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25 October 2020, Volume 15 Issue 5
    

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    Invited paper
  • LI Qingtian1, GUO Xiaokui2
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 265-270. https://doi.org/10.3969/j.issn.1673-6184.2020.05.001
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    Bacteriophage is one of the most abundant and long­standing individuals in the biosphere of the earth. Bacteriophage is also one of the most characteristic candidates to deal with antibiotic resistant bacterial infections. In this paper, we discussed the phage­resistance mechanism of bacteria and bacteriophages’ responses from the aspects of bacteria and phages interactions, such as inhibition of the bacteriophage adsorption, super infection exclusion, restriction modification system, CRISPR­Cas, and abortive infection.
  • Original Article
  • BAO Jialing1,2, MO Biying1,2, LI Tongxin3, LIU Min3, LI Tian1,2, PAN Guoqing1,2, ZHOU Zeyang1,2
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 271-277. https://doi.org/10.3969/j.issn.1673-6184.2020.05.002
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    Microsporidia infects immunocompromised populations such as human immunodeficiency virus(HIV)-positive patients, causing diarrhea and other life-threatening symptoms. Few studies on this infection have been conducted in China. This study collected 22 HIV-positive patients in Chongqing, who have not received antiviral treatment. The immune profile analysis of these 22 patients showed the average lymphocytes were 0.93±0.13×109/L, CD4T cells were 132±22 cells/mL, CD8T cells were 495±91 cells/mL, and CD4/CD8 ratio was 0.37±0.1, indicating all the patients were immunocompromised, thus vulnerable to opportunistic infections. The total DNA was extracted from the respective stool samples. The existence of microsporidia was confirmed by PCR and DNA sequencing. The results showed that the infection rate was 36.3% (8/22), and caused by Encephalitozoon spp, mainly E. hellem and E. intestinalis. Further comparison between Encephalitozoon spp infected and un-infected patients showed that, lymphocytes were 0.51±0.1 vs 1.17±0.17×109/L, P<0.05; CD4+T cells were 71±27 vs 167±28 cells/ mL, P<0.05; CD8T cells were 209±35 vs 658±123 cells/ mL, P<0.05, suggesting the infected patients were severely immune-suppressed. The current study is the first investigation of microsporidia infection in HIV-positive patients in Chongqing area. It demonstrates the correlation between immune-suppression and microsporidia infection, and the high infection rate of Encephalitozoon spp in Chongqing area. Together, this provides evidence to elucidate the mechanisms of microsporidia-host interactions, as well as insights into public health control.
  • MENG Meng, WANG Chao, WU Wei, WANG Yuanyuan
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 278-284. https://doi.org/10.3969/j.issn.1673-6184.2020.05.003
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    In order to improve the laboratory’s ability on antibody-based assays for human immunodeficiency virus (HIV) detection, a total of 268 serum samples which were positively detected by at least one of the current 3 primary antibody-based assays (chemiluminescence, ELISA and colloidal selenium) were subjected to standard western blot assay for HIV detection in the AIDS Confirmation Laboratory in Dongcheng District, Beijing. The results showed that among 268 samples to be identified, 170 were confirmed positive, with a positive rate of 63.43%. The negative rate of 51 confirmed cases was 19.03%. Inconclusive results accounted for 17.54% of screening responses. The results of this study suggest that for potential HIV infected persons, multiple testing with more than one method should be provided to reduce the risk of missed detection.
  • SONG Wuhui, YI Zhigang
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 285-292. https://doi.org/10.3969/j.issn.1673-6184.2020.05.004
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    To establish cell line with high permissiveness for hepatitis C virus (HCV)infection, we established Huh 7 cell lines that harboring a HCV subgenomic replicon (sgJFH1) by blasticidin selection and then treated these replicon cells with interferon gamma to generate HCV cured cells. Two single clones were established (Huh 7A and Huh 7B, respectively). To determine whether these cured cells are more permissive for HCV, Huh7A and Huh7B cells were infected with the Jc1G strain of HCV and the activity of reporter gene Gaussia luciferase (Gluc), HCV protein and RNA level were determined. HCV has an intrinsic ability to trigger interferon production through RIG-I and MDA5 and its adaptors MAVS. To determine whether RIG-I or MDA5 or MAVS play a key role in permissive cell lines, we first analyzed the endogenous expression level of these proteins. Interferon-stimulated genes (ISGs) including ISG56, OAS1, OAS2, Viperin, CXCL10, IFITM1 and IFITM3 have been reported to control viral infection by directly interfering with the pathways and functions required during viral infection. To examine the capacity of the cured cell lines to induce ISGs by IFN, we determined the effect of interferon-α on the expression of ISGs associated with antiviral function in these permissive cell lines. Results showed that the HCV RNA could not be detected in cured cell lines Huh7A and Huh7B. In Huh7A and Huh7B cells infected with Jc1G, the Gluc activity was as high as that in Huh 7.5 cells and nearly 100 folds more than that in Huh 7 cells. Consistently, both HCV RNA and NS3 protein expression levels in Huh 7A, Huh 7B cells and Huh 7.5 cells increased significantly compared to that in Huh7 cells. Compared with parental Huh 7 cells, the expression of these proteins in Huh 7A and Huh 7B cells shows no obvious differences. The same results were observed in their mRNA level. Strikingly, in addition to RIG-I, MDA5 mRNA and protein levels in Huh 7.5 cells were also much less than that in Huh7 as well as Huh7A and Huh7B cells. The results showed that there was no significant difference in the stimulation of ISGs between Huh 7 cells and highly permissive cell lines, including MX1 that was reported to be responsible for the permissiveness for HCV replication in permissive cell lines. To further confirm the role of MX1 in our highly permissive cell lines, we treated cells with different concentration of interferon-α and found out that the expression levels of MX1 were still comparable among the four cell lines at indicated concentration. The data suggested that MX1 may not be associated with permissiveness of Huh 7.5 cells as well as Huh 7A and Huh 7B cells. These results showed that Huh 7A and Huh 7B cells were more permissive for HCV infection, which may provide a useful cell model to study HCV replication and identify novel targets for antiviral drugs.
