Drug resistance and genomic characteristics of a strain of O139 Vibrio cholerae isolated from human bloodstream infection / 中华预防医学杂志

Objective: To analyze the drug resistance and genomic characteristics of a strain of serogroup O139 Vibrio cholerae producing cholera toxin isolated from the bloodstream of a person with bacteremia. Methods: The broth dilution method and automatic drug sensitivity analyzer were used to determine the antibiotic sensitivity of the strain. The complete genome sequence of the strain was obtained by using second-generation gene sequencing and nanopore sequencing. BLAST software was used for comparison and analysis with CARD, Resfinder, ISfinder, VFDB, and other databases. The drug-resistant genes, insertion sequences and virulence genes carried by the strain were identified. MEGA 5.1 software was used to construct a genetic phylogenetic tree based on the core genomic single nucleotide polymorphisms. Results: V. cholerae SH400, as the toxigenic strain, carried multiple virulence-related genes and four virulence islands. The strain was resistant to streptomycin, tetracycline and cotrimoxazole, carrying corresponding drug-resistant genes. The strain also carried IncA/C plasmid with the size of 172914 bp and contained 10 drug-resistant genes. Combined with the genomic evolutionary relationship, this study found that the drug-resistant genes and drug-resistant plasmids carried among strains showed certain aggregation. The traditional ST type of strain SH400 was ST69, and the cgMLST type was a new type highly similar to cgST-252. Conclusion: This strain of serogroup O139 V. cholerae carries the ctxAB gene, multiple drug-resistant genes and IncA/C plasmid, and there are multiple drug-resistant islands.

Application and reflection of laboratory-based monitoring in early warning of infectious diseases / 中华预防医学杂志

Despite the fact that our cognition towards infectious disease prevention, the advanced technology and the economic status of the whole society has made a great progress in the last decade, the outbreak of COVID-19 pneumonia has again enabled the public to acquire more about super-challenges of infectious diseases, epidemics and the relevant preventive measurements. In order to identify the epidemic signals in early stage or even before the onset of epidemic, the data research and utilization of a series of factors related to the occurrence and transmission of infectious diseases have played a significant role in research of prevention and control during the whole period of surveillance and early warning. Laboratory-based monitoring for the etiology has always been an important part of infectious disease warning system due to pathogens as the direct cause of such diseases. China has initially established a laboratory-based monitoring and early warning system for bacterial infectious diseases based on the Chinese Pathogen Identification Network with an aim to identify pathogens, outbreaks and sources. This network has played an essential role in early detection, tracking and precise prevention and control of bacterial infectious diseases, such as plague, cholera, and epidemic cerebrospinal meningitis. This issue focuses on the function of laboratory-based monitoring during the period of early warning, prevention, and control of bacterial infectious diseases, and conducted a wide range of researches based on the analysis of the epidemic and outbreak isolates, together with field epidemiological studies and normal monitoring systems. All of these could illustrate the effect of laboratory surveillance in the infectious disease risk assessment and epidemic investigation. At the same time, we have put forward our review and expectation of scenarios about laboratory-based monitoring and early warning technologies to provide innovative thoughts for promoting a leapfrog development of infectious disease monitoring and early warning system in China.

Comparative Study of the Genetic Diversity, Antimicrobial Resistance, and Pathogenicity of / 生物医学与环境科学（英文）

Objective@#This study was performed to compare the genetic diversity, virulence, and antimicrobial resistance of @*Methods@#A total of 38 clinical strains and 19 strains from healthy individuals were isolated from the samples collected in Ma'anshan City, Anhui Province. Their taxonomy was investigated using concatenated @*Results@#The 57 @*Conclusions@#The taxonomy, virulence properties, and antibiotic resistance of

Effect of Placing Drainage or Not on Rapid Rehabilitation after Primary Total Knee Arthroplasty / 中国康复理论与实践

