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Updated: Jun 9, 2026
A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection
Published on: February 28, 2019
Spontaneous Staphylococcus xylosus infection in mice deficient in NADPH oxidase and comparison with other laboratory
Alfonso S Gozalo1, Victoria J Hoffmann, Lauren R Brinster
1Comparative Medicine Branch, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA. gozaloa@niaid.nih.gov
Abstract:
Staphylococcus xylosus typically is described as a nonpathogenic common inhabitant of rodent skin. Reports of S. xylosus as a primary pathogen in human and veterinary medicine are scarce. Here we report 37 cases, affecting 12 strains of laboratory mice, of spontaneous infections in which S. xylosus was isolated and considered to be the primary pathogen contributing to the death or need for euthanasia of the animal. Infection with S. xylosus was the major cause of death or euthanasia in 3 strains of mice deficient in the production of phagocyte superoxide due to defects in NADPH oxidase. NADPH-oxidase-deficient mice (n = 21) were most susceptible to spontaneous S. xylosus infections. The infections were characterized by abscesses and granulomas in soft tissues, with bacterial migration to internal organs (primarily regional lymph nodes and lungs and, to a lesser degree, muscle, bone, and meninges). In contrast, 9 strains of phagocyte-superoxide-producing mice (n = 16) also had S. xylosus infections, but these were largely confined to eyelids, ocular conjunctiva, and skin and rarely involved other tissues or organs. Because exhaustive bacterial culture and isolation may not be performed routinely from mouse abscesses, S. xylosus infections may be underdiagnosed. S. xylosus should be considered in the differential diagnosis in laboratory mice with abscesses and other skin lesions. This report expands the range of mouse strains and tissues and organs susceptible to spontaneous S. xylosus infection and compares the pathology among various mice strains.
Insights
Staphylococcus xylosus, typically nonpathogenic, caused spontaneous infections and death in laboratory mice. Mice lacking NADPH oxidase were most susceptible, indicating its role in immune defense against this bacterium.
Area of Science:
- Microbiology
- Immunology
- Veterinary Pathology
Background:
- Staphylococcus xylosus is commonly found on rodent skin but rarely identified as a primary pathogen.
- Previous reports of S. xylosus causing significant disease in mammals are limited.
Purpose of the Study:
- To document and characterize spontaneous Staphylococcus xylosus infections in laboratory mice.
- To investigate the role of NADPH oxidase in host defense against S. xylosus.
Main Methods:
- Retrospective analysis of 37 cases of S. xylosus infection in 12 mouse strains.
- Comparison of infection pathology between NADPH oxidase-deficient and wild-type mice.
- Bacterial culture, isolation, and histopathological examination of affected tissues.
Main Results:
- S. xylosus was identified as the primary cause of death or euthanasia in 37 cases across 12 mouse strains.
- NADPH oxidase-deficient mice exhibited severe systemic infections with abscesses and organ dissemination.
- Phagocyte-superoxide-producing mice showed localized infections, primarily affecting skin and ocular tissues.
Conclusions:
- Staphylococcus xylosus can act as a primary pathogen in laboratory mice, particularly those with compromised immune function.
- NADPH oxidase is crucial for controlling S. xylosus infections, preventing systemic spread.
- S. xylosus should be considered in the differential diagnosis of infections in laboratory mice, especially those with skin lesions or abscesses.
