SEARCH FOR DRUG AND METAL RESISTANCE PLASMIDS FROM INDIGENOUS CLINICAL PSEUDOMONADS

On the bases of morphology, cultural and biochemical characteristics, 50 indigenous clinical pseudomonads were identified as Pseudomonas aer uginosa. Resistance patterns of antibiotics upto 500 mu g mL(-1) and i norganic metallic ions upto 3 mg mL(-1) were determined by medium inco rporation method. Five of the isolates lost their resistance to erythr omycin after curing for plasmid elimination with 5 mg mL(-1) of acridi ne orange, thereby indicating the extrachromosomal location of the res istance determinants. Agarose gel electrophoresis using 'Mini prep' me thod for plasmid isolation revealed that six isolates harbour plasmids of different molecular weights (5-28 kb) with Hind III digest of lamb da DNA as ladder. some of the pseudomonad isolates were able to transf er their resistance to Escherichia coil BU 40 by in vivo gene transfer plasmid conjugation.