Since the emergence in 1980s,community-associated methicillin-resistant Staphylococcus Aurues (CA-MRSA) has caught great attention of the researchers and clinical practitioners all over the world. In recent scientific papers,people found that CA-MRSA's capability to adapt itself to the hostile environment and to colonize is a kind of important virulence factor. A newly unveiled gene,designated arginine catabolic mobile element (ACME),in USA300 stains contributes much to this sort of ability. The arginine deiminase encoded by ACME plays an important role in colonization.

Leptospirosis is an important zoonosis with worldwide distribution. As the first procedure in immunity system, the role and significance of innate immunity in controlling infection at the early stage of the disease have gradually been emphasized. Macrophages can phagocytize and kill leptospira, while the pathogenic leptospira can evade the killing by macrophages. In addition, neutrophils, complement system and cytokines also contribute to the defence of leptospira infection.

Immune cells that undergo increased apoptosis include lymphocytes and macrophages,yet the apoptosis of neutrophils is decreased in sepsis.Increase in apoptosis has also been reported in non-immune cells such as gastrointestinal cells,epithelial cells of lung as well as endothelial cells.The altered apoptotic cell death may contribute to the initiation and aggravation of immune and organ dysfunction in sepsis.Elucidating the changes and mechanism of apoptosis and taking measures to control apoptosis may be an effective strategy for the treatment of sepsis.

Objective To explore the inhibition of fusing antimicrobial peptides humanβ-defensin 3 and carbohydrate binding do-main on Staphylococcus aureus N315 and Staphylococcus epidermidis 35984.Methods The direct bactericidal test and other molec-ular biology methods were adopted to detect the inhibition role on Staphylococcus aureus strain N315 and Staphylococcus epidermi-dis strain 35984 and the influence on the key genes expression.Results The direct bactericidal test demonstrated that antimicrobial peptides hBD3 and hBD3-CBD had significantly inhibitory effects on staphylococcus aureus N315 and staphylococcus epidermidis 35984;the inhibitory effects of hBD3-CBD was stronger than that of hBD3;the stability of the inhibitory effects of hBD3-CBD also stronger than that of hBD3.In the key gene expression test,there were significant inhibitions on the agr and mecA gene expressions in Staphylococcus aureus N315 and Staphylococcus epidermidis 35984 by hBD3-CBD.At the same time,hBD3-CBD could inhibit the icaA gene expression and promote icaR gene expression in Staphylococcus epidermidis 35984,which indicated that hBD3-CBD could inhibit the biofilm formation of Staphylococcus epidermidis.Conclusion The fusion strategy of antimicrobial peptide has very important significance for improving the antibacterial efficacy of antimicrobial peptides and brings more hope in their future applications.

Objective To investigate the mechanisms of phagocytosis of virulent Leptospira by peritoneal macrophages of guinea pigs,andevaluatetheroleof innateimmuneinthepathogenesisof leptospirosis. Methods Peritoneal macrophages of guinea pigs were extracted. Three specific inhibitors ( microfilament inhibitor cytochalasin D,microtube inhibitor colchicine and PI3K signalling pathway inhibitor LY294002) were added respectively to the macrophages 1 h before the infection of virulent Leptospira interrogans serovar Lai type strain Lai in vitro.Meanwhile, control group without inhibitor was established.Phagocytosis was observed by laser scanning confocal microscopy and phagocytic rates were evaluated by flow cytometry 3 h after infection.ResultsThe phagocytic rates of control group, cytochalasin D group, colchicine group and LY294002 group were (38.98 ± 0.91)%,(23. 99 ± 1. 40) % ,(40.81±0.91)% and (39.64 ±3.56) %, respectively.The phagocytic rate of cytochalasin D group was significantly lower than that of control group (P < 0. 05), while those of colchicine group and LY294002 group were not significantly different from that of control group (P >0.05). ConclusionMicrofilaments play an important role in the phagocytosis of strain Lai by peritoneal macrophages,but the process is independent on PI3K signalling pathway,and microtubes play little part during the phagocytosis.

Objective · To isolate phages which can fight against extended-spectrum β-lactamase (ESBLs)-producing Escherichia coli (E. coli), and provide basic research for establishment of E. coli phage library and treatment of bacterial infection. Methods · Samples collected from sewage were co-cultured with 93 ESBLs-producing E. coli strains. A phage named JDEC001 was isolated by double agar overlay plaque assay. The biological characteristics, complete genome sequence and comparative genome analyses of JDEC001 were studied respectively. Results · JDEC001 belongs to the lytic phage as a member of the Caudovirales order, Podoviridae family. It has high activity at pH from 5 to 11 and with temperature from 0 to 39 ℃ .Whole-genome sequencing of JDEC001 demonstrated double-stranded DNA genome of 38745 bp with GC content of 49.93%, which encoded 46 open reading frames. The comparative genomics also showed that there was no virulent genes or antibiotic resistant genes in its genome. Conclusion · The phage JDEC001 against ESBLs-producing E. coli was isolated and purified, with good stability in a broad range of pH and temperature.

