyces viscosus Isolation from the Skin of a Cat

Abstract

Actinomyces is an aerobic or microaerobic, Gram-positive, non-acid fast, filamentous, diphtheroidal rod or coccobacillus-shaped bacteria. Actinomycosisis is seen mostly as a dental disease of cattle, however it also occurs in other animal species such as dogs, cats, cows, goats and horses. This report describes a 1 year-old, female, mixed-breed, indoor cat which developed a purulent exudate around the interdigital area for 6 months. Despite various antibacterial treatments the skin lesions of the cat deteriorated. Anamnesis revealed that cat did not show any sign of pruritis however was eating a special diet for dermatologic disorders. The only sign on physical examination was a purulent exudate seen in the interdigital area. Hematological and biochemical profiles were within normal limits. Skin scrapes were negative for parasites and fungi. From the wound swab, Actinomyces viscosus was identified. According to the antibiotic susceptibility test, the isolate was susceptible to amoxicillin and amoxicillin/clavulanic acid. The cat received amoxicillin/clavulanic acid (8.75 mg/kg BID, IM) for a week. After the treatment, there was no discharge around the interdigital area. This case is of interest since Actinomyces viscosus has been rarely encountered in the skin of cats. Veterinarians should include A. viscosus in the differential diagnosis in case with dermal purulent discharge.