Microbial pollution of water with special reference to coliform bacteria and their nexus with environment

Sudip Some, Rittick Mondal, Debasis Mitra, Divya Jain, Devvret Verma, Samanwita Das

Water is essential for the life, but many people lack the accessibility to clean and healthy drinking water and die as a consequence of water-borne infections. Microorganism-mediated water pollution is considered as one of the great concerns to the aquatic environment across the globe. The effluent of fecal matter, hospitals, industry, and cattle farms increase the bacterial load in a water body. Coliform groups of bacteria have long been typically applied as an indicator organism of microbial contamination of the water and historically led to the public health security perception. Among the coliform, Escherichia coli is the indicator of fecal contamination. The multiple tube fermentation technique has been applied as a conventional way to detect coliform in water samples through the fermentation of lactose sugar with production of acid and gas. The potability of water has been measured by the absence or presence of coliform bacteria within the permissible limit referencing the most probable number index value (MPN/100 ml). As fecal pollution indicators, fecal streptococci and Clostridium perfringens are widely used as an alternative to coliform bacteria and have been confirmed via esculin hydrolyzing or catalase-negativity and sulfite reduction tests. Molecular (PCR-based) and enzymatic methods have been applied as a rapid way to detect indicators and other enteric isolates in water samples. Apart from that standard plate count (SPC) of heterotrophic bacteria and biochemical oxygen demand (BOD) techniques also determine the bacterial and organic pollution load in a water sample. Therefore, bacteriological analysis of water indicated that water is polluted by sewage to the extent that it is unsuitable for drinking and also unsuitable for recreation purposes. This is one of the big problems in the twenty-first century is providing everybody with safe drinking or domestic water. The main objective of this article is to highlight the microbial pollution of water with special reference to coliform and its nexus with the environment.