African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5233

Full Length Research Paper

Plasmid mediated transfer of antibiotic resistance and heavy metal tolerance in thermotolerant water borne coliforms

Suman Tewari1, Pramod W Ramteke2, Manikant Tripathi3, Shailendra Kumar3 and Satyendra Kumar Garg3*
1Environmental Microbiology Section, Indian Institute of Toxicology Research, Lucknow, India. 2Department of Biological Sciences, Sam Higginbottom Institute of Agriculture, Technology and Sciences, Allahabad, India. 3Centre of Excellence, DST-FIST Supported Department of Microbiology, Dr. Ram Manohar Lohia Avadh University, Faizabad, India
Email: [email protected]

  •  Accepted: 09 January 2013
  •  Published: 31 January 2013


The antibiotic resistance and heavy metal tolerance pattern of 201 water borne thermotolerant coliforms isolated from rural areas were studied. Most of the isolates exhibited resistance to one or more antibiotics under study, and expressed tolerance to multiple metals. Twenty four strains representing different resistance combinations were tested for plasmid transfer to Escherichia coli K-12 recipient strain. Plasmid transfer was detected in all 24 strains studied for conjugation. Among antimicrobials bacitracin, ampicillin, and among metals nickel, copper, cadmium, cobalt, chromium and arsenic resistances were transferred most frequently. Linked transfer of antibiotics and metals was demonstrated in 12 strains. Thirty two cultures of thermotolerant coliforms were studied for R-plasmid curing using acridine orange. Among antibiotics, curing of resistance was observed for streptomycin, cephaloridine and kanamycin. Curing of resistance to nickel, copper, mercury, chromium, copper and arsenic were also observed. The potential health risk of plasmid mediated resistances to antibiotics and metal ions in coliforms isolated from rural drinking water sources is discussed.


Key words: Thermo-tolerant coliforms, R-plasmids, conjugation transfer, resistance transfer