Biodiversity of organotin resistant Pseudomonas from west coast of India.

Five bacterial isolates were screened for resistance to organotin compound, i.e. tributyltin chloride (TBTC) up to 2 mM. The optimum pH, temperature and salinity for the growth of the isolates were found to be 7, 28 degrees C and 2.5%, respectively. The isolates were tested for survival tolerance to heavy metals (mercury, cadmium and zinc) and co-resistance to antibiotics viz. ampicillin, kanamycin, rifampicin, streptomycin, penicillin, chloramphenicol, tetracycline, nalidixic acid and neomycin. Although our earlier study reported that these five bacterial strains are of different species of Pseudomonas, our present 16S rRNA gene sequence analysis revealed that all the strains are Pseudomonas aeruginosa. One of five isolates P. aeruginosa strain 25W could grow in mineral salt medium with 2 mM of TBTC as a sole source of carbon and survive up to 5 mM of TBTC. In presence of 2 mM of TBTC there was comparable up-regulation of 45 kDa protein in the cell extract of the 25W isolate was found indicating involvement of certain enzymes in TBTC resistance.