Biocide-induced Antimicrobial Peptide Resistance in Porphyromonas gingivalis
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Authors
Kujala, Nicholas G.
Issue Date
2004
Type
Presentation
Language
en_US
Keywords
Alternative Title
Abstract
Defensins belong to a class of small, cationic antimicrobial
peptides (CAMPs) which have evolved as the primary defense against
microbial flora such as Porphyromonas gingivalis, an oral bacteria and major
contributor to periodontal disease. The focus of this research was to determine
the potential for bacteria to develop resistance to defensins after exposure to
sub-lethal levels of the biocide Triclosan and investigate the mechanism of that
defensin resistance in P. gingivalis. In addition, we tested the bacteria for
defensin resistance after exposure to sub-lethal doses of Polymyxin B, a
peptide antibiotic with a similar function as defensins. Defensin resistance is
an inducible gene function that may be activated by several factors, including
sub-lethal levels of biocides and antibiotics. Triclosan (Irgasan™) is a biocide
that has recently been formulated into numerous consumer products including
toothpaste (Total™, Colgate). It is unknown whether the inclusion of
Triclosan into such products has the potential to induced antimicrobial
resistance to host immune system factors such as defensins. Since defensin
resistance can be induced by a number of factors that cause bacterial stress we
hypothesized that sub-lethal levels of Triclosan will induce resistance to
defensins in P. gingivalis. Based on those experiments we concluded that
exposure of P. gingivalis to sub-lethal levels of Triclosan induced a resistance
to defensins but sub-lethal levels of Polymyxin B do not induce such
resistance. When we examined the effect of Triclosan sub-MIC treatments on
the expression of 21 genes associated with P. gingivalis virulence we found
that rgp1, rgp2, recA, lon, groES, groEL, ftsH, dnaK, dnaJ were upregulated
and dksA, dps, clpC, clpB were down-regulated compared to untreated
bacteria. This pattern of changed expression may affect the pathogenisity of
periodontal pathogens and suggests new lines of investigation into the role of
antimicrobials in the treatment of periodontitis.
Description
1 broadside : ill.
Citation
Publisher
Kalamazoo College