Plague is an animal-sourced infectious disease of caused by Yersinia pestis, listed asa Class A notifiable infectious disease in China and an international quarantine infectious disease. It has caused three plague world pandemics in human history. Currently, the natural plague foci are distributed in all continents except Antarctica and Oceania. Madagascar and the Democratic Republic of the Congo (DRC) currently have the highest level of human plague epidemic in the world. In the middle of 20th century, human plague was prevalent in China, with an average of 1 400.8 reported cases per year from 1950 to 1954. After 1955, large-scale outbreaks of human plague were effectively controlled, with an average of 24.7 reported cases per year from 1955 to 1999. From 2000 to the present, human cases have not yet disappeared with a cumulative total of 514 cases had been reported. The plague control strategy based on the One Health concept is a more optimal solution, mainly reflected in the "ecological animal surveillance" and "early diagnosis and disposal of human cases" dual approach. Effective animal surveillance can provide accurate prediction and early warning of the risk that may be spread to humans, while early diagnosis and early treatment of human cases can availably control the spread of the epidemic and effectively reduce the case fatality rate simultaneously.

Objective:To study the epidemic situation of Marmota himalayana plague and Yersinias infection in Yugur Autonomous County of Sunan (Sunan County) of Gansu Province, and to provide new ideas for prevention and control of plague. Methods:From 2014 to 2018, liver and spleen, cecum, throat swabs and blood samples of Marmota himalayana were collected on the spot in Sunan County, where Yersinia strains were isolated and identified, and plague F1 antigen and antibody were detected. Results:A total of 634 liver and spleen samples, 427 cecum samples and 426 throat swabs samples were collected from Marmota himalayana, and 23 strains of Yersinia pestis, 2 strains of Yersinia marcescens, and 1 strain of Yersinia flexneri were detected, with the detection rates of 3.63% (23/634), 0.47% (2/427) and 0.23% (1/426), respectively. The detection rate of Yersinia pestis in different years was statistically significantly different (χ 2 = 13.19, P = 0.010). A total of 1 822 serum samples of Marmota himalayana were detected, and 5 F1 antibody positive samples were detected, with a positive rate of 0.27%, the difference of positive rate between different years was statistically significant (χ 2 = 25.22, P < 0.001); 282 liver and spleen tissue homogenates of Marmota himalayana were detected, 22 F1 antigen positive samples were detected, the positive rate was 7.80%, and there was no statistically significant difference between different years (χ 2 = 7.85, P = 0.097). The 23 strains of Yersinia pestis detected were distributed in Mati Tibetan Township (12 strains), Dahe Township (6 strains) and Qifeng Tibetan Township (5 strains); 1 strain of Yersinia flexneri and 2 strains of Yersinia marcescens were both located in Dahe Township. Conclusion:There is an epidemic of plague among animals in Sunan County from 2014 to 2018, and the areas where Yersinia pestis and non pathogenic Yersinia are detected overlapped.

BACKGROUND: Although previous studies have shown that meteorological factors such as temperature are related to the incidence of bacillary dysentery (BD), researches about the non-linear and interaction effect among meteorological variables remain limited. The objective of this study was to analyze the effects of temperature and other meteorological variables on BD in Beijing-Tianjin-Hebei region, which is a high-risk area for BD distribution. METHODS: Our study was based on the daily-scale data of BD cases and meteorological variables from 2014 to 2019, using generalized additive model (GAM) to explore the relationship between meteorological variables and BD cases and distributed lag non-linear model (DLNM) to analyze the lag and cumulative effects. The interaction effects and stratified analysis were developed by the GAM. RESULTS: A total of 147,001 cases were reported from 2014 to 2019. The relationship between temperature and BD was approximately liner above 0 °C, but the turning point of total temperature effect was 10 °C. Results of DLNM indicated that the effect of high temperature was significant on lag 5d and lag 6d, and the lag effect showed that each 5 °C rise caused a 3% [Relative risk (RR) = 1.03, 95% Confidence interval (CI): 1.02-1.05] increase in BD cases. The cumulative BD cases delayed by 7 days increased by 31% for each 5 °C rise in temperature above 10 °C (RR = 1.31, 95% CI: 1.30-1.33). The interaction effects and stratified analysis manifested that the incidence of BD was highest in hot and humid climates. CONCLUSIONS This study suggests that temperature can significantly affect the incidence of BD, and its effect can be enhanced by humidity and precipitation, which means that the hot and humid environment positively increases the incidence of BD.
Beijing/epidemiology* ; China/epidemiology* ; Dysentery, Bacillary/epidemiology* ; Humans ; Humidity ; Temperature

