16Water quality of a region directly corroborates with the health index of people. People in the 17 Himalayan hills mainly depend upon the spring water for potability. To determine the microbial 18 ecology of the spring waters of Sikkim, the variable region of 16S rRNA has been sequenced 19 using Illumina MiSeq. Phylum wise annotation showed the East and North district are mostly 20 dominated by Proteobacteria (41% and 35.80%), whereas West and South district is dominated 21 by Planctomycetes (38.46%) and Verrucomicrobia (33%). The consistent dominance phyla in 22 the all the four districts were Bacteriodetes (34-24%) which was highest dominancy in North 23 district and lowest in wets district. Genus wise distribution showed the abundance of Brevifolis, 24 2 Flavobacterium, Verrucomicrobia subdivision3, Emticica, Cytophaga, Prosthecobacter, 25 Planctomycetes, Varivorax, Arcicella, Isosphera, Sedimunibacterium etc. The East district 26 showed highest dominancy of genus Emticicia whereas Planctomycetes in the West district. The 27North district was mainly dominated by genus Arcicella and Brevifollis in the South district. 28North on the antonymous showed totally different sets of microbial diversity. North district 29 showed an abundance of Arcicella, Planctomycetes, Schlerensia and Azohydromonas. The heat 30 map produced by Bray Curtis distance method produced three clusters which showed the close 31 relationship between West and East district microbiome that further related to South district. The 32 sample of North district formed out group that showed different community structure from other 33 three districts. The principle component analysis was showed that the east and South district 34 samples are closely related and distantly correlated to the west Sikkim, but the North district 35 showed completely different microbial community. The canonical correspondence analysis 36 showed correlation between bacterial diversity and hydrochemistry and it was found that the 37 bacterial diversity was influenced by the concentration of different metallic ions like sodium, 38 calcium, barium and iron. This is a first report from the Eastern Himalayan region of India and it 39 largely enhances our knowledge about the microbial structure of potable spring water of Eastern 40 Himalayan. This study is useful for Government of India as well as the state government to adopt 41 the different strategic treatment procedures to improve the quality of water that is supplied to the 42 community resides in the Himalayan regions and solely dependent on this untreated spring water. 43 44 45 46 47 48Microbial communities are the key members of many ecosystems on the earth 49 (Lagkouvardos et al., 2016). The word microbial communities can be described in the terms 50 of richness or evenness as well as composition i.e. abundance of taxa and genes in the sample 51 (Rothschild, 1991). They play a significant role in crucial biological functions ranging from 52 nitrogen and carbon cycles in the environment to regulation of metabolic...

In India antibiotics are frequently used for preventing and controlling bacterial pathogens in carp aquaculture system, yet no studies have been performed to evaluate the ecological impact of its intensive and prolonged use. In this work the frequency of oxytetracycline-resistant bacteria from water, palletized feed and different life stages of fish from Indian freshwater carp aquaculture system as well as the level of resistance of selected strains was investigated. Viable as well as antibiotic-resistant bacterial counts were performed by spread plate method in culture media supplemented with the oxytetracycline. Sixty two resistant Gram negative isolates which represented the oxytetracycline-resistant bacterial population, were randomly selected on nutrient agar supplemented with oxytetracycline (50µg/ml) from carp farms and feed pellet samples. Among these bacterial isolates Flavobacterium (21%), Alcaligenes (14.5%), Aeromonas (11%), Pseudomonas (10%) and Enterobacteriace (19%) were the most frequent. The Escherichia, Serratia, Citrobacter, Enterobacter, Shigella and Proteus from Enterobacteriace were recovered. Twelve isolates of oxytetracycline resistant bacteria were mainly dominated in adult fishes by the genus Flavobacterium (23%) and Enterobacteriace(41%). Selected strains exhibited high levels of oxytetracycline resistance with minimum inhibitory concentrations (MICs) ranging from 50 to 600µg/ml.This study shows the presence of an important population of oxytetracycline-resistant bacteria in the microflora of Indian carp aquaculture farms. Therefore the environment of these farms might play important roles as reservoirs of bacteria carrying genetic determinants for high level tetracycline resistance, prompting an important risk to public health.