
Infection mechanism of biofilm‐forming Staphylococcus aureus on indwelling foreign materials in mice
Author(s) -
Makino Taro,
Jimi Shiro,
Oyama Takuto,
Nakano Yuki,
Hamamoto Kouichi,
Mamishin Kanako,
Yahiro Tomoko,
Hara Shuuji,
Takata Tohru,
Ohjimi Hiroyuki
Publication year - 2015
Publication title -
international wound journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 63
eISSN - 1742-481X
pISSN - 1742-4801
DOI - 10.1111/iwj.12061
Subject(s) - biofilm , staphylococcus aureus , medicine , microbiology and biotechnology , mechanism (biology) , bacteria , biology , genetics , philosophy , epistemology
Indwelling foreign‐body infections are a critical medical problem, especially in immunocompromised patients. To examine the pathogenicity of biofilm‐forming bacteria settling on foreign materials, mice implanted with plastic discs were infected with Staphylococcus aureus . After opening a wide subcutaneous pocket on the dorsal side of mice with or without temporal leukocytopenia, a plastic sheet was placed in the left subcutaneous space; subsequently, bacteria in a planktonic state were dispersed over the subcutaneous space. Bacterial numbers were examined 7 days after inoculation. In subcutaneous tissue on the right, S. aureus was found only in leukocytopenic mice. Meanwhile, bacteria were detected on the plastic and neighbouring tissue in both leukocytopenic and normal mice; however, colony‐forming analysis indicated that leukocytopenic mice possessed significantly more bacteria. Tissue reaction against bacteria was pathologically examined. Invading S. aureus induced severe inflammation. In transient leukocytopenic mice, bacterial microcolonies formed on the plastic as well as in the developed necrotic tissue – both of which were shielded from inflammatory cell infiltration – result in bacteraemia. These results indicate that biofilm‐forming S. aureus settling on indwelling foreign material are tolerant against host immunity and assault neighbouring tissue, which may lead to chronic wound infection.