25 February 2022, Volume 17 Issue 1

    

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New Year Greetings
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  Prevent and deal with risks and look forward to the return of normal life

  Qu Di1, ZHANG Wenhong 2

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 1-1.

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  World Health Organization Director-General Tedros Adhanom Ghebreyesus in his New Year's message for 2022 is optimistic about mankind's victory over the new crown epidemic in 2022: mankind is expected to end the new crown epidemic in 2022. Although it has been two years, the total number of new coronary pneumonia (COVID-19) cases worldwide has now reached 287 million, and nearly 5.5 million patients have lost their lives. As we enter 2022, the novel coronavirus (SARS-CoV-2) is still a part of people's daily lives, and Director-General Tedros believes that as long as countries work together, the spread of the virus can be curbed.
Invited paper
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  Research progress on the Omicron variant of severe acute respiratory syndrome coronavirus 2

  GUO Yifei1, ZHANG Jiming1，2，3

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 2-8. https://doi.org/10.3969/j.issn.1673-6184.2022.01.001

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  On November 26, 2021, World Health Organization (WHO) designated the B．1.1.529 variant firstly reported in South Africa as a variant of concern (VOC) of SARS-CoV-2, named Omicron. There are about 50 mutations in this variant, and at least 30 mutations in the spike protein region alone, which far exceeds the number of mutation sites in other endemic strains. The analysis on mutated sites and preliminary experiments confirmed that the variant may be highly contagious and associated with immune escape. How Omicron variant will affect the pandemic has aroused wide public concern in various countries. This review focused on the basic characteristics, detection, pathogenicity, infectivity, and immune escape of Omicron variant.
Original Article
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  Construction of prokaryotic expression vector of herpes simplex virus type 2 capsid scaffolding protein ICP35 and analysis of its expression characteristics

  WANG Jianbin, LI Xueqi, WANG Lichun, WU Huaye, CHENG Jishuai, MOU Tangwei, LI Qihan

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 9-17. https://doi.org/10.3969/j.issn.1673-6184.2022.01.002

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  The aim of this study is to construct the prokaryotic expression vector of capsid scaffolding protein ICP35 of herpes simplex virus type 2 (HSV-2) and to analyze its expression characteristics during HSV-2 proliferation. The UL26.5 gene of HSV-2 encoding capsid scaffolding protein ICP35 was amplified by polymerase chain reaction (PCR) and cloned into the prokaryotic expression vector pET-32a(＋). Then the recombinant plasmid was transformed into Escherichia coli (E.coli) BL21 (DE3) to express capsid scaffolding protein ICP35 which was induced by isopropyl β-D-thiogalactoside (IPTG). The purified ICP35 recombinant protein was used as antigen to immunize rabbits for the preparation of polyclonal antibody specific for ICP35 protein, and the expression characteristics of capsid scaffolding protein ICP35 during HSV-2 proliferation was analyzed by immunofluorescence detection. The results of agarose gel electrophoresis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis respectively showed that the PCR target band appeared around 1 065 bp, the relative molecular weight of recombinant protein target band was about 6.3×10⁴, which was in accordance with the expectation. In addition, the serum antibody of immunized rabbit was able to specifically recognize HSV-2 capsid scaffold protein ICP35. Immunofluorescence assay results showed that the HSV-2 capsid scaffold protein ICP35 appeared around the nucleus as early as 8 h post infection. At 12 h post infection, the expression level of ICP35 increased further and ICP35 began to migrate into the nucleus. The fluorescence of ICP35 gradually converged into spots and could be detected in both cytoplasm and nucleus at 16 h post infection. The successful construction of prokaryotic expression vector of HSV-2 capsid scaffold protein ICP35 and analysis of its expression characteristics during HSV-2 infection will be helpful to study the function of UL26.5 gene, the interaction of proteins, the interaction of virus-host and the screening for antiviral drug targets.
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  Molecular identification of Salmonella enterica serovar Typhi ncRNA617 and its effect on biofilm formation

  JIN Mengtong1, LI Xue2, DANG Juanjuan1, LI Zeyu1, ZHANG Ying1, HUANG Xinxiang1

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 18-29. https://doi.org/10.3969/j.issm.1673-6184.2022.01.003

