INCREASED LEVELS OF ANTIBIOTIC RESISTANCE IN BACTERIA FROM INDUSTRIAL WASTE DISPOSAL SITES

ABSTRACT

Environmental pollution represents one of the serious problems of our society. During anthropogenic activities (mining and ore processing, metal processing industry) toxic compounds and heavy metals are introduced into our environment. Their accumulation in ecosystems creates a huge environmental load and it threats environment and human health. Another emerging environmental threat is a genetic pollution. Genetic pollution is an uncontrolled gene (usually antibiotic resistance gene) flow into populations of non-target bacteria. Slovakia is a country with a long history of mining activities and well-developed metal processing industry. Consequently, extensive areas of Slovakia are contaminated by increased levels of heavy metals. In our experiments bacterial population from several metal processing industrial waste disposal sites (mine tailing Slovinky in the north-eastern part of Slovakia, nickel sludge disposal site near Sered in western part of Slovakia, Hacava-Hnusta and Hodrusa-Hamre in central part of Slovakia) were analysed by cultivation approach. Selected isolates were tested for heavy metal tolerance and resistance to selected antibiotics (ampicillin, tetracycline, chloramphenicol, and kanamycin). As expected, increased levels of heavy metal resistance were detected in tested isolates. Surprisingly, unexpectedly high levels of antibiotic resistance (predominantly to chloramphenicol) were detected in these isolates and statistical analyses confirmed correlation between selected antibiotic and heavy metal resistance. Our results indicate that heavy metals contribute to the growing problem of antibiotic resistance and industrial waste disposal sites could represent a hot-spot for the antibiotic resistance spreading.

Keywords: antibiotic resistance, heavy metals, gene transfer, genetic pollution