Expression of an antisense hla fragment in Staphylococcus aureus reduces alpha-toxin production in vitro and attenuates lethal activity in a murine model

75Citations
Citations of this article
34Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

Isogeneic bacterial strains that differ only in the production of a single microbial factor have been invaluable in studying the pathogenesis of bacterial infections. The targeted, intentional inactivation of a gene encoding a potential virulence determinant generally requires homologous recombination to replace the gene with an inactivated allele. To determine whether the insertion and expression of a fragment of a bacterial gene in an antisense orientation could be used as a rapid alternative to allelic inactivation for producing paired isogeneic isolates, we inverted a 600-bp fragment of the Staphylococcus aureus gene encoding alpha-toxin, hla, behind its native promoter on an Escherichia coli-S. aureus shuttle vector. A transformant of an S. aureus strain carrying the antisense hla fragment produced antisense hla RNA and made 16-fold less alpha-toxin than either its parent or an isogeneic transformant containing vector DNA without hla. Also, intraperitoneal injection of 1.5 x 109 CFU of the antisense hla-containing transformant was significantly less lethal in a murine model than that of the parent (1 of 10 versus 7 of 10 mice expired [P < 0.02]) or the transformant without hla (1 of 10 versus 7 of 7 mice expired [P < 0.001]). We conclude that the expression of a fragment of hla in an antisense orientation in S. aureus on a plasmid vector reduces alpha-toxin production and the lethal activity of the strain in a murine model. The antisense strategy for creating isogeneic strains of bacteria may facilitate molecular investigations into the pathogenesis of infection. It also may be useful in creating novel live- attenuated strains of bacteria for use as vaccine candidates.

Cite

CITATION STYLE

APA

Kernodle, D. S., Voladri, R. K. R., Menzies, B. E., Hager, C. C., & Edwards, K. M. (1997). Expression of an antisense hla fragment in Staphylococcus aureus reduces alpha-toxin production in vitro and attenuates lethal activity in a murine model. Infection and Immunity, 65(1), 179–184. https://doi.org/10.1128/iai.65.1.179-184.1997

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free