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Objective To understand the epidemiological and molecular characteristics of typhoid and paratyphoid in China from 2009 to 2013,and provide evidence for the prevention and control of typhoid and paratyphoid,the development and improvement of surveillance strategies.Methods Epidemiological analysis was conducted on the incidence data of typhoid and paratyphoid,and related public health emergencies in China during 2009-2013.Pathogen isolation and culture,serologic test were conducted for the typhoid and paratyphoid cases from 13 national surveillance sites.The isolates were subjected to antimicrobial susceptibility testing.Pulsed-field gel electrophoresis (PFGE) was performed for the molecular typing of these isolates.Results The average incidence of typhoid and paratyphoid in China during this period was 1.03/100 000.The reported case number and incidence decreased with year.The provinces reporting high case numbers were Yunnan,Guizhou,Guangxi,Hunan,Zhejiang,Guangdong and Xinjiang.The incidence of age group 0-4 years was highest.The proportion of farmers and children outside child care settings showed an increasing tendency over time.The annual incidence peak was during July-August.Twenty five outbreaks occurred during 2009-2013.The results of pathogen isolation and culture showed that the positive rate was 3.00％ (940/31 322),among the positive isolates,the proportion of Salmonella paratyphi A accounted for higher proportion (68.19％,641/940) compared with Salmonella typhi (31.60％,297/940).The drug resistances of Salmonella typhi and Salmonella paratyphi varied,but their resistances to nalidixic acid were highest (50.22％ and 85.33％) respectively.A certain amount of Salmonella typhi isolates showed the resistance to the 3rd generation cephalosporins.PFGE analysis showed divergent patterns of Salmonella typhi compared with limited patterns of Salmonella paratyphi A.Conclusion The epidemic level of typhoid and paratyphoid in China was relatively low,but the outbreak occurred occasionally.It is necessary to enhance the laboratory-based surveillance,particularly the capability of etiological diagnosis,outbreak investigation,response and antibiotic resistance monitoring,and conduct risk factor investigation in provinces with high incidences in recent years.
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Objective To understand the epidemiological and molecular characteristics of typhoid and paratyphoid in China from 2009 to 2013,and provide evidence for the prevention and control of typhoid and paratyphoid,the development and improvement of surveillance strategies.Methods Epidemiological analysis was conducted on the incidence data of typhoid and paratyphoid,and related public health emergencies in China during 2009-2013.Pathogen isolation and culture,serologic test were conducted for the typhoid and paratyphoid cases from 13 national surveillance sites.The isolates were subjected to antimicrobial susceptibility testing.Pulsed-field gel electrophoresis (PFGE) was performed for the molecular typing of these isolates.Results The average incidence of typhoid and paratyphoid in China during this period was 1.03/100 000.The reported case number and incidence decreased with year.The provinces reporting high case numbers were Yunnan,Guizhou,Guangxi,Hunan,Zhejiang,Guangdong and Xinjiang.The incidence of age group 0-4 years was highest.The proportion of farmers and children outside child care settings showed an increasing tendency over time.The annual incidence peak was during July-August.Twenty five outbreaks occurred during 2009-2013.The results of pathogen isolation and culture showed that the positive rate was 3.00％ (940/31 322),among the positive isolates,the proportion of Salmonella paratyphi A accounted for higher proportion (68.19％,641/940) compared with Salmonella typhi (31.60％,297/940).The drug resistances of Salmonella typhi and Salmonella paratyphi varied,but their resistances to nalidixic acid were highest (50.22％ and 85.33％) respectively.A certain amount of Salmonella typhi isolates showed the resistance to the 3rd generation cephalosporins.PFGE analysis showed divergent patterns of Salmonella typhi compared with limited patterns of Salmonella paratyphi A.Conclusion The epidemic level of typhoid and paratyphoid in China was relatively low,but the outbreak occurred occasionally.It is necessary to enhance the laboratory-based surveillance,particularly the capability of etiological diagnosis,outbreak investigation,response and antibiotic resistance monitoring,and conduct risk factor investigation in provinces with high incidences in recent years.
