Etiological and epidemiological characteristics of Vibrio cholerae in Beijing, 2015-2021 / 中华流行病学杂志

Objective: To analyze the etiological and epidemiological characteristics of Vibrio cholerae in Beijing during 2015-2021 and provide evidence for the prevention and control of cholera. Methods: The V. cholerae strains isolated in Beijing during 2015-2021 were analyzed by serotyping and virulence genes detection. Pulsed field gel electrophoresis (PFGE) was performed for the molecular typing of the strains. Based on the collected epidemiological and clinical data of cholera cases,the epidemiological characteristics of cholera were analyzed by descriptive epidemiology method. Results: A total of 76 Vibrio cholerae O1 strains were isolated in Beijing during 2015-2021, including 61 strains from human, 10 strains from environment and 5 strains from seafood. The 76 strains consisted of 68 Ogawa strains and 8 Inaba strains. Six Ogawa strains isolated from sporadic cases carried ctxAB. After NotⅠ digestion, 76 strains were divided into 33 PFGE patterns. From 2015 to 2021, a total of 38 cholera epidemics were reported in Beijing, most of them were sporadic ones, accounting for 92.11% (35/38). A total of 45 cases were reported, and the cases occurred during June-September accounted for 97.78% (44/45). Cholera cases occurred in 9 districts of Beijing, and the cases reported in Chaoyang district accounted for 42.22% (19/45) and in Changping district accounted for 31.11% (14/45). The age of the cholera cases ranged from 19 to 63 years. Except for one case with unknown clinical symptoms, 44 cases had diarrhea symptoms with 84.09% (37/44) of the cases reporting diarrhea (3-9 times/day), followed by yellow watery stool (95.45%, 42/44), abdominal pain (68.18%, 30/44), nausea and vomiting (40.91%, 18/44) and fever (36.36%, 16/44). Conclusion: Vibrio cholerae strains isolated in Beijing during 2015-2021 were mainly O1 serotype Ogawa,most of which were non-toxigenic. The PFGE of the strains varied. Cholera epidemics occurred in 9 districts of Beijing, but most were sporadic ones with incidence peak during June-September.

Application of two RT-PCR methods for detection of norovirus in market-sold oysters and norovirus genetic characteristic analysis, a survey conducted in Beijing / 中华流行病学杂志

Objective: To evaluate the application of real-time RT-PCR and semi-nested RT-PCR in the detection of norovirus in oysters and analyzing the genetic characteristics of the isolates. Methods: Real-time fluorescent RT-PCR and semi-nested RT-PCR were used to detect norovirus GⅠ/GⅡ in fresh oysters collected from the markets in Beijing from November 2014 to October 2015. The detection rate of the parallel test was also analyzed. In addition, the reliability of semi-nested RT-PCR was evaluated by agreement rate and consistency test (Kappa value). The positive products of norovirus GⅠ/GⅡ capsid protein region gene by semi-nested RT-PCR were sequenced. Software BioEdit 7.0.9.0 was used for sequence alignment, and software Mega 6.0 was used to construct the evolutionary tree. Results: In 72 samples, the detection rate of norovirus was 31.94% (23/72) by real-time RT-PCR, 38.89% (28/72) by semi-nested RT-PCR and 48.61% (35/72) by parallel test. The coincidence rate of the two methods was 73.61%, a moderate degree (Kappa value =0.43). A total of 13 norovirus strains were successfully sequenced, and 11 strains (7 GⅡ.17 strains, 2 GⅡ. 4 Sydney_ 2012 strains, 1 GⅡ. 1 strain and 1 GⅡ. 21 strain) were obtained from norovirus positive samples by two RT-PCR methods, two strains (1 GⅡ. 17 strain and 1 GⅡ. 3 strain) were obtained from real-time RT-PCR negative samples which were positive for norovirus by semi-nested RT-PCR. The similarity between these strains and reference strains from diarrhea patients, environmental sewage, and shellfish products were 84.4% - 100.0%. Conclusions: The parallel test of norovirus in oysters by two RT-PCR methods can improve the detection rate and detect more genotypes. Norovirus strains in oysters were highly homologous with reference strains from diarrheal patients, environmental sewage, and shellfish products. Therefore, surveillance, prevention and control for norovirus should be carried out in people who have frequent contacts with oysters and related environments.

