• Review Article

    Roles of Interleukin-17 and Th17 Responses in COVID-19
    Ye Won Kang, Seung Chan Lee, Sang Min Jeon, Eun-Kyeong Jo
    The ongoing coronavirus disease-2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus-2. COVID-19 severity is related to the cytokine storm … + READ MORE
    The ongoing coronavirus disease-2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus-2. COVID-19 severity is related to the cytokine storm phenomenon, which is amplified by pro-inflammatory cytokines and chemokines; it may cause extensive pulmonary damage. Among these cytokines, interleukin (IL)-17, produced mainly by T helper 17 (Th17) cells, is responsible for the immunopathological responses present in acute respiratory distress syndrome. This review discusses the roles of IL-17 and Th17 responses in the pathophysiology of COVID-19. Dysregulated Th17-responses, linked to various risk factors, may contribute to pathological inflammation through the amplification of multiple inflammatory cytokines and chemokines, as well as augmentation of neutrophil infiltration in the lungs of severe COVID-19 patients. A more detailed understanding of the roles of Th17 responses, as well as the mechanisms underlying altered IL-17 production and signaling, may improve therapeutic strategies for severe or critically ill COVID-19 patients by targeting the IL-17 pathway. - COLLAPSE
    September 2021
  • Review Article

    Immune Responses to Varicella Zoster Virus and Effective Vaccines
    Su Jeen Lee, Hun Kim, Kee-Jong Hong, Jae-Hwan Nam
    Varicella zoster virus (VZV) causes two distinct diseases, varicella (chickenpox) during primary infection, and herpes zoster (shingles) resulting from reactivation. The purpose … + READ MORE
    Varicella zoster virus (VZV) causes two distinct diseases, varicella (chickenpox) during primary infection, and herpes zoster (shingles) resulting from reactivation. The purpose of this review is to summarize the present understanding of VZV and the associated immune response, as well as to discuss available vaccines. VZV infection induces both innate and adaptive immune responses, especially an antigen-specific adaptive immune response, which activates humoral immunity and cell-mediated immunity (CMI). Reactivation of VZV can occur when the CMI of latent VZV is reduced, leading to herpes zoster. After VZV infection, natural killer (NK) cells modulate antigen presentation and the production of IFN-γ, an important activator of macrophages. IFN-γ is produced by NK cells and CD4 Th1/CD8 cytotoxic T lymphocytes. The T cell-mediated immune response is an important factor influencing VZV reactivation and herpes zoster, with herpes zoster being associated with reduced levels of VZV-specific T cells. Since the VZV-specific T cell population gradually declines with age, herpes zoster particularly affects the elderly. There are two types of zoster vaccines: live-attenuated and recombinant subunit. However, recombinant vaccines generally have poor immunogenicity when administered alone and require an adjuvant. Therefore, effective adjuvants are needed that especially promote cell-mediated immune responses. Various adjuvants have been developed, many of which enhance T cell immunity more than antibody-based humoral immunity. The information presented in this review may serve as a reference for future VZV immunology studies. - COLLAPSE
    September 2021
  • Original Article

    Comparison of Primers for Oral Mycobiome Study in Intubated Patients
    Yoon Hee Choi, Soo Hyun Kim, Myoung Soo Kim, Hee Sam Na
    In intubated patients, oral fungus including Candida rapidly can increase. Fungal infections cause a significant proportion of health care associated infections. For … + READ MORE
    In intubated patients, oral fungus including Candida rapidly can increase. Fungal infections cause a significant proportion of health care associated infections. For efficient prevention and management, characterization of the oral mycobiome is required. In this study, we tested two primers to characterize the oral mycobiome in intubated patients under mechanical ventilation support. Buccal samples from intubated patients were collected using Levine technique. Two primers (ITS3 and ITS7) targeting internal transcribed spacer (ITS)2 region was tested. Next generation sequencing was applied for mycobiome analysis. Alpha diversity, beta diversity and relative abundance was determined to compare the primer performance. The richness and evenness were significantly higher using ITS7 primer. When phylogenetic distance was included, there was no difference in richness. In beta diversity analysis, most of the samples were closely clustered suggesting that similar mycobiome structure was assigned by the tested primers. When relative abundance of the assigned taxa was compared, Candida was the most abundant genus. At the species level, similar species was assigned by both primers. However, C. sake, C. intermedia, C. parapsiolisis and Yarrowia porcina was only assigned by ITS3 primer, while Alternaria betae-kenyesis was only assigned by ITS7 primer. In intubated patients, diverse oral mycobiome was detected. Although the tested primers predicted similar mycobiome structure, there were several species that was uniquely assigned by each primer. Selecting optimum primer to characterize the oral mycobiome should provide better understanding the mycobiome community in oral cavity. - COLLAPSE
    September 2021
  • Original Article

