Establishment of a real-time fluorescent quantitative RT-PCR rapid detection method for human astrovirus / 中华微生物学和免疫学杂志

Objective:To establish a rapid detection method for human astrovirus based on TaqMan-probe real-time fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR).Methods:According to the conservative sequence of human astrovirus ORF1 b gene, we designed the amplification primers and specific fluorescent probe to establish the human astrovirus TaqMan real-time fluorescent quantitative RT-PCR rapid detection method. The specificity, sensitivity and stability of the method were evaluated. We also used this method to detect human astrovirus in clinical samples. Results:The established human astrovirus TaqMan real-time fluorescent quantitative RT-PCR detection method has good specificity and repeatability for human astrovirus, and the sensitivity can reach 10 2 copies/μl. After testing the clinical samples, the detection rate of human astrovirus by our method was 100%. Conclusions:The human astrovirus TaqMan real-time fluorescent quantitative RT-PCR detection method established in this study is simple, rapid, sensitive, specific and stable. It can be used for clinical human astrovirus detection and epidemiological investigation.

The preliminary analysis on the characteristics of the cluster for the Corona Virus Disease / 中华流行病学杂志

Since December 2019, Corona Virus Disease (COVID-19), a new emerging infection disease occurred in Wuhan, has spread in 27 countries and regions. The clusters of many cases were reported with the epidemic progresses. We collected currently available information for 377 COVID-19 clusters (1 719 cases), excluded the hospital clusters and Hubei cases, during the period from January 1, 2020 to February 20, 2020. There were 297 family clusters (79%), case median 4; 39 clusters of dining (10%), case median 5; 23 clusters of shopping malls or supermarkets (6%), case median 13; 12 clusters of work units (3%), case median 6, and 6 clusters of transportation. We selected 325 cases to estimate the incubation period and found its range is 1 to 20 days, median was 7 days, and mode was 4 days. The analysis of the epidemic situation in a department store in China indicates that there is a possibility of patients as the source of infection during the incubation period of the epidemic. From February 5, 2020 to February 21, 2020, 634 persons were infected in the Diamond Princess Liner. All persons are susceptible to SARS-CoV-2. The older, patients during the incubation period and the worse environment may be the cause of the cases rising. The progress of the two typical outbreaks clearly demonstrates the spread of the early cases in Wuhan. Whatever happens, screening and isolating close contacts remains essential except for clinical treatment during the epidemic. Especially for the healthy people in the epidemic area, isolation is the key.

Analysis on the epidemic factors for the Corona Virus Disease / 中华预防医学杂志

Since December 2019, corona virus disease 2019 (COVID-19) , an emerging infection disease occurred in Wuhan, has spread in the mainland China. The epidemic factors on the basis of knowledge of SARS-CoV-2 were discussed in this paper. This puts a lot of pressure on clinical resources and care. SARS-CoV-2 is a novel corona virus, the onset of COVID-19 is slow, and the pathogenesis of SARS-CoV-2 remains unclear and may lead to multiple organ damage. These put a lot of pressure on clinical resources and care. Source of infection including the patients, asymptomatic carrier and patients in the incubation period are contagious. It is difficult to control source of infection. Routes of SARS-CoV-2 transmission are diversified and the main routes of transmission for COVID-19 are droplet transmission and close contact transmission. All population have susceptibility to SARS-CoV-2. Social factors such population movements and aggregation accelerated the spread of SARS-CoV-2. The Chinese government’s adopted measures are positive and effective, and are accepted by the expert group from the World Health Organization. However, it will be a long-term hard work in the future to seriously summarize and think deeply to achieve public health security in China.

