Neustria gonorrhoeae is a strict human pathogen that causes greater than sixty million cases worldwide of the sexually transmitted disease gonorrhea each year. Without an effective vaccine, antibiotic therapy remains the principle mechanism to reduce or block the transmission of the gonococcus in the community. Unfortunately, because of the development of mutations or the acquisition of resistance determinants, the gonococcus has developed resistance to relatively inexpensive antibiotics;such resistance now requires the use of more expensive antibiotics that are not always available in poor countries. Multidrug efflux pumps possessed by gonococci have an important role in the ability of gonococci to resist antibiotics and antimicrobials of the innate host defensive system. In particular, our work has shown that the MtrC-MtrD-MtrE efflux pump participates in gonococcal resistance to penicillin and macrolides. This efflux pump also recognizes host antimicrobials, such as antimicrobial peptides and progesterone. We have shown that the pump is required for gonococci to cause a sustained infection in experimentally-infected female mice and the degree of in vivo fitness is linked to transcriptional regulators that control mtrCDE gene expression. The importance of DNA- binding proteins in regulating gonococcal resistance to antimicrobials is the topic of this competitive renewal application.
In Specific Aim 1 we will define the transcriptional control processes that modulate expression of the mtrR gene, which encodes a repressor of the mtrCDE efflux pump operand and can control the expression of numerous genes outside of the mar locus. We will assess the importance of such regulation in the ability of gonococci to resist antimicrobials and during infection in experimentally-infected mice.
In Specific Aim 2 we will define the use, regulation and biologic importance of distinct promoters for transcription of the mtrCDE operand.
In Specific Aim 3 we will define the mechanism which the products of genes controlled by MtrR and other regulatory proteins impact levels of gonococcal susceptibility to antibiotics and host-derived antimicrobials. The results from the proposed work will advance our knowledge regarding how gonococci and other human bacterial pathogens use drug efflux pumps and transcriptional regulatory systems to resist both classical antibiotics as well as mediators of innate immunity.

Public Health Relevance

The goal of this project is to understand how Neustria gonorrhoeae uses drug efflux pumps and transcriptional regulators that control levels of efflux pumps and other structures to resist antibiotics or antimicrobials used by the human host during infection. The information gained will help in the development of new antimicrobials to treat or prevent gonorrhea, which remains a worldwide public health problem.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI021150-28
Application #
8449665
Study Section
Drug Discovery and Mechanisms of Antimicrobial Resistance Study Section (DDR)
Program Officer
Hiltke, Thomas J
Project Start
1984-04-01
Project End
2015-03-31
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
28
Fiscal Year
2013
Total Cost
$355,916
Indirect Cost
$64,516
Name
Emory University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Kandler, Justin L; Acevedo, Rosuany Vélez; Dickinson, Mary Kathryne et al. (2016) The genes that encode the gonococcal transferrin binding proteins, TbpB and TbpA, are differentially regulated by MisR under iron-replete and iron-depleted conditions. Mol Microbiol 102:137-51
Unemo, Magnus; Del Rio, Carlos; Shafer, William M (2016) Antimicrobial Resistance Expressed by Neisseria gonorrhoeae: A Major Global Public Health Problem in the 21st Century. Microbiol Spectr 4:
Shafer, William M (2016) Does the Cervicovaginal Microbiome Facilitate Transmission of Neisseria gonorrhoeae From Women to Men? Implications for Understanding Transmission of Gonorrhea and Advancing Vaccine Development. J Infect Dis 214:1615-1617
Kandler, Justin L; Holley, Concerta L; Reimche, Jennifer L et al. (2016) The MisR Response Regulator Is Necessary for Intrinsic Cationic Antimicrobial Peptide and Aminoglycoside Resistance in Neisseria gonorrhoeae. Antimicrob Agents Chemother 60:4690-700
Unemo, Magnus; Shafer, William M (2015) Future treatment of gonorrhea--novel emerging drugs are essential and in progress? Expert Opin Emerg Drugs 20:357-60
Ezewudo, Matthew N; Joseph, Sandeep J; Castillo-Ramirez, Santiago et al. (2015) Population structure of Neisseria gonorrhoeae based on whole genome data and its relationship with antibiotic resistance. PeerJ 3:e806
Su, Chih-Chia; Bolla, Jani Reddy; Kumar, Nitin et al. (2015) Structure and function of Neisseria gonorrhoeae MtrF illuminates a class of antimetabolite efflux pumps. Cell Rep 11:61-70
Johnson, Paul J T; Shafer, William M (2015) The Transcriptional Repressor, MtrR, of the mtrCDE Efflux Pump Operon of Neisseria gonorrhoeae Can Also Serve as an Activator of "off Target" Gene (glnE) Expression. Antibiotics (Basel) 4:188-97
Ohneck, Elizabeth A; Goytia, Maira; Rouquette-Loughlin, Corinne E et al. (2015) Overproduction of the MtrCDE efflux pump in Neisseria gonorrhoeae produces unexpected changes in cellular transcription patterns. Antimicrob Agents Chemother 59:724-6
Bauer, Margaret E; Shafer, William M (2015) On the in vivo significance of bacterial resistance to antimicrobial peptides. Biochim Biophys Acta 1848:3101-11

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