Isolation, characterization and molecular phylogeny of multiple metal tolerant and antibiotics resistant bacterial isolates from river Ganga, Varanasi, India

The present study was focused on the isolation of multiple metal tolerant and antibiotics resistant bacterial strains from water samples of five different Ghats of river Ganga, Varanasi, India. These strains were biochemically characterized and their phylogenetic relatedness was assumed using amplified ribosomal DNA restriction analysis fingerprinting and 16S ribosomal gene sequencing. The presence of heterogeneous groups of bacteria belonging to alpha, beta, gamma proteobacteria, and bacilli was noticed. Some of the bacterial strains like Pseudomonas, Serratia, Enterobacter, and Proteus vulgaris were mainly found at the Dashashwamedh Ghat and the Assi Ghat showing minimum inhibitory concentration 200-300 mg/L for copper, nickel, lead, and chromium. Comamonas sp. mainly isolated from the Samne Ghat and the Rajendra Prasad Ghat was able to grow at very high concentration of lead viz. 400 mg/L. Some of the strains showed multidrug resistant property against 10 different antibiotics which are of most serious concern because these drugs are frequently used against various bacterial infections.