中华微生物学和免疫学杂志最新文献

{"title":"Serum antibodies against norovirus GI.1 and GII.4 in populations in central and eastern China","authors":"Han Zibo, Yun-Jung Kang, Lei Zehua, R. Yuan, Zhenni Wei, S. Shen, Zhen-lu Sun, T. Fang, J. Hou, Lifang Du, Jing Zhang, Qiming Li","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.11.006","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.11.006","url":null,"abstract":"Objective \u0000To detect norovirus (NoV) GⅠ.1- and GⅡ.4-specific IgG, IgA and histo-blood group antigen (HBGA)-blocking antibodies in healthy populations of all age groups in China for better understanding the epidemiological features of norovirus in China from a serological point of view and providing basic data for vaccine development and clinical trial design. \u0000 \u0000 \u0000Methods \u0000Indirect ELISA and HBGA-blocking assay were used to detect NoV-specific IgG, IgA and HBGA-blocking antibodies in serum samples collected from healthy natural populations (n=839, aged from six months to 88 years old) in Guangzhou, Fuyang and Yantai. The results were statistically analyzed. \u0000 \u0000 \u0000Results \u0000The total positive rates of NoV GⅠ.1- and GⅡ.4-specific IgG antibodies were 91.9% and 93.0%. The positive rates of GⅠ.1- and GⅡ.4-specific IgA antibodies were 48.6% and 75.6%, and the titers of HBGA-blocking antibodies to GⅠ.1 and GⅡ.4 norovirus were 5.04 (95%CI: 4.63-5.49) and 18.15 (95%CI: 16.11-20.44). The positive rates of IgG and IgA antibodies generally showed an increasing trend with age. The positive rates of GⅠ.1- and GⅡ.4-specific IgG antibodies ranged from 79.2% to 100.0% and 76.7% to 100.0% in different age groups. They were 81.7% and 85.0% in the age group of 0.5-<1 year, 79.2% and 76.7% in the age group of 1-<2 years, and 98.1% and 96.3% in the age group of 12-<18 years, and maintained at 96% and 98% in the older age groups. The positive rates of GⅠ.1-specific IgA antibody ranged from 11.7% to 93.8% in different age groups and rapidly increased with age. It was 11.7% in the age group of 0.5-<1 year, and reached 93.3% in people aged 45-<60 years and 93.8% in people aged ≥60 years. The positive rates of GⅡ.4-specific IgA antibody ranged from 50.8% to 88.8% in different age groups with 50.8% in people aged 0.5-<1 year, and 86.7%-90.7% in people aged 12-<18 years and older. The titer of GⅠ.1 HBGA-blocking antibody generally increased with age. The antibody titer in populations aged 0.5-<12 years old was lower than that in those aged 18 years and above (GMT: 2.98-4.07 vs 8.21-11.62, P<0.001), and the titer in people of 12-<18 years old was lower than that in those of 45 years old and above (GMT: 5.21 vs 11.03-11.62, P<0.05). No obvious change with age was observed in the titer of GⅡ.4 HBGA-blocking antibody excepting the significant difference between populations of 2-<5 and 22-<45 years old (GMT: 26.73 vs 11.87, P<0.01). \u0000 \u0000 \u0000Conclusions \u0000This study revealed the characteristics of serum NoV GⅠ.1- and GⅡ.4-specific IgG, IgA and HBGA blocking antibodies in populations of different age groups in central and eastern China through analyzing their positive rates and titers and provided preliminary seroepidemiological data for the development of NoV vaccines in China. \u0000 \u0000 \u0000Key words: \u0000Norovirus; Serum antibody; Receptor-blocking assay","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"840-847"},"PeriodicalIF":0.0,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44106525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of the amount of TPCK trypsin adding to MDCK cell suspension for culturing H7N9 avian influenza virus","authors":"Z. Meng, Jiayou Zhang, Chen Liu, Zhegang Zhang, Ran Qiu, D. Luo, Jinrong Shi, Wei Zhao, Z. Xia, Xiaoming Yang","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.11.005","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.11.005","url":null,"abstract":"Objective \u0000To investigate the best amount of TPCK trypsin in Madin Darby canine kidney (MDCK) cell suspension for the culture of H7N9 avian influenza virus. \u0000 \u0000 \u0000Methods \u0000Different concentrations of TPCK trypsin