Two highly conserved and with abundant quantity of lipoproteins in outer membrane of pathogenic species,but not in saprophytic species of leptospira ,LipL32 and LipL21,were selected to construct the fusion gene DNA vaccine pVAX1/LipL21-LipL32,and its ability to induce immune responses in BALB/c mice inoculated with this recombinant DNA vaccine was investigated in the present study.Expression of the fusion-protein LiPL21-LiPL32 was demonstrated in HEK293 cells following transfection with the fusion gene DNA vaccine and the immune responses induced after intramuscular inoculation with this DNA vaccine in BALB/c mice was then evaluated by microscopic agglutination test (MAT),meanwhile the ELISA assay was used to detect the cytokines induced.It was demonstrated that significant level of specific antibodies agglutinating antigens of Leptospira interrogans could be detected by MAT after DNA vaccine inoculation.The production of cytokines IL-10 and TNF-β in mice inoculated with DNA vaccine pVAX1/LipL21-LipL32 was significantly increased in comparison with that of the group inoculated with pVAX1 alone.These results indicate that the recombinant DNA vaccine pVAX1/LipL21-LipL32 may be of potential value to design and develop new generation of vaccines against leptospirosis.

Hemolysins of Leptospira interragans have been shown to be the virulence factor in the pathogenesis of leptospirosis and 10 potential hemolysin genes were charecterized by genomic annotation of L.interrogans serovar.Lai strain 56601. In the present study, the LA0202 gene supposed to encode one of the new potential hemolysin was cloned and the protein encoded was purified. The purified protein was shown to have highly hemolytic activity as demonstrated on the sheep blood agar plate. It was also confirmed that the LA0202 protein-mediated hemolysis on sheep erythrocytes was osmotically protected by PEG6000. Meanwhile, this protein could induce pore formation on sheep erythrocytes and cause damages on the membrane of human L-02 liver cells. In addition, it could induce apoptosis of human L-02 liver cells after treatment of cells with this protein for 24 hours. It is evident that LA0202 protein acting as a pore-formong hemolysin can induce cytotoxic damage on mammalian cells.

Objective To isolate bacteriophages against extensively-drug resistant Acinetobacter baumannii from hospital sewage and analyze their biological characteristics.Methods Extensively-drug resistant Acinetobacter baumannii isolated from several hospitals in Shanghai during December, 2013 to July, 2014 were used as host bacteria, adopting double-layer agar method to isolate bacteriophages from raw sewage of these hospitals.The phage with broad host range was selected for further study, including observation of electron microscopic morphology, examination of thermal stability, pH stability and the optimal MOI, drawing of the adsorption, one-step-growth and infection curves, as well as sequencing of the phage genome DNA. Results An extensively-drug resistant Acinetobacter baumannii bacteriophage vB_AbaP_PD-AB9 ( PD-AB9 for short) with broad host range was isolated, and electron microscopy revealed it belonged to Podoviridae family.The optimal MOI of PD-AB9 was 0.001.PD-AB9 remained stable among 4 ℃to 50 ℃and pH 4 to 11.In the adsorption experiment, the adsorption rate of PD-AB9 reached above 95%within 5 min.PD-AB9 had a latent period of 4 min and a burst size of 213.PD-AB9 could obviously restrain the host growth, with faster effect at the higher MOIs (MOI=1, 0.1, 0.01) than at the lower ones (MOI=0.001, 0.000 1).Furthermore, genome of PD-AB9 proved to be a double-stranded linear DNA with size of 40 938 bp and GC content of 39.34%.Conclusions PD-AB9 exhibits good thermal stability, wide pH tolerance range, very fast adsorption, a short latent period, a large burst size and it could quickly cause effective host lysis after infection.Therefore, PD-AB9 is promised to act as a new antimicrobial agent to control drug-resistant Acinetobacter baumannii infections and its bio information remains to be further studied.

Chongqing Medical University established respiratory system course group and implemented "organ-systems-based curriculum" (OSBC) integration teaching reform.OSBC teaching of respiratory system broke the traditional disciplinary-centred teaching pattern,adopted the disease-centred and clinicaloriented teaching curriculum.The course group carried on the comprehensive reorganization to the curriculum contents and the teaching personnel,compiled integrated teaching materials,optimized teaching methods and evaluation system.OSBC teaching of respiratory system has so far made some achievements,but the integration of different disciplines,the teaching ability of teachers and the students' coordination with OSBC courses still need to be further improved.