Objective To investigate the antibiotic resistance, virulence genes, and sequence types of Enterococcus faecium ( E. faecium) strains isolated from children under 3 years old in Sui county, Henan province. Methods Kirby-Bauer antibiotic testing was performed to analyze the antibiotic sensitivi-ties of E. faecium strains to 15 common antibiotics. PCR analysis was used to detect the virulence genes car-ried by the E. faecium strains. Multilocus sequence typing ( MLST) was performed for the typing of E. faeci-um strains. Results Forty-seven E. faecium strains were isolated from 120 stool samples collected from chil-dren under 3 years old in Sui county, Henan province, of which 95. 7% were antibiotic-resistant strains. Most of the isolated E. faecium strains were resistant to rifampicin, accounting for 91. 5% (43/47) of all isolates, followed by those resistant to erythromycin and tetracycline, which accounted for 68. 1% (32/47). Moreover, high resistance rates to those antibiotics commonly used in clinical treatments of E. faecium infec-tion including β-lactam and aminoglycosides antibiotics were observed. Those strains resistant to more than three kinds of antibiotics belonged to the same clonal complex including 12 strains of clonal complex 17 ( CC17) harboring the virulence gene of hyl. All of the isolated E. faecium strains were susceptible to vanco-mycin, linezolid, chloromycetin and nitrofurantoin. Conclusion The E. faecium strains isolated from chil-dren under 3 years old in Sui county, Henan province were multi-antibiotic resistant. There were drug-resist-ance strains belonging to the CC17 and carrying the virulence gene of hyl.

Objective To evaluate the efficacy and safety of antibacterial drugs conservative therapy versus appendectomy for treating simple acute appendicitis(AA).Methods Randomized controlled trials (RCT) on antibacterial drugs conservative therapy versus appendectomy for treating simple AA were retrieved from CBM (1978 June 2015),CNKI (1979-June 2015),Medline (1950-June 2015),Pubmed (1950-June 2015),Embase (1970-June 2015) and Cochrane library (issue 2,2015) by computer.The included RCTs were performed the data extraction according to the criteria of the Cochrane handbook by two researchers.Then the included d/literatures were performed the quality assessment and the extracted effective data were performed the meta analysis.Results Six RCTs were included involving 1510 patients with AA,among them,767 cases were treated with antibacterial drugs and 743 cases were treated with appendectomy.Compared with surgical treatment,the effect rate of antibacterial medication conservative therapy was decreased by 25.00％ (RD=-0.25,95％ CI:-0.35--0.14),the recurrence rate was increased by 48.43 times (OR=48.43,95％CI:16.94-138.44),the loss time of labor force was shortened by 1.52 d (MD=-1.52,95％ CI:-3.02 0.02),but the occurrence rate of complications(RD=-0.06,95％CI:-0.15 0.03),pain time(MD=-0.76,95％CI:-3.31 1.79),hospital stay time (MD=4.60,95％CI:-0.89 10.09) and sick leave time(MD=-2.39,95％CI:-5.62-0.84) had no statistical differences between the two kinds of treatment method(P＞0.05).Conclusion Appendectomy may be the gold standard method for treaung simple AA.

Objective To investigate the tellurite resistance level,the presence of tellurite resistance (ter) gene cluster and their relationships in non-O157 Shiga toxin-producing Escherichia coli(STEC) isolates.Methods Tellurite resistance level was evaluated by plate dilution method and the ter gene cluster was tested by PCR.Results Only 5 of 39 non-O157 STEC isolates tested in this study were identified to have ter gene cluster,which showed relatively high levels of tellurite resistance ranging from 128 μg/ml to 512 μg/ml.In contrast,the other 34 isolates without ter gene cluster were sensitive to potassium tellurite and showed very low levels of tellurite resistance,the minimal inhibitory concentration (MIC) was ＜1 μg/ml for 29 isolates,8 μg/ml for 2 isolates and 2 μg/ml for 3 isolates.Conclusion Most non-O157 STEC isolates were sensitive to potassium tellurite.It could be concluded that much attention should be paid when screening the non-O157 STEC isolates using the selective medium supplemented with potassium tellurite.

Objective To investigate the effects of shiga toxin ( Stx ) phage on the expression of type Ⅲsecretion system (T3SS) in E.coli O157 ∶H7.Methods A standard E.coli O157 ∶H7 strain, EDL933 and a natural Stx phage defective mutant of EDL 933 strain, TUV93-0 were used for this study .The expression of T3SS proteins was compared between EDL 933 and TUV93-0 strains.The expression of five operons ( LEE1-LEE5 ) was evaluated by measuring the green fluorescent protein ( GFP ) in five different plasmids with LEE1-LEE5 promoters, respectively.Results The expression of T3SS proteins in TUV93-0 mutant were significantly increased than those in EDL 933 strain.Moreover, the expression of LEE1, LEE2 and LEE5 were also increased in TUV93-0 mutant.Conclusion The deletion of Stx phage might enhance T3SS expression through the regulation of LEE 1.

