Expression, Purification, and Characterization of Plasmodium vivax Lactate Dehydrogenase from Bacteria without Codon Optimization.

Plasmodium vivax is the most widespread cause of malaria, especially in subtropical and temperate regions such as Asia-Pacific and America. P. vivax lactate dehydrogenase (PvLDH), an essential enzyme in the glycolytic pathway, is required for the development and reproduction of the parasite. Thus, LDH from these parasites has garnered attention as a diagnostic biomarker for malaria and as a potential molecular target for developing antimalarial drugs. In this study, we prepared a transformed Escherichia coli strain for the overexpression of PvLDH without codon optimization. We introduced this recombinant plasmid DNA prepared by insertion of the PvLDH gene in the pET-21a(+) expression vector, into the Rosetta(DE3), an E. coli strain suitable for eukaryotic protein expression. The time, temperature, and inducer concentration for PvLDH expression from this E. coli Rosetta(DE3), containing the original PvLDH gene, were optimized. We obtained PvLDH with a 31.0 mg/L yield and high purity (>95%) from this Rosetta(DE3) strain. The purified protein was characterized structurally and functionally. The PvLDH expressed and purified from transformed bacteria without codon optimization was successfully demonstrated to exhibit its potential tetramer structure and enzyme activity. These findings are expected to provide valuable insights for research on infectious diseases, metabolism, diagnostics, and therapeutics for malaria caused by P. vivax.

Clinicopathological Characteristics of Inflammatory Myositis Induced by COVID-19 Vaccine (Pfizer-BioNTech BNT162b2): A Case Report.

As more individuals were coronavirus disease 2019 (COVID-19) vaccinated, unexpected side effects appeared. Herein, we present the case of a 30-year-old man with myopathy in both extremities after the second dose of the Pfizer-BioNTech (BNT162b2) COVID-19 vaccine. Symptoms, swelling and pain, started from the proximal upper and lower extremities and extended to the distal parts. Although he underwent massive hydration, the muscle enzyme level continuously increased. He complained of dysphagia and dysarthria. Microscopically, muscle biopsy showed multifocal or scattered macrophage infiltration and degenerated myofibers. In contrast to general myopathy including inflammatory myositis and rhabdomyolysis, vaccine-induced inflammatory myositis shows a prolonged increase in muscle enzyme levels and multifocal macrophage infiltration with necrosis of the muscle fibers. Symptoms improved with glucocorticoid and immunosuppressive treatment. If vaccinated individuals experience severe and continuous muscle pain and swelling, clinicians should consider vaccine-induced inflammatory myositis, measure the muscle enzyme levels, and perform muscle biopsy for a definite diagnosis.

Trends of age-related non-communicable diseases in people living with HIV and comparison with uninfected controls: A nationwide population-based study in South Korea.

OBJECTIVES: We aim to compare the trends of non-communicable diseases (NCDs) and death among people living with HIV (PLWH) and uninfected controls in South Korea. METHODS: We identified PLWH from a nationwide database of all Korean citizens enrolled from 1 January 2004 to 31 December 2016. A control cohort was randomly selected for PLWH by frequency matching for age and sex in a 20:1 ratio. To compare NCD trends between the groups, adjusted incidence rate ratios for outcomes across ages, calendar years and times after HIV diagnosis were calculated. RESULTS: We included 14 134 PLWH and 282 039 controls in this study; 58.5% of PLWH and 36.4% of the controls were diagnosed with at least one NCD. The incidence rates of cancers, chronic kidney disease, depression, osteoporosis, diabetes and dyslipidaemia were higher in PLWH than in the controls, whereas those of cardiovascular disease, heart failure, ischaemic stroke and hypertension were lower in PLWH. Relative risks (RRs) for NCDs in PLWH were higher than controls in younger age groups. Trends in the RRs of NCDs tended to increase with the calendar year for PLWH vs. controls and either stabilized or decreased with time after HIV diagnosis. The RR of death from PLWH has decreased with the calendar year, but showed a tendency to rise again after 2014 and was significant at the early stage of HIV diagnosis. CONCLUSIONS: Although the RR of each NCD in PLWH showed variable trends compared with that in controls, NCDs in PLWH have been increasingly prevalent.

