Detection of Mercury and Cadmium Resistance Among Multiple Antibiotic Resistant Enteric Bacteria From Municipal Sewage Water in Malda, India

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 (Cd 2+ and Hg 2+ ) 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.