Virulence factors detection and single nucleotide polymorphism assay of extraintestinal pathogenic E.coli in elderly nosocomial infection / 天津医药

ABSTRACT

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.