A Strategy for the Rapid Development of a Safe Vibrio cholerae Candidate Vaccine Strain.

Dmitry S Karpov,Roman S Ovchinnikov,Elizaveta V Divisenko,Evgenii V Usachev,Sergei M Yudin,Anna V Goncharenko,Andrei A Pochtovyi,Artem P Tkachuk,Yaroslava M Chalenko,Vladimir A Gushchin,Daria V Vasina,Valentin V Makarov

doi:10.3390/ijms222111657

Abstract

Approximately 1/6 of humanity is at high risk of experiencing cholera epidemics. The development of effective and safe vaccines against Vibrio cholerae, the primary cause of cholera, is part of the public health measures to prevent cholera epidemics. Natural nontoxigenic V. cholerae isolates represent a source of new genetically improved and relatively safe vaccine strains. However, the genomic engineering of wild-type V. cholerae strains is difficult, and these strains are genetically unstable due to their high homologous recombination activity. We comprehensively characterized two V. cholerae isolates using genome sequencing, bioinformatic analysis, and microscopic, physiological, and biochemical tests. Genetic constructs were Gibson assembled and electrotransformed into V. cholerae. Bacterial colonies were assessed using standard microbiological and immunological techniques. As a result, we created a synthetic chromoprotein-expressing reporter operon. This operon was used to improve the V. cholerae genome engineering approach and monitor the stability of the genetic constructs. Finally, we created a stable candidate V. cholerae vaccine strain bearing a recA deletion and expressing the β-subunit of cholera toxin. Thus, we developed a strategy for the rapid creation of genetically stable and relatively safe candidate vaccine strains. This strategy can be applied not only to V. cholerae but also to other important human bacterial pathogens.

Highlights

Pathogenic strains of Vibrio cholerae cause cholera, an acute infectious disease characterized by a sharp loss of water due to profuse diarrhoea, which can be fatal in the absence of rehydration therapy [1]
V. albensis is the name for species comprising non-O1 and non-O139 V. cholerae strains [20,21]
We provide a four-step strategy for using an amilCP-based reporter system for the rapid development and quality control assessment of candidate vaccine strains against important human pathogens using V. cholerae as an example

Summary

Introduction

Pathogenic strains of Vibrio cholerae cause cholera, an acute infectious disease characterized by a sharp loss of water due to profuse diarrhoea, which can be fatal in the absence of rehydration therapy [1]. The appearance of multidrug-resistant V. cholerae strains replacing antibiotic-susceptible strains [3] increases the risk of high severity of future cholera epidemics and outbreaks. V. cholerae represents a global health threat, stimulating the development of public health measures to limit the spread of pathogenic strains to prevent cholera epidemics. Vaccination with oral cholera vaccines (OCVs) is considered by the World Health Organization to be an essential tool in cholera outbreak prevention and control. Two- or higher-dose vaccine regimens, more effective, are more expensive and less feasible than a single-dose regimen. These data indicate the need for further improvement of cholera vaccines

Methods

Results

Conclusion