| E.coli was one of the most common pathogenic bacteria in medical and veterinary clinical and caused serious damage to human health and development of stockbreeding.Pathogenic Escherichia coli was one of the most common pathogens in human and animal clinical,not only threat to human and animal health,but also most important objects of study in food sanitation,water supply sanitation and epidemiology in recent years.The 20th century is the 100 years that anti-infective drugs industry performance brilliant,and the discovery of antibiotics in human medicine was one of the most important breakthrough.Antimicrobial agents play an important role in the control of E.coli infections, but as the extensive application of antibacterial drugs,the emerging about drug-resistant strains and multi-drug resistant strains of E.coli become particularly more and morre。The problem of drug resistance has become an important factors affecting human health and the development of stockbreeding。Our laboratory had used the method of kirby-Bauer recommended by the WHO,using E.coli ATCC25922 as quality control,in order to test drug resistance of E.coli separated in pig pathogenic in various districts of Chongqing,the test of resistance of E.coli to26 antibiotics drug shows that multi-drug resistant strains is 100%,substantially the level of resistance increases,all isolates were without a single drug resistant strains are resistant to more than 12 kinds of drugs,multi-drug resistant strains resistant focus on 18 kinds of drug-resistant to 22 kinds of drugs,Subjects that E.coli resistance to antibiotics is very serious,in The preliminary laboratory research,not only the purpose zone S2is found in the location of a 900 bp in the four strains DJ26,CS6,HC16,HC20,but also a specific Of the band in the location of about 460 bp(S1).To further understand the relationship between gene intI1(S2)ang the more specific gene(S1)in the four strains and bacterial resistance and multiple drug resistance, By molecular biology's method,this study has carried the four strain's integrase of intI1(S2)as well as the other specific bands(S1)on the clone,the sequence determination and analysis,the reorganization express and the reorganizing strain's(CZ21)drug resistance examination in-depth analysis of its impact on bacterial resistance。We compared the sequence result with the results published by the GenBank,and discovered that the S2 sequence and the E.coli gene intI1 was identity 99 percent in homology,and basic groups hiatus at the 14,21,453,836,841,894 points。The basic groups hiatus was A,A,A,C,A,C respectively。The S1 sequence and the E.coli gene intI1 was 99 percent in homology also,and basic groups hiatus at the 12,19,449 points。The basic groups hiatus was was A,A,A respectively.And the sequence S1 and the 3 bp～460bp of S2 sequence was identity 100 percent in homology。By molecular biology methods,this study reformed the sequence S2(integrase gene intI1)to E. coli bacteria BL21 and HC21,and respectively gained strains BL21B and CZ21。Then we use the method of kirby-Bauer recommended by the WHO to test the resistance of recombinant strain BL21B and CZ21 to The Pioneer V,Gentamicin,Amikacin,Norfloxacin,Penicillin,Lite Ling,and other 26 kinds of antibiotics,and at the same time on the BL21 and HC21 as comparison.Sensitivity test results showed that,BL21B and BL21 are sensitive to 26 kinds of antibiotics,and the recombinant strain CZ21 was still resistant to 20 kinds of antibiotic such as Gentamicin, Amikacin,Norfloxacin,Penicillin。In spite of before or after the reorganization,The drug resistance of Bacillus HC21 was consistent with the results,and has not changed significantly.Thus,regardless of the bacterial integrase enzyme gene intI1 complete or not,the resistance of E.coli and multi-drug resistance have no significant impact.Although this study can not be directly exposed the relationship about the integrity of the bacterial integrase gene intI1 whit the bacterial drug resistance and multi-drug resistance,but this study provide a new way of thinking and research direction to the further research of capturing and dissemination of resistance gene of bacteria integron。... |
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