The longterm goals of the project are to identify the full array of efflux pumps of Staphylococcus aureus that contribute to multiple antimicrobial resistance and to elucidate the determinants of their expression, their role in microbial physiology and their effect on bacterial response to antimicrobials in infection. The work will focus on genetic analysis of regulatory elements and on bacterial fitness and response to antimicrobials in a subcutaneous abscess model, collaborating with other project groups to assess the efficacy of novel antimicrobial compounds in abscesses and the extent to which efflux pumps affect that efficacy. There are four specific aims: 1) assess the effects of NorB, NorD, and Tet38 efflux pumps and their regulators on response to antimicrobials in animal models of infection;2) evaluate the regulation of expression of abcA encoding an ABC family efflux pump and assess its effects on membrane and cell wall-targeting agents;3) analyze the global array of pumps over expressed in an abscess environment and determine their contribution to resistance to established agents and novel compounds;and 4) test novel compounds discovered in other subprojects of the program project for resistance to efflux pump expression and for efficacy and development of resistance in mammalian infection models. The work will utilize genetic manipulation and allelic exchange in S. aureus, measurements of gene expression with RT-PCR, and established murine models of infection (subcutaneous abscess, renal abscess, lethality) utilizing a genomically defined strains of methicillin resistant and other S. aureus. The overall goal of the program project is to take a well-integrated, multidisciplinary approach to understanding antibiotic resistance development and transmission, and to integrate that effort with the search for compounds that compromise resistant pathogens, including methicillin-resistant S. aureus (MRSA), by inhibiting novel targets and pathways. This project will add to understanding of resistance mechanisms related to multidrug efflux pumps and provide strains for testing the effect of such pumps on novel compounds active against new targets and pathways. It will also utilize mammalian models of a common MRSA infection to test compound activity in vivo.

Public Health Relevance

Multidrug resistance in S. aureus is an increasing clinical and public health problem that requires additional understanding of its mechanisms of development and spread and establishment of novel targets that may be exploited to develop new effective therapies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Program Projects (P01)
Project #
5P01AI083214-06
Application #
8531139
Study Section
Special Emphasis Panel (ZAI1-LG-M)
Project Start
Project End
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
6
Fiscal Year
2013
Total Cost
$341,496
Indirect Cost
Name
Massachusetts Eye and Ear Infirmary
Department
Type
DUNS #
073825945
City
Boston
State
MA
Country
United States
Zip Code
02114
Qiao, Yuan; Lebar, Matthew D; Schirner, Kathrin et al. (2014) Detection of lipid-linked peptidoglycan precursors by exploiting an unexpected transpeptidase reaction. J Am Chem Soc 136:14678-81
Van Tyne, Daria; Gilmore, Michael S (2014) A delicate balance: maintaining mutualism to prevent disease. Cell Host Microbe 16:425-7
Van Tyne, Daria; Gilmore, Michael S (2014) Friend turned foe: evolution of enterococcal virulence and antibiotic resistance. Annu Rev Microbiol 68:337-56
Elsholz, Alexander K W; Wacker, Sarah A; Losick, Richard (2014) Self-regulation of exopolysaccharide production in Bacillus subtilis by a tyrosine kinase. Genes Dev 28:1710-20
Santa Maria Jr, John P; Sadaka, Ama; Moussa, Samir H et al. (2014) Compound-gene interaction mapping reveals distinct roles for Staphylococcus aureus teichoic acids. Proc Natl Acad Sci U S A 111:12510-5
Foulston, Lucy; Elsholz, Alexander K W; DeFrancesco, Alicia S et al. (2014) The extracellular matrix of Staphylococcus aureus biofilms comprises cytoplasmic proteins that associate with the cell surface in response to decreasing pH. MBio 5:e01667-14
Pukkila-Worley, Read; Feinbaum, Rhonda L; McEwan, Deborah L et al. (2014) The evolutionarily conserved mediator subunit MDT-15/MED15 links protective innate immune responses and xenobiotic detoxification. PLoS Pathog 10:e1004143
Sassoubre, Lauren M; Ramsey, Matthew M; Gilmore, Michael S et al. (2014) Transcriptional response of Enterococcus faecalis to sunlight. J Photochem Photobiol B 130:349-56
Varahan, Sriram; Harms, Nathan; Gilmore, Michael S et al. (2014) An ABC transporter is required for secretion of peptide sex pheromones in Enterococcus faecalis. MBio 5:e01726-14
Valentino, Michael D; McGuire, Abigail Manson; Rosch, Jason W et al. (2014) Unencapsulated Streptococcus pneumoniae from conjunctivitis encode variant traits and belong to a distinct phylogenetic cluster. Nat Commun 5:5411

Showing the most recent 10 out of 51 publications