Antibiotic resistance, serotype and molecular typing of Listeria monocytogenes from foods in Shandong Province from 2013 to 2016 / 中华疾病控制杂志

Objective To understand the main serotypes, antibiotic resistance profiles and molecular typing characteristics of Listeria monocytogenes（LM) isolated from foods in Shandong Province from 2013 to 2016. Methods The antibiotic sensitivity of LM was tested by broth microdilution method. The serotypes were determined by slide agglutination and PCR, and the molecular typing was carried out by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing(MLST) . Results Most of 191 LM strains were sensitive to the eight antibiotics tested. Tetracycline resistance was most prevalent (15/191, 7.85%). There was no significant difference in the 8 antibiotic resistance monitored for 4 years (P=1.000). The serotype 1/2a, 1/2b and 1/2c accounted for 38.82% (66/170), 18.82% (32/170), and 42.36% (72/170), respectively. The patterns of SDSRZXDZ016, S2014L031 and SDSRZX030, totally accounted for 33.78%, were the dominant types. The main ST types were ST9, ST8 and ST121, which accounted for 81.18% (69/85). The clinical common types, ST3, ST7 and ST87 accounted for 8.23% (7/85), mainwhile new ST type was not found. Conclusion The LM strains isolated in Shandong Province from 2013 to 2016 were sensitive to most antibiotics, but some strains were resistant to tetracycline and erythromycin. The dominant serotypes were 1/2c and 1/2a. Serotype 4b, prone to outbreaks of listeriosis, was not found. The main PFGE types were SDSRZXDZ016, S2014L031 and SDSRZX030, which were continuously found from 2013 to 2016. The main ST types were ST8, ST9 and ST121. The clinical types, ST3, ST7 and ST87 were isolated from food and should be paid seriously attention to.

Etiology and epidemiological characteristics of gastroenteritis virus in food-borne diarrhea from three cities in Shandong Province, 2017 / 中华预防医学杂志

To analyze the etiology and epidemiological characteristics of gastroenteritis virus in foodborne diseases from three cities in Shandong. From January to December 2017, six sentinel hospitals in Jinan, Yantai and Linyi city of Shandong Province were selected as the research sites. Stool samples of 1 397 diarrhea patients were collected, as well as basic information and clinical symptoms. Duplex quantitative RT-PCR was used to detect Norovirus genogroupⅠ (Nov GⅠ) and genogroupⅡ (Nov GⅡ), Sapovirus (SAV) and Human astrovirus (HAstV), respectively, quantitative RT-PCR was used to detect group A Rotavirus (RVA), and quantitative PCR was used to detect Enteric adenovirus (EAdV). The specific gene of the virus were sequenced and typed. It was compared that the gastroenteritis virus rate in cases with different characteristics and the clinical symptoms difference between the virus positive and negative cases. The median age ((25), (75)) was 23 (1, 42) , mainly male, 57.48% with 803 cased and children under 5 years old, 36.36% with 508 cases. The positive rate of gastroenteritis virus was 33.93% (474 cases), and that of Jinan, Linyi and Yantai City were 32.03% (147/459), 41.54% (189/455) and 28.57% (138/483), respectively (0.001). Nov GⅡ had the highest positive rate, 16.54% (231 cases), which, mainly GⅡ.P16/GⅡ.2 (48.28%, 56/116), peaked in May (24.75%, 50/202) and June (19.59%, 38/194). In patients of gastroenteritis virus positive, 44.51% (211/474) had vomiting symptoms, higher than that of patients of gastroenteritis virus negative (34.13%, 315/923). The difference was statistically significant (0.001). In Shandong Province, the majority of gastroenteritis patients were male and children under 5 years old. Nov GⅡ possessed highest epidemic intensity, and peaked in spring and summer. Viral gastroenteritis had atypical clinical symptoms.