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Objective To analyze the spatial and temporal clustering characteristics of typhoid and paratyphoid fever and its change pattern in Yunnan, Guizhou and Guangxi provinces in southwestern China in recent years. Methods The incidence data of typhoid and paratyphoid fever cases at county level in 3 provinces during 2001-2012 were collected from China Information System for Diseases Control and Prevention and analyzed by the methods of descriptive epidemiology and geographic informatics. And the map showing the spatial and temporal clustering characters of typhoid and paratyphoid fever cases in three provinces was drawn. SaTScan statistics was used to identify the typhoid and paratyphoid fever clustering areas of three provinces in each year from 2001 to 2012. Results During the study period, the reported cases of typhoid and paratyphoid fever declined with year. The reported incidence decreased from 30.15 per 100000 in 2001 to 10.83 per 100000 in 2006 (annual incidence 21.12 per 100000);while during 2007-2012, the incidence became stable, ranging from 4.75 per 100000 to 6.83 per 100000 (annual incidence 5.73 per 100000). The seasonal variation of the incidence was consistent in three provinces, with majority of cases occurred in summer and autumn. The spatial and temporal clustering of typhoid and paratyphoid fever was demonstrated by the incidence map. Most high-incidence counties were located in a zonal area extending from Yuxi ofYunnan to Guiyang of Guizhou, but were concentrated in Guilin in Guangxi. Temporal and spatial scan statistics identified the positional shifting of class Ⅰ clustering area from Guizhou to Yunnan. Class Ⅰ clustering area was located around the central and western areas (Zunyi and Anshun) of Guizhou during 2001-2003, and moved to the central area of Yunnan during 2004-2012. Conclusion Spatial and temporal clustering of typhoid and paratyphoid fever existed in the endemic areas of southwestern China, and the clustering area covered a zone connecting the central areas of Guizhou and Yunnan. From 2004 to 2012, the most important clustering area shifted from Guizhou to Yunnan. Findings from this study provided evidence for the identifying key areas for typhoid and paratyphoid fever control and prevention and allocate health resources.
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Objective@#To study the preferred colonization sites of O1 Vibrio cholerae (V.cholerae) and the colonization ability difference for O1 and O139 V. cholerae on soft-shelled turtle's surface.@*Methods@#8 O1 and O139 V. cholerae strains were obtained from branch of diarrheal diseases, Chinese center for disease control and prevention. 63 soft-shelled turtles weighing 150 g and 9 cm in length (diameter of calipash) were selected for use in the study. The preferred colonization sites and proliferation trend were studied by using bioluminescent imaging method. The colonization factors for O1 V. cholerae strains were studied by constructing colonization gene mutant strains (VC1897dmshA, VC1897dgbpA and VC1897dtcpA), performing competition colonization assays and analyzing the competitive indexes. After pairing off O1 and O139 strains respectively to perform 16 competition groups, the colonization difference of these two strains were studied by competition colonization assays.@*Results@#The colonization sites by V. cholerae on soft-shelled turtles surfaces was clustered. More V. cholerae strains colonized on turtle's calipash and carapace on dorsal side and less strain colonized on ventral side. The competition colonization assays showed that colonization ability of O1 serogroup mshA mutant strains were 7.26 times lower than VC1897dlacZ. Besides, the CI value (O139/O1) of 11 out of the 16 competition groups were greater than 2 (between 2.07 and 59.84). Two groups showed values of 1.43 and 0.93 respectively and 3 groups lower than 0.7.@*Conclusion@#The preferred colonization sites for O1 V. cholerae strains on body surface were observed.MSHA was one of the main colonization factors for its colonization. Our study suggested that in general, O139 V. cholerae strains have stronger colonization ability than O1 strains. Besides, strains isolated from soft-shelled turtles tend to have stronger colonization ability than strains isolated from patients.
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Objective To analyze the spatial and temporal clustering characteristics of typhoid and paratyphoid fever and its change pattern in Yunnan, Guizhou and Guangxi provinces in southwestern China in recent years. Methods The incidence data of typhoid and paratyphoid fever cases at county level in 3 provinces during 2001-2012 were collected from China Information System for Diseases Control and Prevention and analyzed by the methods of descriptive epidemiology and geographic informatics. And the map showing the spatial and temporal clustering characters of typhoid and paratyphoid fever cases in three provinces was drawn. SaTScan statistics was used to identify the typhoid and paratyphoid fever clustering areas of three provinces in each year from 2001 to 2012. Results During the study period, the reported cases of typhoid and paratyphoid fever declined with year. The reported incidence decreased from 30.15 per 100000 in 2001 to 10.83 per 100000 in 2006 (annual incidence 21.12 per 100000);while during 2007-2012, the incidence became stable, ranging from 4.75 per 100000 to 6.83 per 100000 (annual incidence 5.73 per 100000). The seasonal variation of the incidence was consistent in three provinces, with majority of cases occurred in summer and autumn. The spatial and temporal clustering of typhoid and paratyphoid fever was demonstrated by the incidence map. Most high-incidence counties were located in a zonal area extending from Yuxi ofYunnan to Guiyang of Guizhou, but were concentrated in Guilin in Guangxi. Temporal and spatial scan statistics identified the positional shifting of class Ⅰ clustering area from Guizhou to Yunnan. Class Ⅰ clustering area was located around the central and western areas (Zunyi and Anshun) of Guizhou during 2001-2003, and moved to the central area of Yunnan during 2004-2012. Conclusion Spatial and temporal clustering of typhoid and paratyphoid fever existed in the endemic areas of southwestern China, and the clustering area covered a zone connecting the central areas of Guizhou and Yunnan. From 2004 to 2012, the most important clustering area shifted from Guizhou to Yunnan. Findings from this study provided evidence for the identifying key areas for typhoid and paratyphoid fever control and prevention and allocate health resources.
