An Investigation into the Microbiological Quality of Groundwater in an Industrial Hub in Mid-Hills of Northern India

Abstract

Frequent water-borne disease outbreaks affecting human health have been reported in district Solan, which is a rapidly industrialing region of Himachal Pradesh, a northern state of India. For ascertaining the cause, microbiological assessment of drinking groundwater sources of the region was undertaken. For this, thermotolerant coliform study and genome typing were undertaken. Multiple tube fermentation technique was employed in selected five sources to detect thermotolerant coliforms during the seasons of monsoon and post-monsoon in the years 2018-19. Thermotolerant coliforms varied in Most Probable Number from 2-34 per 100 ml water indicating contaminated water sources, densities being significantly more in monsoon months (p< 0.05). Four different coliform morphotypes were obtained from all the sources on Eosin Methylene Blue plates. Of these, the only strain, designated as Nalagarh Water Strain (NGW), was recovered from all sources, suggesting its prevalence. Based upon biochemical and morphological attributes, the strain was recognized as Escherichia coli. Conversely, molecular characterization (16S rRNA ribotyping) identified it as Raoultella planticola (GenBank accession No. MK318824). The strain was deposited in a National Culture Collection Centre, National Centre for Microbial Resources, Pune, Maharashtra (India) with deposition accession number MCC 4064 for future utility in public research activities. Microbiological assessment evinced contaminated drinking water sources, probably causing diarrhoeal diseases. 16S rRNA ribotyping assisted in correct identification of the microorganism.