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  The purpose of this study is to investigate the molecular characteristics of non-coding RNA617 in Salmonella enterica serovar Typhi (S. Typhi), as well as its effect on biofilm formation and its mechanism. Northern blot was used to detect the expression of ncRNA617; 5’RACE (5’-rapid amplification of cDNA end) and 3’RT-PCR (reverse transcriotion-polymerase chain reaction) were used to identify possible transcription initiation and termination sites. ncRNA617 knockout strain, complemented strain and overexpression strain of S. Typhi were constructed. The bacterial biofilm formation experiment was used to observe the effect of ncRNA617 on the formation of biofilm; qPCR (quantitative real-time PCR) was used to analyze the effect of ncRNA617 on the expression level of genes related to biofilm formation. Northern blot showed the presence of ncRNA617 with a length of about 300 nt; 5’RACE and 3’RT-PCR revealed that the 5’end of the transcript was located at 967 nt downstream of the mig-14 stop codon, and the 3’end of the transcript was located at 2378-2560 nt upstream of start codon of t2681. Biofilm formation experiment showed that compared with wild control strain, the biofilm formation ability of the ncRNA617 knockout strain was enhanced (P<0.05). The biofilm formation ability of the complemented strain was restored to the level of the wild strain, and the biofilm formation ability of the overexpression strain decreased (P<0.05). qPCR results showed that ncRNA617 negatively regulated the transcriptional expression levels of several biofilm formation related genes. Predicted by bioinformatics methods, it was found that ncRNA617 had different binding regions with regulated genes. It is concluded that ncRNA617 exists in S. Typhi and its length is about 270～452 nt. ncRNA617 may negatively regulate gene expression by targeting genes related to biofilm formation, and then negatively regulates the biofilm formation of S. Typhi.
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  Characteristics and influencing factors of AIDS patients combined with syphilis in a hospital in Shanghai

  ZHENG Fang1, GAO Danhong1, ZHANG Yu2, SHEN Yinzhong1，3

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 30-34. https://doi.org/10.3969/j.issn.1673-6184.2022.01.004

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  The purpose of the current study is to understand the characteristics of AIDS patients combined with syphilis in Shanghai in recent years, explore the influencing factors of AIDS patients with syphilis, and provide a scientific basis for the prevention and control of such diseases in Shanghai. Through the collection of relevant data on the diagnosis of AIDS combined with syphilis cases discharged from the Shanghai Public Health Clinical Center during 2013 to 2019, the case characteristics and trend of changes were analyzed, and the relevant factors affecting AIDS patients with syphilis were studied. The results showed that the prevalence rate of syphilis among AIDS patients in Shanghai was 10.55%, The overall infection rate of AIDS complicated with syphilis in this hospital showed an upward trend from 2013 to 2019 (χ2＝17.640，P<0.05). July-August is the peak period of annual admissions. The patients were mainly from local residents (55.49%), the male to female ratio was 14∶1, and the average age was (38±12) years old. Through logistic regression analysis, it was found that the factors affecting AIDS and syphilis were gender, age, source of cases, and CD4^＋T lymphocyte count. Among them, local, 21-40 years old, male and CD4^＋T lymphocyte count ≤500 /μL are high risk factors for AIDS patients with syphilis infection. This study suggests that the number of AIDS-combined syphilis infection cases in Shanghai from 2013 to 2019 is on the rise. The key population for prevention and control is Shanghai’s young and middle-aged male residents. The ability to actively monitor such populations should be improved, and screening efforts should be increased as well as good health education. The key prevention and control period is July and August each year, and precise prevention and control are expected to achieve obvious results.
Case Analysis
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  Comparative identification report of a strain of P. shigella by VITEK 2 Compact, MALDI-TOF MS and 16S rDNA gene sequencing 　

  ZHU Weiping, DENG Hongyan, LIU Jun

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 35-40. https://doi.org/10.3969/j.issn.1673-6184.2022.01.005

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  Plesiomonas shigelloides belongs to the genus Orthomonas of Enterobacteriaceae. It is a gram-negative bacterium and opportunistic pathogens of human beings. It was firstly found in the gastrointestinal tract, but there was no clear evidence that it was enteropathogenic, and only a few cases supported that it could cause sepsis and gastroenteritis. Vibrio cholerae is a gram-negative bacterium belonging to Vibrio. Serotypes O1 and O139 are the pathogenic bacteria of class A infectious diseases of cholera. They can cause severe vomiting and diarrhea by invasiveness and cholera enterotoxin. Blood flow infection of serotype non-O1/O139 group is occasionally reported in China. This patient was with chronic liver disease. There was no obvious inducement for abdominal pain, diarrhea and vomiting. Blood was collected for culture when they were afraid of cold and shivering. A gram-negative bacilli was detected and identified as Vibrio cholerae by VITEK 2 compact automatic bacterial identification and drug sensitivity analysis system. After qualitative analysis and 16S rDNA gene sequencing, the patient was confirmed to be infected with Plesiomonas shigelloides. According to the results of drug sensitivity test, piperacillin/tazobactam was given for anti infection. After symptomatic treatment of blood transfusion and liver protection, the patient was discharged from hospital with no recurrence. The results of this report suggest that when Vibrio cholerae and other clinically rare bacteria are identified by vitEK-2 Compact, a comprehensive judgment should be made based on bacterial colony morphology, auxiliary biochemical tests and clinical conditions of patients. If necessary, mass spectrometry, gene sequencing and other detection methods can be used for rechecking.
Review
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  Regulation of interleukins on anti-tuberculosis immune response of lymphocytes

