Adhesive And Inactivative Characteristics Of Multi-antibiotic Resistant Escherichia Coli On Zeolite Surface

With the growing scarcity of water resources,the rainwater utilization has become the principal approach of urban water resources development.Microbial safety problems among rainwater utilization have aroused people’s concern.Under the background of the abuse of antibiotics,the proliferation,migration and control of antibiotic-resistant microorganism is of great significance to water safety.This paper explored the distribution and surface features of multi-antibiotics resistant Escherichia Coli(MARE)in the rain and receiving waters,and using zeolite as the porous filter medium,studied the migration and adhesion of multi-antibiotic-resistant E.coli,as well as the inactivation law on the surface of copper modified zeolite.Main conclusions were obtained as follows:(1)Amounts of Antibiotic-resistant bacterial(ARB)were found to exist in both rain and its receiving waters with different concentration and distribution.The concentration of ARB in rainwater-runoff was much higher than that in roof-runoff,and the concentration of ARB in the receiving waters varied in a wide range.The proportion of ARB in roof-runoff was higher than that in rainwater-runoff and the receiving waters.(2)Three MARB strains chosen from rainwater-isolated ARB were identified as Escherichia coli and their surface characteristics were studied.Antibiotic culture conditions and strain had little impact on MARB’s zeta potential and had a great influence on hydrophobicity.As ionic strength got higher,the Zeta potential of MARE increased.(3)The adhesive characteristics of MARE on the surface of zeolite were explored,which were influenced by ionic strength,antibiotics culture conditions,different strains and medium particles.Under the same culture condition,The higher the ionic strength,the greater the bacterial adhesion;When cultivated in antibiotic culture,bacterial adhesion may increase or decrease;There was little significant difference in the adhesion of different bacterial strain.(4)Copper-modified zeolite was prepared and characterized.After being copper-modified,zeolite had a smaller pore diameter and surface area,and higher surface potential,and the adhesion of E.coli enhanced.(5)The removal of MARE on copper-modified zeolite includes both adhesion and inactivation,with removal rate of 80%to 95%.The overall removal rate was not affected by ionic strength,bacterial species and culture conditions.Adhesion plays a major role under high ionic strength,and inactivation plays a major role under low ionic strength.