| Objective: A preliminary investigation was conducted of the colonization,drug resistance status and distribution of drug resistance genotypes of VRE in the intestines of 355 high-risk patients with vancomycin-resistant enterococcus(VRE)infection in this region,which can provide a basis for VRE’s clinical infection prevention,control strategies and treatment.Methods: Collected from January 2018 to January 2019 in our hospital in hospitalized patients included in the standard(VRE infection high-risk groups)stool specimens or anal swab specimens(only applicable to patients in the ICU)355 cases and healthy controls(in)the stool specimens of 40 cases,with homemade enterococcus strains(PSE)for selective medium to separate,Columbia blood AGAR medium for strains of purification,intestinal isolates strains identified by VITEK MS;With the identified enterococcus,the BHI AGAR medium containing vancomycin(6 μg/ml、8 μg/ml、32 μg/ml)was used for VRE preliminary screening,and the VRE preliminary screening(+)intestinal isolates were obtained.A total of 9 cases of VRE clinical isolates were collected from January 2018 to January 2019.With the method of E-test(vancomycin E-test strip,tekolanin E-test strip,M-H AGAR plate),the values of the minimum inhibitor-concentration(MIC)of VRE preliminary screening(+)intestinal isolates and VRE clinical strains were determined,and their drug resistance phenotypes were confirmed.The VITEK 2 Compact(AST-GP67)was used for VRE’s antimicrobial sensitivity test.VITEK MS was used to analyze the homology between VRE intestinal isolates,VRE clinical isolates,and VRE intestinal isolates and clinical isolates.Van A,Van B,Van C,Van D,Van E,Van G,Van L,Van M and Van N were detected by PCR amplification-agarose gel electrophoresis-imaging.PCR amplification positive products(2 cases of intestinal isolates and 2 cases of clinical isolates)from 4 bacterial strains were randomly sampled with random number form and sent to Shanghai sangon bioengineering co.,LTD for sequencing.All data were statistically analyzed using SPSS23.0 statistical software.Experimental strains preserved in the process of using homemade milk powder cryopreserved tube,put in-80 ℃ cryogenic refrigerator preservation.Quality control strains: enterococcus faecalis ATCC29212(sensitive),enterococcus faecalis ATCC51299(resistant).Results: 1.In the enterococcus isolated from the intestinal tract,a total of 474 strains of enterococcus were isolated and identified from 355 cases of high-risk population,including 291 strains of enterococcus excreta(61.39%),111 strains of enterococcus faecalis(23.41%)and 72 strains of other enterococci(15.19%).A total of 77 strains of enterococcus were isolated and identified in 40 healthy controls,including 31 strains of enterococcus faecalis(40.26%),25 strains of enterococcus faecalis(32.47%)and 21 strains of other enterococci(27%).2.A total of 551 strains of enterococcus(474 strains of enterococcus from high-risk group and 77 strains of enterococcus from healthy control group)were isolated and identified.BHI AGAR medium containing 6μg/ml,8μg/ml and 32μg/ml of vancomycin were used to conduct preliminary screening(+),and vancomycin e-test strips were used to confirm VRE(+),respectively.The initial screening results showed that the number of cases of enterococci resistant to vancomycin at different concentrations were 60,22 and 10,respectively.Finally,10 cases were confirmed as VRE with vancomycin e-test.A BHI AGAR medium of 32 ug/ml was taken to be taken to be preliminary screened(+),and the forms of VRE(+)were confirmed to be identical with the e-test strips of vancomycin.3.Out of the VRE group with high-risk infection,10 cases were detected,including 6 cases from neurosurgery department,1 case from ICU,2 cases from endocrinology department,and 1 case from oncology department.All of the VRE samples were taken with enterococcus faecalis.No enterococcus faecalis and other enterococci were found.VRE was not detected by the health group.4.Drug sensitivity results of 19 VRE strains(including 10 VRE intestinal isolates and 9 VRE clinical strains)showed that resistance rates of VRE to penicillin,quinolones,erythromycin and lincomycin were 100%.The drug resistance rates of VRE intestinal isolates and VRE clinical strains to high concentration gentamicin were 40% and 33.3%,respectively.The drug resistance rate to high concentration gentamicin was 40% and 33.3%,respectively.The sensitivity to furantoin was 50% and 20%,respectively.The sensitivity of VRE to quinoputin/dafuptine,linezolid,tegacycline and high-concentration streptomycin was 100%.5.All 19 VRE strains(including 10 cases of VRE intestinal isolates and 9 cases of VRE clinical strains)were detected with both Van A and Van M resistance genotypes at the same time,with the detection rate of 100%;Only 4 strains of VRE resistance were found to be conformable with the genotype,with inconsistencies.No Van B,Van C,Van D,Van E,Van G,Van L and Van N resistant genotypes were detected.6.Homology analysis: The homology of VRE intestinal isolates with each other is 50% ~ 60%;The homology of VRE clinical strains with each other is 80% ~ 95%.;The homology of VRE with each other is 75% ~ 95%,and the homology of most clinical strains and intestinal isolates is about 80% ~ 90%.7.Sequencing results of drug-resistant genes:Conclusion: 1.Enterococcus faecalis and enterococcus faecalis accounted for the majority of enterococcus enterococcus isolated from the intestinal tract,followed by enterococcus ornithae,enterococcus enterococcus enterococcus lead and enterococcus partridge,enterococcus raviose and enterococcus durabilis were rare.2.PSE AGAR medium combined with vancomycin 8μg/ml and 32μg/ml BHI AGAR medium can be used to screen VRE,which has the advantages of economy,high efficiency,low requirements for experimental equipment,can be carried out at the grassroots level,and is suitable for large-sample screening,and can be used to carry out large-scale VRE screening for high-risk groups of transplanting/infection in clinical practice.3.All 19 forms of VRE(including 10 forms of VRE intestinal isolates and 9 forms of VRE clinical strains)are forms of enterococcus,all of which are multi-resistant bacteria;VRE is resistant to most of the antibiotics,but is sensitive to streptotropin(quinoputin/dafutin),oxazolanone(linezolid),and glycyl ring(tegacycline).Therefore,linezolid and tegacycline can also be used for clinical treatment of most VRE infections in this region.4.All 19 VRE strains(including 10 cases of VRE intestinal isolates and 9 cases of VRE clinical strains)were detected with both Van A and Van M drug-resistant genotypes,and the drug-resistant phenotype was not completely consistent with the genotype.The homology of each VRE intestinal isolates was low(50% ~ 60%).VRE clinical strains have a high degree of homology(80% ~ 95%)with each other;There is a high degree of homology(mostly 80% ~ 90%)between the forms of intestinal VRE and clinical VRE.The importance of VRE hospitalization screening was suggested,and dynamic monitoring and relevant disinfection and isolation work should be done well for VRE screening positive people. |
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