| Water environment is related to the survival and development of human society,and its pollution has become one of the most important environmental problems in the world.Antibiotics are widely used in animal husbandry and disease treatment.Antibiotics bring great convenience to life,but at the same time,they also cause serious antibiotic pollution.The presence of antibiotics in aquatic environment will make drug resistant bacteria multiply,and the drug-resistant strains produced in clinical and animal husbandry come into the environment with feces,they all threaten the ecological safety of the water environment.Meropenem is one of the most important antibacterial drugs of clinical treatment of bacterial infection,if the meropenem resistant strains in the environment invade into the human body again,may cause serious public health problem.In order to study the resistance mechanism of the Meropenem resistant bacteria in the water environment around the hospitals in Shandong Province,and explore its pollution status,transmission mechanism and potential risk,this experiment selected 11 sampling points from five different regions of the hospital in Shandong province,mainly involving hospital waste water and surrounding rivers,,and the research is carried out from the following aspects:(1)Study on distribution of meropenem resistant microbes in the water environment around the hospital.The bacteria were screened by the selective medium containing meropenem.The bacterial species were determined by 16 S rDNA sequencing,and the multiple antimicrobial resistance of the strain was determined by detecting the minimum inhibitory concentration(MICs).The results showed that 1 sample is not detected bacteria,1 not detected drug-resistant bacteria,and 5 samples of the content of resistant bacteria were less than 1%.The results of MICs showed that there are 13 strains of bacteria have resistance to various antibiotics.(2)Detect the diversity of meropenem resistant microbes in the water environment aroundthe hospital.Using the High Throughput Sequencing technology to analysis of the diversity of drug resistant bacteria,and study the types of drug-resistant bacteria and multidrug-resistant bacteria.The results showed that there were 4 OTUs,7 classes,13 orders,15 families and 16 genera in 3 original water samples.And there were 4 doors,6 classes,7 orders,8 families and9 genera of 9 OTUs in 3 water treated with meropenem,accounts for 45% of the total number of bacteria.It shows that in the environment containing antibiotics,drug-resistant bacteria will proliferate and threatening the safety of water environment.(3)The possibility level of meropenem resistant strains in the environment of transfer.The plasmid of resistant bacteria was identified by PFGE electrophoresis,extracted by alkaline lysis,and joined with other species of bacteria after enzyme digestion.Detected the transfer of resistant genes,and evaluated it's risk.The results showed that the bacterias named M19 and M27 did contain plasmids,but they did not interact with other bacteria.Because the drug resistance is divided into conjugative and non-conjugative properties,the latter can not be passed through bacteriophage,which may be the reasons for the unsuccessful joint transfer experiment.(4)The study of resistance mechanism of Chinese and Meropenem resistant bacteria in water environment.The mechanism and status of drug resistance were analyzed by detecting drug resistance genes.The results showed that among the 18 target genes,TEM-1(TEM-229)and SIM had the highest detection rate,both of which were 100%.The detection rate of OXA-1,CTC-M-2,TEM-2 and adeB were the lowest,only detected in one strain,and the SHV gene was not detected.TEM-1 belongs to different beta lactamase genes,therefore,bacterial resistance is the result of a variety of mechanisms.Carrying multidrug resistant genes is an important reason of multiple drug resistance.The above results show that there is a certain proportion of drug-resistant and even multidrug-resistant bacteria in the water environment,which seriously threaten the ecological safety of water environment. |
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