A Modified Simple Scoring System Using the Red Blood Cell Distribution Width, Delta Neutrophil Index, and Mean Platelet Volume-to-Platelet Count to Predict 28-Day Mortality in Patients With Sepsis.

BACKGROUND: Recently, a new scoring system was developed that uses the red blood cell distribution width (RDW), delta neutrophil index (DNI), and platelet count (PC) to predict mortality in patients with sepsis. We investigated whether a modified simple scoring system based on the RDW, DNI, and mean platelet volume-to-PC (MPV/PC) ratio could predict the mortality of patients with sepsis, and compared it to the previous scoring system. METHODS: We conducted a retrospective cohort study of 264 adults who had been treated for sepsis in an emergency department between January 2016 and February 2019. Each patient was rated on a scale of 0 to 3 according to the modified scoring system. Point values were assigned based on RDW > 14.5%, DNI > 5.0%, and MPV/PC ratio >10.1. RESULTS: The 28-day mortality rate was 14.4%. Those who died had higher scores than those who survived (mean: 1.55 ± 0.92 vs 0.93 ± 0.78, P < .001). The area under the curve for the new scoring system was higher than that of the previous scoring system (0.685 vs 0.645). CONCLUSION: The modified scoring system was a good predictor of the 28-day mortality and was more useful than the previous scoring system for predicting mortality in patients with sepsis.

Enhancing Omicron Sublineage Neutralization: Insights From Bivalent and Monovalent COVID-19 Booster Vaccines and Recent SARS-CoV-2 Omicron Variant Infections.

BACKGROUND: Omicron variants have rapidly diversified into sublineages with mutations that enhance immune evasion, posing challenges for vaccination and antibody responses. This study aimed to compare serum cross-neutralizing antibody responses against various SARS-CoV-2 Omicron sublineages (BA.1, BA.5, XBB.1.17.1, FK.1.1, and JN.1) in recipients of monovalent COVID-19 boosters, bivalent booster recipients, and individuals who had recovered from Omicron BA.5 infections. METHODS: We conducted a micro-neutralization assay on serum samples from monovalent BNT162b2 booster recipients (N = 54), bivalent BNT162b2 booster recipients (N = 24), and SARS-CoV-2 Omicron BA.5-recovered individuals (N = 13). The history of SARS-CoV-2 Omicron infection was assessed using ELISA against the SARS-CoV-2 NP protein. RESULTS: Bivalent booster recipients exhibited significantly enhanced neutralization efficacy against Omicron sublineages compared to those who had received monovalent booster vaccinations. Omicron BA.5-recovered individuals displayed similar neutralizing antibodies (NAbs) to the bivalent booster recipients. Despite the improved neutralization in bivalent recipients and BA.5-recovered individuals, there were limitations in neutralization against the recently emerged Omicron subvariants: XBB.1.17.1 FK.1.1, and JN.1. In both monovalent and bivalent booster recipients, a history of Omicron breakthrough infection was associated with relatively higher geometric mean titers of NAbs against Omicron BA.1, BA.5, and XBB.1.17.1 variants. CONCLUSION: This study underscores the intricate interplay between vaccination strategies, immune imprinting, and the dynamic landscape of SARS-CoV-2 variants. Although bivalent boosters enhance neutralization, addressing the challenge of emerging sublineages like XBB.1.17.1, FK.1.1, and JN.1 may necessitate the development of tailored vaccines, underscoring the need for ongoing adaptation to effectively combat this highly mutable virus.

Coexisting cytomegalovirus colitis in an immunocompetent patient with Clostridioides difficile colitis: A case report.

BACKGROUND: Clostridioides difficile (C. difficile) colitis is one of the most common infections in hospitalized patients, characterized by fever and diarrhea. It usually improves after appropriate antibiotic treatment; if not, comorbidities should be considered. Cytomegalovirus (CMV) colitis is a possible co-existing diagnosis in patients with C. difficile infection with poor treatment response. However, compared with immunocompromised patients, CMV colitis in immunocompetent patients is not well studied. CASE SUMMARY: We present an unusual case of co-existing CMV colitis in an immunocompetent patient with C. difficile infection. An 80-year-old female patient was referred to the infectious disease department due to diarrhea, abdominal discomfort, and fever for 1 wk during her hospitalization for surgery. C. difficile toxin B polymerase chain reaction on stool samples was positive. After C. difficile infection was diagnosed, oral vancomycin treatment was administered. Her symptoms including diarrhea, fever and abdominal discomfort improved for ten days. Unfortunately, the symptoms worsened again with bloody diarrhea and fever. Therefore, a sigmoidoscopy was performed for evaluation, showing a longitudinal ulcer on the sigmoid colon. Endoscopic biopsy confirmed CMV colitis, and the clinical symptoms improved after using ganciclovir. CONCLUSION: Co-existing CMV colitis should be considered in patients with aggravated C. difficile infection on appropriate treatment, even in immunocompetent hosts.