Organic Photoredox-Catalyzed Decarboxylative Trifluoromethylselenolation of Aliphatic Carboxylic Acids with [Me4N][SeCF3].

Oxidative decarboxylation/trifluoromethylselenolation of primary, secondary, and tertiary aliphatic carboxylic acids with the nucleophilic [Me4N][SeCF3] salt and an organic photocatalyst is described. The reaction proceeds smoothly at room temperature under transition-metal-free conditions and affords the corresponding trifluoromethylselenolated products in good yields. Advantages of the method include good functional group tolerance, without preactivation of the acids, and late-stage functionalization of the complex drug molecules. This protocol represents the first decarboxylative trifluoromethylselenolation of carboxylic acids to trifluoromethyl selenoethers.

TfOH-Promoted Transition-Metal-Free Cascade Trifluoroethylation/Cyclization of Organic Isothiocyanates by Phenyl(2,2,2-trifluoroethyl)iodonium Triflate.

An efficient and transition-metal-free method for the synthesis of the structurally diversified trifluoroethylthiol phenanthridines and 3,4-dihydroisoquinolines is described. Various 2-isothiocyanobiaryls and aryl alkyl isothiocyanates reacted with phenyl(2,2,2-trifluoroethyl)iodonium triflate in CH2Cl2 in the presence of trifluoromethanesulfonic acid at 40 °C to form the corresponding trifluoroethylation/cyclization products in good to quantitative yields. This work represents the first construction of trifluoroethylthiol phenanthridine and isoquinoline derivatives from isothiocyanates in the absence of transition-metal catalysts by a one-pot procedure.

Pd-catalyzed divergent trifluoroethylation and arylation of arylboronic acids by aryl(2,2,2-trifluoroethyl)iodonium triflates.

Highly electrophilic aryl(2,2,2-trifluoroethyl)iodonium triflates have been used for the first time as trifluoroethyl and aryl transfer reagents in Pd-catalyzed functionalization of arylboronic acids. Electron-rich arylboronic acids reacted with aryl(2,2,2-trifluoroethyl)iodonium triflates (2a-b) in CH3CN in the presence of Pd2(dba)3 and K3PO4 at room temperature to provide trifluoroethyl arenes in up to 82% yield, while the reactions of both electron-rich and -poor arylboronic acids with 2a-b in DMF in the presence of Pd[P(t-Bu)3]2 and Cs2CO3 at 40 °C afforded arylation products in up to 99% yield. This tunable protocol allows access to trifluoroethyl arenes or biaryls in good to excellent yields under mild conditions and without the addition of extra ligands.

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>

Etiological surveillance and analysis of infectious diarrhea in Beijing in year 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the pathogenic form, epidemic features and serotype distribution of the pathogenic bacteria causing infectious diarrhea in Beijing.</p><p><b>METHODS</b>A total of 2118 samples of rectal swabs and stool specimens of diarrheal patients were collected from 6 surveillant intestinal tract clinics during the period between April and October, 2010. Enteric multiple pathogens including Vibrio cholerae, Vibrio parahaemolyticus, Salmonella, Shigella and diarrheagenic Escherichia coli were detected by the isolation culture, biochemical identification and serotyping methods. The population distribution, temporal distribution and serotype distribution of the above pathogenic bacteria were analyzed by descriptive statistical methods.</p><p><b>RESULTS</b>478 strains isolated from the total 2118 specimens were positive for pathogen detection, accounting to 22.6%. Among the 478 strains of pathogenic bacteria, Shigella accounting for 40.8% (195/478) was the most frequent pathogen, followed by Vibrio parahaemolyticus accouting for 23.8% (114/478), Salmonella accounting for 19.0% (91/478) and diarrheagenic Escherichia coli accounting for 4.8% (23/478). Enteric pathogenic bacteria spread mainly among adults aging between 20 and 39; and the distribution was different among different age groups, while the highest detected rate was in 30 - 39 age group, accounting for 27.2% (92/338). The detected rate of pathogenic bacteria showed evident seasonal variations, with a peak from July to October, whose detected rates were 23.5% (114/486), 32.8% (176/536), 36.1% (90/249) and 25.9% (29/112) respectively. The detected rates in other months were all under 16.0%. Shigella Sonnei was the dominant serotype, accounting for 83.1% (162/195). O3:K6 was the dominant serotype among Vibrio parahaemolyticus, accounting for 63.2% (72/114). Salmonella Enteritidis and Salmonella Typhimurium were dominant serotypes among Salmonella, accounting for 13.2% (12/91) and 12.1% (11/91) separately. Enterpathogenic Escherichia coli and enterotoxigenic Escherichia coli were the dominant serotypes among Diarrheagenic Escherichia coli, accounting for 69.6% (16/23) and 30.4% (7/23) respectively.</p><p><b>CONCLUSION</b>The three main pathogenic bacteria causing infectious diarrhea in Beijing are Shigella, Vibrio parahaemolyticus, Salmonella; and there are obvious changes in the serotype distribution of Shigella and Samonella compared to previous years.</p>

