Genetic source tracking of an anthrax outbreak in Shaanxi province, China.

Background: Anthrax is an acute zoonotic infectious disease caused by the bacterium known as Bacillus anthracis. From 26 July to 8 August 2015, an outbreak with 20 suspected cutaneous anthrax cases was reported in Ganquan County, Shaanxi province in China. The genetic source tracking analysis of the anthrax outbreak was performed by molecular epidemiological methods in this study.

Optimization of Pulsed-field Gel Electrophoresis Procedure for Bacillus cereus.

In order to develop a rapid and reliable method for B. cereus genotyping, factors influencing PFGE results, including preparation of bacterial cells embedded in agarose, lysis of embedded cells, enzymatic digestion of intact genomic DNA, and electrophoresis parameters allowing for reproducible and meaningful DNA fragment separation, were controlled. Optimal cellular growth (Luria-Bertani agar plates for 12-18 h) and lysis conditions (4 h incubation with 500 µg/mL lysozyme) produced sharp bands on the gel.

[Study on the single nucleotide polymorphism in capsule plasmid gene of Bacillus anthracis in the China isolates].

Objective: To study the characteristic of single nucleotide polymorphism (SNP) in capsule plasmid gene of Bacillus anthracis isolated from China.

Methods: 95 Bacillus anthracis isolates from different sources were selected. 23 SNP sites were amplified by PCR method, sequenced and analyzed by clustering analysis.

[Study on the identification characteristics of rRNA genes on Yersinia pestis].

Objective: To study the identification characteristics of rRNA genes on Yersinia (Y.) pestis.

Methods: By means of comparative genomics, we compared the rRNA genome sequences of nine completely sequenced strains of Y.

[Study on the application and evaluation of methods for gene and antigen detection in plague surveillance program].

Objective: To apply and evaluate new methods regarding specific gene and antigen detection in plague surveillance program.

Methods: 1798 samples from natural foci of plague were tested, using internal quality control multiple-polymerase chain reaction, F1 antigen marked by immuno chromatographic assay and enzyme linked immunosorbent assay. Culture of Yersinia pestis and reverse indirect hemagglutination assay were used as reference diagnostic methods.

[Use of variable-number tandem repeats to examine genetic diversity of Bacillus anthracis].

Objective: To study the genotyping of Bacillus anthracis based on multiple-locus variable-number tandem repeats(VNTR) in the B. anthracis genome.

Methods: We selected 13 VNTR loci (which cited from published articles) to study 88 strains of B.

[Surveillance on severe acute respiratory syndrome associated coronavirus in animals at a live animal market of Guangzhou in 2004].

Objective: To study the prevalence of severe acute respiratory syndrome coronavirus (SARS-CoV) like virus in animals at a live animal market of Guanzhou in 2004 before and after culling of wild animal action taken by the local authority, in order to predict the re-emerging of SARS from animal originals in this region.

Methods: Animals at live animal market were sampled for rectal and throat swabs in triplicate. A single step realtime reverse transcription-polymerase chain reaction (RT-PCR) diagnostic kit was performed for screening SARS-CoV like virus, the manual nested RT- PCR and DNA sequencing were performed for confirmation.

[Study on the internal control on polymerase chain reaction in Yersinia pestis detection].

Objective: For the detection of Yersinia pestis by polymerase chain reaction (PCR), internal control (IC) is required in order to prevent false negative results that might be caused by PCR inhibitors.

Methods: F1 antigen was amplified by PCR with primer F1 and the PCR product of primer F1 were cloned with TOPO TA cloning Kit. The plasmid of positive clone was then digested with HpaI.

[Study on the relation between the absence of one IS100 in 102 kb pgm locus of Yersinia pestis and the stability of pigmentation phenotype].

Objective: To study the relation between the absence of one IS100 in the 102 kb pgm locus of Yersinia pestis and the stability of pigmentation phenotype (pgm(+)).

Methods: We amplified the segment including IS100 in 102 kb pgm locus of Yersinia pestis that isolated from all ecotypes in China by polymerase chain reaction (PCR). There were 171 strains isolated from 18 ecotypes in this study.

[Molecular biological characteristics and genetic significance of Yersinia pestis in China].

Objective: To understand the molecular biological characteristics in order to analyse the genetic background of Yersinia pestis in China.

Methods: Primary datum on ribotyping, pulsed field gene electrophoresis (PFGE), random amplified polymorphic DNA (RAPD) and insertion sequence (IS) of Yersinia pestis were used and under cluster analysis. Genetic interval and various methods of recognized molecular feature between different strains were evaluated.

[Genetic analysis of Yersinia pestis strains isolated in China].

Objective: The strains of Yersinia pestis isolated in different period and different natural foci in China were analyzed.

Methods: Traditional and molecular biological methods were used. Rhamnose fermentation, rRNA gene copy number, nitrite reduction, and the glycerol fermentation were important characters for typing, and pulse field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) profile could reflect the genetic distance between the strains.