were added during the periods of cell growth and virus production. Their effects on cell growth, viability, glucose and lactate metabolism, and hemagglutination titer were monitored every 12 h. Inter-batch differences were analyzed. The amount of trypsin added in the cell growth phase was 0, 1 μg/ml, 2 μg/ml, 4 μg/ml, 6 μg/ml, 8 μg/ml, 10 μg/ml and 15 μg/ml. The amount of trypsin added during the virus production period was 0, 0.5 μg/ml, 1 μg/ml, 1.5 μg/ml, 2 μg/ml and 2.5 μg/ml. When the hemagglutination titers were same, the adding amount was further optimized at different multiplicity of infection (MOI) of 0.001, 0.005, 0.025 and 0.05. \u0000 \u0000 \u0000Results \u0000No significant linear effects of TPCK trypsin concentration on cell number, viability, and glucose and lactate metabolism were observed. No toxicity to cell growth was observed when TPCK trypsin concentration reached 15 μg/ml. After the inoculation of H7N9 avian influenza virus, the hemagglutination titers in the 1 μg/ml, 1.5 μg/ml, 2 μg/ml and 2.5 μg/ml TPCK trypsin groups reached the peaks at 48 h, which were 1∶26.5. At 60 h, the hemagglutination titers of the latter two groups decreased faster than those of the former two groups. When the MOI was 0.005, the hemagglutination titer of the 1.5 μg/ml group at 48 h was 26.5 higher than 26 in the 1 μg/ml group under the same condition. There were differences between different batches of TPCK trypsin. \u0000 \u0000 \u0000Conclusions \u0000Adding 1 μg/ml and 1.5 μg/ml of trypsin could better promote the proliferation of H7N9 avian influenza virus, and 1.5 μg/ml of trypsin had a wider range of MOI applicability. \u0000 \u0000 \u0000Key words: \u0000MDCK cells; H7N9; Avain influenza virus; TPCK trypsin; Optimization study","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"835-839"},"PeriodicalIF":0.0,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42291273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction, characterization and stability analysis of infectious clone of live attenuated dengue virus type 4 Ban18HK20 strain","authors":"Enyue Fang, Ling Wang, Danhua Zhao, Ming Li, Ming-liang Liu, Yuhua Li","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.11.004","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.11.004","url":null,"abstract":"Objective \u0000To construct a stable infectious clone of live attenuated dengue virus (DENV) type 4 Ban18HK20 strain for better understanding the virulence determinants of DENV and improving the development of chimeric vaccines. \u0000 \u0000 \u0000Methods \u0000Specific primers were constructed according to the genome of Ban18HK20 strain and used to subclone six cDNA fragments, which were linked into a high-copy plasmid pSPTM to obtain a stable full-length cDNA clone of DENV. RNA was transcribed from the full-length cDNA in vitro and electrotransfected into Vero cells to recover the virus. Biological characteristics of the recovered virus were identified using plaque assay, indirect immunofluorescence assay, growth kinetics test and pathogenicity study in mouse brain. Genetic stability of the virus passaged 15 generations was studied using RT-PCR amplification. \u0000 \u0000 \u0000Results \u0000Restriction enzyme digestion and sequencing analysis indicated that the infectious clone was constructed successfully. The recovered virus was consistent with the parental virus in terms of plaque morphology, DENV E protein expression, growth characteristics and pathogenicity in mouse brain. Sequencing analysis showed that the recovered virus had the same genome sequence as the parental virus with good hereditary stability. \u0000 \u0000 \u0000Conclusions \u0000A stable infection clone of Ban18HK20 was constructed and a reverse genetics technology platform for DENV research was established. \u0000 \u0000 \u0000Key words: \u0000Dengue virus; Reverse genetics; Infectious clone; Virus recovery","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"827-834"},"PeriodicalIF":0.0,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46505706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic analysis of antibodies induced by