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International Journal of Biodiversity
Volume 2013 (2013), Article ID 265356, 8 pages
Research Article

Diversity of Mercury Resistant Escherichia coli Strains Isolated from Aquatic Systems in Rio de Janeiro, Brazil

1Departamento de Ciências Biológicas, Escola Nacional de Saúde Pública Sergio Arouca (Ensp), Fundação Oswaldo Cruz (FIOCRUZ), Rua Leopoldo Bulhões 1480 Manguinhos, 21041-210 Rio de Janeiro, RJ, Brazil
2Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
3Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil

Received 8 March 2013; Revised 24 May 2013; Accepted 26 May 2013

Academic Editor: Steven Lee Stephenson

Copyright © 2013 Raquel Costa de Luca Rebello et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Escherichia coli may harbor genetic mercury resistance markers which makes this bacterial species a promising alternative for bioremediation processes. The objective of this study was to investigate phenotypic and genetic characteristics related to diversity and mercury resistance among 178 Escherichia coli strains isolated from residential, industrial, agricultural, and hospital wastewaters and recreational waters at Rio de Janeiro city. Genetic and conventional methods were carried out in order to determine mercury resistance. Random amplification of polymorphic DNA (RAPD-PCR) and denaturing gradient gel electrophoresis (DGGE) were used to investigate genetic variability. RAPD data revealed a high degree of polymorphism among E. coli mercury resistant strains and showed reproducibility and good discriminative results. DGGE typing detected diversity within the merA gene fragment. Our findings represent an improvement in epidemiological studies of   E. coli and support the evidence of nonclonal nature of mercury resistant E. coli strains circulating in rural and urban aquatic systems in Rio de Janeiro city.