Identification and evaluation on methods with upstream flank sequences of CRISPR1, regarding Escherichia coli and Shigella / 中华流行病学杂志

Objective To analyze the effect of the identification and evaluation of Escherichia (E.) coli and Shigella,based on the upstream flanking sequences of CRISPR1.Methods Both CRISPR and cas sequences were obtained through the BLAST with repeating sequences against the publicly complete genome in GenBank that related to E.coli and Shigella.Clustal X was used to perform multi-sequences alignment of the flanking sequences.PCR method was used to amplify the upstream flanking sequences of CRISPR1 in order to appraise the effect of identification and evaluation of upstream flanking sequences on E.coli and Shigella,which were based on the upstream flanking sequences of CRISPR1.Results The results showed that 73.4％ of the strains containing the I-E CRISPR/Cas that belonged to the phylogroups A,B1,D while 8.4％ strains carried the I-F CRISPR/Cas.Another 17.2％ of the strains owned CRISPR3-4 (non-CRISPR/Cas) only belonged to the phylogroups B2.All the Shigella strains carried I-E CRISPR/Cas.More than 99％ of similarity the CRISPR1 upstream-flanking sequences was seen in E.coli (except B2) and Shigella and E.coli (B2).Both sensitivity and specificity were greater than 91％ after PCR amplification in the region to identify the E.coli and Shigella.Conclusion The upstream of CRISPR1 could achieve a preliminary identification effect on E.coli and Shigella.

Identification and evaluation on methods with upstream flank sequences of CRISPR1, regarding Escherichia coli and Shigella / 中华流行病学杂志

Objective To analyze the effect of the identification and evaluation of Escherichia (E.) coli and Shigella,based on the upstream flanking sequences of CRISPR1.Methods Both CRISPR and cas sequences were obtained through the BLAST with repeating sequences against the publicly complete genome in GenBank that related to E.coli and Shigella.Clustal X was used to perform multi-sequences alignment of the flanking sequences.PCR method was used to amplify the upstream flanking sequences of CRISPR1 in order to appraise the effect of identification and evaluation of upstream flanking sequences on E.coli and Shigella,which were based on the upstream flanking sequences of CRISPR1.Results The results showed that 73.4％ of the strains containing the I-E CRISPR/Cas that belonged to the phylogroups A,B1,D while 8.4％ strains carried the I-F CRISPR/Cas.Another 17.2％ of the strains owned CRISPR3-4 (non-CRISPR/Cas) only belonged to the phylogroups B2.All the Shigella strains carried I-E CRISPR/Cas.More than 99％ of similarity the CRISPR1 upstream-flanking sequences was seen in E.coli (except B2) and Shigella and E.coli (B2).Both sensitivity and specificity were greater than 91％ after PCR amplification in the region to identify the E.coli and Shigella.Conclusion The upstream of CRISPR1 could achieve a preliminary identification effect on E.coli and Shigella.

Association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia coli O26 : H11 or NM / 中华流行病学杂志

Objective To investigate the association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia (E.) coli O26:H11 or NM.Methods A total of 135 E.coli O26:H11 or NM strains were collected from NCBI database.Software CRT and CRISPR Finder were used to extract CRISPR and Excel was used to assign the spacer of unique number and type CRISPR.And the relationship between CRISPR and stx phage was analyzed.Results All the 135 E.coli O26:H11 or NM strains had the CRISPR.For CRISPRI,CRISPR2.1,CRISPR2.2 and CRISPR3-4,19,22,1 and 1 subtypes were found,respectively.According to the four CRISPR sites,the strains could be divided into 40 subtypes.Stx-phage was only observed in the group C of CRISPR.Compared with E.coli of stx-phage negative,E.coli with stx-phage harbored more spacers.Conclusions CRISPR loci was extensively existed in E.coli O26:H11 or NM,and many subtypes were found in these strains.The presence of stx-phage was related to the molecular distribution of CRISPR in E.coli O26:H11 or NM.CRISPR might be a valuable biomarker to identify strains with high virulent potential.

