Affiliation:
1. Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada K1N 8J2
Abstract
ABSTRACT
Bacteria growing in biofilms are more resistant to antibiotics than their planktonic counterparts. How this transition occurs is unclear, but it is likely there are multiple mechanisms of resistance that act together in order to provide an increased overall level of resistance to the biofilm. We have identified a novel efflux pump in
Pseudomonas aeruginosa
that is important for biofilm-specific resistance to a subset of antibiotics. Complete deletion of the genes encoding this pump, PA1874 to PA1877 (PA1874-1877) genes, in an
P. aeruginosa
PA14 background results in an increase in sensitivity to tobramycin, gentamicin, and ciprofloxacin, specifically when this mutant strain is growing in a biofilm. This efflux pump is more highly expressed in biofilm cells than in planktonic cells, providing an explanation for why these genes are important for biofilm but not planktonic resistance to antibiotics. Furthermore, expression of these genes in planktonic cells increases their resistance to antibiotics. We have previously shown that
ndvB
is important for biofilm-specific resistance (T. F. Mah, B. Pitts, B. Pellock, G. C. Walker, P. S. Stewart, and G. A. O'Toole, Nature 426:306-310, 2003). Our discovery that combining the
ndvB
mutation with the PA1874-1877 gene deletion results in a mutant strain that is more sensitive to antibiotics than either single mutant strain suggests that
ndvB
and PA1874-1877 contribute to two different mechanisms of biofilm-specific resistance to antibiotics.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
288 articles.
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