Objective:To explore the effect of placing drainage or not on rapid rehabilitation after total knee arthroplasty (TKA). Methods:From January, 2018 to September, 2020, 80 patients with knee osteoarthritis who underwent primary TKA in our hospital were analyzed retrospectively, and they were divided into groups A and B, with 40 cases in each group. Drainage was placed routinely in group A and not in group B. The postoperative serum inflammatory factors, postoperative pain score, postoperative complication rate, postoperative time out of bed, hospital stay, knee function score, range of motion of knee and World Health Organization Quality Of Life-abbreviated version score (WHOQOL-BREF) were compared between two groups. Results:There was no significant difference in the levels of C-reactive protein between two groups on the 1st to 3rd day after operation (t < 0.410, P > 0.05). There was no significant difference in Visual Analogue Score between two groups from 12 h to 48 h after operation (t < 0.300, P > 0.05). The incidences of postoperative complications were 5.0% in group A and 2.5% in group B, with no significant difference between two groups (χ2 = 0.346, P > 0.05). The time of getting out of bed and hospital stay was significantly shorter in group B than in group A (t > 4.863, P < 0.001). The scores of knee joint function, range of motion of knee and WHOQOL-BREF significantly increased after operation in both groups (t > 6.099, P < 0.001), however, there was no significant difference between two groups (P > 0.05). Conclusion:Placement or non-placement of drainage after primary TKA does not affect postoperative complications, knee joint function and quality of life of patients with knee osteoarthritis, however, non-placement of drainage can promote postoperative recovery and discharge.

Genetic Diversity, Antimicrobial Resistance, and Virulence Genes of Isolates from Clinical Patients, Tap Water Systems, and Food / 生物医学与环境科学（英文）

Objective@#This study aimed to evaluate the genetic diversity, virulence, and antimicrobial resistance of isolates from clinical patients, tap water systems, and food.@*Methods@#Ninety isolates were obtained from Ma'anshan, Anhui province, China, and subjected to multi-locus sequence typing (MLST) with six housekeeping genes. Their taxonomy was investigated using concatenated sequences, while their resistance to 12 antibiotics was evaluated. Ten putative virulence factors and several resistance genes were identified by PCR and sequencing.@*Results@#The 90 isolates were divided into 84 sequence types, 80 of which were novel, indicating high genetic diversity. The isolates were classified into eight different species. PCR assays identified virulence genes in the isolates, with the enterotoxin and hemolysin genes , , , and found in 47 (52.2%), 13 (14.4%), 22 (24.4%), and 12 (13.3%) of the isolates, respectively. The majority of the isolates (≥ 90%) were susceptible to aztreonam, imipenem, cefepime, chloramphenicol, gentamicin, tetracycline, and ciprofloxacin. However, several resistance genes were detected in the isolates, as well as a new variant.@*Conclusions@#Sequence type, virulence properties, and antibiotic resistance vary in isolates from clinical patients, tap water systems, and food.

Correlation of Social-psychological Health and Joint Function in Patients during Rehabilitation for Joint Impairment / 中国康复理论与实践

Objective:To explore the influence of social-psychological factors on outcome of joint rehabilitation. Methods:From October, 2015 to April, 2017, 64 inpatients accepting joint rehabilitation were divided into anxiety group and non-anxiety group, and depression group and non-depression group, according to the scores of Hamilton Anxiety Scale and Hamilton Depression Scale. They were assessed with routine joint scores as initial and final stages of joint rehabilitation, as well as Symptom Checklist-90 (SCL-90) and World Health Organization Disability Assessment Schedule 2.0 (WHO-DAS 2.0). The correlation of joint scores to scores of SCL-90 and WHO-DAS 2.0 was analyzed with Spearman correlation analysis. Results:There were significant differences in joint scores between the depression and the non-depression groups initially and finally (|t| > 2.106, P < 0.05). The joint score at the initial stage was negatively correlated with the interpersonal factor score of SCL-90 (r = -0.257, P < 0.05). The joint score at the final stage was negatively correlated (P < 0.05) with the dimension one (r = -0.257) and four (r = -0.278) of WHO-DAS 2.0, total score (r = -0.263), and interpersonal (r = -0.328) and hostile (r = -0.385) factor scores of SCL-90. Improvement of joint score negative correlated with dimension one of WHO-DAS 2.0 score (r = -0.249, P < 0.05). Conclusion:The social-psychological factors affect the outcome of joint rehabilitation. It is necessary to explore the way to take the the social-psychological assessment into the routine three stage evaluation of the joint rehabilitation protocol.