Changes of resistant phenotype and CRISPR/Cas system of four Shigella strains passaged for 90 times without antibiotics / 中华流行病学杂志

Objective To explore the stability of resistant phenotypes and changes of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) gene system on four Shigella strains in the absence of antibiotics.Methods Four clinical isolated Shigella strains that resistant to different antibiotics were consecutive passaged for 90 times without antibiotics.Agar dilution method was used to determine the minimum inhibitory concentration of Shigella strains.After sequence analysis with PCR,CRISPR Finder and Clustal X 2.1 were applied to identify the changes of CRISPR loci in the Shigella strains.Results After the consecutive transfer of 90 generations,sensitivity to certain antibiotics of four Shigella strains with different drug resistant spectrums increased.Mel-sf1998024/zz resistance to ampicillin,cephalexin,cefotaxime,chloramphenicol decreased,mel-s2014026/sx resistance to norfloxacin,trimethoprim decreased,mel-sf2004004/sx drug resistance to ampicillin,cefuroxime,cefotaxime,chloramphenicol,trimethoprim decreased and mel-sf2013004/bj resistance to chloramphenicol decreased.The spacer of which matched gene codes Cas and its upstream repeat in 3'end of CRISPR3 got lost in mel-sf1998024/zz and mel-sf2013004/bj.Conclusions Shigella strains could reduce or lose their resistance to some antibiotics after consecutive transfers,without the interference of antibiotics.CRISPR3 locus had dynamic spacers in Shigella strains while CRISPR3 locus and cas genes might have been co-evolved.

Association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia coli O26 : H11 or NM / 中华流行病学杂志

Objective To investigate the association between phage-mediated shiga toxin and molecular distribution of CRISPR in Escherichia (E.) coli O26:H11 or NM.Methods A total of 135 E.coli O26:H11 or NM strains were collected from NCBI database.Software CRT and CRISPR Finder were used to extract CRISPR and Excel was used to assign the spacer of unique number and type CRISPR.And the relationship between CRISPR and stx phage was analyzed.Results All the 135 E.coli O26:H11 or NM strains had the CRISPR.For CRISPRI,CRISPR2.1,CRISPR2.2 and CRISPR3-4,19,22,1 and 1 subtypes were found,respectively.According to the four CRISPR sites,the strains could be divided into 40 subtypes.Stx-phage was only observed in the group C of CRISPR.Compared with E.coli of stx-phage negative,E.coli with stx-phage harbored more spacers.Conclusions CRISPR loci was extensively existed in E.coli O26:H11 or NM,and many subtypes were found in these strains.The presence of stx-phage was related to the molecular distribution of CRISPR in E.coli O26:H11 or NM.CRISPR might be a valuable biomarker to identify strains with high virulent potential.

Changes of resistant phenotype and CRISPR/Cas system of four Shigella strains passaged for 90 times without antibiotics / 中华流行病学杂志

Objective To explore the stability of resistant phenotypes and changes of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) gene system on four Shigella strains in the absence of antibiotics.Methods Four clinical isolated Shigella strains that resistant to different antibiotics were consecutive passaged for 90 times without antibiotics.Agar dilution method was used to determine the minimum inhibitory concentration of Shigella strains.After sequence analysis with PCR,CRISPR Finder and Clustal X 2.1 were applied to identify the changes of CRISPR loci in the Shigella strains.Results After the consecutive transfer of 90 generations,sensitivity to certain antibiotics of four Shigella strains with different drug resistant spectrums increased.Mel-sf1998024/zz resistance to ampicillin,cephalexin,cefotaxime,chloramphenicol decreased,mel-s2014026/sx resistance to norfloxacin,trimethoprim decreased,mel-sf2004004/sx drug resistance to ampicillin,cefuroxime,cefotaxime,chloramphenicol,trimethoprim decreased and mel-sf2013004/bj resistance to chloramphenicol decreased.The spacer of which matched gene codes Cas and its upstream repeat in 3'end of CRISPR3 got lost in mel-sf1998024/zz and mel-sf2013004/bj.Conclusions Shigella strains could reduce or lose their resistance to some antibiotics after consecutive transfers,without the interference of antibiotics.CRISPR3 locus had dynamic spacers in Shigella strains while CRISPR3 locus and cas genes might have been co-evolved.

