Pandemics, pathogenicity and changing molecular epidemiology of cholera in the era of global warming

BACKGROUND: Vibrio cholerae, a Gram-negative, non-spore forming curved rod is found in diverse aquatic ecosystems around the planet. It is classified according to its major surface antigen into around 206 serogroups, of which O1 and O139 cause epidemic cholera. A recent spatial modelling technique estimated that around 2.86 million cholera cases occur globally every year, and of them approximately 95,000 die. About 1.3 billion people are currently at risk of infection from cholera. Meta-analysis and mathematical modelling have demonstrated that due to global warming the burden of vector-borne diseases like malaria, leishmaniasis, meningococcal meningitis, viral encephalitis, dengue and chikungunya will increase in the coming years in the tropics and beyond. CHOLERA AND CLIMATE: This review offers an overview of the interplay between global warming and the pathogenicity and epidemiology of V. cholerae. Several distinctive features of cholera survival (optimal thriving at 15% salinity, 30 °C water temperature, and pH 8.5) indicate a possible role of climate change in triggering the epidemic process. Genetic exchange (ctxAB, zot, ace, cep, and orfU) between strains and transduction process allows potential emergence of new toxigenic clones. These processes are probably controlled by precise environmental signals such as optimum temperature, sunlight and osmotic conditions. Environmental influences on phytoplankton growth and chitin remineralization will be discussed alongside the interplay of poor sanitary conditions, overcrowding, improper sewage disposal and global warming in promoting the growth and transmission of this deadly disease. CONCLUSION: The development of an effective early warning system based on climate data could help to prevent and control future outbreaks. It may become possible to integrate real-time monitoring of oceanic regions, climate variability and epidemiological and demographic population dynamics to predict cholera outbreaks and support the design of cost-effective public health strategies

Cell surface and stress tolerance properties of a newly isolated Lactobacillus plantarum Ch1

We investigated the role of salt, ethanol, hydrogen peroxide on the survival and cell surface hydrophobicity (CSH) of Lactobacillus plantarum Ch1 possessing probiotic properties. Survivability of the strain exposed to elevated (3.40 M) ethanol concentration, salt (0.5–2 M), hydrogen peroxide (0.029–0.29 M) was not significantly (P>0.01) affected. With the sole exception of oxidative stress, CSH of intact Lactobacillus plantarum Ch1 increased linearly to the respective stress doses, the observed relationships were supported by strong positive correlations between elevated stress levels and increasing CSH values, suggesting a concentration dependent change in CSH of intact cells. The results of our study imply CSH to be a predominant factor for Lactobacillus plantarum Ch1 to endure stress conditions and may be of substantial importance during designing probiotic foods/beverages containing this strain