Detection system for Escherichia coli-specific virulence genes: absence of virulence determinants in B and C strains

Kuhnert, Peter; Hacker, J; Mühldorfer, I; Burnens, André; Nicolet, Jacques; Frey, Joachim (1997). Detection system for Escherichia coli-specific virulence genes: absence of virulence determinants in B and C strains. Applied and environmental microbiology, 63(2), pp. 703-709. American Society for Microbiology

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We describe a rational approach to simultaneously test Escherichia coli strains for the presence of known virulence genes in a reverse dot blot procedure. Specific segments of virulence genes of E. coli designed to have similar hybridization parameters were subcloned on plasmids and subsequently amplified by PCR as unlabeled probes in amounts sufficient to be bound to nylon membranes. Various pathogenic isolates and laboratory strains of E. coli were probed for the presence of virulence genes by labeling the genomic DNA of these strains with digoxigenin and then hybridizing them to the prepared nylon membranes. These hybridization results demonstrated that besides the E. coli K-12 safety strain derivatives, E. coli B and C strains are also devoid of genes encoding any of the investigated virulence factors. In contrast, pathogenic E. coli control strains, used to evaluate the method, showed typical hybridization patterns. The described probes and their easy application on a single filter were shown to provide a useful tool for the safety assessment of E. coli strains to be used as hosts in biotechnological processes. This approach might also be used for the identification and characterization of clinically significant E. coli isolates from human and animal species.

Item Type:

Journal Article (Original Article)


05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Institute of Veterinary Bacteriology
05 Veterinary Medicine > Other Institutions > Emeriti, Vetsuisse Faculty

UniBE Contributor:

Kuhnert, Peter, Burnens, André, Nicolet, Jacques, Frey, Joachim


500 Science > 570 Life sciences; biology
600 Technology > 630 Agriculture




American Society for Microbiology




Peter Kuhnert-Ryser

Date Deposited:

15 Dec 2014 11:50

Last Modified:

05 Dec 2022 14:38

PubMed ID:





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