Analysis on the etiological and molecular epidemiological characteristics of Vibrio parahaemolyticus in Beijing / 中华流行病学杂志

Objective To understand the etiological and molecular-epiderniological characteristics of Vibrio parahaemolyticus in Beijing.Methods Stool specimens from sporadic diarrheal patients were collected during April to December,2010.Culture and serotyping were used to detect the Vibrio parahaemolyticus from the 2118 specimens.All the positive strains were tested for drug sensitivity by Kirby-Bauer method.Real-time PCR was used to detect the existence of three virulence genes tlh,tdh and trh.Molecular typing on Vibrio parahaerrolyticus isolates was completed by pulsed field gel electrophoresis(PFGE).Results 114 out of the 2118 specimens were Vibrio parahaemolyticus positive,with the positive rate as 5.38％.114 isolates belonged to 23 serotypes,with the dominant (63.16％)serotype as O3:K6.Strains isolated from clinical manifestation patients were resistant to antibiotics-ampicillin and gentamicin,while with high sensitivity to amoxicillin,ceftriaxone,chloromycetin,imipenem,nalidixic acid and tetracycline.Virulence gene detection was positive to tlh for all the strains,but most to tdh,while only one strain to trh.The positive rate oftdh among O3:K6 strains(98.61％)was higher than that in those non-O3:K6 strains(85.71％)(P=0.0098).114 isolates were discriminated into 54 different PFGE patterns,while 72 O3:K6 strains into 34 patterns without the clustering characteristic.Conclusion Vibrio parahaemolyticus strains isolated from diarrheal patients in Beijing were dominated by O3:K6 strains,with stronger virulence.The positive rates of genes tlh and tdh were high.Vibrio parahaemolyticus strains showed high sensitivity to most antibiotics.The prevalent Vibrio parahaemolyticus strains in Beijing had various sources of clones.

Etiology of hand-foot-and-mouth disease and genetic characteristics of Coxsackievirus A16 in Beijing, 2009 / 病毒学报

This study aimed to reveal the pathogen spectrum of hand-foot-and-mouth disease (HFMD) and genetic characteristics of Coxsackievirus A16 (CoxA16) isolates in Beijing in 2009. From 1044 clinical specimens collected from 975 HFMD cases at Beijing Pediatrics Hospital, Beijing You'an Hospital and Beijing Ditan Hospital in 2009, viral nucleic acids of enterovirus were detected by reverse transcriptase polymerase chain reaction (RT-PCR). Enterovirus isolations were conducted with rhabdomyosarcoma (RD) cell line on 200 throat swabs having positive RT-PCR results. Sequencing and analyses of VP1 encoding gene were performed on 9 CoxA16 isolates in this study. The results showed that CoxA16 (49.4%) and EV71 (36.4%) were the major pathogens for the epidemics of HFMD in 2009 in Beijing, and CoxA16 was the predominant serotype, while there were also other enterovirus co-circulating, such as CoxA4, CoxA10, and CoxA9; the CoxA16 strains prevalent in Beijing in 2009 belonged to subgenotype B1a and B1b.