  • SU Meng, Lü Liangdong
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 293-301. https://doi.org/10.3969/j.issn.1673-6184.2020.05.005
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    Recent studies demonstrate that the structure of ribosome was committed to dynamic regulation during cell development and stress adaptation. We used NCBI BLAST to analyze the sequence similarity of ribosomal protein RpsI, RpmI and RpmJ between Mycobacterium tuberculosis and Mycobacterium smegmatis and found a striking variation in RpsI N terminal. To further study the influence of this variation on ribosomal function, we constructed a M. smegmatis recombinant strain in which the original rpsI was replaced by the counterpart from M. tuberculosis. The genotype of this strain was verified by PCR. We estimated the growth rate of recombinant strain and empty-control strain under different temperatures. Universal serial liquid dilution method was applied to measure the minimum inhibition concentration (MIC90) of five different ribosome-targeting antibiotics. We found that the recombinant strain became more sensitive to amikacin which binds to the A site of ribosome. These results demonstrate that the sequence variation in Mycobacterial RpsI may impact the structure of ribosomal A site.
  • Review
  • XIA Aihong, LI Xin, QUAN Juanjuan, YAO Zhihong, XU Zhengzhong, MENG Chuang, CHEN Xiang, JIAO Xinan
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 302-308. https://doi.org/10.3969/j.issn.1673-6184.2020.05.006
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    With the development of animal husbandry, the growth of the pet market, the relationship between humans and animals continues to be strengthened globally. The distance between humans and animals has been shorten, which makes cross-species transmission easily. Research on zoonoses usually focuses on diseases transmitted from animals to humans, such as bovine spongiform encephalitis (BSE), acquired immunodeficiency syndrome (AIDS), and avian influenza. However, the exchange of microorganisms can be carried out in both directions. In recent years, more and more reports indicate that humans are transmitting pathogens to animals, including SARS-CoV-2, methicillin-resistant Staphylococcus aureus, influenza A virus, Cryptosporidium parvum, and Ascaris lumbricoides. Therefore, this article reviews the diseases transmitted from humans to animals and provides a basis for the effective prevention and treatment of human and animal diseases.
  • ZHOU Yunjiao1, JIANG Qingling2, WANG Qiao1
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 309-315. https://doi.org/10.3969/j.issn.1673-6184.2020.05.007
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    Immune system acts as a natural barrier and kills pathogenic organism that can cause infection. However, dysregulated immune response may lead to many diseases and even death. In this article we will discuss the immune response against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and understand how a complex of protection measures, including mechanical barriers, innate and adaptive immune responses, coordinate and combat against pathogenic elements. Meanwhile, coronavirus infection might elicit overreactive immune reactions, called cytokine storm, resulting in overwhelming inflammation and even death. We will also briefly discuss the challenges and difficulties in human coronavirus vaccine development due to the antibody-dependent enhancement effect.
  • GU Keyi1,WANG Huijing1,ZHAO Chao2,3
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 316-321. https://doi.org/10.3969/j.issn.1673-6184.2020.05.008
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    Two subgroups of coronavirus disease 2019(COVID-19) patients deserved special medical attention, one being hypertension patients, the other being hypertension patients treated with angiotensin converting enzyme inhibitors (ACEI). Relatively high susceptibility of hypertension patients to the disease and severe prognosis for the ones using ACEI indicate that there is a close relationship between virus infection and hypertension, which puts forward the demand for rational medication for the special group of patients with hypertension. In this paper, we analyzed the balance between angiotensin converting enzyme 2 (ACE2), the functional receptor of SARS-CoV-2, and ACE, and then discussed the relationship between hypertension and virus susceptibility, as well as the possible pathogenesis of COVID-19 in hypertension. Because the angiotensin converting enzyme inhibitors (ACEI) play an important role in the population of hypertension, we give guidance and suggestions on the medication of hypertension before and after virus infection in this population for clinical reference in this paper by the analysis of pharmacology and etiology.
  • CHEN Shiqi, MAO Richeng, ZHANG Jiming
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 322-330. https://doi.org/10.3969/j.issn.1673-6184.2020.05.009
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    Chronic hepatitis B virus infection is difficult to cure due to the persistence of covalently closed circular DNA and viral-mediated inactivation of host immune responses. Existing nucleoside (acid) analogs or pegylated interferon therapy are difficult to achieve a high ratio of HBV surface antigen clearance. This article reviews the structure and function of HBV core protein, the classification and application prospects of core protein allosteric modulators.
  • XU Nuo1, ZHOU Bangyue1, SHI Yi1, PAN Xingyuan1,2, QIN Tao3, XU Zhengzhong4, YIN Yinyan1,2,4
    JOURNAL OF MICROBES AND INFECTIONS. 2020, 15(5): 331-336. https://doi.org/10.3969/j.issn.1673-6184.2020.05.010
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    Salmonella is an important foodborne pathogen, which seriously threatens the global public health. The host innate immune response plays a significant role for resisting infection. Nowadays, Salmonella has evolved a series of strategies to escape the innate immune response for persistent infections. This review gives a detailed summarization on the new strategies of Salmonella, including receptors (TLRs, NLRs, RIPs), cytokines (IL-22 and IL-4) and mTOR signaling pathway-mediated immune escape.