Opportunity and challenge on molecular epidemiology / 中华流行病学杂志

Molecular epidemiology,a branch of epidemiology,combines the theories and methods,both in epidemiology and molecular biology.Molecular epidemiology mainly focuses on biological markers,describing the distribution,occurrence,development and prognosis of diseases at the molecular level.The completion of Human Genome Project and rapid development of Precision Medicine and Big Data not only offer the new development opportunities but also bring about a higher demand and new challenge for molecular epidemiology.

Opportunity and challenge on molecular epidemiology / 中华流行病学杂志

Molecular epidemiology,a branch of epidemiology,combines the theories and methods,both in epidemiology and molecular biology.Molecular epidemiology mainly focuses on biological markers,describing the distribution,occurrence,development and prognosis of diseases at the molecular level.The completion of Human Genome Project and rapid development of Precision Medicine and Big Data not only offer the new development opportunities but also bring about a higher demand and new challenge for molecular epidemiology.

Survey on the early reperfusion therapy status in patients with ST-segment elevation myocardial infarction hospitalized in tertiary and secondary hospitals in Henan province / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the early reperfusion therapy status for patients with ST elevation acute myocardial infarction (STEMI) hospitalized in tertiary and secondary hospitals in Henan province.</p><p><b>METHODS</b>Baseline data, early reperfusion treatment and in-hospital mortality of STEMI patients hospitalized in 17 hospitals in Henan province (8 tertiary hospitals, 9 secondary hospitals) from June 2011 to June 2012 were obtained using a uniformed questionnaire.</p><p><b>RESULTS</b>One thousand six hundred and eighty six patients were enrolled, of which 886 patients were hospitalized in tertiary hospitals and 880 patients were early hospitalized in secondary hospitals. Six hundred and fifty four patients (38.8%, 654/1 686) underwent early reperfusion therapy (543 with thrombolysis and 111 with primary percutaneous coronary intervention (PCI)). There was no difference in the proportion of early reperfusion therapy between tertiary and secondary hospitals (40.1% (355/886) vs. 37.4% (299/800), P = 0.257). The median time from symptom onset to first medical contact, door-to-needle and door-to-balloon was 132 min, 18 min and 60 min, respectively. The median time from symptom onset to first medical contact (150 min vs. 120 min, P = 0.001), door-to-needle (30 min vs. 18 min, P = 0.003) and symptom onset-to-thrombolysis (3.5 h vs. 2.7 h, P = 0.001) were significantly longer in tertiary hospitals than in secondary hospitals. No difference was found in median time of door-to-balloon, symptom onset-to-primary PCI or symptom onset-to-elected PCI between tertiary and secondary hospitals (all P > 0.05). The proportion of door-to-needle ≤ 30 min was lower in tertiary hospitals than in secondary hospitals (46.4% (84/181) vs. 62.2% (153/246), P = 0.001). However, there was no difference in the proportion of door-to-balloon ≤ 90 min between tertiary and secondary hospitals (58.8% (60/102) vs. 57.1% (4/7), P = 1.000). In-hospital mortality was also similar between tertiary and secondary hospitals (5.8% (51/886) vs. 5.5% (44/800), P = 0.820).</p><p><b>CONCLUSIONS</b>Early reperfusion rate is low, and thrombolysis is the main early reperfusion therapy in both tertiary and secondary hospitals in Henan province. Tertiary hospitals did not take advantage of their primary PCI capability. There is great room for improvement in early reperfusion therapy in tertiary and secondary hospitals.</p>

Bioinformatics Analysis of Clustered Regularly Interspaced Short Palindromic Repeats in the Genomes of Shigella / 生物医学工程学杂志

