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The objective of the study was to detect the presence of fimH geneamong the drug resistanst strains of Acinetobacter baumannii.fimH gene was found to be associated with a catch bond mechanism which led to better evolution of biofilm formation. Since there are not many studies done with this gene it would be a timely investigation and this study mainly aims in molecular characterizationof fimHgene among clinical isolates of A.baumannii. Semi quantitative bio adherent assay was done by the multidrug resistant strains of A.baumannii to find the formation of biofilm. The DNA was extracted with the help of kit and PCR was performed for amplification. Pearson correlation analysis was done to find the existing correlation between the fimHgene and MDR strains of A.baumanniiwith significant p-value of (<0.05). From the screened 73 genomes of MDR A.baumannii 6.8% showed positive amplicons for the fimH gene which were related to biofilm and porin formation (Fig. 1). Correlation of its existence was high in beta lactamase (100%), cephems (100%), folate (100%) resistant strains, followed by aminoglycosides (80%), carbapenems (60%) and fluoroquinolones (60%) and efflux pumps (20%). In Spite of various measures undertaken to prevent the disease, the prevalence of the pathogen is multiplying. The current study recorded the presence of fimHgene (6.8%) among the clinical isolates of A.baumannii. This gene can be used as a target to develop new drugs and vaccines to combat the menace of A.baumannii infection
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Objective To examine the detection rate of 30 known virulence factors (VFs) of extraintestinal pathogenic Escherichia coli(ExPEC), and to investigates the epidemiology of ExPEC in elderly nosocomial infection. Methods A to?tal of 140 ExPEC clinical isolates from elderly nosocomial patients in hospitals in Tianjin were investigated. Multiplex PCR was performed to detect the 30 virulence factors among the E.coli strains and the detection rate of virulence factors for Ex?PEC were compared between isolates from different sites of infection.Fifty E. coli strains were shown to carry fimH gene that was amplified and sequenced. These sequences were used besides3 references strains (CFT037、UTI89 and K-12 ) to detect SNPs of fimH gene using DNAMAN Version 6.0.3.93 these 53 fimH sequences were used for genotyping and building dendrogram by MEGA4 software. Results In ExPEC, the following virulence factor genes, fimH, traT, fyuA, iutA and kpsMT II, had a higher detection rate than those of the rest . The following virulence factor genes, kpsMT II, K5, papC, pa?pEF ,papG allele II (Internal), papA, cnf1 (CNF), sfa/focDE and rfc had a a higher detectionrate from non-urine origin sam?ples than those from urine origin samples. fimH SNPs analysis of the 50 clinical isolated samples and 3 references samples showed 60 SNPs at 57 polymorphic sites. The fimH SNPs analysis classified the 53 strains into 25 genotype. The genetic fin?gerprintings of 11 isolates were exactly the same. Conclusion Many kinds of virulence factors can be found in ExPEC of el?derly nosocomial infection. The ExPEC strain isolated from non-urine origin had a stronger pathogenicity than those from urine-origin specimens. fimH SNPs analysis is suitable for molecular epidemiological investigation of ExPEC in hospital.
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Objective To investigate the effect of fimH gene on type 1 fimbriae adhesion of uropathogenic Escherichia coli (UPEC) and the gene variations between type 1 fimbriae adhesion positive and negative bacteria.Methods A total of 171 UPEC strains (not catheter associated) were collected from the Second Hospital of Tianjin Medical University,Tianjin First Center Hospital,and Tianjin Children's Hospital during January 2012 and January 2013.fimH gene was detected by PCR technique,and type 1 fimbriae adhesion was detected by yeast agglutination test.RT-PCR was used to exterminate gene transcript factor impacting on adhesion.Chi-square and Yates' chi-squared tests were performed to comparefimH gene sequences between the adhesion positive and negative bacteria.Results Among 171 UPEC strains,142 (83％) werefimH gene positive,and type 1 fimbriae was expressed in 98 strains (57％).All adhesion positive strains carriedfimH gene.Among 44 strains with positivefimH gene and negative adhesion RT-PCR revealed thatfimH gene did not transcript in 8 strains (18％).The sequencing results showed that gene mutation on the 51 st amino acid site was more prevalent in the adhesion positive group compared with the negative group (x2 =6.64,P =0.010).In adhesion,mutations on the 190th and 219th amino acid sites were observed in 6 strains and 7 strains of negative group,respectively; while not observed in the adhesion positive group (x2 =4.69 and 5.87,P ＜ 0.05).Negative adhesion in other 23 strains was not attributed to single nucleotide polymorphism.Conclusion Adhesion function of type 1 fimbriae mignt be affected by mutation and deletion offimH gene.Three key site mutations may also affect the adhesion function of type 1 fimbriae.Besides fimH gene,there may be other genes that can affect the adhesion function of type 1 fimbriae.
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Objective:To observe cellular,humoral and mucosal immune responses induced by DNA-or protein-based of FimH of UPEC type 1.Methods:After mice were immunized respectively with recombinant plasmid pcDNA3.1/fimH or pcDNA3.1/fimC,and the combinant FimH and FimC protein,the anti-FimH protein IgG of sera and SIgA in bladders were detected by ELISA.The lymphocyte phenotypes of CD3,CD4 and CD8 were analyzed by FCM.Results:The titers of IgG in sera and SIgA in the bladders were all low in the group immunized by recombinant FimH plamid,but the percentage of CD4+T cells in spleen was high,which revealed that recombinant FimH plamid was able to trigger better cellular immune response.The titers of IgG were very high in the group immunized by FimH protein,which suggested that the FimH protein was able to trigger better humoral immune response,but SIgA in the bladders was not detectable.Conclusion:The DNA for FimH can induce humoral,mucosal and cellular immune response.FimH protein can only induce humoral immune response.FimC protein is able to enhance the immunogenicity of FimH protein.