Biography

Dr Bart Eijkelkamp completed his Master's degree in Biomolecular Sciences at the Vrije Universiteit Amsterdam in 2007. In the following year he commenced his PhD at Flinders University, investigating the antimicrobial resistance and virulence features of Acinetobacter baumannii, a highly significant human bacterial pathogen. Upon completion of his PhD in 2012, Dr Eijkelkamp took up a position as a post-doctoral researcher in the Research Centre for Infectious Diseases at the University of Adelaide. He continued his research into the resistance and virulence features of major bacterial pathogens, with a strong focus on the role of metal ions and host lipids on bacterial fitness. Whilst at the University of Adelaide, Dr Eijkelkamp was awarded a Beacon Research Fellowship which allowed him to establish his own research group. In 2019, he returned to Flinders University where he continued as a Research Academic in Microbiology. The Eijkelkamp Laboratory (www.EijkelkampLab.com) examines how the host nutritional status affects bacteria during infection.

Research Program

Our research examines how bacterial pathogens adapt to adverse conditions encountered at the host-pathogen interface, focusing on antimicrobial free fatty acids and metal ion stress. These factors strongly aid immune-mediated clearance of bacterial pathogens, and their dietary deficiencies are directly linked to an increased risk of contracting bacterial infections. However, metal ions and fatty acids are also critical nutrients to the pathogen, therefore our research studies how bacteria deal with maintaining an appropriate cellular homeostasis of metals ions and fatty acids in distinct host niches.

We focus on bacterial membrane biosynthesis and the transport systems that play key roles in the efflux of fatty acids and metal ions during stress. Through dietary supplementation of fatty acids (DHA or AA) or metals (zinc), we examine the possible adverse or beneficial impacts of these micronutrients upon bacterial pathogens during infection, using murine models. We also study how fatty acids and metal ions impact antibiotic efficacy, as significant synergy has been observed, but is not well understood. Overall, our aim is to understand the molecular basis of immune-mediated and antibiotic clearance of bacteria at the host-pathogen interface. This work will aid in the optimisation of dietary intervention strategies and antibiotic treatment in susceptible populations such as premature babies, the elderly and intensive-care patients.

We study these aspects of fatty acid and metal ion homeostasis in two major respiratory pathogens; Streptococcus pneumoniae, representing the leading bacterial pathogen in terms of annual mortality, and Acinetobacter baumannii as the world’s most problematic multidrug-resistant hospital pathogen. 

Projects

The role of metal ion toxicity during infection

Our laboratory has identified and characterised the major zinc and copper transport systems in A. baumannii. Our current work focusses on the impact of simultaneous fluxes of distinct metal ions during infection, and how this affects bacterial pathogenesis. This is of primary interest as ratios of distinct metals are to be maintained within defined thresholds due to the synergistic antimicrobial activity of particular metal ion combinations, such as zinc and copper. To study the impact of metal ion fluxes in the complex environment as seen during infection, we have successfully established a murine model of zinc deficiency and subsequent zinc supplementation. This model also holds clinical relevance due to the global significance of human zinc deficiency, which affects nearly 2 billion people.

Selected publications:

• PLoS Pathogens: Dietary zinc and the control of Streptococcus pneumoniae infection (https://doi.org/10.1371/journal.ppat.1007957)

• ACS Infectious Diseaes: The role of zinc efflux during Acinetobacter baumannii infection (https://doi.org/10.1021/acsinfecdis.9b00351)

• Nucleic Acids Research: DksA is a conserved master regulator of stress response in Acinetobacter baumannii (https://doi.org/10.1093/nar/gkad341)

The effects of antimicrobial fatty acids on bacterial physiology.

