25 August 2023, Volume 18 Issue 4

    

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Invited paper
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  Clinical reseach progress of long COVID

  LIAO Xuejiao1, WU Shuting1, MA Zhenghua1, LU Hongzhou1，2

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 193-202. https://doi.org/10.3969/j.issn.1673-6184.2023.04.001

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  Global public health is facing great challenges due to the infection caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) and its mutated strains. Although we have entered the post-pandemic era, a new crisis is the long-term effects of SARS-CoV-2 infection, which can involve multiple organs, mainly manifested by pulmonary, neuropsychiatric, cardiovascular and gastrointestinal symptoms. In some coronavirus disease 2019 (COVID-19) patients, symptoms including complications can last for months or even years, which is called long COVID-19. In the future, long COVID may significantly affect patients’ quality of life and social healthcare costs as the number of recovering patients increases dramatically, further placing a huge burden on families and society. Therefore, it is very important to study the long-term health status and dynamic changes of COVID-19 patients during the recovery period.
Original Article
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  RNA-FISH based on the new generation of hybridization chain reaction to detect enterovirus A71 RNA and its interaction with the viral 3D polymerase

  XING Yifan, Fu Meixian, LONG Jianer

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 203-210. https://doi.org/10.3969/j.issn.1673-6184.2023.04.002

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  RNA-fluorescence in situ hybridization (RNA-FISH) is widely utilized to detect the specific RNA sequences and its contribution in cells or tissues through the complementary hybridization with the fluorescence-labeled nucleotide probes. Given the weak signal, RNA-FISH would be combined with the specific signal amplification technique to improve the signal-to-background ratio. However, due to the low resolution, the traditional signal amplification technology is difficult to eliminate the high background and can not quantify RNA accurately. It is an obvious obstacle to the application of RNA-FISH. Based on the third generation hybridization chain reaction (HCR v3.0) technology, the half split probes were designed to eliminate the non-specific hybridization background and trigger fluorescence signal amplification. Here, we established the sensitive and specific RNA-FISH based on HCR v3.0 to detect the viral RNA of enterovirus A71 (EV-A71). Furthermore, combining RNA-FISH with immunofluorescence staining technology (IF) and high-resolution confocal laser imaging, we successfully detected and quantified the viral RNA and 3D polymerase of EV-A71 during the viral infection in a single-cell level. We observed that the viral RNA decreased whereas 3D polymerase increased significantly in the late stage of EV-A71 infection. It was apparently different from the traditional quantification by reverse tran-scriptase quantitative polymerase chain reaction(RT-qPCR) and western blot, which were based on the total cells during viral infection. It demonstrates that the new generation of RNA-FISH technology based on hybridization chain reaction can overcome the shortcoming of masking the change of virus composition by the increase or decrease of population cell number, so as to truly reflect the change of virus in a single cell.
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  The value of miRNA hsm-let-7 family from exosomes in differential diagnosis of pleural effusion

  DONG Zeling1, DENG Fenglin1, ZHU Jiehua1, WANG Juan2, DU Wensheng1

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 211-218. https://doi.org/10.3969/j.issn.1673-6184.2023.04.003

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  The purpose of this study is to investigate the differential expression of miRNA in pleural fluid and serum exosomes from patients with tuberculous pleurisy, which is to provide a basis for diagnosis and differential diagnosis of tuberculous pleurisy. Serum and pleural fluid specimens from 20 patients who had tuberculous pleurisy (experiment group) and 20 patients who had pneumonia with inflammatory pleural effusion (control group 2) were collected. 20 healthy persons’ serum (control group 1) were collected, too. The exosomes were separated and total RNA were extracted for expression level analysis of miRNA with real-time quantitative polymerase chain reaction (PCR) technology. The results showed that compared with control group 1, the level of miRNA expression in serum exosomes from control group 2 was increased in different degree, among them the let-7a-5p, let-7c-5p, let-7i-5p and miRNA-126-3p increased significantly. The expression level of miRNA in the serum exosomes from experimental group was higher than that of control group 2, especially let-7a-5p, let-7d-5p, let-7e-5p, miRNA-126-3p, let-7g-5p and let-7c-5p (P<0.05). Compared with control group 2, the expression levels of miRNA in pleural effusion exosomes from the experimental group were higher, and let-7f-5p, let-7g-5p, let-7d-3p were obviously higher than those in the control group 2. The expressions of miRNA in pleural effusion and serum exosomes were also significantly different in the experimental group. So it was concluded that the expressions of miRNA in pleural fluid and serum exosomes from patients with tuberculous pleurisy were different from general pneumonia with pleural effusion. The hsm-let-7 family members might be used as a good differential diagnostic index between tuberculous pleural effusion and common inflammatory pleural effusion.
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  Effect of outer membrane vesicles of Salmonella enterica serovar Typhi on proliferation of colorectal cancer cells under different culture conditions