This study was aimed to explore the features of clustered regularly interspaced short palindromic repeats (CRISPR) structures in Shigella by using bioinformatics. We used bioinformatics methods, including BLAST, alignment and RNA structure prediction, to analyze the CRISPR structures of Shigella genomes. The results showed that the CRISPRs existed in the four groups of Shigella, and the flanking sequences of upstream CRISPRs could be classified into the same group with those of the downstream. We also found some relatively conserved palindromic motifs in the leader sequences. Repeat sequences had the same group with corresponding flanking sequences, and could be classified into two different types by their RNA secondary structures, which contain "stem" and "ring". Some spacers were found to homologize with part sequences of plasmids or phages. The study indicated that there were correlations between repeat sequences and flanking sequences, and the repeats might act as a kind of recognition mechanism to mediate the interaction between foreign genetic elements and Cas proteins.

Molecular characteristics of Clustered Regularly Interspaced Short Palindromic Repeat in Shigella / 中华流行病学杂志

<p><b>OBJECTIVE</b>To detect the molecular characteristics of Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) in Shigella and to analyze the distribution of CRISPR related to the time of isolation.</p><p><b>METHODS</b>Of the 52 Shigella strains, 41 were isolated from Henan, 6 from Jiangxi and 5 isolated from Beijing. Both CRISPR locus of S1, S2, S3 and S4 in Shigella were detected by polymerase chain reaction (PCR). The PCR products were sequenced and compared.</p><p><b>RESULTS</b>The positive rates of CRISPR locus in Shigella were 33.69% (S1), 50.00% (S2), 82.69% (S3) and 73.08% (S4), respectively. Two subtypes were discovered in S1 and S3 locus. Three subtypes were discovered in S2 locus. Four different subtypes were discovered in S4 locus. The isolates from Henan strains were divided into two groups by the time of isolation. Distributions of S1 were different, before or after 2004, on Shigella. S1 could not be detected after 2004. There were no statistical differences of S2, S3 and S4 in two groups.</p><p><b>CONCLUSION</b>Different CRISPR subtypes or Shigella were discovered. A significant correlation was noticed between the CRISPR S1 related to the time of isolation but not between S2, S3 or S4 on the time of isolation.</p>

Dynamic changes in serum inflammatory cytokines and their association with neurogenic pulmonary edema in patients with severe hand-foot-mouth disease / 中华实用儿科临床杂志

Objective To investigate the dynamic changes in the serum inflammatory cytokines and their association with neurogenic pulmonary edema (NPE) in the patients with severe hand-foot-mouth disease (HFMD).Methods Eighty-nine patients with severe HFMD from March 2010 to December 2012 were recruited in the study.The patients were divided into NPE group and central nervous system diseases (CNSD) group according whether they had NPE.The cytokines,including interleukin (IL)-4,IL-6,IL-10,IL-17,tumor necrosis factor-α (TNF-α) and interferon-γ(IFN-γ)were evaluated by using enzyme-linked immunosorbent assay on day 1,3 and 5 after admission to hospital.Risk factors for NPE involvement during hospital stay were analyzed with multivariate Logistic regression analysis.Results (1) Compared with the CNSD group,the serum levels of IL-6 (Ftime =1.876,P =0.177,Ftime* group =2.192,P =0.145,Fgroup =7.855,P =0.007),TNF-α(Ftime =13.133,P =0.001,Ftime* group =0.291,P =0.592,Fgroup =3.644,P =0.042),IL-10 (Ftime =14.580,P =0.001,Ftime* group =2.612,P =0.078,Fgroup =16.823,P =0.000),INF-γ (Ftime =3.093,P =0.045,Ftime* group =0.513,P =0.600,Fgroup =20.141,P =0.000) were significantly higher than those in NPE group.(2)The serum levels of TNF-α,IL-10,INF-γ rose to the peak on the third day.(3) By using multivariate Logistic regression analysis,age (OR =3.383,95％ CI:1.173-4.759),days of fever (OR =4.925,95％ CI:1.758-3.794),hyperglycaemia (OR =3.465,95％ CI:1.303-5.220),leucocytosis (OR =7.579,95 ％ CI:2.530-12.704) and elevation of IL-10 (OR =1.228,95 ％ CI:1.007-1.523) were entered into equation.In the risk evaluation model,these variables remained independent predictors for NPE.Conclusions Abnormal cytokine productions appear to be responsible for the pathogenesis of NPE,and might be an effective tool for predicting NPE in infants with severe HFMD.

