Contact: Claire Bowles
01 71 331-2772
New Scientist

Killing Fields: A Bacterial Pesticide May Threaten Human Life

Companies in North America want to spray crops with a bacterium that might cause a deadly lung infection in people with cystic fibrosis. Experts on the bacterium, Burkholderia cepacia, are calling for a ban on its use in pest control until it is proved safe.

Good Bugs of Madison, a spin-off from the University of Wisconsin, hopes that the bacterium will outcompete fungi that can grow on peas, maize and potatoes, keeping the plants free from infection.

But B. cepacia can cause a severe and incurable lung infection in people with cystic fibrosis. The US Environmental Protection Agency (EPA) is blocking an application for large-scale testing filed last year by Good Bugs until the company provides more evidence that its strain of B. cepacia represents no threat to human health. Phil Hutton, head of the EPA's microbial branch in Washington DC, says: "We have not yet received information we feel is adequate to make that judgment."

The EPA, together with the Canadian Pest Management Regulatory Authority, is also reviewing a similar application by another company, Agrium of Calgary, Alberta. And Jonathan Barry, president of Good Bugs, told New Scientist he was confident that he could gain permission to test the bacterial spray in Britain.

Barry believes the strain of B. cepacia used by Good Bugs, isolated from soil, is quite safe. But that doesn't reassure Robert Beall, president of the US Cystic Fibrosis Foundation. "We don't think it should be used in any agricultural setting until we know what's safe and what's not. We don't know yet if there are any truly nonpathogenic forms of this organism."

There may be none. "Molecular genetic evidence indicates there might be a threat to health regardless of which strains are selected," says Alison Holmes of Imperial College School of Medicine in London.

In a paper to appear in Emerging Infectious Diseases, Holmes, John Govan of the University of Edinburgh and Richard Goldstein of Boston University document the bacterium's ability to mutate rapidly. The researchers call for a moratorium on its use in agriculture. Goldstein says that B. cepacia is resistant to most antibiotics and kills around a third of cystic fibrosis patients it infects within a year.

Goldstein has studied an outbreak of B. cepacia at the University of Mississippi Medical Center three years ago, in which 300 patients were hit. DNA analysis suggests that the infection had passed between patients with and without cystic fibrosis. "It suggests non-CF patients may be a source of infection," says Goldstein. "This is incredibly important if they're going to start spraying it in the environment."

Martin Scott, medical and scientific director of the UK Cystic Fibrosis Trust, says he is concerned about the possibility of an application being made in Britain to test the spray. "It seems very premature to start spraying it around before we know what the risk is going to be," he says.

Alison Hamer of the British agriculture ministry's Pesticides Safety Directorate says that no new biopesticide could get a licence without meeting strict British and European regulations. "The whole process is very rigorous," she says.

Material presented on this home page constitutes opinion of the author.
Copyright © 1998 Steven J. Milloy. All rights reserved. Site developed and hosted by WestLake Solutions, Inc.