EPA Notice on Microbial Pesticides Concerns

from March 1998 Phytopathology News

The soil bacterium Burkholderia (formerly Pseudomonas) cepacia was registered in 1992 as a microbial pesticide by the U.S. Environmental Protection Agency (USEPA) and investigation continues on its use as a biocontrol agent for soilborne and foliar diseases. This notice is intended to inform the research community about public health concerns regarding the registration and use of B. cepacia as a microbial pesticide

Apprehension about the use of B. cepacia as a biocontrol agent has been increasing recently. This concern is due to serious and sometime fatal infection, associated with bacteria identified as B. cepacia, of individuals with cystic fibrosis and certain other immune system compromising illnesses. Infection of susceptible individuals often progresses rapidly and is frequently refractive to treatment by many antibiotics. Positive identification of B. capacia as the causal agent of these infections has been uncertain in the past. This confusion has been due in part to B. cepacia colonization of the lungs of cystic fibrosis patients in the absence of pathogenicity or fatality. However, recent studies are suggestive of possible causality of morbidity and fatality by some strains identified as B. cepacia, although infection from environmental sources has not been demonstrated. Currently there is uncertainty in the taxonomic classification of the numerous strains identified as B. cepacia. It is unclear whether the strains used as microbial pesticides are identified to the strains associated with human infection, or even whether they comprise the same species. Since distinction between clinical and environmental strains was, in part, the basis of the safety assessment for the original B. cepacia registration, the continued use of this microbe is being questioned, especially by the medical community. Until the relationship between biological control strains and strains associated with human infection is known, new registrations, or additional uses of currently registered strains, which increase the possibility of human exposure, will be problematic. Additional research is needed to identify genetic and phenotypic traits and markers, as well as other taxonomic characteristics and tests for pathogenicity, that will distinguish between human pathogenic B. cepacia strains and those used as microbial pesticides. For this reason expressed above, it is highly recommended that individuals or organizations contemplating registration of B. cepacia or closely related bacteria contact the USEPA. for information regarding the registration of B. cepacia, contact: Denise Greenway, EPA Office of Pesticide Programs (7511W), 401 M Street, Washington, DC 20460, E-mail: greenway.denise@epamail.epa.gov. USEPA also welcomes information that may help to resolve the issues discussed above. A symposium addressing biological control and medical issues of B. cepacia is scheduled for the joint APS/ESA meeting in 1998. An update on the regulatory issues is to be presented. For information regarding this symposium, contact: Jennifer Parke, Jennifer.Parke@oregonstate.edu.


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