leptospiral vaccines","authors":"Ying Zhang, Yinghua Xu, Xiangyin Liu, Jinlong Zhang, Zhi-bin Chen, Guo-zhu Wang, Xiao-fang Xin, M. Zeng","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.11.009","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.11.009","url":null,"abstract":"Objective \u0000To investigate the dynamic changes of antibodies induced by leptospiral vaccines. \u0000 \u0000 \u0000Methods \u0000Antigens for antibody detection were screened out. ELISA was used to analyze antibody responses induced at different time points after immunizing guinea pigs with different batches of leptospiral vaccines from different manufacturers. To investigate the relationship between antibody responses induced by leptospiral vaccines and their protective effects in animal model, guinea pigs were challenged with Leptospira after immunization. \u0000 \u0000 \u0000Results \u0000There was no significant antigen-antibody reaction between the LigA protein or Patoc Ⅰ antigen and the serum samples of guinea pigs immunized with leptospiral vaccines. Notable IgG and IgM antibody reactions were observed in all vaccination groups when using bacterial proteins from seven Leptospira reference strains which were used for the preparation of leptospiral vaccines as envelope antigens. Antigen-specific IgG antibodies peaked at 35 d after the last immunization, and the highest peak of antigen-specific IgM antibodies was reached 11 d after the last immunization. Results of the challenge test showed that non-diluted leptospiral vaccines induced significant IgG and IgM antibody reactions in guinea pigs as compared with those diluted three or nine times, showing good protective effects. \u0000 \u0000 \u0000Conclusions \u0000Analysis of the dynamic changes of antibodies induced by leptospiral vaccines revealed that there was correlation between the induced serum antibody responses and the protective effects. This study provided reference for further study on alternative methods for evaluating leptospiral vaccine potency. \u0000 \u0000 \u0000Key words: \u0000Leptospira; Vaccine; Antibody; Protection","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"864-868"},"PeriodicalIF":0.0,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45967889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of lncRNA-mtb in Mycobacterium tuberculosis-infected macrophages","authors":"Jiang Zichao, Hu Zhidong, Luo Wei, Wang Qian","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.11.007","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.11.007","url":null,"abstract":"Objective \u0000To study the mechanism of lncRNA-mtb in Mycobacterium tuberculosis (M.tuberculosis)-infected macrophages. \u0000 \u0000 \u0000Methods \u0000A predicting software and Western blot assay were used to verify the non-coding nature of lncRNA-mtb. RT-qPCR was performed to detect lncRNA-mtb expression in macrophages infected by different Mycobacteria. Cytokine secretion was detected with ELISA after silencing the expression of lncRNA-mtb in macrophages with RNA interference (RNAi) technology. Western blot and RT-qPCR were performed to analyze whether the activation of macrophage inflammation could be induced by lncRNA-mtb during M. tuberculosis infection. Effects of lncRNA-mtb silencing on the bactericidal activity of M. tuberculosis-infected macrophages were evaluated. \u0000 \u0000 \u0000Results \u0000Increased expression of lncRNA-mtb was observed in macrophages infected with M. tuberculosis H37Rv or H37Ra. After silencing the expression of lncRNA-mtb, IL-1β secretion in H37Rv infected-macrophages was significantly decreased. Further studies revealed that lncRNA-mtb might be involved in the activation of NLRP3 in M. tuberculosis-infected macrophages. The bactericidal activity of macrophages against H37Ra was impaired after silencing the expression of lncRNA-mtb. \u0000 \u0000 \u0000Conclusions \u0000Enhanced expression of lncRNA-mtb could be induced in macrophages infected with H37Rv or H37Ra. Moreover, lncRNA-mtb was involved in M. tuberculosis-induced inflammation in cells. Silencing lncRNA-mtb wolud attenuate the ability of macrophages to clear