Thesis
The ecology of Legionella spp in compost
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2023
- Thesis identifier
- T17418
- Person Identifier (Local)
- 201159754
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Legionella species can cause infection in humans, ranging from mild to life-threatening. These bacteria are commonly associated with water environments, but have also been sporadically linked with composts and associated habitats. Gardening is a popular pastime for millions of people in the UK and further afield, and the presence of human pathogens in the garden environment has the potential to pose a risk to public health. However, there is limited research examining environmental Legionella spp in areas other than the water habitat and therefore the level of risk posed is unclear. The key aim of this thesis was therefore to investigate the ecology of Legionella spp in compost in order to improve understanding of the potential risk. Compost samples from different sources were examined and found that Legionella spp are commonly present in products available in the UK: 15/24 (62.5%) samples tested by culture and 22/22 (100%) samples tested by PCR identified Legionella spp. Storage conditions were then assessed to determine if greenhouse conditions encourage growth of these organisms further increasing likelihood of exposure. DNA extraction and semi-quantitative PCR methods were developed and applied to compost samples stored in three mock greenhouse systems. The work showed that humidity is likely a critical factor in the maintenance and proliferation of these organisms in compost. In addition, Legionella spp. may behave differently in peat-containing composts than in peat-free composts in the greenhouse setting. To determine where Legionella enters the compost environment, and therefore identify opportunities to reduce the presence of these organisms in the compost chain, samples from a green waste processing site were examined. Legionella spp were identified using PCR at all stages of the manufacturing process, suggesting they may be present in small numbers throughout. The work outlined in this thesis has added to the available knowledge on Legionella spp. in the compost environment. Further work is required to define and minimise risks posed to workers and members of the public exposed to these organisms in this environment.
- Advisor / supervisor
- Knapp, Charles W.
- Beattie, Tara K.
- Resource Type
- DOI
Relations
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