Adhesion Characteristics Of Multi-antibiotic Resistant Bacteria Isolated From Storm Water Runoff In Packed Sand Columns

With the importance of rainwater resources,the safety and security of rainwater quality has been paid more and more attention.At the same time,due to the abuse of antibiotics,rainwater runoff cause drug resistance of pathogenic micro-organisms,which lead to the migration of drug-resistant pathogens in water system,causing a threat to water security and human health.Based on the problem of bacterial contamination in rainwater storm,this paper explored the distribution of bacteria those show drug resistance in rainwater and tried to settle whether bacterias will change the characteristics of the surface after obtaining the drug resistance,then having bad effect on the water environment.In this paper,the multi-drug resistant bacteria were selected and the research on the migration and adhesion of multi-drug resistant bacteria in sand quartz filter columns under different water environment factors.Main conclusion was obtained as followed:(1)There are much more multi-drug resistant bacterias in rainwater,and most of those have shown multiple drug resistance.The ratio of drug resistance in isolated bacteria was 96.95%,with 62.30%of multi-drug resistant strains.Resistant bacteria on the SXT,AMP,GEN,TC were much higher proportion of drug resistance,AMIK,LVXO drug resistance was lower.(2)After the bacteria became multi-resistant,the surface characteristics changed at different ionic strength solutions.Under the same antibiotic culture conditions,the higher the ionic strength,the smaller the Zeta potential of the bacterial surface.For the same bacteria,when it got resistance,the hydrophobicity also significantly increased.(3)Ionic strength,antibiotic culture conditions and different bacteria has a significant impact on the adhesion to the sand quartz surface.Under the same culture condition,the higher the ionic strength,the higher the bacterial adhesion rate constant,the lower the potential of the DLVO repulsion potential energy,the greater the bacterial adhesion;In the same ionic strength and an antibiotic culture condition,bacterial adhesion rate constant Kd increased and then bacterial adhesion increased.In the same ionic strength and an antibiotic culture condition,the adhesion of Enterobacter cloacae KU942498 was higher than that of Escherichia coli AB604196 and Escherichia coli JN578647.(4)Different organic matters(humic acid,alginic acid,extracellular polymer)have a significant effect on the adhesion of multi-drug-resistant bacteria.When the humic acid or alginic acid are present in the water,the adhesion of bacteria went up with the increase of ionic strength in an antibiotic culture condition.Under the same ionic strength and the antibiotic culture condition,bacterial adhesion decreased by the effect of HA and SA.Rather than humic acid,alginic acid prefer to inhibit the phenomenon of bacterial adhesion;After removing the bacterial extracellular polymer,Zeta potential had little difference,while the hydrophobicity increased,the adhesion of bacteria significantly enhanced.