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Objective@#To investigate the serotype and drug resistance of 815 Salmonella isolates from Hunan Province, so as to provide insights into management of Salmonella infections.@*Methods@#Salmonella isolates were collected from stool samples of foodborne diarrheal patients and food samples in Hunan Province from 2020 to 2021, and serotyped. Antimicrobial susceptibility test was performed using the broth microdilution method.@*Results@#A total of 10 groups and 39 serotypes were characterized in 815 Salmonella isolates. Among the 646 Salmonella isolates of human sources, 388 isolates were identified as serogroup B (60.06%), with S. typhimurium and its variants aspredominant serotypes (364 isolates, 56.35%), and among 169 foodborne isolates, 61 isolates were characterized as serogroup B (36.09%) with S. london as the predominant serotype (26 isolates, 15.38%). There were 597 antimicrobial resistant Salmonella isolates of human sources, with a drug resistance rate of 92.41%, and the percentage of ampicillin resistance was 81.58%. There were 140 foodborne antimicrobial resistant isolates, with a drug resistance rate of 82.84%, and the proportion of tetracycline resistance was 72.78%. However, Salmonella isolates from both humans and foods were sensitive to imipenem. In addition, there were 577 multidrug resistant Salmonella isolates, including 490 multidrug resistant isolates of human sources and 87 foodborne multidrug resistant isolates.@*Conclusions@#S. typhimurium and its variants and S. london were predominant serotypes of Salmonella isolates from 815 foodborne diarrheal patients and food samples in Hunan Province from 2020 to 2021, and a high rate of multidrug resistance was detected.
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Objective@#To analyze the epidemiological characteristics of human brucellosis and trace back source of infection of human brucellosis in Hunan province during 2010-2018, and provide evidence for the prevention and control of human brucellosis.@*Methods@#The surveillance data of human brucellosis in Hunan during 2010-2018 were analyzed with software Excel 2016 and ArcGIS 10.5, the epidemic characteristics were described using cases number, constituent ratio and rate. The conventional biotype methods were used for the identification of Brucella species, UTS-PCR was applied to further confirm the results from conventional biotype detections, then six virulence genes of two clinical Brucella strains were detected by PCR assay. Cluster analysis of two Brucella strains were performed with Multiple locus variable-number tandem repeat analysis (MLVA) for the investigation of the infection source of human brucellosis.@*Results@#From 2010 to 2018, a total of 728 human brucellosis cases were reported in Hunan with the annual incidence rate of 0.12/100 000. The incidence rate was 2.50/100 000 in Chenzhou and 1.90/100 000 in Yongzhou, higher than those in other areas. The number of counties reporting cases increased from 5 in 2010 to 69 in 2018. Most cases were reported in age group 45-54 years, accounting for 38.32% (279/728). The cases in farmers accounted for 59.07% (430/728) of the total. The male to female ratio of the cases was 2.75 ∶ 1. The reported case number was highest during May-July, accounting for 45.33% (330/728). The incidence was high in summer and autumn, and the peak was in May. The conventional identification showed that two strains were all Brucella melitensis biovar 1, consistent with UTS-PCR amplification results. Six virulence genes were found in two isolated strains, suggesting that the Brucella melitensis strains in this study had strong virulence. MLVA results confirmed that two strains detected in Hunan had complete identical MLVA-16 genotype with strains isolated from goat and camel in Inner Mongolia Autonomous Region, indicating that there was molecular epidemiology relationship between these strains and the source of infection were originated from Inner Mongolia.@*Conclusions@#The epidemic of human brucellosis in Hunan is becoming serious, and disease has spread to general population and non-epidemic areas. Two Brucella melitensis strains detected in Hunan were originated from Inner Mongolia. The quarantine and inspection in animal transportation should be strengthened to prevent human outbreaks of brucellosis.
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Objective@#To establish a real-time fluorescence recombinase acid amplification (RAA) method for the detection of adenovirus type 3(HAdV-3)without extraction nucleic acid.@*Methods@#According to the conserved sequence of adenovirus type 3 gene, a pair of primers and a probe were designed, and a real-time fluorescence RAA without extracting nucleic acid was established and optimizing the condition of DNA-free extraction. The sensitivity of the method was analyzed by a series of dilution and the specificity of the method was evaluated by detecting the original samples of other respiratory viruses. The clinical samples of HAdV-3 were detected and compared with the traditional real-time fluorescence quantitative PCR method for nucleic acid extraction.@*Results@#The sensitivity of the real-time fluorescence RAA method was as high as that of qPCR in the detection of 10 series diluted HAdV-3 strains. The highest corresponding CT value of qPCR was 36.87. The sensitivity of the real-time fluorescence RAA method was similar to that of the real-time fluorescence quantitative PCR method . There was no cross-reaction to other common types of respiratory viruses. The two method were used to detect 56 clinical samples at the same time, and the result were completely consistent.@*Conclusions@#We provide the first report of the real-time fluorescent RAA assays for the detection of HAdV-3 without extracting nucleic acid and it has high sensitivity and specificity. Is suitable for rapid detection of HAdV-3 in clinical laboratories and on-site unite.