  LIU Xi1，2，　SHEN Hongbo2，　WANG Feifei3，　XU Junfa1

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 41-46. https://doi.org/10.3969/j.issn.1673-6184.2022.01.006

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  Cytokines of interleukins (IL) can regulate the differentiation, proliferation and effector function of immune cells. The expression of specific interleukins induced by Mycobacterium tuberculosis (Mtb) antigens could be used to characterize Mtb infection in humans. In host’s anti-tuberculosis immune defense, interleukins can directly regulate the bactericidal activity of phagocytes to inhibit intracellular Mtb growth. Interleukins can also induce the proliferation and effect function of T cells to further enhance the bactericidal activity of phagocytes. Some interleukins are being tested in clinical trials as an adjuvant immunotherapy for tuberculosis treatment. Here, this study reviewed the latest research progresses of interleukins regulating anti-tuberculosis immune response of lymphocytes, and discussed the rationale for the development of interleukins as potential adjunctive treatment in tuberculosis.
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  Research progress on drug-resistance of Elizabethkingia meningoseptica

  WU Qile1, FANG Zixuan1, YUAN Shuying1, CHEN Yanwen1, CHEN Li2, SUN Guiqin1

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 47-54. https://doi.org/10.3969/j.issn.1673-6184.2022.01.007

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  Elizabethkingia meningosepticum (EM), which causes nosocomial pneumonia, neonatal meningitis, bacteremia and other diseases, is one of the most important pathogens of nosocomial infections. In recent years, the detection rate of EM in the intensive care unit (ICU) has shown an upward trend. Due to the widespread use of antibiotics, EM is multi-drug resistant to commonly used clinical antibiotics such as β-lactams, aminoglycosides and fluoroquinolone, which brings great difficulties to clinical treatment. At present, researches on EM resistance mechanisms in different countries mainly include the production of drug-inactivating enzymes, changes in drug targets, and the formation of biofilms. EM has multiple drug-resistant genes such as GOB, BLaB, CME, which mediate their multiple resistance. This article reviewed the drug resistance and resistance mechanism of EM, hoped to provide references for the prevention and control of nosocomial infections of EM.
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  Research progress of respiratory syncytial virus vaccine and antibody preparations

  WU Xiaoying1, MENG Qinghong2, YAO Kaihu2, XU Hongmei1, FU Zhou3

  JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(1): 55-64. https://doi.org/10.3969/j.issn.1673-6184.2022.01.008

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  Respiratory syncytial virus (RSV) infection is an important global health problem. There is lack of specific treatment methods in clinical practice. Active prevention by vaccination or passive prevention by using antibody preparations are important measures to avoid severe infections and reduce deaths. Different RSV vaccines need to be developed for different populations. There are four main types of RSV vaccines under development. Live attenuated vaccines may be most suitable for infants. Subunit vaccines have the risk of causing enhanced respiratory diseases and are not suitable for infants with negative RSV serum vaccination, but they are mainly suitable for the elderly and pregnant women. Ensuring safety and immunogenicity is an important issue that needs to be solved in the development of RSV vaccines. Although there are many challenges in the development of RSV vaccines, more than 30 RSV vaccines have entered the clinical research stage, showing potential for application. Among them, the F nanoparticle vaccine has taken the lead in entering phase III clinical trials, but it has not achieved the expected effect in the elderly and pregnant women. Before the RSV epidemic season, using specific antibody is also an effective means to prevent severe infection in high-risk groups. The long-acting monoclonal antibody MEDI8897, which is more cost-effective than palivizumab, has entered phase III clinical trials, and has got priority R&D qualification. Polyclonal immunoglobulin RI-002 has shown good preventive effects in immunodeficiency populations, and has practical significance for further research.