Two Cases of Multi-antibiotic Resistant Cronobacter spp. Infections of Infants in China / 生物医学与环境科学（英文）

Infections by Cronobacter spp. are hazardous to infants since they can lead to neonatal meningitis, bacteremia, and necrotizing enterocolitis. Cronobacter spp. are frequently resistant to β-lactam derivatives, macrolides, and aminoglycosides. In addition, multi-resistant strains have also been detected. In China, the isolation rate of Cronobacter spp. from commercial powdered infant formula (PIF) or follow-up formula (FUF) is relatively high. Nevertheless, clinical cases of Cronobacter infection have been ignored to date. Here we describe two cases of Cronobacter infection detected at the Wuhan Women and Children Medical Care Center Hospital (Wuhan City, China). We provide the genomic analysis of the isolates and the antibiotic-resistance profiles of the two strains. The Cronobacter strains identified in this study were not susceptible to third-generation cephalosporins, aminoglycoside, and/or trimethoprim-sulfamethoxazole. Whole genome sequencing revealed various genes known to encode antibiotic resistance. Future studies are needed to determine whether the genes predicted in this study are functional. As with Enterobacter spp., the antibiotic resistance of Cronobacter is a serious issue that requires more attention.

Application of PulseNet China Database in tracking and warning 4 cholerae outbreaks in Anhui province, in 2012 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To track the source of infection regarding 4 Cholerae outbreaks in Anhui province in 2012 through the application of PulseNet China Database (PNCD).</p><p><b>METHODS</b>Cholerae virulence genes were amplified by PCR and typed by pulse field gel electrophoresis(PFGE). Results from electrophoresis were cluster-analyzed by BioNumericsV4.0 software and compared with PNCD.</p><p><b>RESULTS</b>Virulence gene CT and TCP of the tested vibrio cholera showed both positive. Homology of the strains from four cholera outbreaks was more than 98%, based on the homologous and cluster analysis through enzyme digested PFGE electrophoresis. Those strains were highly homologous with the cholera epidemic strains identified in Hunan, Sichuan,Zhejiang, Shanghai and Hubei by PNCD, with the homology as 100% .</p><p><b>CONCLUSION</b>Four cholera outbreaks in Anhui province, 2012 were highly correlated with the outbreaks occurring in Hunan and Sichuan during the same time period, indicating that PNCD could effectively and quickly tracking down the source of infection on the cholera outbreaks and providing early warning of the situation.</p>

Cronobacter carriage in neonate and adult intestinal tracts / 生物医学与环境科学（英文）

A total of 7 Cronobacter strains were isolated from 703 fecal samples collected in Jinan from June 13 to December 30, 2011, with the positive rate of Cronobacter spp. being 1.0% (95% confidence interval 0.6%-1.4%). Three Cronobacter sakazakii stains were isolated from 157 fecal samples of healthy neonates (95% confidence interval 0.4%-5.5%). This number was slightly higher than that isolated from 273 fecal samples of healthy adults, in which 1 strain of C. sakazakii and 1 strain of Cronobacter malonaticus were isolated, and that from 173 fecal samples of adults with acute diarrhea, in which 1 strain of C. sakazakii and 1 strain of C. malonaticus were isolated, but the differences were not statistically significant (P>0.05). The Cronobacter isolates were all from different genetic sources. It should be noted that Cronobacter carriage may cause infection under certain conditions, especially in neonates.

The fundamental role of stage control technology on the detectability for Salmonella networking laboratory / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluated the fundamental role of stage control technology (SCT) on the detectability for Salmonella networking laboratories.</p><p><b>METHODS</b>Appropriate Salmonella detection methods after key point control being evaluated, were establishment and optimized. Our training and evaluation networking laboratories participated in the World Health Organization-Global Salmonella Surveillance Project (WHO-GSS) and China-U.S. Collaborative Program on Emerging and Re-emerging infectious diseases Project (GFN) in Shanghai. Staff members from the Yunnan Yuxi city Center for Disease Control and Prevention were trained on Salmonella isolation from diarrhea specimens. Data on annual Salmonella positive rates was collected from the provincial-level monitoring sites to be part of the GSS and GFN projects from 2006 to 2012.</p><p><b>RESULTS</b>The methodology was designed based on the conventional detection procedure of Salmonella which involved the processes as enrichment, isolation, species identification and sero-typing. These methods were simultaneously used to satisfy the sensitivity requirements on non-typhoid Salmonella detection for networking laboratories. Public Health Laboratories in Shanghai had developed from 5 in 2006 to 9 in 2011, and Clinical laboratories from 8 to 22. Number of clinical isolates, including typhoid and non-typhoid Salmonella increased from 196 in 2006 to 1442 in 2011. The positive rate of Salmonella isolated from the clinical diarrhea cases was 2.4% in Yuxi county, in 2012. At present, three other provincial monitoring sites were using the SBG technique as selectivity enrichment broth for Salmonella isolation, with Shanghai having the most stable positive baseline.</p><p><b>CONCLUSION</b>The method of SCT was proved the premise of the network laboratory construction. Based on this, the improvement of precise phenotypic identification and molecular typing capabilities could reach the level equivalent to the national networking laboratory.</p>