Clustered regularly interspaced short palindromic repeat associated protein genes cas1 and cas2 in Shigella / 中华流行病学杂志

Objective To detect the distribution of clustered regularly interspaced short palindromic repeat(CRISPR)associated protein genes cas1 and cas2 in Shigella and to understand the characteristics of CRISPR with relationship between CRISPR and related characteristics on drug resistance. Methods CRISPR associated protein genes cas1 and cas2 in Shigella were detected by PCR,with its products sequenced and compared.Results The CRISPR-associated protein genes cas1 and cas2 were found in all the 196 Shigella isolates which were isolated at different times and locations in China. Consistencies showed through related sequencing appepared as follows:cas2,cas1 (a) and cas1(b)were 96.44%,97.61%and 96.97%,respectively. There were two mutations including 3177129 site(C→G)and 3177126 site(G→C)of cas1(b)gene in 2003135 strain which were not found in the corresponding sites of Z23 and 2008113. Results showed that in terms of both susceptibility and antibiotic-resistance,strain 2003135 was stronger than Z23 and 2008113. Conclusion CRISPR system widely existed in Shigella,with the level of drug resistance in cas1(b) gene mutant strains higher than in wild strains. Cas1(b)gene mutation might be one of the reasons causing the different levels of resistance.

Clustered regularly interspaced short palindromic repeat associated protein genes cas1 and cas2 in Shigella / 中华流行病学杂志

Objective To detect the distribution of clustered regularly interspaced short palindromic repeat(CRISPR)associated protein genes cas1 and cas2 in Shigella and to understand the characteristics of CRISPR with relationship between CRISPR and related characteristics on drug resistance. Methods CRISPR associated protein genes cas1 and cas2 in Shigella were detected by PCR,with its products sequenced and compared.Results The CRISPR-associated protein genes cas1 and cas2 were found in all the 196 Shigella isolates which were isolated at different times and locations in China. Consistencies showed through related sequencing appepared as follows:cas2,cas1 (a) and cas1(b)were 96.44%,97.61%and 96.97%,respectively. There were two mutations including 3177129 site(C→G)and 3177126 site(G→C)of cas1(b)gene in 2003135 strain which were not found in the corresponding sites of Z23 and 2008113. Results showed that in terms of both susceptibility and antibiotic-resistance,strain 2003135 was stronger than Z23 and 2008113. Conclusion CRISPR system widely existed in Shigella,with the level of drug resistance in cas1(b) gene mutant strains higher than in wild strains. Cas1(b)gene mutation might be one of the reasons causing the different levels of resistance.

Clustered regularly interspaced short palindromic repeat associated protein genes cas1 and cas2 in Shigella / 中华流行病学杂志

<p><b>OBJECTIVE</b>To detect the distribution of clustered regularly interspaced short palindromic repeat (CRISPR) associated protein genes cas1 and cas2 in Shigella and to understand the characteristics of CRISPR with relationship between CRISPR and related characteristics on drug resistance.</p><p><b>METHODS</b>CRISPR associated protein genes cas1 and cas2 in Shigella were detected by PCR, with its products sequenced and compared.</p><p><b>RESULTS</b>The CRISPR-associated protein genes cas1 and cas2 were found in all the 196 Shigella isolates which were isolated at different times and locations in China. Consistencies showed through related sequencing appeared as follows: cas2, cas1 (a) and cas1 (b) were 96.44%, 97.61% and 96.97%, respectively. There were two mutations including 3177129 site(C→G)and 3177126 site (G→C) of cas1 (b) gene in 2003135 strain which were not found in the corresponding sites of Z23 and 2008113.</p><p><b>RESULTS</b>showed that in terms of both susceptibility and antibiotic-resistance, strain 2003135 was stronger than Z23 and 2008113.</p><p><b>CONCLUSION</b>CRISPR system widely existed in Shigella, with the level of drug resistance in cas1 (b) gene mutant strains higher than in wild strains. Cas1 (b) gene mutation might be one of the reasons causing the different levels of resistance.</p>

