Amalgam Research Today is a free monthly online journal that collates and summarizes the latest research about Amalgam, including details on dental fillings, dentistry, side-effects.

Linkage of a novel mercury resistance operon with streptomycin resistance on a conjugative plasmid in Enterococcus faecium.

Davis IJ, Roberts AP, Ready D, Richards H, Wilson M, Mullany P

Division of Microbial Diseases, Eastman Dental Institute, University College London, 256 Gray's Inn Road, London, WC1X 8LD, UK.

It has been shown that the mercury in dental amalgam and other environmental sources can select for mercury resistant bacteria and that this can lead to an increase in resistance to antibiotics. To understand more about this linkage we have investigated the genetic basis for mercury and antibiotic resistance in a variety of oral bacteria. In this study we have cloned and sequenced the mer operon from an Enterococcus faecium strain which was resistant to mercury, tetracycline, and streptomycin. This strain was isolated, in a previous investigation, from a cynomolgus monkey post-installation of amalgam fillings. The mer operon was contained within a putative transposon (Tnmer1) of the ISL3 family. This element was located on a streptomycin resistant plasmid, pPPM1000, which shares homology with pRE25.

Published 23 May 2005 in Plasmid, 54(1): 26-38.
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