Molecular characterization of Vibrio parahaemolyticus collected from human infections in Shenzhen, between 2002 and 2008 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To determine the occurrence and distribution of specific clones of pathogenic Vibrio parahaemolyticus(VP)isolated in Shenzhen and to assess the relationship between serotype O3:K6 and the globally distributed pandemic clone.</p><p><b>METHODS</b>A total of 1005 VPs isolated from diarrhea patients in 2002-2008 were sero-typed. Real-time PCR was used to detect the virulence genes tlh, toxR, tdh, trh and orf8 in 281 isolates from 68 different serotypes. The main serotypes were typed by pulsed field gel electrophoresis(PFGE). Strains with dominant serotypes and PFGE patterns were assayed by GS-PCR and toxRS sequencing for the identification of pandemic clone. Multilocus sequence typing(MLST)analysis was reserved for exemplary 41 O3 : K6 and O1 : K25 isolates.</p><p><b>RESULTS</b>Seventy-nine serotypes were observed among the 1005 isolates, including O3 : K6(57.9%), O4 : K8(8.16%), O1 : KUT(5.87%), O1 : K25(5.27%), O4 : K68(1.39%), O1 : K56(1.39%) and O9 : K44(0.99%). Most of the strains(99.36%)showed PCR positive to tlh, toxR, and tdh but eleven strains were tdh negative. MLST showed that all the 36 O3 : K6 isolates belonged to ST3 and all the 5 O4 : K8 strains were ST189. These results matched the description of the pandemic VP clone.</p><p><b>CONCLUSION</b>A recognizable burden of diarrheal illness caused by VP had been seen in Shenzhen. Results from serotyping indicated that although there existing a large variety of diversities, the dominant serotype appeared to be O3 : K6. VP isolates identified in Shenzhen mainly showed as tdh positive but trh negative, in consistent with the current pandemic O3 : K6 clone. The pandemic O3 : K6 clone did appear to co-exist with other clones of O3 : K6, as well as O4 : K8,O1 : K25. Potential outbreak of VP could be monitored through the laboratory-based surveillance programs, suggesting that the strategies related to prevention and control of VP should be prioritized in Shenzhen.</p>

Single nucleotide polymorphisms characteristics of the Yersinia Pestis in China / 中国地方病学杂志

Objective To study the single nucleotide polymorphisms (SNP) characteristics of Yersinia pestis strains from different natural foci in China.Methods Genome-wide comparison was done to find SNP sites by the Mummer program among 9 Yersinia pestis genome which was downloaded from NCBI.Then 13 genic fragments including 19 SNP sites were amplified by PCR and sequenced in 133 Yersinia pestis strains,and the results were cluster analyzed with the BioNumerics software.Results Three thousand seven hundred and eighty sequence variation sites were found by genome-wide comparison.Using the different combinations of SNP sites,UPGMA cluster analysis revealed obvious geographic regional and eco-aggregation characteristics of Yersinia pestis strains isolated from China.Conclusions As relatively stable genetic markers,SNP can better reflect the genome characteristics of Yersinia pestis in different plague natural foci of China.