Molecular typing and antibiotic resistance of Shigella isolated from 2011 to 2014 in Shandong Province / 中华疾病控制杂志

Objective To study the characteristics and epidemic trend of Shigella in Shandong province through the analysis of serotype, virulence genes, molecular typing and drug sensitivity. Methods The serotype was classified using the method of slide agglutination. Polymerase chain reaction (PCR) was used to amplify the related virulence genes. The molecular typing was carried out by pulsed field gel electrophoresis (PFGE), and the antibiotic sensitivity of the strains was determined by micro-broth dilution method. Results The main serogroups of 44 Shigella strains were Shigella flexneri (54.55%) and Shigella sonnei (43.18%). The carrying rates of ipaH, Set1, Sen and ial were 100%, 43.18%, 56.82% and 50.00%, respectively. By PFGE typing, the strains of Shigella flexneri were divided into 18 patterns with a low similarity. The strains of Shigella sonnei were divided into 14 patterns, and the similarity of 89.47% of the strains was more than 90%. 44 strains of Shigella had different levels of resistance to 14 of the 15 antibiotics. 93.18% of the strains were multidrug resistant. Conclusion The Shigella in Shandong province is dominated by serogroups of Shigella flexneri and Shigella sonnei, with high virulence gene carrying rate, clustering distribution and severe antibiotic resistance. It is necessary to strengthen the monitoring on serotype, traceability and antibiotic resistance of Shigella in Shandong province.

Expression of recombinant human cytomegalovirus fusion proteins pp150/MDBP fragments and its application / 生物工程学报

Human cytomegalovirus (HCMV) infection is an ubiquitous herpesvirus disease in human populations. It is rarely pathogenic to healthy adults, yet it may cause severe outcome to organ transplant recipients, the immunocompromised individuals and pregnant women. Using DNA from HCMV AD169 strain as template, the UL32 gene encoding pp150 protein fragment and the UL57 gene encoding MDBP protein fragment were amplified by PCR technique. After the construction of cloning vector pMD18-T-UL32, pMD18-T-UL57, pMD18-T-UL32/UL57 and expression vector pET-11a-UL32/UL57, the recombinant fusion proteins pp150/MDBP were induced with IPTG in BL21 host strain. The results showed that the relative molecular weight of recombinant fusion proteins pp150/MDBP is about 27 kD, the product of fusion proteins takes 17.45% in the total proteins in host bacteria, the analytical result was positive to the fusion proteins pp150/MDBP via Western blot technique, while the purified recombinant fusion proteins have strong antigenicity detected by ELISA and protein chip compared with whole virus antigens from HCMV. It was demonstrated that when used for the detection of serum from the clinical patients it has the same detection rate compared with the whole virus antigen. It needs further research for application.

Optimization of a Liquid Chip System for the Detection of Serum Biomarkers of Colorectal Cancer and Its Application / 中国生物工程杂志

Liquid chip technology have been licensed to be used in clinic because of its advantage of high-throughput, high-sensitivity, good signal to noise ratio, reaction in liquid phase, convenient operation and short time consuming, etc. The optimization of a liquid chip system for the detection of serum biomarkers of colorectal tumour and initial application in the detection of CEA were studied. The optimized reaction conditions of liquid chip were determined through orthogonal design after it was prepared. The results showed that the consuming reaction time of the coated antibody and the antigen was 1hour. The microspheres, biotinylated detecion antibody and the consuming complexes and avidin-PE time of the microspheres and the biotinylated tested antibody was 1hour, 1hour and 15minutes respectively.the consuming time of the complexes and avidin-PE was fifteen minutes, The optimized dilution of the biotinylated tested detection antibody was 1∶300 and the optimized concentration of avidin-PE was 12?g/ml. Totally 55 clinical samples were detected by the liquid chip and by Enzyme-Linked Immunosorbent Assay (ELISA) simultaneously and the results of the two methods were compared. The results of the two methods showed good correlation between positive and negative samples but the detection limits and the dynamic ranges of the liquid chip method were more sensitive and wider than those of the ELISA. The multiple tumour biomarkers may be detected simultaneously and the time of clinical test and manpower requirements were reduced by the liquid chip method.