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<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>Different 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.</p><p><b>RESULTS</b>Our 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.</p><p><b>CONCLUSION</b>The 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.</p>
Subject(s)
Arginine , Bacterial Proteins , Cytochrome c Group , Membrane Transport Proteins , Vibrio choleraeABSTRACT
<p><b>OBJECTIVE</b>Through analyzing the typhoid epidemics and to determine and monitor regional resistance characteristics of the shift of drug resistant profile on Salmonella (S.) Typhi, to understand the related epidemiological characteristics of typhoid fever and to provide evidence for the development of strategies, in Guangxi.</p><p><b>METHODS</b>Data of typhoid fever from surveillance and reporting system between 1994 to 2013 was collected and statistically analyzed epidemiologically. The susceptibility of 475 S. Typhi isolates from patients on ten antibiotics was tested by broth micro-dilution method and minimum inhibition concentration was obtained and interpreted based on the CLSI standard.</p><p><b>RESULTS</b>From 1994 to 2013, a total of 57 928 cases of typhoid fever were reported in Guangxi province with an annual incidence of 6.29/100 000 and mortality as 0.03%. The higher incidence was observed in the population under 20 years of age. There was no significant difference on incidence between male and female, but farmers and students were among the hardest hit groups. More cases were seen from the northern part of the province. Cases appeared all year round with the peak from May to October. A total of 13 major outbreaks during 2001 to 2013 were reported and the main transmission route was water-borne. All the strains were sensitive to third generation cephalosporins cefotaxime and fluoroquinolones norfloxacin. The susceptibility rates to tetracycline, chloramphenicol, ampicillin and gentamicin was around 98% but relative lower susceptible rate to ciprofloxacin was seen as 89.89% . The lowest susceptibility was found for streptomycin and sulfamethoxazole agents, with the rates as 67.73% and 65.89% , respectively. One strain was found to have been resistant to ciprofloxacin and another 47 isolates with reduced susceptibility to ciprofloxacin. Twenty eight isolates were found to be resistant to multiple antibiotics and one displayed ampicillin, chloramphenicol, streptomycin, sulfamethoxazole tetracycline and nalidixic acid (ACSSxT-NAL) resistance profile. This was the first report in China. Multi-drug resistant strains were frequently isolated from small scale outbreaks of typhoid fever.</p><p><b>CONCLUSION</b>The incidence of typhoid fever in Guangxi was still high and some strains showed multi-drug resistance and reduced susceptibility to ciprofloxacin, indicating that the surveillance and monitor programs on drug resistance of S. Typhi should be strengthened, to prevent large scale outbreaks of typhoid fever in this province.</p>
Subject(s)
Female , Humans , Male , China , Epidemiology , Disease Outbreaks , Drug Resistance, Multiple, Bacterial , Salmonella typhi , Typhoid Fever , EpidemiologyABSTRACT
Objective To characterize Hfq-dependent phenotypes in stress response and to dissect Hfq-dependent transcription of virulence genes and stress-responsive genes in Vibrio cholera.Methods The hfq null mutant strain (△hfq) and the complemented mutant strain (△hfq/pUC18-hfq) were constructed from the wild-type Vibrio cholera.Comparisons on the motility,biofilm formation,growth under various oxygen-supplying conditions,outer membrane resistance,and sensitivity to oxidative stress were analyzed between the wild type strain and the mutant strains.Reverse-transcript fluorescence quantitative PCR (RT-qPCR) was used to determine the transcriptional levels of target genes in the above mentioned strains.Results △hfq and △hfq/pUC18-hfq strains were successfully constructed.The motility,outer membrane resistance and sensitivity to oxidative stress were reduced,but biofilm formation was enhanced in the hfq null mutant strain.RT-qPCR testified that Hfq had regulation effects on gene transcription for forming falagellum,extracellular polysaccharide,outer membrane protein and oxidative stress in Vibrio cholera.Conclusion As a RNA chaperone,Hfq could affect Vibrio cholera in its biofilm formation,resistance to oxidative stress and antibiotics resistance through regulating the transcription of multiple metabolic genes and virulence genes,which indicates that Hfq,combined with other regulators,may play a key role in the complex regulation of metabolic genes and virulence genes.