DETECTION OF MERCURY AND CADMIUM RESISTANCE AMONG MULTIPLE ANTIBIOTIC RESISTANT ENTERIC BACTERIA FROM MUNICIPAL SEWAGE WATER IN MALDA, INDIA

Abstract

The plasmid mediated co-resistance to antibiotics and heavy metals among environmental as well as clinical bacteria have been reported from various parts of the globe. In the current study, the sewage water samples (n=9), collected within from Malda town (West Bengal state, India), were processed microbiologically for the isolation of bacteria (n=12), which were identified, following conventional methods, as Pseudomonas aeruginosa (n=3), Proteus vulgaris (n=2), Escherichia coli (n=5) and Klebsiella pneumoniae (n=2). The isolated bacteria had resistance to ³4 antibiotics among ampicillin (Am), cholramphenicol (Cm), trimethoprim (Tm), tetracycline (Tc), ciprofloxacin (Cp) and gentamicin (Gm), and to heavy metals (Cd²⁺ and Hg²⁺) tested, and contained a single plasmid conferring such resistances. The highest resistance was shown among E. coli isolates, having the resistance pattern of ‘Am-Cm-Tm-Tc-Cp-Gm’. The multiple antibiotic resistance indices for the isolated sewage-water bacteria ranged 0.4 – 0.6. Thus, the current study further authenticated the association between antibiotic resistance and heavy metal tolerance among sewage-water bacteria (from our part of the world), the sources of origin for which were the niches with high antibiotic pollution and/or human-fecal contamination.