ACTIVITY OF TETRCYCLINE-MERCURY AGAINST RESISTANT BACTERIA STRAINS.

Luciana Cursino,* Edmar Chartone-Souza, Andréa M.A. Nascimento (Department of General Biology, Institute of Biological Sciences, Federal University of Minas Gerais) UFMG, Av. Antônio Carlos, 6627 CEP 31-270-901,Campus Pampulha, Belo Horizonte, Minas Gerais, Brazil.

Mercury is one of the most toxic elements present in the environment. The presence of these heavy metal in the ecosystems receiving great attention due to their bioaccumulation and translocation through the food chain. Furthermore, the presence of antimicrobials residues, as antibiotics, principally in aquatic ecosystems, is increasing because the indiscriminate discharges from hospitals. Some antibiotics, specially the tetracycline has anionic properties that enable it to capture free íons, as calcium (Ca++), for instance. The aim of this work was to determine if tetracycline is enable to capture mercuric íons (Hg++). the bacterial strains of Escherichia coli H12 (isolated from amazon rubber tree tappers and indians), and Pseudomonas sp. P16, Pseudomonas sp. P24 and Pseudomonas sp. P11(isolated from patients with hospital infections) were grown in liquid medium (Nutrient broth-Difco) during 18 hours at 37°C (pré-inocullum) after a 1% of pré-inocullum of all cultures were inoculated in the same medium supplemented with different tetracycline and/or mercury concentrations. These preliminary results indicate that the presence of sulfate of tetracycline and mercury chloride (HgCl2) together in concentrations that separately permitted growth, now inhibited the growth of these bacteria. It suggest the formation of a complex tetracycline-mercury which could be facilities to entry in the bacterial cell, or inhibited the antibiotic bacterial efflux leading to the cell death. This strategy could be used as a model against bacterial strains tetracycline resistant, or as compound of low cost to remove mercury human contamination.