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The effect of air pollution on the interaction between bacteria and bacteriophage

Primary Supervisor: Dr Julie Morrissey, Department of Genetics and Genome Biology

Secondary Supervisor: Professor Martha Clokie, Dr Andy Millard

PhD project title: The effect of air pollution on the interaction between bacteria and bacteriophage.

University of Registration: University of Leicester

Project outline:

Air pollution is the world’s largest single environmental health risk, being responsible for an eighth of all global deaths per year (World Health Organisation, 2017). High levels of atmospheric particulate matter (PM) cause increased respiratory and infectious diseases, including pneumonia. How PM effects bacterial behaviour, however, is not well understood which is worrying considering the role of bacteria in infectious and respiratory diseases.

Our ground breaking studies, which received worldwide media attention, showed that exposure to PM alters the behaviour of respiratory tract bacteria (Hussey et al., 2017). Our publication showed that PM induces changes in Streptococcus pneumoniae and Staphylococcus aureus biofilm formation and altered the tolerance of biofilms to antibiotics (Hussey et al., 2017). Importantly PM exposure increased in vivo colonisation of the respiratory tract.

Our recent evidence has shown that PM effects the interaction between bacteria, altering how they form mixed species biofilms and colonise, and even effecting growth. This has important implications for how PM can impact the microbial communities which are essential for health and well-being, with recent evidence showing that air pollution does indeed impact the balance of microbiomes.

An important aspect of microbiomes that are often overlooked are bacteriophages (viruses that specifically infect bacteria). Phages are the most abundant biological entity on the planet, with numbers often 10x higher than their bacterial hosts. Despite their abundance we know virtually nothing about most phages, with only a relatively small being characterised in detail. Of those phages that have been studied we know they can have dramatic effects on their bacterial hosts and the world we live in. These effects range from reducing the amount of CO2 that is fixed in the oceans, that impacts the global carbon budget. To increasing the virulence of their bacterial hosts by the carriage of genes that encode for toxins, that results in disease in humans. eg the causative agent of cholera is carried by a phage that infects Vibrio cholerae.

Given phages are known to have important roles in all other systems where they have been studied, it is highly likely they do in this system.

Our hypothesis is that PM will impact how phage interact with bacteria altering how the bacteria are infected by phage and altering bacterial behaviour. Thus the aim of this project is to determine how PM affects phage interaction with bacteria and answer the following questions.

  1. Does exposure to PM change the rate of prophage induction within bacteria such as Staphylococcus aureus and Haemophilus influenzae?
  2. What is the impact of PM on phage infection dynamics?
  3. How does PM exposure on phage effect bacterial colonisation?

The student will be part of a collaborative lively and friendly interdisciplinary research team. We have international expertise in the impact of air pollution on bacteria, infectious diseases and bacteriophage. Leicester is at the forefront of phage research in the Europe, with expertise in fundamental phage biology, phage genomics and phage therapy. Therefore the student will have a unique opportunity to learn about microbiology, infection, climate and environmental challenges as well as be trained in a wide range of molecular microbiology techniques and the use of clinical samples.


  1. Hussey et al., 2018. Air pollution alters Staphylococcus aureus and Streptococcus pneumoniae biofilms, antibiotic tolerance, and colonisation. (2017) Environmental Microbiology 19:1868-1880.

BBSRC Strategic Research Priority: Understanding the Rules of Life: Microbiology

Techniques that will be undertaken during the project:

  • Microbiological techniques
  • RNA and DNA analysis
  • Bioinformatics
  • Electron and microscopy

Contact: Dr Julie Morrissey, University of Leicester