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Objective@#To understand the epidemiologic characteristics and pathogen spectrum of hand, foot and mouth disease (HFMD) in Hunan Province during 2008—2017 and provide the basis for the prevention and control strategy of hand, foot and mouth disease.@*Methods@#Collecting data from national disease reporting information system throughout 2008—2017, the descriptive epidemiological method were used to analyze the data of HFMD monitoring and the result of pathogenic agent detection.@*Results@#A total of 1, 255, 530 HFMD cases were reported throughout 2008—2017, including 10097 severe cases and 394 deaths. The average annual attack rate is 190.38/100, 000. The peak incidence of HFMD occurred in summer and fall. The reported incidence is on the rise. The number of critically ill and the number of deaths is declining. Proportion of male cases was higher than that of females. The majority of the children were those under 5 years of age. Enterovirus (EV)-A71, coxsackievirus (CV)-A16 and other other EV positive cases accounted for 33.29%, 20.04% and 46.67% of laboratory diagnosed cases.@*Conclusions@#The epidemic of hand, foot and mouth disease in Hunan has obvious seasonal and population characteristics. There are different dominant pathogens causing HFMD in different years.
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Objective@#To make etiological diagnosis and evaluate the protective effects of post-exposure prophylaxis(PEP) in an event of one dog injured seven persons.@*Methods@#Direct immunofluorescence assay (DFA) and nested polymerase chain reaction (PCR) were employed to detect nucleoprotein and nucleoprotein(N) gene of rabies virus in the brain tissues of the dog, the positive samples were sequenced for the full length of N gene of rabies virus, then the homology of the N gene of rabies virus was analyzed after the phylogenetic tree was constructed. Rapid fluorescent focus inhibition test (RFFIT) was applied to detect the rabies virus neutralizing antibodies(RVNA) on day 0, 14 and 40 after PEP.@*Results@#The cerebral, cerebellar and hippocampal tissues were positive by DFA and nested PCR. The phylogenetic tree indicated the rabies virus belonged to the rabies virus genotype I. The homology of the nucleotide and amino acid of the rabies virus N gene were over 86% with the vaccine strains. The titer of the RVNA increased significantly from the day 0 to day 14 after PEP, the lowest was 5.78 IU/ml and the highest was 26.15 IU/ml. On the day 40, the highest RVNA titer was 51.96 IU/ml. No rabies cases occurred in a one year follow-up visit.@*Conclusions@#Normative PEP can effectively prevent the occurrence of rabies cases.
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Objective To analyze the conding region of hantanvirus S gene and predict the structure of nucleoprotein for diagnostic antigen study.Methods RT-PCR was used to amplify the S gene of hantanvirus Hunan03 strain after designing specific primers.The amplification product was cloned into pGM-T vector and then the recombinant vector was transformed into E.coli TOP10,gene sequencing was carried out after blue-white selection and PCR screening for positive clones.The database of NCBI and Swiss-Prot/TrEMBL were used to predict and analyze the structure,biological characteristics and protein structures of S gene.Results The amplification product was about 1290 bp,the pGM-T/S vector was constructed and successfully sequenced,the whole length of the open reading frame (ORF) was composed of 1290 nucleotide residues,among them the GC content was 44.11％ and the AT content was 55.89％,it was composed of 429 amino acids (20 kinds),the accession number of the sequence submitted to GenBank was JN712306,its homology of nucleotides to the 76-118 strain was 83％ and the homology of amino acids was 98％,ten nonspecific variation sites were found.The grand average of hydropathicity was-0.405.There were three transmembrane domains and four non transmembrane domains in the secondary structure of nucleoprotein including 55％ of helix structure,6.1％ of sheet structure and 38.9％ of loop structure.Conclusion The bioinformatics analysis of Hunan03 strain S gene might be important for provide the substructure data to reveal the significance of S gene characteristics on hemorrhagic fever renal syndrome (HFRS) prevention and control.