Expression And Purification Of Brucella BvfA Protein And Analysis Of Clinical Characteristics Of Brucellosis

Part Ⅰ Prokaryotic expression and purification of Brucella BvfA proteinObjective: Through prokaryotic expression and induction and purification,the recombinant protein Brucella virulence factor A（BvfA）was prepared,which was convenient for further analysis of the crystal structure of BvfA protein,and exploring interaction of Brucella with the host and screening of antibodies.Methods: Search BvfA gene sequence in NCBI,design primers,amplify BvfA gene sequence and insert it into V29H（p ET30 a retrofit series）expression vector,V29 H contains maltose-binding protein（MBP）tag protein to promote crystallization.The recombinant plasmid was transformed into BL21（DE3）and Rosetta competent cells to induce its expression,and the protein was purified by affinity chromatography.The purified product was identified by SDS-PAGE.Results: The full-length sequence of BvfA gene was 336 bp.The molecular weight of BvfA protein was 11 k Da,and the MBP tag was about 42 k Da.MBP-BvfA protein was purifiedConclusion: Prokaryotic expression vector V29H-BvfA was constructed and MBP-BvfA protein was purified.Part Ⅱ Analysis of clinical characteristics of patients with brucellosisObjective: To retrospectively evaluate the epidemiological,clinical,and laboratory results of brucellosis patients in Anhui Province.Methods: The clinical data of 109 patients with brucellosis admitted to the First Affiliated Hospital of Anhui Medical University from January 2012 to March 2021 were collected from the electronic medical system of the hospital.The clinical data were grouped and compared according to presence or absence of bacteremic brucellosis and the three stages of brucellosis.Results: The most common symptoms in 109 patients with brucellosis were fever（89.0 %）,followed by chills（52.3 %）,arthralgia（48.6 %）and weight loss（30.3 %）.The laboratory examination results showed that anemia（65.1%）,C-reactive protein（CRP）（91.7 %）,erythrocyte sedimentation rate（ESR）（86.2%）,aspartate aminotransferase （AST）（40.4 %）,and lactate dehydrogenase（LDH）（43.1%）increased.The incidences of fever（96.1%）,arthralgia（58.8%）,anorexia（35.3%）,leukopenia（31.4%）and elevated AST（51.0%）in bacteremia group were higher than those in non-bacteremia group.In addition,the median LDH level in bacteremia group（332.0 mg / L,IQR,209.0-553.0）was higher than that in non-bacteremia group.However,the albumin level in bacteremia group（36.0 mg / L,IQR,33.9-38.2）was lower.The percentage of fever（94.9%）and the median LDH level（316.0 U / L（IQR,218.0 – 517.5））in acute phase were higher than percentage of fever（72.0%）and the median LDH level（209.0 U / L（IQR,162.0 – 276.0））in subacute phase.Conclusion: Brucellosis has become an important public health problem in Anhui Province and is a disease with diverse clinical manifestations.Our data show that fever of unknown origin,arthralgia,elevated AST and LDH should be considered as bacteremia of brucellosis for early administration.