[Effect of environmental factors on the formation of several typical tetracycline resistance genes in soil].

The extensive use of veterinary tetracycline in the stock husbandry has led to the increasingly serious environmental pollution, the tetracycline resistance genes induced by which could bring more hazardous environmental risk than veterinary tetracycline. This study investigated the effects of environmental factors on the formation of several typical tetracycline resistance genes (tetA, tetC). The results showed that temperature, light and pH could have impacts on the formation of tetracycline resistance genes in soil, the amounts of the tetracycline resistance bacteria and resistance genes induced in different treatments all reached the maximum in the proper environmental condition (25 degrees C, 500 lx, pH7.5), which were all significantly higher than those in other environmental conditions (P < 0.05). In contrast, the adverse condition such as high temperature, strong light and high pH could effectively inhibit the formation of tetracycline resistance genes, probably due to the reduction of tetracycline residues or the direct influence on the formation of tetracycline resistance genes. And the results also showed that environmental factors could affect the growth of tetracycline resistance bacteria. Further analysis proved that the content of tetracycline resistance gene in soil had a positive correlation with the number of tetracycline resistance bacteria in the studied samples, therefore an inferred result was concluded that the growth of tetracycline resistance bacteria played a key role in the formation of the tetracycline resistance genes.