Establishment of a real-time fluorescent quantitative RT-PCR rapid detection method for human astrovirus / 中华微生物学和免疫学杂志

Objective:To establish a rapid detection method for human astrovirus based on TaqMan-probe real-time fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR).Methods:According to the conservative sequence of human astrovirus ORF1 b gene, we designed the amplification primers and specific fluorescent probe to establish the human astrovirus TaqMan real-time fluorescent quantitative RT-PCR rapid detection method. The specificity, sensitivity and stability of the method were evaluated. We also used this method to detect human astrovirus in clinical samples. Results:The established human astrovirus TaqMan real-time fluorescent quantitative RT-PCR detection method has good specificity and repeatability for human astrovirus, and the sensitivity can reach 10 2 copies/μl. After testing the clinical samples, the detection rate of human astrovirus by our method was 100%. Conclusions:The human astrovirus TaqMan real-time fluorescent quantitative RT-PCR detection method established in this study is simple, rapid, sensitive, specific and stable. It can be used for clinical human astrovirus detection and epidemiological investigation.

Pathogenic mechanisms of influenza virus and Staphylococcus aureus co-infection:research progress / 军事医学

Studies have shown that co-infection of influenza viruses with bacteria is an important cause of high mortality during the epidemic of influenza.There are at least 12 species of bacteria that have been reported to be able to co-infect with influenza.Among those species,co-infection with Staphylococcus aureus is not only the most common but also the most lethal.However,the pathogenesis of high mortality from co-infection with influenza virus/S.aureus remains elusive.In addition,co-infection of influenza virus/S.aureus can induce severe pneumonia.There is new evidence that influenza virus can reduce the host′s tolerance to pathogenic or inflammatory injury,and the two pathogens can also synergistically aggravate toxic effects on the host.Here,we review the mechanisms of severe mortality of influenza infection associated with S.aureus co-infections in order to contribute to prevention and control of influenza in the future.

Analogy of CRISPR-Cas systems to mammalian immune systems and research progress in their functions / 军事医学

The immune system of bacteria against phage shares a lot of similarity with that of mammals, especially the adaptive immune system.The elements and components of the bacterial adaptive immune system———clustered regularly interspaced short palindromic repeats ( CRISPR ) and the mammalian adaptive immune system have a lot of parallel mechanisms.We could acquire new understanding about the immune function of CRISPR systems through that analogy.In recent years, researchers have found CRISPR-Cas system can play significant roles in regulating bacterial growth and metabolism.These researches have revealed new functions of CRISPR beyond immunity.The ability of CRISPR to affect gene expression has attracted increasing attention.Further studies are needed to shed light on the complicated functions of CRISPR.

Biological characteristics and sequence typing analysis of S.flexneri 4c in Beijing, Shanghai and Shenyang of China / 军事医学

Objective To study the serotype , biochemical characteristics , virulence gene and multilocus sequence typ-ing(MLST) of S.flexneri 4c in Beijing, Shanghai and Shenyang .Methods Seventy-six strains of S.flexneri 4c isolated from stool samples which had been collected from above-mentioned cities of China were identified with Denka Seiken serum and MASF monoclonal serum .Biochemical characteristics of each strain were identified by API 20E test strip and PCR technology was used for detecting 12 pair virulence genes of S.flexneri.MLST was used to analyze the characteristics . Results The serum agglutination antigen structure of S.flexneri 4c was(Ⅳ:7,8).MASF:B+,Ⅳ:Ⅰ+,7 (8) +.S.flexneri 4c developed different results in biochemical reactions and carried different rates of virulence genes , respectively .The IND test positive rate was 17.11%; MEL weakly positive rate was 3.9%, and ARA test weakly positive rate was 22.37%. Virulence genes were carried at a rate of 89.47% -100%, MLST typing was ST245.Conclusion S.flexneri 4c with serum agglutination antigen structure (Ⅳ:7,8) is a new serotype of S.flexneri.The main biochemical reactions are glucose fermentation and mannitol decomposition .A variety of Shigella related virulence genes are carried .MLST generation is consistent,suggesting that the bacteria might have evolved from ST 270 cloning.

Survey and analysis of the microenvironment and airborne microbes in one warship / 军事医学

Objective To find out about the temperature ,relative humidity, concentration and species of air microbes in the warship , and to detect the possible pathogenic agents responsible for the high incidence of respiratory diseases among the crew.Methods A digital hygrometer was used to measure the indoor tempreture and relative humidity .Open agar set-tling plates were used to sample the air bacteria in the ship .Pure bacterial colonies were isolated from those on the original plates by repeated streak inoculation .The species of bacteria were determined by gram staining ,light microscope observation and 16S rDNA sequencing .Results Spots that met the standard requirement of temperature accounted for 20%but relative humidity was up to the stevrdard ineach place investigated .Although the concentration of airborne microbes was under the standard limit,bacteria were various.There were 18 different bacteria isolated from the air sample , including Chryseobacteri-um jejuense,Acinetobacter baumannii, Bacillus sporothermodurans, Staphylococcus aureus, Staphylococcus capitis, Staphylo-coccus hominis subsp.hominis strain and subsp.novobiosepticus, Staphylococcus cohnii subsp.cohnii and subsp.urealytic-us,Enhydrobacter aerosaccus,Corynebacterium casei,Macrococcus caseolyticus,Corynebacterium ammoniagenes,Brevibacillus panacihumi,Comamonas koreensis,Bacillus subtilis,Sphingobium yanoikuyae, Chryseobacterium hominis.Conclusion The high incidence of respiratory diseases among officers and soliders might be related to the lower tempreture and some airborne bacteria in the warship .