Impact Of The Length Of Variable Region Of Class1Integron And Plasmid Elimination On Expression Of Integrase In Bacterias

Objective:To study the relationship between class1integron and Multi-drug resistant bacteria in Gram-negative bacteria, to identify the mechanism of integrons by detect the different expression of intll gene in different variable regions of integrons and different ways of plasmid elimination.Methods:87strains of Pseudomonas Aeruginosa and101strains of Escherichia coli were isolated from the clinical departments. The drug sensitive tests were conducted by using the K-B method.25strains of.P. Aeruginosa with intll gene was grouped into2groups depending on the length of variable regions of their integrons, and the relative expression of intll gene of different variable regions were detected by Real-time fluorescent quantitative PCR, and the condition of drug-resistance for the bacteria in the2groups was compared. Ultraviolet ray, SDS and berberine hydrochloride were used to eliminate plasmids with class1integron, then the effect of elimination and the relative expression of intll gene was detected.Results:Both in Pseudomonas Aeruginosa and Escherichia coli, the rate of multi-drug resistance in bacteria with class1integron is much bigger than bacteria without class1integron. Among the clinical strains of P. Aeruginosa with intI gene, the bacteria with short variable region expressed more intI mRNA than the bacteria with long variable region, but was less resistant to antibiotics than the bacteria with long variable region. SDS had obvious effect on plasmid elimination and the expression of intI1was less; berberine hydrochloride had medium effect on plasmid elimination but the expression of intI1was more; ultraviolet ray presented weak capacity in plasmid elimination but it promoted the expression of intI1.Conclusions:Class1integron is closely related to multi-drug resistance in bacteria both in Pseudomonas Aeruginosa and Escherichia coli. The expression level of intI has related on the length of variable region in intgeron. Different ways of plasmid elimination have different regulation of the expression level of intI. There are17pictures,12tables and41refrences.