Clinical implications of gut microbiota and cytokine responses in coronavirus disease prognosis.

Objectives: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects gut luminal cells through the angiotensin-converting enzyme-2 receptor and disrupts the gut microbiome. We investigated whether the gut microbiome in the early stage of SARS-CoV-2 infection was associated with the prognosis of coronavirus disease (COVID-19). Methods: Thirty COVID-19 patients and 16 healthy controls were prospectively enrolled. Blood and stool samples and clinical details were collected on days 0 (enrollment), 7, 14, and 28. Participants were categorized into four groups by their clinical course. Results: Gut microbiota composition varied during the clinical course of COVID-19 and was closely associated with cytokine levels (p=0.003). A high abundance of the genus Dialister (linear discriminant analysis [LDA] effect size: 3.97856, p=0.004), species Peptoniphilus lacrimalis (LDA effect size: 4.00551, p=0.020), and Anaerococcus prevotii (LDA effect size: 4.00885, p=0.007) was associated with a good prognosis. Starch, sucrose, and galactose metabolism was highly activated in the gut microbiota of the poor prognosis group. Glucose-lowering diets, including whole grains, were positively correlated with a good prognosis. Conclusion: Gut microbiota may mediate the prognosis of COVID-19 by regulating cytokine responses and controlling glucose metabolism, which is implicated in the host immune response to SARS-CoV-2.

The Incidence and Risk Factors of Renal Insufficiency among Korean HIV infected Patients: The Korea HIV/AIDS Cohort Study.

Renal insufficiency is one of the common issues in people living with human immunodeficiency virus (PLHIV). We studied the incidence and risk factors for renal insufficiency in male PLHIV using the Korea HIV/acquired immunodeficiency syndrome (AIDS) Cohort Study. Among the 830 enrolled patients, 32 (3.9%) cases of renal insufficiency occurred over 9576 patient-years of follow-up. The incidence of renal insufficiency in HIV-infected men in this study was 3.3 per 1000 patient-years. Diabetes mellitus, dyslipidemia, tenofovir or non-nucleoside reverse transcriptase inhibitor exposure for >1 year, and AIDS-defining illness were risk factors for renal insufficiency.

A Case of African Tick-Bite Fever in a Returning Traveler from Southern Africa.

African tick-bite fever (ATBF), caused by Rickettsia africae, is the second most frequent cause of fever after malaria in travelers returning from Southern Africa. As the Korean outbound travelers are increasing every year, tick-borne rickettsial diseases as a cause of febrile illness are likely to increase. We describe a febrile Korean returning traveler who showed two eschars after visiting the rural field in Manzini, Swaziland. We performed nested polymerase chain reaction using the eschar and diagnosed the patient with ATBF. He was treated with oral doxycycline for 7 days, and recovered without any complications. We believe that the present case is the first ATBF case diagnosed in a Korean traveler.

Shedding and extensive and prolonged environmental contamination of goat farms of Q fever patients by Coxiella burnetii.

BACKGROUND: A majority (>70%) of Q fever patients in South Korea do not have a history of animal contact. Therefore, unconscious environmental exposure is suspected. The aim of this study was to investigate exposure of Q fever patients to environmental contamination and animal shedding. METHODS: Two goat farmers were enrolled. One was diagnosed with Q fever 3 years ago (Farm 1). Among 20 goats on Farm 1, five were tested randomly and found to be Q fever PCR-positive. Three of the five were Q fever ELISA-positive. Two of five environmental samples taken in 2015 were PCR-positive. In 2018, 17 of 18 environmental samples were PCR-positive. On Farm 2, 54 of the 77 goats were PCR-positive, and 63 were ELISA-positive. Twelve of 14 environmental samples were PCR-positive. Repeat administration of oxytetracycline to goats led to a gradual reduction in PCR-positive tests over a 5-month period. However, PCR-positivity of the farm environment persisted for 5 months. CONCLUSION: The environment on farms owned by Q fever patients was contaminated extensively and persistently, even after antibiotic treatment of goats and environmental decontamination. Undetected environmental contamination can be a major source of sporadic Q fever infection in South Korea.

