Assessing clonality of Vibrio cholerae Inaba isolates by characterization of nonsense mutations in wbeT

The transferase gene wbeT of six clinical isolates of Vibrio cholerae O1 biotype El Tor was analysed. Two unique mutations were identified in the wbeT gene of three Inaba isolates. Due to their random nature, mutations in wbeT can be used to determine the clonal origin of clinical Inaba isolates

Immunization against anthrax using Bacillus subtilis spores expressing the anthrax protective antigen

Protective immunity to anthrax can be achieved by antibodies raised against the secreted protective antigen (PA) and this forms the basis of the current acellular vaccines for human use. Bacillus subtilis spores have previously been used for delivery of heterologous antigens by the oral and nasal routes and their intrinsic heat-stability make them attractive vaccine vehicles. In this study we have expressed PA, or segments of PA, in B. subtilis using two strategies. First, display on the spore coat, and second, in the germinated spore (or vegetative cell). Using parenteral delivery we show that recombinant spores can be used to confer protective immunity in a murine model using an in vitro toxin neutralization assay and a challenge experiment with the latter showing protection to 100 median lethal dose of B. anthracis spores. PA must be secreted from the live bacterium or alternatively displayed on the spore surface to confer protective immunity. Intracellular expression of PA failed to confer protective immunity. The highest levels of protective immunity were achieved when PA was displayed on the spore surface as well as in the germinating spore. (c) 2006 Elsevier Ltd. All rights reserved