| With the abuse of antibiotics in human clinical medicine,animal husbandry and aquaculture,a large number of biologically active antibiotics enter the environment,and bacteria enhance their resistance through gene mutation or capture of foreign drug resistance genes under the pressure of huge environmental selection.Ability,while integro as a genetic component is usually associated with bacterial resistance.In this study,the self-contained biocarrier membrane device was used to investigate the changes of bacterial integrons under the action of stress factors over time.The results showed that higher concentrations of tetracycline and chromium chloride stress significantly affected a class of integrons in biofilm bacteria.Abundance,its abundance shows a tendency to gradually increase with time and gradually decrease.A certain concentration of sodium hypochlorite stress will also increase the abundance of a class of integrons.It shows that bacteria with a class of integrons have higher survival rate under certain stress.The three types of integron abundance showed a gradual decrease under various stresses,indicating that the three types of integrons are not the main mechanism of bacteria against tetracycline and heavy metal stress.No second class integrants were detected in this experiment.In addition,in order to explore the relationship between bacterial resistance and integrons in nature,Qingdao Second and Sixth Beaches were selected as research objects and samples were collected.Screening of 271 strains isolated from seawater and beach samples using resistance screening plates.60(22.1%)strains of multidrug-resistant organism(MDRO),drug susceptibility test results showed that the resistance rate of 60 MDRO to 15drug-sensitive papers ranged from 31.6% to 81.7%,of which The resistance rates of sulfonamides,aminoglycosides and fosfomycin antibiotics were higher,and the resistance rate to streptomycin was the highest(81.7%);60 strains of MDRO belonged to 24 genera,of which genus Stenotrophomonas accounted for The ratio is the largest(16%).After analyzing the drug resistance data,it was found that there was no significant difference in the drug resistance between the second and sixth beaches,but the drug resistance in seawater was more serious than that in the beach.The resistance rate of bacteria in different places in the bathing beach was related to the intensity of tourists..By analyzing the correlation between specific resistance genes and drug resistance phenotypes,it was found that the resistance of MDRO to tetracycline and streptomycin was significantly correlated with the detection rate of related drug resistance genes.11 strains of integron-positive strains and 3 strains of three types of integron-positive strains were detected in 60 strains of MDRO.The gene cassette arrangement of one type of integron variable-regionpositive strains included four types: aadA1,aadA5-orfA,and dfrA1-orfA-aadA1,dfrA12,no gene cassette for three types of integro was detected.The integron detection rate of MDRO is low,indicating that the integrin-mediated drug resistance is not the main resistance mechanism of multidrug-resistant organism in Qingdao beach.Under the influence of the stress factors set in this study,the abundance of a class of integrons in the filter biofilm showed a significant increase and then decreased.In addition,the experimental results show that the MDRO pollution of Qingdao beach is serious and rich in diversity,showing strong resistance to common antibiotics,but the detection rate of integro is low,indicating that the integrant is not the main drug-resistant bacteria in the bath.Resistance mechanism. |
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