M. tuberculosis. \u0000 \u0000 \u0000Key words: \u0000Mycobacterium tuberculosis; lncRNA-mtb; Macrophage; Inflammation","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"848-855"},"PeriodicalIF":0.0,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47631438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure and biological functions of Helicobacter pylori lipopolysaccharide","authors":"Tiankuo Yang, Xiaoqiong Tang, Yalin Shen, Hong Tang","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.11.012","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.11.012","url":null,"abstract":"Helicobacter pylori (H.pylori) infection is one of the most common chronic infectious diseases in humans. It is the leading cause of chronic gastritis and peptic ulcer, and also the most important risk factor for gastric cancer. H. pylori lipopolysaccharide has unique chemical structures that are critical to the persistent infection and pathogenesis of H. pylori in human gastric mucosa. Recent studies have elucidated the H. pylori lipid A constitutive modification pathway, redefined the core-oligosaccharide and O-antigen domains, discovered that the heptan commonly present in the lipopolysaccharide structure of European strains is absent in East Asian strains and more importantly, the identification of ADP-heptose (the donor of heptose residues in lipopolysaccharide structure) as the newly discovered pathogen-associated molecular pattern, which is dependent on the type Ⅳ secretion system of H. pylori to induce inflammatory responses in host cells. This paper reviewed the resent research progress in the structure and biological functions of H. pylori lipopolysaccharide. \u0000 \u0000 \u0000Key words: \u0000Helicobacter pylori; Lipopolysaccharide; Heptose; ADP-heptose","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"880-884"},"PeriodicalIF":0.0,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48477638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishment of a multiplex PCR for rapid identification of Mycobacterium species","authors":"S. Yin, Chenqi Yan, Zhi-guang Liu, Xiuqin Zhao, Xiaoqin Li, Machao Li, Hai-can Liu, Y. Lou, K. Wan","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.10.008","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.10.008","url":null,"abstract":"Objective \u0000To establish and evaluate a multiplex PCR method for rapid identification of Mycobacterium species in order to provide an approach for rapid diagnosis of pathogens causing tuberculosis. \u0000 \u0000 \u0000Methods \u0000Four genes including 16S rRNA, Rv0577, RD9 and mtbk_20680 were selected to establish the multiplex PCR method. Specific primers were designed and the reaction system and conditions were optimized. The sensitivity and specificity of the multiplex PCR method were evaluated through identifying Mycobacterium africanum (M.africanum), Mycobacterium bovis (M.bovis), M. bovis BCG, seven common non-tuberculosis Mycobacterium (NTM), seven reference species of common respiratory bacteria and 93 clinical strains of Mycobacterium tuberculosis (MTB) isolated from patients with tuberculosis in Gansu Province of China. \u0000 \u0000 \u0000Results \u0000The fragments of 16S rRNA, Rv0577, RD9 and mtbk_20680 genes were 543 bp, 786 bp, 369 bp and 231 bp in length, respectively. MTB strains of the Beijing genotype were positive for all of the four genes, while the non-Beijing genotype strains were negative for mtbk_20680. M. africanum, M. bovis and M. bovis BCG strains were negative for 16S rRNA and Rv0577. NTM strains only carried 16S rRNA and none of four genes were detected in the seven species of respiratory bacteria. Among the 93 clinical MTB strains, 80 (86.02%) belonged to the Beijing genotype and the other 13 (13.98%) were non-Beijing genotype strains. The specificity of the multiplex PCR method was 100%. \u0000 \u0000 \u0000Conclusions \u0000The established multiplex PCR method could accurately distinguish Mycobacterium, Mycobacterium tuberculosis complex (MTBC), NTM, MTB, and Beijing and non-Beijing genotype MTB with high sensitivity and specificity. \u0000 \u0000 \u0000Key words: \u0000Multiplex