Biofilms are complex bacterial communities attached to a surface. The formation of biofilms has a profound impact on human health and industrial processes and has been recognized as an important, but poorly studied aspect of the bacterial life cycle, Biofilm development includes a transition from individual, planktonic (free-swimming) bacteria to a mode of life attached to a surface as part of a multi-cellular community, and the subsequent return to a planktonic existence. One of the most widely recognized properties of bacteria growing in a biofilm is their increased resistance to antimicrobial agents. Despite increasing interest in understanding how resistance develops, little is known about the molecular mechanisms that drive biofilms cells towards this highly resistant state. Our evidence supports the central hypothesis of this proposal: antimicrobial resistance of biofilm-grown cells requires distinct genetic elements. Herein, we propose a series of complimentary approaches to elucidate molecular mechanisms underlying biofilm-specific antibiotic resistance using three model antibiotics. While part of the proposed work will continue our efforts to study known biofilm-specific functions in P. aeruginosa (Specific Aim I), work described in Specific Aims II and III will begin in depth analysis of two newly discovered genetic loci required for resistance to antibiotics in a biofilm. The multiple experimental approaches outlined in this proposal should lead to a better understanding of the mechanism(s) involved in development of biofilm-specific antibiotic resistance, and potentially to new therapeutic strategies for modulating these properties.
Specific Aim I. Studies of known genes in biofilm-specific antibiotic resistance.
Specific Aim II. Determine the role of a glucan synthetase enzyme in the development of biofilm-specific antibiotic resistance.
Specific Aim III. Studies of the role of a putative new efflux pump in biofilm-specific antibiotic resistance.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
Project #
Application #
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Peters, Kent
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Dartmouth College
Schools of Medicine
United States
Zip Code
Ha, Dae-Gon; O'Toole, George A (2015) c-di-GMP and its Effects on Biofilm Formation and Dispersion: a Pseudomonas Aeruginosa Review. Microbiol Spectr 3:MB-0003-2014
Shanks, Robert M Q; Meehl, Michael A; Brothers, Kimberly M et al. (2008) Genetic evidence for an alternative citrate-dependent biofilm formation pathway in Staphylococcus aureus that is dependent on fibronectin binding proteins and the GraRS two-component regulatory system. Infect Immun 76:2469-77
Kuchma, Sherry L; Brothers, Kimberly M; Merritt, Judith H et al. (2007) BifA, a cyclic-Di-GMP phosphodiesterase, inversely regulates biofilm formation and swarming motility by Pseudomonas aeruginosa PA14. J Bacteriol 189:8165-78
Merritt, Judith H; Brothers, Kimberly M; Kuchma, Sherry L et al. (2007) SadC reciprocally influences biofilm formation and swarming motility via modulation of exopolysaccharide production and flagellar function. J Bacteriol 189:8154-64
Toutain, Christine M; Caizza, Nicky C; Zegans, Michael E et al. (2007) Roles for flagellar stators in biofilm formation by Pseudomonas aeruginosa. Res Microbiol 158:471-7
Caiazza, Nicky C; Merritt, Judith H; Brothers, Kimberly M et al. (2007) Inverse regulation of biofilm formation and swarming motility by Pseudomonas aeruginosa PA14. J Bacteriol 189:3603-12
Shanks, Robert M Q; Caiazza, Nicky C; Hinsa, Shannon M et al. (2006) Saccharomyces cerevisiae-based molecular tool kit for manipulation of genes from gram-negative bacteria. Appl Environ Microbiol 72:5027-36
Swiatecka-Urban, Agnieszka; Moreau-Marquis, Sophie; Maceachran, Daniel P et al. (2006) Pseudomonas aeruginosa inhibits endocytic recycling of CFTR in polarized human airway epithelial cells. Am J Physiol Cell Physiol 290:C862-72
Kenan, Daniel J; Walsh, Elisabeth B; Meyers, Steven R et al. (2006) Peptide-PEG amphiphiles as cytophobic coatings for mammalian and bacterial cells. Chem Biol 13:695-700
Furukawa, S; Kuchma, S L; O'Toole, G A (2006) Keeping their options open: acute versus persistent infections. J Bacteriol 188:1211-7

Showing the most recent 10 out of 16 publications