Objective:To understand the characteristics and differences of diarrhea-related symptoms caused by different pathogens, and the clinical features of various pathogens causing diarrhea.Methods:Etiology surveillance program was conducted among 20 provinces of China from 2010 to 2016. The acute diarrhea outpatients were collected from clinics or hospitals. A questionnaire was used to survey demographics and clinical features. VFeces samples were taken for laboratory detection of 22 common diarrhea pathogens, to detect and analyze the clinical symptom pattern characteristics of the patient’s.Results:A total of 38 950 outpatients were enrolled from 20 provinces of China. The positive rates of Rotavirus and Norovirus were the highest among the five diarrhea-causing viruses (Rotavirus: 18.29%, Norovirus: 13.06%). In the isolation and culture of 17 diarrhea-causing bacterial, Escherichia coli showed the highest positive rates (6.25%). The clinical features of bacterial diarrhea and viral diarrhea were mainly reflected in the results of fecal traits and routine examination, but pathogenic Vibrio infection was similar to viral diarrhea. Conclusion:Infectious diarrhea presents different characteristics due to various symptoms which can provide a basis for clinical diagnosis.

Yersiniosis is one of the "other infectious diarrhea" of the notifiable infectious diseases and also an important food-borne disease. However, it lacked the basis or standard for diagnosis. The Chinese Preventive Medicine Association coordinated experienced researchers from National Institute for Communicable Disease Control and Prevention, China CDC and other institutes to produce the group standard entitled "Diagnosis of Yersiniosis" (T/CPMA 005-2019). Based on the principle of "legality, scientificity, advancement, and feasibility" , the standard gives a clear definition for Yerisiniosis, stipulates diagnosis basis, principles and main differential diagnosis and provides two informative appendixes for epidemiological and clinical characteristics and a normative appendix for laboratory detection. The standard provides accurate basis and methods of Yersiniosis diagnosis for hospitals and CDCs at all levels in China. It will solve the problems that Yersiniosis cannot be clearly diagnosed for clinical cases and in the outbreaks.

