The present study was conducted along River Teesta in Eastern Himalaya. Water and sediment samples were collected from six sampling points during the monsoon and winter seasons along the course of the river. The background information was collected by analysing physico-chemical parameters and the heavy metal concentrations. Culturable bacterial diversity using culture-based and molecular based 16S rRNA approaches characterized bacterial isolates to 5 major phyla, majority belonging

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... a, Actinobacteria and Firmicutes followed by Bacteroidetes, Alpha-Proteobacteria, Beta-Proteobacteria, Gamma-Proteobacteria, Actinobacteria, Bacilli, Flavobacteriia, Deinococci, Sphingobacteriia and Cytophagia. The total of 245 characterized isolates belonged to 69 genera. Diversity indices were calculated for each site. There were variations in the community structure of culturable bacteria along the river stretch with some common and unique groups. Heavy metal tolerance and antibiotic resistance profiles showed some isolates to be tolerant to high levels of heavy metals and multiple antibiotic indicating a major concern. The antibiotic resistance diversified along the human impacted downstream sites. The present report on bacterial diversity and the associated metal and antibiotics tolerance is the first of its kind on Teesta river, the only major river system flowing through the state of Sikkim and parts of North Bengal.