The therapeutic effect analysis of three kinds of methods for the management of post traumatic knee stiffness / 中华外科杂志

<p><b>OBJECTIVES</b>To investigate the therapeutic effect of rehabilitation, arthroscopy and "hybrid technique" for posttraumatic knee stiffness (PTKS), and to make the best choice for the treatment.</p><p><b>METHODS</b>From February 2004 to November 2009, 66 patients suffered from PTKS were treated, and the clinical data were studied retrospectively, 36 male and 30 female patients with an average age of 41 years were analyzed, knee stiffness time averaged 15 months (0.5 - 108.0 months), 21 cases of patients were treated with rehabilitation (rehabilitation group), 22 cases of patients with arthroscopy + rehabilitation (arthroscopy group) and 23 cases of patients with mini-invasive "hybrid technique" + rehabilitation (hybrid technique group). For each case, the difference of range of motion (ROM) and hospital for special surgery (HSS) score of the knee before and after the treatment were analyzed statistically. The characters of PTKS including the course of the disease, the degree of extensor mechanism involving, physical examination and other ancillary data were also analyzed. The management methods for PTKS were summarized.</p><p><b>RESULTS</b>Total 66 cases were followed up ranging from 24.0-72.5 months and the mean time was 34.2 months. The average ROM was improved obviously: rehabilitation group increased from 45° ± 22° to 95° ± 24° (t = -11.2, P < 0.05), arthroscopy group from 47° ± 26° to 118° ± 11° (t = -11.0, P < 0.05) and hybrid technique group from 36° ± 22° to 110° ± 14° (t = -13.4, P < 0.05). Both ROM and HSS score of the knee before and after the treatment for each group showed significant difference statistically (t = -9.1, -6.0, -5.2, P < 0.05). Wound necrosis, tearing, re-fracture and extension lag were not found. According to Judet standard at final follow-up, 15 cases were excellent, 3 cases good and 3 cases normal in rehabilitation group; 15 cases were excellent, 5 cases good and 2 cases normal in arthroscopy group; 14 cases were excellent, 8 cases good and 1 case bad.</p><p><b>CONCLUSIONS</b>Pathology of PTKS is complex, satisfactory result could be obtained through individualized treatment program, which were established depend on the course of the disease, the degree of extensor mechanism involving, physical examination and ancillary data. The timely and effective surgical interference followed by a comprehensive rehabilitation program is the key point for satisfied outcome.</p>

Multilocus variable-number tandem-repeat analysis for molecular subtypes of Shigella isolates in Beijing / 中华预防医学杂志

<p><b>OBJECTIVE</b>Selecting variable-number tandem-repeat (VNTR) loci for different serogroups of Shigella spp to explore and establish multilocus variable-number tandem-repeat analysis (MLVA) method, in order to study the molecular characteristic of the isolated strains.</p><p><b>METHODS</b>Of the Shigella strains found by dysentery surveillance in Beijing from 2001 to 2009, 180 strains were selected for this study, according to the number and serotypes of the surveillant strains, at the ratio of 15%; including 50 strains of Shigella sonnei and 130 strains of Shigella flexneri. After screening the polymorphism of the 18 VNTR loci, 10 VNTR loci (sh1-sh10) were retained and constructed three groups of multi-PCR methods to detect all he 180 strains and analyze MLVA molecular subtypes using capillary segments.</p><p><b>RESULTS</b>A range of 2 to 11 alleles were found on the 10 VNTR loci among the 180 Shigella strains, with a diversity index value between 0.158 and 0.766. The 10 loci showed diversity in different serogroups, such as only one allele found in sh6 of Shigella flexneri, sh2 and sh3 of Shigella sonnei individually. The isolated 180 strains were divided into 84 MLVA subtypes, with a resolution ratio D value at 0.967 (95%CI: 0.956 - 0.978). The 130 strains of Shigella flexneri were divided into 63 subtypes, named as TF001-TF063; among which TF001, TF002 and TF 005 were the dominant subtypes, accounting to 17, 16 and 15 strains respectively. The 50 strains of Shigella sonnei were divided into 21 subtypes, named as TS001-TS021; among which TS002 (14 strains) and TS001 (7 strains) were the dominant subtypes.</p><p><b>CONCLUSION</b>MLVA subtyping method including 10 VNTR loci was preliminarily developed. The MLVA cluster analysis revealed that the subtypes of Shigella strains isolated in Beijing were diverse, and suggested the possibility of multiple-clone source.</p>

