Naturally Occurring Dermatitis Associated with Staphylococcus aureus in DS-Nh Mice.

Abstract

A naturally occurring epizootic of dermatitis involved all the mice, provisionally designated as DS-Nh, housed under conventional conditions, regardless of age or sex. The disease primarily attacked the lateral aspect of the face, neck and shoulders. The histopathologic features of the dermatitis varied in severity, but all affected regions showed signs of chronic dermatitis, including infiltration of inflammatory cells, parakeratosis and amyloidosis, and contained Gram-positive cocci clusters. Bacteriologically, coagulase-positive Staphylococcus aureus (S. aureus) was recovered in pure culture from the skin lesions. The disease experimentally induced with the S. aureus isolates was indistinguishable from those observed in naturally occurring cases. The results suggested that S. aureus may be casually associated with the disease.

Role of the Nh (Non-hair) Mutation in the Development of Dermatitis and Hyperproduction of IgE in DS-Nh Mice

“…Histopathology revealed marked mono- nuclear cell infiltration accompanied by edema in the dermatitis sites of DS-Nh (Nh/+) mice. These changes are very similar to those described in previous reports [2,3,13]. In contrast, no pathological changes were observed in BALB/c-Nh (Nh/+) mice.…”

“…An Nh-congenic mouse strain with a genetic background The DS-Nh (DS Non-hair) mouse [2,3,13] is a spontaneous hairless mutant of the DS mouse [11] that has been established as an inbred strain from a closed colony of dd mice at Aburahi Laboratories, Shionogi & Co., Ltd. One unique characteristic of this mutant strain is the development of spontaneous dermatitis under conventional conditions regardless of age or gender. Haraguchi et al [2] stated that all the mice bred under SPF conditions developed dermatitis by 24 weeks of exposure to a conventional environment.…”

“…An Nh-congenic mouse strain with a genetic background The DS-Nh (DS Non-hair) mouse [2,3,13] is a spontaneous hairless mutant of the DS mouse [11] that has been established as an inbred strain from a closed colony of dd mice at Aburahi Laboratories, Shionogi & Co., Ltd. One unique characteristic of this mutant strain is the development of spontaneous dermatitis under conventional conditions regardless of age or gender. Haraguchi et al [2] stated that all the mice bred under SPF conditions developed dermatitis by 24 weeks of exposure to a conventional environment. They proposed a hypothesis that Staphylococcus aureus (S. aureus) infection is causally associated with dermatitis, based on their findings that S. aureus could be isolated from the skin lesions, that intranasal infection with S. aureus isolates caused dermatitis, and that dermatitis could not be found in the SPF DS-Nh mouse [2].…”

“…Haraguchi et al [2] stated that all the mice bred under SPF conditions developed dermatitis by 24 weeks of exposure to a conventional environment. They proposed a hypothesis that Staphylococcus aureus (S. aureus) infection is causally associated with dermatitis, based on their findings that S. aureus could be isolated from the skin lesions, that intranasal infection with S. aureus isolates caused dermatitis, and that dermatitis could not be found in the SPF DS-Nh mouse [2]. In different to that of the DS mouse was used for the latter.…”

“…For the development of dermatitis, DS-Nh mice should be maintained under conventional conditions [2]. All the mice used in the following study were therefore bred and maintained under SPF conditions [9] at Aburahi Laboratories until 5 to 6 weeks of age, and were then transferred into a conventional environment at Shionogi Developmental Research Laboratories.…”