Effectiveness of Chromosomal and Plasmid-linked Genes for Enumerating Biotechnology Agents In Vivo
George, S. Elizabeth
Nelson, Gail M.
- Publisher: Microbial Ecology in Health and Disease
Microbial Ecology in Health and Disease
Following the release of biotechnology agents, detection methods for monitoring human exposure to these microorganisms should be available. Enzymatic markers from chromosomal (lacZY) and plasmid (xylE) DNA were evaluated in an in vivo mouse model. Mice were treated orally or intranasally with Pseudomonas aureofaciens 3732RN-L11 (lacZY), 3732RN-L11::pRO1940 (lacZY xylE), or ATCC 13985. All strains were cleared within 5 days from the cecum or lungs. Direct plating, without intermediate antibiotic resistance selection, was used to detect the genetic markers. Chromosomal-linked lacZ was stable in vivo and in vitro but plasmid-linked xylE was not. Of the isolates recovered, 75% (in vivo, oral), 98% (in vivo, intranasal), and 16% (in vitro) remained XyIE+. Though more tedious to enumerate, both lacZY and xylE are plausible alternatives to antibiotic resistance markers for in vivo biotechnology risk assessment studies.Keywords: Biotechnology Risk Assessment, Pseudomonas aureofaciens, Colonization in vivo.