Structural variation of the superintegron in the toxigenic Vibrio cholerae O1 El Tor / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To understand the genetic structures and variations of the superintegron (SI) in Vibrio cholerae isolated in the seventh cholera pandemic.</p><p><b>METHODS</b>Polymerase chain reaction scanning and fragment sequencing were used. Sixty toxigenic V. cholerae O1 El Tor strains isolated between 1961 and 2008 were analyzed.</p><p><b>RESULTS</b>Some variations were found, including insertions, replacements, and deletions. Most of the deletions were probably the result of recombination between V. cholerae repeat sequences. The majority of the variations clustered together. The SIs of the strains isolated in the 1960s and 1970s showed more diversity, whereas SI cassette variations in strains isolated in the 1990s and after were lower, with ∼24 kb signature sequence deletion. This indicates the predominant SI in the host during the epidemic in the 1990s and after. The insertion cassettes suggested the mobilization from the SIs of other V. cholerae serogroups and Vibrio mimicus.</p><p><b>CONCLUSION</b>The study revealed that structural variations of SIs were obvious in the strains isolated in epidemics in different decades, whereas the divergence was based on syntenic structure of SIs in these El Tor strains. Also, the continuing cassette flows in the SIs of the host strains during the seventh cholera pandemics were displayed.</p>

Molecular typing of Legionella pneumophila isolates from China with pulsed field gel electrophoresis / 中华流行病学杂志

Objective To analyze the molecular types of Legionella (L.) pneumophila strains isolated in China,and to develop the PulseNet-China Database of L.pneumophila.Methods Pulsed field gel electrophoresis (PFGE) was used to analyze 262 L.pneumophila strains collected from 11 provinces between 2004 and 2009 in China.Different kinds of genomic DNA in different L.pneumophila strains were isolated and separated after digesting with Asc Ⅰ.BioNumerics software was used to analysis the PFGE fingerprints.Results L.pneumophila strains isolated in China were quite different regarding their PFGE patterns.There were 108 PFGE types among the 262 strains tested in this study.The similarity value of these strains was in the range of 16%-100% and the same types were discovered in different provinces and years.Conclusion L.pneumophila strains isolated in China were with high genetic variations.There might be different clones existed in China.The development of PulseNet China Database was thus of great significance in monitoring the L.pneumophila strains in the future.

Epidemiological characteristics and molecular typing of Salmonella in Beijing from 2008 to 2009 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study the epidemiological characteristics and molecular phenotypes of Salmonella by pulsed-field gel electrophoresis (PFGE) in Beijing from 2008 to 2009.</p><p><b>METHODS</b>A total of one hundred thirty-seven isolates recovered from the WHO Global Salmonella Surveillance system and entero clinic surveillance system were identified by biochemical tests and serotyping. The related epidemiological informations were also analyzed. The isolates were further typed by PFGE.</p><p><b>RESULTS</b>The prevalence of Salmonella from 2008 to 2009 showed obvious seasonal character. High incidence occurred from June to September, and 64.1% (84/131) isolates were recovered in this period. Patients of 18 - 40 year-old were 46.1% (58/128) and 80 patients were male and 40 patients were female with the ratio of 1.57:1. These 137 Salmonella isolates belonged to 20 serotypes, including Enteritidis (46.7%, 64/137) and Typhimurium (17.5%, 24/137) as the dominant serotype. In total, 71 PFGE profiles were identified. Four PFGE patterns of S. Enteritidis isolates (JEGX01.CN0001, JEGX01.CN0003, JEGX01.CN0002, JEGX01.CN0019) and S. Typhimurium pattern of JPXX01.CN0001 were dominant patterns.</p><p><b>CONCLUSION</b>The prevalence of Salmonella from 2008 to 2009 showed distribution characteristics of sex, age and seasons. The numerous PFGE patterns of Salmonella showed diversity of these isolates and different clones existed in Beijing.</p>

