title: 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.
mesh_terms: D000818:Animals; D005856:Germ-Free Life; D006321:Heart / Q000382:microbiology; D007121:Immunocompetence; D007153:Immunologic Deficiency Syndromes / Q000382:microbiology*; D007668:Kidney / Q000382:microbiology; D008099:Liver / Q000382:microbiology; D008168:Lung / Q000382:microbiology; D008198:Lymph Nodes / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D011425:Propionibacterium acnes / Q000254:growth & development / Q000472:pathogenicity*; D013154:Spleen / Q000382:microbiology