  ZENG Minmin1，JI Ying1, 2，WANG Yurou1, GE Yitong1，ZHENG Xueming1, 2，MENG Ran1，HUANG Xinxiang1

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 219-226. https://doi.org/10.3969/j.issn.1673-6184.2023.04.004

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  The aim of this study was to investigate the effect of outer membrane vesicle (OMV) of Salmonella enterica serovar Typhi (S. Typhi) on the proliferation of colorectal cancer cells under different culture conditions. Ultracentrifugation was used to extract OMV secreted by S. Typhi in normal, acid, hyperosmotic, oxidative LB medium, and LPM medium. The morphology, particle size and protein distribution of OMV under different conditions were compared. The colorectal cancer cells HT-29, SW480 and CT-26 were cultured in vitro. CCK-8 assay was used to detect the effect of OMV on the proliferation of colorectal cancer cells, and the colony formation experiment was used for further verification. The cell cycle was analyzed by flow cytometry. The toxicity of OMV in mice was evaluated through body weight and hematoxylin-eosin (HE) staining of liver and kidney tissues. The results showed that there was no significant difference in morphology and size of OMV under different culture conditions. Compared with other culture conditions, S. Typhi could secrete more OMV under hyperosmotic stress. In normal and acid LB medium the relative molecular weight of proteins in OMV was 37×10³—72×10³, in hyperosmotic and oxidative LB medium it was 25×10³—72×10³, and in LPM medium it was 8×10³—55×10³. OMV secreted in LPM medium could significantly inhibit the proliferation of SW480 and CT-26 cells, and arrest the cell cycle of SW480 cells in G2/M phase, without obvious hepatorenal toxicity to mice. It is concluded that OMV secreted by S. Typhi in LPM medium exhibit a direct inhibitory effect on the proliferation of colorectal cancer cells (SW480, CT-26), and it is expected to be a therapeutic drug for the treatment of colorectal cancer.
Case Analysis
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  A case report of a child with sudden enteritis caused by methicillin-resistant Staphylococcus aureus and literature review

  ZHU Huiyi, SUN Xiaopu, YANG Sen, GUO Yilin, ZHANG Yawen, LU Chengyu, CHEN Dehui

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 227-234. https://doi.org/10.3969/j.issn.1673-6184.2023.04.005

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  Methicillin-resistant Staphylococcus aureus (MRSA) rarely causes enteritis, and MRSA enteritis is generally more common in patients with long-term antibiotic use and gastrointestinal surgery. In this case, the child had no history of long-term medication and surgery, and suddenly developed fever, vomiting, shifting right lower abdominal pain. Appendicitis was suspected at the beginning, but no imaging signs of appendicitis were found on the abdominal computed tomography (CT), with abnormally dilated intestinal tube and fecal retention, and a large amount of dark green watery stool was drained through the canal. After etiological tests of throat swab and fecal specimens, the child was diagnosed with MRSA enteritis. After oral administration of vancomycin and symptomatic treatment, the child recovered and was discharged from hospital. This case and MRSA enteritis-related literatures were reviewed to conduct an in-depth analysis of the pathogenesis, clinical manifestations, treatment plan of MRSA enteritis, so as to provide new ideas for the standardized diagnosis and treatment of MRSA enteritis.
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  A case of tunnel infection of peritoneal dialysis catheter caused by Actinomyces Turicensis

  WANG Dan, YANG Xianggui, XU Ying

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 235-239. https://doi.org/10.3969/j.issn.1673-6184.2023.04.006

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  Actinomyces turicensis is a single-cell prokaryotic microorganism, which is the main oral flora of healthy people. If it enters other parts to cause infection, it may cause actinomycosis. This article introduced a case of tunnel infection of peritoneal dialysis catheter caused by Actinomyces turicensis. The patient was treated with meropenem and cefotaxime, and the disease was improved and the patient was discharged. By introducing the clinical characteristics, laboratory detection and treatment methods of Actinomyces turicensis infection, this study helps clinicians to become more familiar with the diagnosis and treatment of this kind of disease, and emphasizes that the clinical and laboratory should maintain timely and effective clinical communication to achieve early diagnosis and treatment.
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  Analysis of 8 cases of bloodstream infection with Bacteroides fragilis in cancer patients