Objective To analyze the subtypes of eae genes in various non-O157 Shiga toxin-pro-ducing Escherichia coli ( STEC) strains isolated in China.Methods The complete nucleotide sequences of 10 eae genes were amplified by PCR and sequenced.The BLASTn software was used to analyze the se-quences for eae gene subtyping.A phylogenetic tree was constructed based on the10 ea e gene sequences to-gether with the gene sequences of 30 different subtypes in GenBank and those of STEC strains of 7 prevalent serotypes (O157 ∶H7, O26 ∶H11, O103 ∶H2, O111 ∶H8, O145 ∶H28, O45 ∶H2 and O121 ∶H19) using MEGA 5.0.Multilocus sequence typing (MLST) was performed on the 10 STEC strains with reference to the Escherichia coli ( E.coli) MLST website ( http://mlst.warwick.ac.uk/mlst/dbs/Ecoli) for the typing of multiple loci.A minimum spanning tree ( MST) was constructed using the BioNumerics software to inves-tigate the phylogenetic relationships between the 10 eae gene-positive STEC strains in this study and hemolyt-ic uremic syndrome-associated enterohemorrhagic E.coli ( HUSEC) strains as well as all human STEC strains of O157, O26, O45, O103, O111, O121 and O145 serotypes submitted to the E.coli MLST website data-base.Results The complete nucleotide sequences of eae genes in 10 non-O157 STEC strains were 2.8 kb in length and belonged to 3 known subtypes.The predominant subtype wasβ1, accounting for 60%of the 10 STEC strains (6/10), followed byθandγ1 subtypes with two strains in each type.The eae gene sequences in certain strains were identical to those of the prevalent serotypes.Seven sequence types ( STs) were identi-fied from the 10 STEC strains carrying eae gene.Conclusion The eae genes harbored by the non-O157 STEC strains isolated from different specimens in China were diverse and had close phylogenetic relationships with the highly pathogenic and prevalent STEC strains.This study implied that the STEC strains harboring eae gene had high pathogenic potential.

Objective To investigate the effect of FNR on type Ⅲ secretion system (T3SS) in E.coli O157 ∶ H7.Methods fnr mutant was constructed by λRed recombineering technology promoted by Bet and Exo proteins using PCR products.Results Through bacterial infection assays and immunofluorescence microscopy,it was found that the adhesion ability was decreased insignificantly infnr mutant compared to the wild type ZAP198.However,the secreted proteins were reduced significantly in the mutant from the secretion profile.Conclusion The reason might be that high ClpXP protein caused by the deletion of fnr degraded GrlA resulting in the inhibition of LEE(locus of enterocyte effacement) and T3SS.

Objective To understand the molecular characteristics of human-derived non-O157 Shiga toxin-producing Escherichia coil (STEC) strains circulating in five regions of China.Methods Twenty-seven non-O157 STEC strains isolated in five geographic regions were investigated by serotyping, stx1/stx2 subtyping and PCR screening for adhesion and other virulence genes.A multilocus sequence typing (MLST) scheme provided by E.coil MLST database were performed to amplify and sequence seven housekeeping genes (adk, icd, fumC, rgyrB, purA, mdh and recA) in those strains.Results Twenty-seven non-O157 STEC strains were typed into 16 O∶H serotypes.Among those strains, 11 harbored stx1a, 12 harbored stx1c, two harbored stx2e and the other three strains respectively harbored stx1a+stx2b, stx2d and stx2g.Positive rates of eae, efa1, saa, paa, toxB, astA and ehxA genes were 18.5%, 18.5%, 29.6%, 22.2%, 11.1%, 11.1% and 25.9%, respectively.The 27 strains were typed into 16 different sequence types (STs) based upon MLST.Conclusion Human-derived non-O157 STEC strains circulating in five regions of China are heterogeneous in their serotypes, stx1/stx2 subtypes and virulence gene profiles.

