Detection of RTX toxin genes in gram-negative bacteria with a set of specific probes

Kuhnert, Peter; Heyberger-Meyer, B; Burnens, André; Nicolet, Jacques; Frey, Joachim (1997). Detection of RTX toxin genes in gram-negative bacteria with a set of specific probes. Applied and environmental microbiology, 63(6), pp. 2258-2265. American Society for Microbiology

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The family of RTX (RTX representing repeats in the structural toxin) toxins is composed of several protein toxins with a characteristic nonapeptide glycine-rich repeat motif. Most of its members were shown to have cytolytic activity. By comparing the genetic relationships of the RTX toxin genes we established a set of 10 gene probes to be used for screening as-yet-unknown RTX toxin genes in bacterial species. The probes include parts of apxIA, apxIIA, and apxIIIA from Actinobacillus pleuropneumoniae, cyaA from Bordetella pertusis, frpA from Neisseria meningitidis, prtC from Erwinia chrysanthemi, hlyA and elyA from Escherichia coli, aaltA from Actinobacillus actinomycetemcomitans and lktA from Pasteurella haemolytica. A panel of pathogenic and nonpathogenic gram-negative bacteria were investigated for the presence of RTX toxin genes. The probes detected all known genes for RTX toxins. Moreover, we found potential RTX toxin genes in several pathogenic bacterial species for which no such toxins are known yet. This indicates that RTX or RTX-like toxins are widely distributed among pathogenic gram-negative bacteria. The probes generated by PCR and the hybridization method were optimized to allow broad-range screening for RTX toxin genes in one step. This included the binding of unlabelled probes to a nylon filter and subsequent hybridization of the filter with labelled genomic DNA of the strain to be tested. The method constitutes a powerful tool for the assessment of the potential pathogenicity of poorly characterized strains intended to be used in biotechnological applications. Moreover, it is useful for the detection of already-known or new RTX toxin genes in bacteria of medical importance.

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 11:58

Last Modified:

05 Dec 2022 14:38

PubMed ID:





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