Etiological characteristics of influenza A (H1N1) 2009 virus in Beijing / 中华流行病学杂志

Objective To analyze the results of detection on influenza A (H1N1) 2009 virus in Beijing from May 2009 to December 2009 and to understand the epidemiologic characteristics during the pandemic period. Methods The study was conducted from the May 1 to December 27,2009. A total of 101 852 throat swab samples were detected with the real-time RT-PCR assay by the Beijing Network Laboratory. Data was statistically analyzed. Results 9843 samples showed influenza A (H1N1) 2009 positive, with an overall positive rate as 9.66%. In terms of the positive rates, they were 2.85% from May to June, 3.32% from July to August and 8.35% from September to October. The peak month fell in November (29.67%) and December (24.33%). The positive rates among the following subpopulations were: 8.40% among the suspected cases, 4.75% among close contact cases, 11.46% among the influenza-like illness cases and 7.33% among the cluster cases with fever. Positive cases mainly fell in age groups 5-14 and 15-24. The ratio of male to female was 1.5:1.Conclusion During the pandemic period of influenza A (H1N1) 2009, positive cases gradually increased during May to November but slowly decreasing in December.

Etiological analysis of enteric infectious diseases during Beijing Olympic Games / 中华预防医学杂志

<p><b>OBJECTIVE</b>To understand pathogen patterns of enteric infectious diseases and its impact on this pattern due to aggregation of a great deal of foreign visitors during Beijing Olympic Games.</p><p><b>METHODS</b>The diarrheal patient's rectal swabs and stool specimens were collected from Olympic stadium and hospitals of four districts, including Dongcheng, Xicheng, Haidian and Chaoyang. Enteric multiple pathogens were detected from the total 45 specimens. The culture method was used for the enteric bacteria, ELISA and RT-PCR for the enteric viruses. Molecular typing of Salmonella Enteritidis isolation was completed by PFGE.</p><p><b>RESULTS</b>It was found that 26 out of 45 cases were positive with 57.8 percent for pathogen detection, and 24 were identified as enteric pathogenic bacteria, including Vibrio parahaemolyticus, Salmonella, diarrheagenic Escherichia coli and Campylobacter jejuni, two as norovirus. There were mixed infections of two pathogenic bacteria for three cases. Ten kinds of pathogens were detected from foreign cases, while five kinds from Chinese cases. A total of 5 PFGE patterns were identified in 10 Salmonella Enteritidis isolates from national and foreign diarrheal cases, which were concentrative in some extent.</p><p><b>CONCLUSION</b>Vibrio parahaemolyticus, Salmonella, diarrheagenic Escherichia coli and Campylobacter jejuni were found to be the primary bacterial pathogens during the Olympic Games. Enteric virus infection existed in summer diarrhea.</p>

Study on the epidemiologic characteristics of norovirus infection in Beijing / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the epidemiological characteristics of norovirus infection in Beijing.</p><p><b>METHODS</b>Both outbreaks and sporadic cases of acute gastroenteritis were studied through questionnaires while the stools of patients were collected. Noroviruses were detected by ELISA or RT-PCR, and PCR products were cloned and sequenced.</p><p><b>RESULTS</b>Eight outbreaks were reported between November 2006 and March 2007, which were confirmed as nosocomial infections. A total of 158 positive cases were detected among 409 sporadic cases of acute virus gastroenteritis with a positive rate of 38.63%. The highest positive rate (55.00%) was found in group aged from 40 to 44, while the lowest positive rate (21.74%) fell into groups aged from 55 to 59. The positive cases aged from 6 months to 91 years with the mean age of 40 years old including 84 males and 74 females. Data from sequence analysis showed that norovirus epidemic strains helonged to the GII/4 variants in Beijing, which were almost identical to the variants causing epidemics both in the Netherlands and in Japan.</p><p><b>CONCLUSION</b>Norovirus was important, causing virus-borne diarrhea between 2006 and 2007 in Beijing, and the epidemic strains were consistent with those isolated from both the Netherlands and Japan in 2006.</p>