Assessment of the application of variable-number tandem repeat loci of Salmonella Enteritidis in subtyping multiple-locus variable-number tandem repeat analysis / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility of the application of variable-number tandem repeat (VNTR) loci of Salmonella Enteritidis (S. enteritidis) in subtyping mutiple-locus variable-number tandem repeat analysis (MLVA).</p><p><b>METHODS</b>A total of 16 isolates of S.enteritidis from different place and time in China were preliminarily assessed by choosing 11 reported VNTR loci, the loci with single amplified bands were picked to subtype all 104 S. enteritidis isolates. The isolates were also analyzed by pulse field gel electrophoresis (PFGE) to compare the superiority or inferiority of MLVA method and PFGE method.</p><p><b>RESULTS</b>Seven VNTR loci were selected from the preliminary screening to expand the analysis, and the 7 VNTR loci had grouped 104 of S.enteritidis isolates into either 16 MLVA subtypes or 22 PFGE subtypes, with the D value at 0.7222 and 0.7974, respectively. Comparing with the isolates in MLVA subtypes, the isolates in PFGE showed a stronger resolving power. Meanwhile the results in PFGE showed a more disperse frequency distribution than those in MLVA.</p><p><b>CONCLUSION</b>These results indicate that some VNTR locus which have shown a good polymorphism internationally, may fail to show polymorphism in China, thereby, more VNTR loci should be included in MLVA and the wide screening may benefit the unity of global laboratorial methods.</p>

Characteristics of Yersinia enterocolitica genes isolated in Ningxia Hui autonomous region from 1997 to 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the distribution of virulent genes of Yersinia enterocolitica (Y. enterocolitica) in Ningxia Hui autonomous region and the characteristics of the molecular patterns of Y. enterocolitica.</p><p><b>METHODS</b>283 strains of Y. enterocolitica were isolated in Ningxia Hui autonomous region between year 1997 and 2010. The genes ail, ystA, ystB, yadA and virF were analyzed by PCR method; the chromosomal DNA of Y. enterocolitica was digested by restriction endonucleases NotI and processed by pulsed-field gel electrophoreses (PFGE); and then the cluster analysis were conducted by BioNumeric computer software towards the above results.</p><p><b>RESULTS</b>Of all, 209 strains of serotypes O:3 and O:9 Y.enterocolitica showed positive virulence of genes ail, ystA, yadA and virF; 97.6% (204/209) of which, the ystB virulence were negative. The virulence of all genes in serotype O:8 and serum-unclassified strains were negative. 9 out of 11 strains of serotype O:5 Y. enterocolitica showed negative virulence of the above five genes. By PFGE, according to the NotI Macrorestriction Map on chromosomal DNA, the 29 strains of serotype O:3 Y. enterocolitica were divided into 12 PFGE patterns, 2 of which were dominant patterns which could be found in over 5 strains; and the 180 strains of serotype O:9 Y. enterocolitica were divided into 13 patterns, 4 of which were dominant patterns which existed in over 10 strains; which were isolated individually from pigs and house mouse, pigs and dogs as well as pigs and wild rabbits.</p><p><b>CONCLUSION</b>Y.enterocolitica serotypes O:3 and O:9 were pathogenic in Ningxia, and serotype O:3 becomes predominant gradually. O:5, O:8 and serum-unclassified serotypes were non-pathogenic.</p>

Multilocus sequence typing and pulsed-field gel electrophoresis analysis of Salmonella Paratyphi A isolates from 2000 to 2008, China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze molecular and evolution characteristics of Salmonella Paratyphi A isolates from 2000 to 2008, China.</p><p><b>METHODS</b>Using pulsed-field gel electrophoresis (PFGE) method with SpeI restriction enzyme, and multilocus sequence typing (MLST) method based on housekeeping genes (aroC, thrA, hisD, purE, sucA, dnaN, hemD, adk, and purA), the genomic variations of 118 Salmonella Paratyphi A isolates from 10 regions during 2000 to 2008 were analyzed.</p><p><b>RESULTS</b>Using PFGE method, 118 Salmonella Paratyphi A isolates were clustered into 32 PFGE patterns, and 5 patterns were predominant (5 isolates or above). However, only 2 MLST types were identified for all isolates with MLST method. Among all Salmonella Paratyphi A isolates, the sequences of housekeeping genes were highly conservative and showed a high degree of cloning.</p><p><b>CONCLUSION</b>For Chinese epidemic Salmonella Paratyphi A isolates during 2000 - 2008, MLST method showed low discrimination power and the MLST method should not be applied to outbreak and epidemiological surveillance of Salmonella Paratyphi A. Currently, nationwide paratyphoid fever epidemics is caused by highly clonal isolates in China. As the time changes, these isolates also accumulate sporadic mutations.</p>