Bags of compost sold in the UK may be a significant source of Legionella bacteria, including strains that cause human disease, scientists have said.
Tests on 22 brands of compost available in the UK found that 14 contained a variety of Legionella bugs. Four showed evidence of Legionella longbeachae, which can cause serious infections leading to dmission to hospital or death.
Dr Tara Beattie of Strathclyde University led the research.
She said: “Disease-causing micro-organisms are widespread in the environment and therefore it is not too surprising that species of Legionella that can cause human disease are present in compost.
“Any environment where you have pathogenic bacteria could be a source of infection, and we already know that compost has been linked to human Legionella infection in countries such as Australia and New Zealand.
“Within the UK and across Europe composts have traditionally been composed of peat, whereas sawdust and bark are more often used to produce compost in Australia and New Zealand, where Legionellosis associated with compost is more common.
“It may be that the change in composition of composts in the UK, moving away from peat-based products, could be resulting in species such as Legionella longbeachae being present in compost, and therefore more cases of infection could occur.”
Last month health experts recommended putting warning labels on compost bags after a spate of Legonella longbeachae infections in Scotland.
Five people have been affected since the outbreak began. The latest victim was being treated in hospital in Dundee two weeks ago.