Study On The Drug Resistance Of Pathogenic Escherichia Coli In Urinary Tract And The Relationship Between Drug Resistance And Colonization

Objective Urinary tract pathogenic Escherichia coli(UPEC)is the main pathogen causing urinary tract infection.Adhesin is considered to be the most important virulence factor of UPEC,mainly including type I pili,P-type fimbriae,S-type fimbriae,FIC fimbriae and Afa /Dr fimbriae.I-type fimbriae is the most common.Fim H protein,encoded from Fim H gene and located on the top of the type I ferma,can adhere to human urethral epithelial cells and is a key link in urinary tract infection;P-type pili is also widespread and is considered a key factor in the UPEC infection continued the kidneys causing renal pyelonephritis.The aim of this study was to investigate the differences in gene levels,transcription levels and adhesion levels of fim A,fim B,fim H,pap A,pap B,pap C and pap GII in UPEC with different levels of resistance,and to analyze the relation of drug resistance and adhesion function,thereby improving the accuracy of adhesion blocking treatment.Methods Collected from March 2012 to October 2015 Tianjin four first-class hospitals(Tianjin Medical University Second Hospital,Tianjin,a central hospital,Tianjin Children’s Hospital,Tianjin Medical University General Hospital)non-implanted catheter Patients with urine samples were isolated from non-repetitive infections of Escherichia coli 100 strains,of which 50 strains were resistant strains and resistant strains.The strain was tested by the French Bio Mérieux Vitek Ⅱ system,and the drug susceptibility test was carried out.PCR was used to amplify the gene fragment,and then the virus factor was detected by agarose gel electrophoresis.The positive strain of the single virulence factor was detected by fluorescence quantitative PCR(Rt-PCR)to detect the relative expression of virulence factor genes.The ability of UPEC to express type I glumes was tested by adhesion experiments with yeast cells.The ability to express P-type fimbriae was detected by coagulation test with human type A erythrocytes.Yeast cells and erythrocyte agglutination test were used to detect the adhesion of type I pili and P fimbriae.Comparison between the two groups using chi-square test and t-test.Results The detection positive rates of Fim H,Fim A,Fim B,Pap GII,Pap A,Pap B and Pap C in the sensitive group were 90%,48%,76%,16%,26% 64% and 32% respectively by gene fragment amplification.And the detection positive rate was 84%,46%,58%,42%,36%,56% and 38% in the resistant group.The detection positive rate of pap GII gene in the sensitive group was significantly higher than that in the resistant group(χ~2 = 8.208,P <0.05).But there was no significant difference of other genes in the detection positive rate of other genes between the two groups(P> 0.05).The results showed that the expression of fim H,fim B and pap C in the sensitive group were higher than those in the resistant group.Adhesion test showed that the adhesion ability of the sensitive strains was higher than that of the resistant group(χ~2 = 5.769,P < 0.05).No significant difference was observed of P type fimbriae adhesion ability between two groups(χ~2=2.439,P>0.05).Conclusion UPEC virulence factor gene Fim H has extensive spreadability both in sensitive and resistant strains.The adhesion ability of I type fimbriae of the UPEC sensitive group was higher than that of the resistant group,suggesting that it was related to the adaptive cost of the resistant bacteria.In addition to fim H gene and pap GII gene these key factors,UPEC I-type pilus and p-type fimbriae adhesion function is also affected by fim and pap gene cluster encoding other genes of the deletion and transcription.