Dermatophilus chelonae was isolated from one Egyptian tortoise (Testudo kleinmanni) and four bowsprit tortoises (Chersina angulata) at the Knoxville Zoo. The tortoises were housed indoors in adjacent sections of an open tripartite, wooden box.
The Egyptian tortoise died without premonitory signs. Dermatophilus chelonae was cultured from a large intra-coelomic granuloma.
The infections in the bowsprit tortoises were manifested as dermatitis in all four tortoises and as bilateral, septic arthritis in two of the four animals. The cutaneous lesions were raised, yellow-white nodules, 0.2–0.5 cm in diameter, covered with dry flaking skin. Each tortoise had multiple skin lesions (>10), most frequently on the neck and in deep recesses around the neck and legs. Two tortoises also had bilateral septic arthritis of the stifle joints. The severity of the lesions required euthanasia of one tortoise. Another tortoise died following 11 months of antibiotic treatment.
Treatment consisted of debriding skin lesions with a cotton-tipped applicator dipped in a dilute povidone-iodine solution (Burns Veterinary Supply, Rockville Centre, New York 11570 USA). Infected stifle joints were debrided and flushed with a dilute povidone-iodine solution. Affected tortoises were treated with parenteral ampicillin and amikacin. Intramuscular enrofloxacin, amoxicillin and oral metronidazole were also administered to each tortoise. Lesions usually regressed within 3–6 months following treatment but recurred in each tortoise within 12 months. Prolonged amoxicillin therapy (SmithKline Beecham, Westchester, Pennsylvania 19389 USA; 10 mg/kg IM q 48 h for 30–45 days) and keeping the animals in a drier environment appears to be successful in resolving the infections.
Our experience suggests that the unique microscopic morphology of Dermatophilus sp. may cause it to be easily missed in lesions and cultures from reptiles. The organisms were seen as branching, gram-positive filaments and coccoid forms without longitudinal planes of divisions by light microscopy. Considering the size and superficial location of lesions and the chelonid’s environment, contamination is sometimes hard to avoid.
Dermatophilosis is a widely recognized skin disease of mammals caused by the actinomycete, Dermatophilus congolensis. This organism occasionally causes extra-epidermal infections in mammals.4,5 In addition, dermatophilosis has been observed in several lizard species, a boa constrictor (Constrictor constrictor) and an American alligator (Alligator mississippiensis).1-3,6
1. Chineme, C.N., P.B. Addo. 1980. Pathologic changes in lizards (Agama agama) experimentally infected with Dermatophilus congolensis. J. Wildl. Dis. 16:407–412.
2. Jacobson, E.R. 1991. Diseases of the integumentary system of reptiles. In: Nesbitt G.H., and L.J. Ackerman. Dermatology for the Small Animal Practitioner, Exotics, Feline, Canine. Veterinary Learning Systems. Trenton, New Jersey. Pp. 225–239.
3. Jacobson, E.R. 1989. Dermatophilosis in reptiles. In: Abstracts, Third International Colloquium on the Pathology of Reptiles and Amphibians, Orlando, Florida. P. 47.
4. Jones, R.T. 1976. Subcutaneous infection with Dermatophilus congolensis in a cat. J. Comp. Path. 86:415–421.
5. Lloyd, D.H. 1984. Immunology of dermatophilus: recent developments and prospects for control. Prev. Vet. Med. 2:93–102.
6. Masters, A.M., T.M. Ellis, J.M. Carson, et al. 1995. Dermatophilus chelonae sp. nov., isolated from chelonids in Australia. Int. J. Syst. Bacteriol. 45: 50–56.