Objective: In this study, we analyze the regulation mechanisms of the expression of ampD in AmpC β-lactamase and the regulation mechanism of β-N-acetylglucosaminidase (NagZ) in Yersinia enterocolitica. Methods: We construct the mutation strains of Yersinia enterocolitica AmpD (AmpD1-3) gene (ampD1-3), Low-Molecular-Mass Penicillin-Binding Proteins (LMM PBPs) gene (pbp4, pbp5a, pbp5b, pbp7), NagZ gene (nagZ), and ampR gene by deleting and complementing genes, and induce them by cefoxitin. We determined the activity of AmpC β-lactamase activity (U) of mutant strains (basal level and induce level) by using cephalothiophene hydrolysis method, the promoter activity of AmpC β-lactamase ((relative light unit (RLU)) was detected by the luxCDABEreporter system, and the activity of β-N-acetylglucosaminidase (nmol/L) was determined by by using 4-nitrophenyl N-acetyl-β-D-glucosaminide as the chromogenic substrate. Results: AmpD1 (Basal level: (3.29±1.58) U; Induced level: (4.08±1.75) U) was the most potent one. The YEΔ5b, YEΔ4Δ5b, YEΔ5aΔ5b and YEΔ5bΔ7 of ampC promoter activity increase significantly, whichYEΔ4Δ5b is the highest one (Basal level: (106 903.16±61 910.61) RLU; Induced level: (205 427.45±45 352.17) RLU). The YEΔ4Δ5bΔ7 of ampC promoter activity is the highest among triple mutant strain (Basal level: (304 108.04±99 274.53) RLU; Induced level: (531 440.21±68 891.02) RLU). Quadruple deletion strain YEΔ4Δ5aΔ5bΔ7 have the highest ampC promoter activity (Basal level: (1 013 810.99±260 955.96) RLU; Induced level: (1 230 214.59±205 526.79) RLU). After the deletion of nagZ gene, there is no significant change in β-lactamase activity of YEΔD1D2D3ΔZ, while β-lactamase activity of YEΔ4Δ5aΔ5bΔ7ΔZ shows a significant decrease (Basal level: (0.30±0.20) U; Induced level: (0.29±0.21) U), which basically drops to the wild strain level. Conclusion This is the first report of ampC multi-step upregulation mechanism driven by three AmpD homologues in Yersinia enterocolitica. The AmpC regulation mode with the function of single PBP4, PBP5a or PBP7 is relatively low, which work in coordination with PBP5b. Yersinia enterocolitica have both NagZ-depend and NagZ-independent mechanisms for β-lactamase expression.

Objective: To analyze the etiological characteristics of infectious diarrhea among people under 5 years old in Dongcheng District, Beijing. Methods: The age, time of infection, clinical symptoms and laboratory test results of the cases who didn't used antibiotics within 3 days in the second maternal and child health care hospital were collected from 2012 to 2015, through the information management system of infectious disease monitoring technology platform. To compare the detection rate of virus and bacteria in children with different sex, time and age,and the difference of clinical characteristics between virus detection group and bacteria detection group by chi square test. Results: 1 977 cases of infectious diarrhea were collected, the median of the month age (P₂₅, P₇₅) was 14.19 (8.31, 23.15) months. The virus detection rate was 34.3% (679 cases); the bacterial detection rate was 14.6% (288 cases). The difference of virus detection rate in children with different months was statistically significant (χ²=72.38, P<0.001), the virus detection rate of 24-60 months (40.9% (188/460)) was the hightest, and the detection rate of 0-5 months (15.3% (48/314)) was the lowest. The difference of bacteria detection rate was also statistically significant (χ²=32.67, P<0.001), and the detection rate of 12-17 months (19.0% (81/426)) was the highest, the detection rate of 0-5 months (6.7% (21/314)) was the lowest. The proportion of vomit and water sample in the virus detection group was 22.2% (136 cases) and 73.3% (449 cases), respectively, which were higher than those in bacteria detection group (8.1% (18 cases) and 57.2% (127 cases)), the difference was statistically significant (χ² values were 125.92 and 19.60; P values were both<0.001); the proportion of mucus stool and fever was 0.8% (5 cases) and 14.0% (86 cases), respectively, which were lower than those in bacterial detection group (4.1% (9 cases) and 18.5% (41 cases)), and the difference was statistically significant (χ² values were 8.50 and 23.01; P values were 0.004 and <0.001). Conclusion The virus detection rate of infantile infective diarrhea is higher than that of bacteria in Dongcheng district of Beijing, and the clinical characteristics are significantly different.

In order to investigate the distribution of Yersinia enterocolitica in Citellus dauricus plague focuses in Inner Mongolia,three different ecological environ/ments were chosen as the sampling area.Feces,tongue roots throat swabs,and intestinal contents of rodent,livestock,and poultry were separately collected,and different Y.enterocolitica strains were isolated,and identified.PCR analysis was conducted to detect the toxicity genes of Y.enterocolitica.Statiscal analysis was performed by chisquare test.Of the 3 260 samples,65 Y.enterocolitica strains were isolated and the overall detection rate was 1.99％.To include O ∶ 3/3,O ∶ 5/1A,O ∶ 4/4 serum biological type,the pathogenic strain of serotype O ∶ 3 and biological typt 3 carryinq toxicity genes ail,ystA,VirF yadA and rfbc was isolated from pigs in Citellus dauricus plague focuses,Inner Mongolia are the major carrier of pathogenic Y.enterocolitica distributed in three different ecological environment,and distributed mainly in agricultural area.

