Red X iconGreen tick iconYellow tick icon
A postgraduate research opportunity at the University of Otago.


Close date
Friday, 22 February 2019
Academic background
Sciences, Health Sciences
Host campus
Pathology and Biomedical Science (Christchurch)
Dr Sandy Slow, Professor Steve Chambers, Professor David Murdoch


Every year in New Zealand, particularly over spring and summer, gardeners are hospitalised with Legionnaires' disease, an often severe and fatal pneumonia. The cause is infection by Legionella longbeachae, a bacterium that lives in the soil and is also found in composted plant material and potting mix. In both natural and man-made environments, Legionella bacteria are intracellular parasites of free-living amoeba. Humans are “accidental hosts” when lung macrophages become infected following exposure to contaminated materials. As it is not contagious, infection is solely acquired from environmental sources rather than from other people.

In the environment, following amoebal uptake, Legionella are able to resist the host's defenses and hijack the cell's resources so it can replicate, significantly increasing in numbers. It then lyses and kills the amoeba, releasing the bacteria to repeat the cycle anew. Such environmental amplification of L. longbeachae numbers via its' amoebal host is likely to be a major contributing factor for the increase in Legionnaires' disease cases during spring and summer. However, little is known about this key relationship or even which amoebal species are important hosts. As a result our ability to plan strategies to reduce the potential risk of human infection and disease is severely limited.

This project aims to gain a greater understanding of the relationship between L. longbeachae and its amoebal host by:

  1. Determining the presence or absence of various amoebal species using PCR to test potting mix products that have been found to be positive for L. longbeachae
  2. Isolate and identify the main amoebal species present by sequencing the 18S ribosomal gene and comparing against microbial sequence databases
  3. Test the isolated amoebae's preference for uptake of L. longbeachae compared to other laboratory cultured bacteria (for example E. coli) in a series of in vitro “eating experiments”

Preferred student expertise

  • Microbiology
  • Molecular Biology

Further information

This project is one of the many available for the 2019 intake of BBiomedSc(Hons) at the University of Otago, Christchurch campus.

Visit the University of Otago, Christchurch website for more information about the Honours programme.

The Infection Group website

Dr Sandy Slow's staff profile
Professor Steve Chambers' staff profile
Professor David Murdoch's staff profile


Dr Sandy Slow
Tel +64 3 364 0585

Useful information

Similar research opportunities

Back to top