  ZHANG Xiaoyu1，2, ZHANG Li2, WU Weixing2, QI Jun2, WU Zongyong2, WANG Min1

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 240-245. https://doi.org/10.3969/j.issn.1673-6184.2023.04.007

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  Bacteroides fragilis (BF) is a symbiotic bacterium in human intestinal tract, and also an anaerobic bacterium with relatively high positive rate in clinical work. 11 strains of anaerobic bacteria isolated from 8 cancer patients from June 2020 to December 2021 were identified as Bacteroides fragilis by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS ) technique. Analysis results of medical records showed that: five patients suffered with colorectal cancer; Surgery is the most common predisposing factor of Bacteroides fragilis bloodstream infetion (4/8); Imipenem and cilastatin sodium was selected for treatment in 4 patients, and the other 4 patients took other different types of antibiotics. Seven patients who effectively treated with antibiotics got controll of fever and infection. Their reexamination results of blood culture turned to be negative. This case analysis of bloodstream infection caused by Bacteroides fragilis in cancer patients can provide evidence for microbiology detection and clinical diagnosis and treatment.
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  A case of acute diarrhea caused by Vibrio furnissii

  LUO Yibing1, FU Lei1, QIN Shanshan1, ZENG Jianghui1, 2

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 246-250. https://doi.org/10.3969/j.issn.1673-6184.2023.04.008

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  Vibrio furnissii is a gram-negative short bacilli isolated from the feces of patients with diarrhea. Domestic and foreign reports of Vibrio furnissii infection are rare. This article reported a case of Vibrio furnissii infection in an acute diarrhea patient who was treated in the Second People’s Hospital of Nanning, and the patient’s diarrhea infection symptoms were typical, showing 4 years of repeated diarrhea, 7-8 times per day. Vibrio furnissii from this case was difficult to distinguish from Vibrio fluvialis due to the similarity of the biochemical reaction, and the results were different from the mass spectrometry identification results. Finally, the genome after 16S rRNA sequencing was compared with the corresponding model strain gene for average nucleotide identity (ANI). This pathogen was accurately identified as Vibrio furnissii. The growth and laboratory detection of Vibrio furnissii were introduced, and the related literatures at home and abroad were retrospectively analyzed, which is of certain guiding significance to improve the understanding of laboratory personnel about the bacterium and the clinical diagnosis and treatment of diarrheal diseases caused by Vibrio furnissii.
Review
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  Research progress on vaginal microbiome and its relationship with human papillomavirus infection and cervical disease

  JI Lingyun1，2，WU Jing3，ZHOU Yang3，WU Wenjuan1

  JOURNAL OF MICROBES AND INFECTIONS. 2023, 18(4): 251-256. https://doi.org/10.3969/j.issn.1673-6184.2023.04.009

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  The human vaginal microbiota (VMB), which plays a vital role in maintaining health and homeostasis, exhibits low diversity compared to the microbiomes of other organs. Cervical cancer (CC) is a common malignancy in women and has been shown to be highly associated with persistent infection with high-risk human papillomavirus (HPV). VMB is associated with human papillomavirus infection and cervical lesions, and may play a positive role in the progression of HPV infection and cervical intraepithelial neoplasia (CIN). On the one hand, lactobacillus can reduce the permeability of cervical cells, and reduce inflammatory response, inhibit the growth of cervical cancer cells, but the bacterias enhancing the diversity of VMB can express virulence and attachment genes, which cause damage to cervix and epithelial cells, causing HPV infection and high-grade disease states; On the other hand, HPV-associated E7 oncoprotein can reduce the secretion of defense peptides which are conducive to the growth of lactobacillus through NF-β-κB and Wnt/β-catenin signaling pathways, resulting in an increase in vaginal pH, which further facilitates the growth of vaginal pathogenic bacteria, and ultimately leads to structural changes of VMB. This review focuses on the relationship between the vaginal microbiome, persistent HPV infection and cervical dysplasia and the factors that mediate these relationships, which will help to find new targets for VMB-related diseases.