The Distribution And Inactivation Studies Of Antibiotic-resistant Bacteria In Construction Of Water Supply System

With the extensive use of antibiotics, antibiotics can go into the natural environment through different pathways, which lead to the emergence of antibiotic-resistant bacteria. There are already reports of resistant bacteria in sewage and surface water, but research in the construction of water supply system in this field is comparatively too few. This paper is oriented to study resistant bacteria in building water supply system and investigates the drug resistance characteristics of the 9 categories 18 kinds of antibiotics from tap-water and hot water. Besides, the paper studies the common sterilization techniques (chlorine and ultraviolet) of inactivated bacterial resistance performance. The main research results are as follows:Firstly, the resistant bacteria exist in the public construction of water supply system. In the construction cold water system, the concentration of vancomycin-resistant bacteria is up to 1701 CFU/L, and the lowest concentration is 1 CFU/L to levofloxacin-resistant bacteria. While in the hot water system, the concentration of vancomycin-resistant bacteria is up to 2392 CFU/L, and the lowest concentration is 1 CFU/L to levofloxacin-resistant bacteria.Secondly, the resistant bacteria show multiple drug resistance. Screened bacterial exhibit for two or more antibiotic resistant and multi-drug resistance is Normal Distribution. There are 81.75% of strains resistant to at least three antibiotics, and most bacteria show resistance to 3-5 antibiotic categories.Thirdly, the paper studies on the resistance patterns of bacteria in construction of water supply systems (hot and cold water). They are in different degree of resistance to the 18 kinds of the selected antibiotic. In cold water system, the resistance level of imipenem is 76% which is the highest and the lowest resistance level is 4% of gentamicin. In hot water system the resistance level of imipenem is 93% which is the highest and the lowest resistance level of tetracycline is 11%.Fourthly, the sterilization inactivated tests of the resistant bacteria showed that, either sodium hypochlorite disinfection or ultraviolet disinfection, the Sterilizing efficiency of the resistant bacteria which had expressed resistance were different from the Sterilizing efficiency of the resistant bacteria which had no expressed resistance. The sterilizing effect was different of the different resistant bacteria which were resistant to the same antibiotic and the sterilizing effect was different when the same resistant bacteria expressed resistance to different antibiotics. And temperature affect the inactivation efficiency of resistant bacterial, but it does not demonstrate the consistency with the law.Fifthly, resistant bacteria to different sterilization methods showed different resistance or susceptibility. Whether the resistant bacterial expression and bacterial resistance to different antibiotics under different sterilization methods, the sterilizing effect differences.