The role of environmental enrichment in the aetiopathogenesis of facial, periorbital and retroorbital abscesses in mice.

In this observational retrospective study, an outbreak of abscesses was correlated with the presence of sharp edges in damaged plastic environmental enrichment within the cages. In 2010, Lawson reported cases of mandibulofacial and maxillofacial abscess in mice and proposed excessive barbering or grooming, leading to the mastication and fragmentation of hair, as an aetiopathogenesis of abscesses. In contrast, in this study, the presence of hair was not found in any of the histopathology, and abscesses were present in the periorbital area. colonises the skin, nasopharynx and intestines, and may cause pyogenic infections if a breach in local defences promotes staphylococcal invasion. Whole genome sequencing and analysis supported the hypothesis that this outbreak resulted from clonal expansion of infected C57BL6/J mice imported into the area and infection transmission from humans to mice was ruled out. An additional aetiopathogenesis is proposed for abscesses with the sharp edges of damaged plastic environmental enrichment items leading to oral mucosal injury allowing entrance into tissues, its carriage into the submucosa, followed by abscess formation.