Host fatty acids hold dual roles during infection, modulating an immune response and directly killing invading bacteria. The primary antimicrobial host fatty acids are the omega-3 fatty acid docosahexaenoic acid and the omega-6 fatty acids arachidonic acid. The relative dietary intake of these fatty acids has shifted from 1:1, to a dramatic 20-fold relative increase in the consumption of omega-6 fatty acids. This has been associated with an increased risk of developing severe bacterial infections and omega-3 supplementation studies have shown a decrease in the incidence of respiratory infections. Our research has shown that the omega-3 fatty acid docosahexaenoic acid also exerts a greater antimicrobial activity upon major respiratory pathogens as compared to the omega-6 fatty acid arachidonic acid. Our current research examines how these host fatty acids exert their antimicrobial activity upon S. pneumoniae and A. baumannii, and which molecular mechanisms are employed by these pathogens to overcome their toxicity.

Selected publications:

• mBio: To Make or Take: Bacterial Lipid Homeostasis during Infection (https://doi.org/10.1128/mbio.00928-21)

• mBio: The membrane composition defines the spatial organization and function of a major Acinetobacter baumannii drug efflux system (https://doi.org/10.1128/mbio.01070-21)

• mBio: Identification of novel Acinetobacter baumannii host fatty acid stress adaptation strategies (https://doi.org/10.1128/mbio.02056-18)
   

Funding Sources

Research Grants/Fellowships:

• Flinders Foundation Health Seed Grant

Eijkelkamp, Bahari, Widger (2024; $22,952)

• Organ Donation Funds (Intensive & Critical Care Unit - Flinders Medical Centre)

Eijkelkamp, Bahari, Dixon, Donnelley, Parsons, Widger (2023 – 2025) $49,890

• Australian Research Council

CIC Discovery Project DP210100553 - Bacterial polycyclic aromatic hydrocarbon transport and degradation (2021 - 2023) $416,025

• National Health and Medical Research Council

CIA Project Grant 1159752 - A molecular balancing act: Understanding metal ion homeostasis in A. baumannii during infection (2019 - 2021) $642,521

• Flinders University

CIA Microbial Imaging Unit - Microbial Flow Cytometry Analyses ($70,000)

CIA Microbial Imaging Unit - Microbial Microscopy ($45,000)

CIA COVID-19 Urgent Research Scheme - Limiting the impact of underlying respiratory conditions to reduce COVID-19 death rates (2020) $43,610

• University of Adelaide

Beacon Research Fellowship - Defining the role of zinc at the host-pathogen interface (2018 - 2021) $670,000

• Channel 7 Children’s Research Foundation

CIA Grant - Optimal dietary metal ion uptake and its role in protection against childhood bacterial disease (2016) $35,000

Awards:

• Early Career Researcher Award, Adelaide Protein Group (2016) $1,500
• Daniel Walker Medal for ECR Research Excellence, University of Adelaide (2015) $1,000
• BD Student Award, Australian Society of Microbiology (2010) $1,500

Travel Grants:

• Hospital Research Foundation Travel Grant (2019) $4,000
• CASS Foundation Travel Award (2015) $3,250
• Faculty of Sciences ECR International Conference Travel Scheme (2015) $2,000
• UK Biochemical Society Travel Award (2015) $1,000
• Flinders University Research Student Conference Travel Grant (2009) $2,800
• Vrije Universiteit Amsterdam Travel Grant (2007) $640
• The Netherlands Cancer Council Travel Award (2007) $3,500

• Mar 2024 Brynley Davies  - SA/NT Nancy Millis Student Award
• Oct 2023 Brynley Davies  - Best Molecular Science & Technolgy HDR Student Presentation
• Oct 2022 Jack Waters - Best Molecular Science & Technolgy HDR Student Poster Presentation
• Oct 2022 Alice Ascari - Best Molecular Science & Technolgy HDR Student Presentation
• Aug 2022 Alice Ascari - Adelaide Protein Group People's Choice Award
• Jul 2022 Alice Ascari - Best Student Poster - Australian Lipids Meeting
• Jul 2022 Maoge (Lawrence) Zang - Student Presentation Award - BacPath
• Nov 2021 Maoge (Lawrence) Zang - Best Molecular Science & Technolgy HDR Student Presentation
• Apr 2020 Maoge (Lawrence) Zang - ASM Nancy Millis Award