PCR; Mycobacterium; Mycobacterium tuberculosis; Beijing genotype","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"771-777"},"PeriodicalIF":0.0,"publicationDate":"2019-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49366824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of mesenchymal stem-like cells in cerebral cortex of normal rats","authors":"Jun‐ting Chen, Shuang Liu, Jia Zhang, Xiaoyan Wang, Wei Wei","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.10.009","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.10.009","url":null,"abstract":"Objective \u0000To investigate whether the cells with the characteristic of mesenchymal stem cells (MSCs) could be found in rat cerebral cortex. \u0000 \u0000 \u0000Methods \u0000Rat cerebral cortex samples were digested with typeⅡ collagenase into single cells. Culture medium for MSCs was used for cell culture. The morphology of the cells was observed under a microscope. MSC-specific surface markers were detected by flow cytometry. Differentiation potential favoring adipogenesis or osteogenesis of the subcultured cells was analyzed. Lymphocyte transformation test (LTT) was performed to analyze their immunosuppressive function. Bone marrow MSCs (BM-MSCs) were used as positive control cells in all experiments. \u0000 \u0000 \u0000Results \u0000The fibroblast-like cells isolated from the cerebral cortex of rats were morphologically heomeogeneous after cell culture and grew in a spiral pattern. On the surface of these cells, CD29, CD90 and CD146 were highly expressed at mRNA level, while the expression of CD45 and CD31 at mRNA level were not detected. Moreover, they could be induced to differentiate into adipocytes and osteoblasts. Results of LTT showed that they were functionally equivalent to BM-MSCs in inhibiting the proliferation of spleen lymphocytes induced by concanavalin A. \u0000 \u0000 \u0000Conclusions \u0000This study suggested that the cells with the characteristic of MSCs could be detected in rat cerebral cortex. \u0000 \u0000 \u0000Key words: \u0000Cerebral cortex; Mesenchymal stem cell; Lymphocyte transformation test","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"778-783"},"PeriodicalIF":0.0,"publicationDate":"2019-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46073206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contamination status and characteristics of food-borne pathogenic bacteria in retail meat products in Taiyuan","authors":"Wenyan Qin, Jing Wang, Suxia Yao, Yang Wang, Jiting Han, Hongxia Yang, Xuebin Xu","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.10.002","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.10.002","url":null,"abstract":"Objective \u0000To investigate the contamination status of Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus and bacterial resistance in retail meat products in Taiyuan, Shanxi Province. \u0000 \u0000 \u0000Methods \u0000In the epidemic season of diarrhea in 2017, poultry and meat product specimens were randomly collected from the farmer′s markets and supermarkets of 10 districts and counties of Taiyuan. Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus were isolated form these specimens. Serotypes of Salmonella strains were analyzed. ELSIA was used to detect Staphylococcus aureus enterotoxin (A-E). Vibrio parahaemolyticus isolates were tested for the virulence genes encoding direct hemolysin (tdh) and indirect hemolysin (trh). Antibiotic resistance of the three food-borne pathogens were analyzed using microdilution methods. \u0000 \u0000 \u0000Results \u0000A total of 38 food-borne pathogens were isolated from 123 poultry and livestock meat product specimens with a positive rate of 30.9%, of which mainly were Salmonella (26 strains, 21.1%), followed by Vibrio parahaemolyticus (8 strains, 6.5%) and Staphylococcus aureus (4 strains, 3.3%). The 26 strains of Salmonella belonged to 10 serotypes. The Salmonella strains isolated from pork specimens had diverse serotypes. Salmonella serovar Derby, Salmonella serovar Gold-coast and Salmonella serovar Liverpool were isolated from raw and cooked pork food for the first time in Taiyuan. All Salmonella strains isolated form chicken products were Salmonella enteritis. The enterotoxin types of the four Staphylococcus aureus strains were three E-type and one complex type (A/E). All Vibrio parahaemolyticus isolates were negative for tdh or trh gene. Ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracyclines (ACSSuT) resistance was prevalent in multi-drug resistant (MDR) Salmonella strains, but there was high sensitivity to fluoroquinolones and cephalosporins. MDR Staphylococcus aureus accounted for 75%. No third-generation cephalosporin- or fluoroquinolone-resistant or MDR Vibrio parahaemolyticus strains were isolated. \u0000 \u0000 \u0000Conclusions \u0000There were food-borne multi-pathogenic bacteria contamination in retail raw and cooked meat products in Taiyuan. Salmonella strains had diverse serotypes and high MDR rate. It was suggested that the regulatory authorities should strengthen the management of antibiotic use in aquaculture and specialized laboratory-based monitoring of meat supply chain. \u0000 \u0000 \u0000Key words: \u0000Meat products; Food-borne pathogenic bacteria; Contamination; Multi-drug resistance","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"731-736"},"PeriodicalIF":0.0,"publicationDate":"2019-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44786995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro growth characteristics of Cryptococcus gattii VGI/VGII and their virulence diversity to Galleria mellonella","authors":"Chen Yang, Liangli Jin, Lifeng Wang, Xinying Xue, D. Shen","doi":"10.3760/CMA.J.ISSN.0254-5101.2019.10.001","DOIUrl":"https://doi.org/10.3760/CMA.J.ISSN.0254-5101.2019.10.001","url":null,"abstract":"Objective \u0000To understand the in vitro growth characteristics of Cryptococcus gattii VGⅠ and VGⅡ isolated in China and the diversity in their virulence to Galleria mellonella. \u0000 \u0000 \u0000Methods \u0000Based on the results of multilocus sequence typing for eight strains of Cryptococcus gattii isolated in China, the strains were cultured in vitro to draw growth curves, observe the melanin production and measure the capsule thickness. The median lethal time (LT50) and median lethal dose (LC50) at 48 h of Cryptococcus gattii were calculated using Galleria mellonella infection test. Fourteen strains of Cryptococcus neoformans were studied for comparison. \u0000 \u0000 \u0000Results \u0000The eight Cryptococcus gattii strains were six VGⅠ and two VGⅡ. The growth curves of Cryptococcus gattii VGⅠ and VGⅡ were similar to that of Cryptococcus neoformans when culture at 30℃. The total number for each of them could reach 108 CFU/ml at 96 h under 30℃. However, the total number at any time point at 37℃ was less than that at 30℃. There was no significant difference in the amount of melanin produced by Cryptococcus neoformans under 30℃ and 37℃, but both VGⅠand VGⅡ types of Cryptococcus gattii could produce more amount of melanin under 37℃ than under 30℃. The ratio of capsule/cell wall diameter of Cryptococcus gattii VGⅠwas greater at 37℃ than that at 30℃ with statistical significance (P<0.001). Cryptococcus neoformans showed the longest LT50, followed by VGⅠand VGⅡ types of Cryptococcus gattii. The LT50 of Cryptococcus gattii VGⅡ at the concentration of 1×106 CFU/ml was 72 h, and its LC50 at 48 h was 1×108 CFU/ml. \u0000 \u0000 \u0000Conclusions \u0000Like Cryptococcus neoformans, Cryptococcus gattii VGⅠ and VGⅡ grew faster under 30℃ than under 37℃, but more melanin was produced and thicker capsule was formed under 37℃ than under 30℃. Among Cryptococcus neoformans and VGⅠ and VGⅡ types of Cryptococcus gattii, Cryptococcus gattii VGⅡ showed the shortest LT50 and the strongest virulence to Galleria mellonella. \u0000 \u0000 \u0000Key words: \u0000Cryptococcus gattii; Molecular type; Growth characteristics; Galleria mellonella; Virulence","PeriodicalId":10089,"journal":{"name":"Chinese journal of microbiology and immunology","volume":"39 1","pages":"725-730"},"PeriodicalIF":0.0,"publicationDate":"2019-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45518274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}