The gene characterization of VP1 and 2A of Enterovirus type 71 / 中华微生物学和免疫学杂志

Objective To detect VP1 and 2A genes of Enterovirus type 71 (EV71) isolated from clinical specimens of patients with light or heavy symptoms and analyze the homogeneity and phylogenetic tree. Methods Fifty clinical specimens of children with hand-foot-and-mouth disease ( HFMD) were dealed with, which were tested by RT-PCR assay with specific primer pairs for EV71. EV71 isolates from patients with light or heavy clinical symptoms were tested by RT-PCR assay with two specific primer pairs for VP1 and 2A genes of EV71 respectively. All of the PCR products were sequenced and compared with that of previously isolated EV71 isolates available from GenBank by homogeneity and phylogenetic tree analyses. Results The RT-PCR results indicated that 30 isolates were EV71, 13 of 30 isolates were from clinical specimens of patients with light symptoms of hand-foot and mouth, the other were from clinical specimens of patients with heavy symptoms of complications. VP1 genes and 2A genes of 10 EV71 isolated strains including 5 light strains and 5 heavy strains were sequenced and compared with that of previously isolated 5 EV71 Chinese isolates available from GenBank (fuyangEU703814.1, xi_anHM003207. 1, shandongEU753418.1, shenzhenFJ607337.1, henanGU366191. 1) by homogeneity and phylogenetic tree analyses. The homogeneity of VP1 and 2A genes of the 10 EV71 isolated strains and 5 previously isolated strains were between 94.7% -99.4% and 93.6% -99.3% respectively, with the representative isolates of A and B genotypes was between 81.0%-84. 6% and 78. 4%-82. 2% respectively. The data suggested that all of the 10 Chinese isolates belong to EV71 genotype C. There were only 87.8% -90.2% homology among these 10 strains and the representative strains of C1, C2, C3 sub-genotypes of EV71 but 96. 8% -99.6% homology among these 10 strains and the representative strains of C4 sub-genotypes of EV71, this suggested that these 10 Chinese isolates composed the C4 sub-genotype, of the C genotype, that formed a single branch in the phylogenetic tree. Conclusion EV71 of sub-genotype C4 distributed in Mainland China, and VP1 genes have close genetic relationship between isolated strains. There is no obvious difference in 2A genes between clinical specimens of patients with light or heavy symptoms by homogeneity and phylogenetic tree analyses.

Multi-drug resistance and characteristic of integrons in Shigella spp. isolated from China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in Shigella spp.</p><p><b>METHODS</b>Ninety Shigella strains (83 S. flexneri and 7 S. sonnei) were isolated from the stools of patients in China. Susceptibility to 8 antimicrobials was tested for all isolated strains. PCR, RFLP and sequencing analysis of integrons were applied to all of them.</p><p><b>RESULTS</b>High prevalence of multi-drug resistance (95.6%) was identified. Of the isolates 79 (87.8%) carried integrase genes of class 1 integron (3.3%), class 2 integron (10.0%) or both (74.4%). No intI3 was detected in the tested isolates. The prevalence of intI2 was significantly higher in isolates with multi-drug resistance to at least 3 antibiotics than that in isolates with resistance to 2 and less antibiotics (P<0.05). Gene cassettes dfrA17-aadA5, dfrA12-orfF-aadA2 of class 1 integron and dfrA1-sat1-aadA1 of class 2 integron were identified.</p><p><b>CONCLUSION</b>The class 2 integron may play a role in the emergence of multi-drug resistance in Shigella spp.</p>