Objective Clone and mutagenesis analysis of nhaA gene in Vibrio cholerae O1 and O139. Methods 40 strains of Vibrio cholerae O1 and O139 were collected. A full length nhaA gene fragment was amplified with PCR and cloned into plasmid vector pcDNA3. Homology and mutagenesis of nhaA gene in Vibrio cholerae O1 and O139 were analyzed after sequencing the nhaA gene. Results nhaA gene of Vibrio cholerae O1 and O139 were successfully amplified and cloned. Sequence analysis manifested that nhaA gene of Vibrio cholerae O1 and O139 in China share a high homology with reference sequence of wide-type Vibrio cholerae O1 in GENEBANK(99% and 96% respectively). The amino acid mutagenesis rates of nhaA gene in Vibrio cholerae O1 and O139 were 2% and 11% respectively. The important residues(Asp133,Asp163,Asp164,His225,Leu73 and Gly338 )had no mutation. But in residues 203 and 221 of nhaA gene Vibrio cholerae O1 and O139 had common mutation. Conclusions Mutagenesis of nhaA gene and NhaA protein may be the result of Vibrio cholerae adaptation to survival environment.

Objective To investigate the pathogens inducing a posto perative nosocomial infection. Methods Specimens was collected fro m exudates or air for bacteria culture and identification. Re sults The postoperative infection was induced by staphylococcus x ylosus. Conclusions The relevant factors affecting the po stoperative nosocomial infection include incomplete sterilization of operative r oom and operative tools. Thus strict control measures must be put into effect.

Objective:To study the possibility of dengue virus E gene vaccine.Methods:The recombinant eukaryotic expression plasmid pcDNA3 E was first transfected into NIH3T3 cells by lipofectin SDS PAGE and Western blotting analyzed the expression of E gene Then the recombinant plasmid was intramuscularly injected to BALB/c mice,and the specific humoral and cellular immunity were tested Results:The recombinant plasmid DNA could induce specific immune reactions and the immune response could last a long time Conclusion:The dengue virus E gene vaccine could induce specific immune reaction,which might have provided some material and new experimential data for the further study of dengue vaccines