To determine the lysis spectrum of Yersinia enterocolitica bacteriophage phiYe-F10 and to analyze the relationship between the lysis ability of phiYe-F10 and the virulence gene of Yersinia enterocolitica. To observe the lysis ability of the phage phiYe-F10 to the different Yersinia strains with the double-layer technique. The strains used in this study including 213 of Yersinia enterocolitica and 36 of Yersinia pseudotuberculosis and 1 of Yersinia pestis. The virulence genes of these Yersinia enterocolitica (attachment invasion locus (ail) and enterotoxin (ystA, ystB) and yersinia adhesin A (yadA), virulence factor (virF), specific gene for lipopolysaccharide O-side chain of serotype O : 3 (rfbc) were all detected. Among the 213 Yersinia enterocolitica, 84 strains were O : 3 serotype (78 strains with rfbc gene), 10 were serotype O : 5, 13 were serotype O : 8, 34 were serotype O : 9 and 72 were other serotypes. Of these, 77 were typical pathogenic Yersinia enterocolitica harboring with virulence plasmid (ail+, ystA+, ystB-, yadA+, virF+), and 15 were pathogenic bacterial strains deficiency virulence plasmid (ail+, ystA+, ystB-, yadA-, virF-) and the rest 121 were non pathogenic genotype strains. PhiYe-F10 lysed the 71 serotype O : 3 Yersinia enterocolitica strains which were all carried with rfbc+, including 52 pathogenic Yersinia enterocolitica, 19 nonpathogenic Y. enterocolitica. The phiYe-F10 can not lysed serotype O : 5, O : 9 and other serotype Y. enterocolitica, the lysis rate of serotype O : 3 was as high as 84.5%. The phiYe-F10 can not lysed Yersinia pseudotuberculosis and Yersinia pestis. Yersinia phage phiYe-F10 is highly specific for serotype O : 3 Yersinia enterocolitic at 25 degrees C, which showed a typical narrow lysis spectrum. Phage phiYe-F10 can lysed much more pathogenic Y. enterocolitica than nonpathogenic Y. enterocolitica.
Bacterial Proteins ; genetics ; metabolism ; Bacteriophages ; genetics ; isolation & purification ; physiology ; Host Specificity ; Virulence Factors ; genetics ; metabolism ; Yersinia enterocolitica ; genetics ; metabolism ; virology

OBJECTIVETo determine the function of twin-arginine translocation system (Tat) and gene cluster in Vibrio strains and to analyze the homology of tat gene cluster among different Vibrio spp. strains based on N16961 and tatABC mutant strains N169-dtat.

METHODSDifferent serotypes of biotype strains of Vibrio spp. were selected to detect the transcription of 4 genes of Tat transport system and upstream ubi aarF gene and downstream cyt551 gene by the total RNA reverse transcription and homologicity of the gene cluster by sequencing analysis.

RESULTSOur results showed that the 4 genes of tat cluster (tatA, tatB, tatC, and tatE) were intragenic and co-transcribed. We found that ubi aarF gene could be co-transcribed with tatA, tatB, but not with tatC. The electron transport chain and energy metabolism-related genes, cytochrome C551 peroxidase gene, and 4 genes located at upstream of tatABC operon were not transcribed with tatABC. Although the co-transcription between ubi aarF and tatAB was blocked in N169-dtat strain, they were still transcribed separately. Homologous analysis of genes of tat cluster in different types of Vibrio cholerae showed that tat gene cluster was a very conservative.

CONCLUSIONThe ubi and aarF gene might be co-transcribed with genes of tat cluster in Vibrio cholerae, which and the close relationship showed that they might play a key function in Vibrio cholerae.