The large-scale application of veterinary antibiotics in livestock industry makes swine wastewater a major source of antibiotics pollution . And abuse of antibiotics (overuse or misuse) has been shown to be a major factor in emergence of bacterial resistance to antimicrobials . Genetic diversity and neutral or silent changes within genes are responsible for drug resistance  and microbes can acquire drug resistance by gene mutation or horizontal gene transformation, which makes diseases more difficult and expensive to be diagnosed and treated . Furthermore, increase of drug resistant microbes in ecosystem may lead to worldwide public health issues. The mineral feed and the corrosion of metallic installations could be major sources of heavy metals in swine wastewater . Bacteria could develop stable resistance to heavy metals after long term exposure at low levels .