Resuscitation of bacterial biofilm by Sunlight: Effects on Vibrio cholerae, Shiga Toxin Producing Escherichia coli.

Abstract

There is significant evidence that suggests that bacteria go through various mobile and immobile phases during their lifetime. All these various phases, in turn, facilitate the pathogenic bacteria to cause and spread diseases during the seasonal outbreaks. These reversible mobile and immobile phases in bacteria are most evidently seen through the making and then the breaking out of biofilms. Many environmental factors induce bacteria to enter a sessile state in the form of biofilms, while many cause them to break out those biofilms and become activated i.e, pathogenic. In this study, we focused on the effect of sunlight as a factor for the bacteria to break out of those biofilms and be resuscitated to cause diseases. Biofilms of a number of cholera strains and shiga toxin producing E.coli that cause diseases during the months of March to July were subjected to sunlight throughout the winter season (December to February) using four different phases, i.e., methods of data collection and its effects were observed and analyzed using appropriate statistical analysis. The resulting data and statistical analysis suggests that biofilms in the winter sunlight do not get resuscitated and a significant amount of planktonic bacteria does not come out of the biofilms to cause diseases. As a result, during the winter seasons, the incidence rate of some of the diseases may stay low as the causative bacteria in the waters stays immobile within the biofilm structures. However, in order to provide any conclusive evidence, round the year study including more samples is required.