    Molecular Characterization of Carbapenem-resistant, Colistin-resistant Klebsiella pneumoniae Isolates from a Tertiary Hospital in Jeonbuk, Korea
    Tae Hee Lee, Minhyeon Cho, Jaehyeon Lee, Joo-Hee Hwang, Chang-Seop Lee, Kyung Min Chung
    Klebsiella pneumoniae resistant to both carbapenem and colistin has become a major clinical challenge. Although such resistant isolates are rare, they have … + READ MORE
    Klebsiella pneumoniae resistant to both carbapenem and colistin has become a major clinical challenge. Although such resistant isolates are rare, they have been sporadically reported from many areas of the world. To investigate the prevalence and resistant mechanisms to carbapenem-resistant, colistin-resistant K. pneumoniae among Korean patients, we selected these resistant K. pneumoniae from clinical isolates collected over a period of five years at a tertiary hospital in Jeonbuk, Korea. The minimum inhibitory concentration of a variety of antibiotics against the resistant isolates was determined by the macrodilution method or the E-test. PCR analysis was used to determine sequence types (STs) and identify the genes involved in resistance to carbapenem and colistin. In 338 K. pneumoniae clinical isolates, two exhibited both carbapenem and colistin resistance. The ST of these belonged to ST11 and ST258, the most prevalent STs with K. pneumoniae carbapenemases, but the isolates did not carry any prevalent carbapenem-hydrolyzing β-lactamase genes. The carbapenem resistance was mediated by loss of porins OmpK35 and/or OmpK36 associated with DHA-1 AmpC β-lactamase. The colistin resistance was caused by amino acid changes in PmrB, PmrC, PmrE, PmrK, and MgrB, including novel amino acid changes in PmrE and PmrK. We first reported novel carbapenem-resistant and colistin-resistant K. pneumoniae ST11 and ST258 with mutations within ompK35, ompK36, mgrB, and pmr genes in Korea. The results suggest that non- carbapenemase-producing carbapenem-resistant, colistin-resistant K. pneumoniae might be prevalent in Korea, and that better measures are necessary to control the spread of the resistant pathogen. - COLLAPSE
    September 2021
  • Original Article

    Antibacterial Effect of Eight Probiotic Strains of Bifidobacterium against Pathogenic Staphylococcus aureus and Pseudomonas aeruginosa
    Yae Jin Choi, Hea Soon Shin
    Bifidobacterium strains inhibit growth or cell adhesion of pathogenic bacteria and against multidrug-resistant bacteria. Furthermore, when combined with certain antibiotics, probiotics can … + READ MORE
    Bifidobacterium strains inhibit growth or cell adhesion of pathogenic bacteria and against multidrug-resistant bacteria. Furthermore, when combined with certain antibiotics, probiotics can boost their antibacterial activity. The objective of present report was to evaluate the antibacterial effect of Bifidobacterium spp. In the first part of the investigation, we evaluated the antibacterial activities of viable and inactivated cells, from a total of 12 Bifidobacterium species, on the growth of three different common pathogens associated with multi-drug resistance such as Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Eenterococcus faecalis. Also, eight strains of sonication-inactivated Bifidobacteria exhibited antibacterial activity against S. aureus and P. aeruginosa. Additionally, eight viable Bifidobacterium strains exhibited antibacterial activity on the growth of pathogenic species. Therefore, we observed the antimicrobial activity, of Bifidobacteria against pathogenic bacteria, on the solid medium utilizing the agar well diffusion method. Some Bifidobacterium supernatants such as B. longum and B. pseudocatenulatum, showed synergism with the antibacterial activity of antibiotics. The results exhort that Bifidobacteria could be employed as an effective control for nosocomial pathogenic bacteria, and reduce the risk of the development of S. aureus and P. aeruginosa infection. The present authors propose that Bifidobacteria might be a useful probiotic microorganism, for combining modality with antibiotics, without adverse effects. - COLLAPSE
    September 2021
  • Original Article

    Isolation and Genomic Analyses of an Early SARS-CoV-2 Strains from the 2020 Epidemic in Gwangju, South Korea
    Min Ji Kim, Ji-eun Lee, Tae sun Kim, Jungwook Park, Mi hyeon Lim, Da jeong Hwang, Jin Jeong, Kwang gon Kim, Ji-eun Yoon, Hye young Kee, Jong-jin Park, Jin jong Seo, Jae Keun Chung
    Since the first identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China in late December 2019, the coronavirus disease 2019 … + READ MORE
    Since the first identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China in late December 2019, the coronavirus disease 2019 (COVID-19) has spread fast around the world. RNA viruses, including SARS-CoV-2, have higher gene mutations than DNA viruses during virus replication. Variations in SARS-CoV-2 genome could contribute to efficiency of viral spread and severity of COVID-19. In this study, we analyzed the locations of genomic mutations to investigate the genetic diversity among isolates of SARS-CoV-2 in Gwangju. We detected non-synonymous and frameshift mutations in various parts of SARS-CoV-2 genome. The phylogenetic analysis for whole genome showed that SARS-CoV-2 genomes in Gwangju isolates are clustered within clade V and G. Our findings not only provide a glimpse into changes of prevalent virus clades in Gwangju, South Korea, but also support genomic surveillance of SARS-CoV-2 to aid in the development of efficient therapeutic antibodies and vaccines against COVID-19. - COLLAPSE
    September 2021