We investigated the carrying situation of Escherichia albertii from healthy people engaged in breeding and slaughtering poultry for a long time.We collected stool samples from people engaged in breeding and slaughtering poultry and other healthy people.After enriched with EC broth,eae-positive enrichment culture was directly streaked on MacConkey,and eaepositive lactose non-fermenting isolate was retained for further investigation.The 16S rDNA sequencing and multilocus sequence typing (MLST) were applied in the identification of E.albertii from suspected strains.Intimin subtypes and cdtB types of E.albertii strains were detected.Pulsed-field gel electrophoresis (PFGE) was used to detected genetic polymorphism of strains from this study and animal source ones.Results showed that two isolates were identified as E.albertii from 189 stools of people exposed to slaughtering chickens and ducks and one from 58 stools in control groups.No isolate was identified as E.albertii from 138 stools samples of people exposed to breeding poultry.Intimin subtypes of three isolates from stool samples were subtyped as sigma,iota 2,nu,and cdtB types were closely related to types Ⅱ/Ⅲ/Ⅴ.PFGE patterns of the three strains was distinguishable (＜80％ similarity),and appeared in different cluster with chickens,ducks and other sources of E.albertii strains.The rate of carrying E.albertii to a certain extent exist in healthy people engaged in slaughtering chickens and ducks,and the relationship between these strains and strains from poultry should be further investigated.

OBJECTIVETo investigate the molecular typing feature of enteropathogenic Escherichia coli (EPEC) strains isolated from different reservoirs in eight provinces of China from 2006 to 2014.

METHODSAccording to the time, place, reservoir, and PFGE pattern of the EPEC strains isolated from stools of humans with diarrhea, animal feces, and foods in eight provinces of China between 2006 and 2014, 149 EPEC strains were selected and characterized by multilocus sequence typing (MLST) using seven housekeeping genes provided by E.coli MLST database. Strain analysis demonstrated 56 different sequence types (STs). SeqMan II, MEGA 5.05, and eBURST V3 were applied to analyze the genetic relationships of domestic and forein existing 392 strains (243 EPEC strains included in the E.coli MLST database and 149 EPEC strains comprised in the present study).

RESULTSAmong the 56 different STs, the prevalent ST was ST-40, which included 19 (19/149, 12.8%) isolates. Nineteen new STs were identified. Eleven new alleles were detected in six house-keeping genes (adk, fumC, gyrB, icd, mdh, and purA). Six STs were simultaneously detected among EPEC strains isolated from patients with diarrhea and animals. And these EPEC strains were all aEPEC strains. Two STs were simultaneously identified among EPEC strains isolated from patients with diarrhea and foods. Also, these EPEC strains were all aEPEC strains. 33 out of 173 STs were divided into five major clone complexes by eBURST, STC-29, STC-10, STC-20, STC-28, and STC-517. The remaining EPEC strains included in the other 140 STs were part of the other clone complexes or just were singletons.

CONCLUSIONA high degree of phylogenetic heterogeneity was observed among the EPEC strains isolated in eight provinces of China. The EPEC strains with same STs of human isolates isolated from animal feces and foods were all aEPEC strains.

Animals ; China ; Diarrhea ; Enteropathogenic Escherichia coli ; Escherichia coli ; Escherichia coli Proteins ; Feces ; Humans ; Multilocus Sequence Typing ; Phylogeny

Objective To confirm whether or not let-7b and miR-199a were significantly associated with malignant melanoma growth and proliferation. Methods An over -expression plasmid and an inhibitor, which targeted on let-7b and miR-199a, was constructed. B16F10 cells were divided into seven groups: control group, let-7b plasmid group, miR-199a plasmid group, empty plasmid group, let-7b inhibitor group, miR-199a inhibitor group, inhibitor control group. Foreign gene was transfected into B16F10 cells, let-7b and miR-199a expression were validated from RNA level, protein level and cell level. Results The relative let-7b or miR-199a gene expression of the let-7b plasmid group (3.8776±0.1372)and miR-199a plasmid group (2.8660±0.2821)were significantly higher than control group (P＜0.05), the relative let-7b or miR-199a gene expression of the let-7b inhibitor group (0.2057±0.0263) and miR-199a inhibitor group(0.2656±0.0253) were significantly lower than control group(P＜0.05). The cyclinD1 expression of the let-7b plasmid group(2.023±0.315) and let-7b inhibitor group (1.857±0.377) were significantly higher than control group (0.997±0.041) (P＜0.05), whereas, the Met expression of themiR-199a plasmid group (5.19±0.309) and miR-199a inhibitor group (4.87±0.044) were significantly higher than control group (2.2±0.198) (P＜0.05). The let-7b plasmid group and miR-199a plasmid group B16F10 cell growth rate were slower than control group, especially on the third day after transfection, the growth rate gradually dropped to the lowest value (P＜0.05). In addition, the apoptosis rates of the let-7b plasmid group and miR-199a plasmid group reach to (11.8±1.19)% and (11.3±1.59)%,which were significantly higher than control group (P＜0.05). Conclusions let-7b and miR-199a may be a negative regulator on the B16F10 cell growth and proliferation.