Pathogens and response to antimicrobials

Our science bridges food safety, biology of human bacterial pathogens and control of infectious diseases in humans.

We study human bacterial pathogens with focus on Staphylococcus aureus and Listeria monocytogenes and how they survive environmental challenges such as antibiotics and biocides.

Research focus

Antibiotic resistance
Antibiotic resistance genes are transferred between bacteria and we know little of the transfer processes and where it occurs. We examine how bacteriophages (phages) contribute to transfer of resistance genes in S. aureus. See how in the movie Antibiotic Resistance Transfer in Staphylococcus aureus/Trends in Microbiology.

Bacterial genes can also contribute to antibiotic resistance genes as seen for example in persister cells. In S. aureus we investigate the bacterial genes that influence survival in the presence of antibiotics to find new ways of improving the efficacy of antibiotics.

Quorum sensing and biofilms
Quorum sensing enables S. aureus to sense the density of S. aureus cells and control virulence gene expression accordingly. Biofilms may be a place where quorum sensing is particularly important. We search for compounds and organisms that interfere with S. aureus quorum sensing in order to develop new treatment options for serious staphylococcal infections.

Food safety
We study transmission of bacterial pathogens in food production chains with particular focus on interventions. Among the challenges is Listeria monocytogenes where we examine carbohydrate metabolism and its role in survival both in the environment and within the human host. Also, we are interested in bacterial response to biocides and the possible contribution of biocide tolerance to persistence of bacteria in food production systems and hospitals.

Main findings

Baldry M, Nakamura Y, Nakagawa S, Frees D, Matsue H, Núñez G, Ingmer H. Application of an agr-Specific Antivirulence Compound as Therapy for Staphylococcus aureus-Induced Inflammatory Skin Disease. J Infect Dis. 2018 Aug 14;218(6):1009-1013.
Here we show that inhibition of the S. aureus quorum sensing system by an "anti-viruolence" compound we can reduce the symptoms of atopic dermatitis in a mouse model.

Fillol-Salom A, Alsaadi A, Sousa JAM, Zhong L, Foster KR, Rocha EPC, Penadés, JR, Ingmer H, Haaber J. Bacteriophages benefit from generalized transduction. PLoS Pathog. 2019 Jul 5;15(7):e1007888.
Here we show that phages which have a lifecycle as part of the bacterial chromosome benefits from enabling the bacterial host to transfer antibiotic resistance genes in the process of transduction. 

Bojer MS, Lindemose S, Vestergaard M, Ingmer H. Quorum Sensing-Regulated Phenol-Soluble Modulins Limit Persister Cell Populations in Staphylococcus aureus. Front Microbiol. 2018 Feb 20;9:255. doi: 10.3389/fmicb.2018.00255. eCollection 2018. PubMed PMID: 29515541; PubMed Central PMCID: PMC5826201.
Here we show that the staphylococcal toxins influence the ability of the cells to form persister cells. This suggests an auto-regulatory loop where the bacteria themselves can control their ability to survive lethal concentrations of antibiotics in the persister state.

Research funding