Related Experiment Videos
Studies on pathogenicity and persistence of Propionibacterium acnes in mice
Abstract:
The pathogenicity of Propionibacterium acnes was studied using immunodeficient and germ-free (GF) mice. P. acnes injected i.p. to immunocompetent (ddY and BALB/c-nu/+) and -deficient mice (CBA/N and BALB/c-nu/nu) decreased rapidly and only as small number were recovered from organs from day 7 on. The organisms injected similarly into GF-immunocompetent (GF-CF1) mice also decreased but when injected into GF-immunodeficient (GF-BALB/c-nu/nu) mice a small number persisted as late as week 4. When GF-immunocompetent (GF-ICR) mice were treated with cortisone and anti-mouse thymocyte serum, a small number of organisms were also recovered for 4 weeks after injection. Upon injection into irradiated GF-nu/nu mice, the number of viable P. acnes decreased relatively slowly and were recovered even at week 22. After oral administration a small number of P. acnes were readily detected from organs of GF-nu/nu mice but rarely from GF-nu/+ mice. The results indicate that P. acnes organisms have very low pathogenicity to mouse. However, small numbers persisted in organs of P. acnes-monoassociated immunodeficient mice. The mechanisms of this persistency of the nonpathogenic bacteria is discussed.
Insights
Propionibacterium acnes shows low pathogenicity in mice. However, this bacterium persists in immunodeficient mice, suggesting immune status is key to its clearance.
Area of Science:
- Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- Propionibacterium acnes (P. acnes) is a bacterium often associated with skin conditions.
- Understanding its interaction with the host immune system is crucial for elucidating its role in disease.
Purpose of the Study:
- To investigate the pathogenicity and persistence of P. acnes in various mouse models.
- To determine the influence of host immunity and germ-free status on P. acnes survival.
Main Methods:
- P. acnes was administered via intraperitoneal injection and oral administration.
- Experiments utilized immunocompetent, immunodeficient, germ-free, and irradiated mice.
- Bacterial recovery from organs was assessed at different time points post-administration.
Main Results:
- P. acnes demonstrated rapid clearance in immunocompetent mice.
- In immunodeficient mice (germ-free and non-germ-free), P. acnes persisted for extended periods (up to 4 weeks or longer).
- Irradiated germ-free mice showed slow P. acnes clearance, with recovery up to 22 weeks.
Conclusions:
- P. acnes exhibits very low pathogenicity in mice.
- Host immune deficiency is a critical factor enabling the persistence of P. acnes.
- Mechanisms underlying P. acnes persistence in immunodeficient hosts warrant further investigation.