Enhanced antibody responses in fully vaccinated individuals against pan-SARS-CoV-2 variants following Omicron breakthrough infection.

Omicron has become the globally dominant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, creating additional challenges due to its ability to evade neutralization. Here, we report that neutralizing antibodies against Omicron variants are undetected following COVID-19 infection with ancestral or past SARS-CoV-2 variant viruses or after two-dose mRNA vaccination. Compared with two-dose vaccination, a three-dose vaccination course induces broad neutralizing antibody responses with improved durability against different SARS-CoV-2 variants, although neutralizing antibody titers against Omicron remain low. Intriguingly, among individuals with three-dose vaccination, Omicron breakthrough infection substantially augments serum neutralizing activity against a broad spectrum of SARS-CoV-2 variants, including Omicron variants BA.1, BA.2, and BA.5. Additionally, after Omicron breakthrough infection, memory T cells respond to the spike proteins of both ancestral and Omicron SARS-CoV-2 by producing cytokines with polyfunctionality. These results suggest that Omicron breakthrough infection following three-dose mRNA vaccination induces pan-SARS-CoV-2 immunity that may protect against emerging SARS-CoV-2 variants of concern.

Longitudinal study of meningococcal carriage rates in university entrants living in a dormitory in South Korea.

University students, especially those living in dormitories, are known to have a high risk of invasive meningococcal disease. We performed a longitudinal study to investigate the change in Neisseria meningitidis carriage rates and identify the risk factors for carriage acquisition in university students in South Korea. We recruited university entrants who were admitted to a student dormitory. Pharyngeal swabs were taken from participants at baseline, 1 month, and 3 months, and the subjects completed a questionnaire. Culture and real-time polymerase chain reaction (PCR) for species-specific ctrA and sodC genes were performed. The cultured isolates or PCR-positive samples were further evaluated for epidemiologic characterization using serogrouping, PorA typing, FetA typing, and multilocus sequence typing (MLST). At the first visit, we enrolled 332 participants who were predominantly male (64.2%) with a median age of 19 years. Meningococcal carriage rates increased from 2.7% (95% confidence interval [CI] 0.9-4.4%) at baseline to 6.3% (95% CI 3.4-9.0%) at 1 month and 11.8% (95% CI 7.8-15.6%) at 3 months. Nongroupable isolates accounted for 50.0% of all isolates, with serogroup B being the next most prevalent (24.1%). In the study population, male sex (OR 2.613, 95% CI 1.145-5.961, p = 0.022) and frequent pub or club visits (OR 3.701, 95% CI 1.536-8.919, p = 0.004) were significantly associated with meningococcal carriage. Based on serotype and MLST analyses, six carriers transmitted meningococci to other study participants. N. meningitidis carriage rates among new university entrants who lived in a dormitory significantly increased within the first 3 months of dormitory stay, probably owing to the transmission of identical genotype among students. Based on the risk of meningococcal disease, meningococcal vaccination should be considered for students before dormitory admission.

Splenic uptake on FDG PET/CT correlates with Kikuchi-Fujimoto disease severity.

Kikuchi-Fujimoto disease (KFD) is usually self-limiting, but prolonged systemic symptoms often result in frequent hospital visits, long admission durations, or missed workdays. We investigated the role of fluorine-18 fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing KFD severity. We reviewed the records of 31 adult patients with pathologically confirmed KFD who underwent 18F-FDG PET/CT between November 2007 and April 2018 at a tertiary-care referral hospital. Disease severity was assessed using criteria based on clinical manifestations of advanced KFD. Systemic activated lymph nodes and severity of splenic activation were determined using semi-quantitative and volumetric PET/CT parameters. The median of the mean splenic standardized uptake value (SUVmean) was higher in patients with severe KFD than those with mild KFD (2.38 ± 1.18 vs. 1.79 ± 0.99, p = 0.058). Patients with severe KFD had more systemically activated volume and glycolytic activity than those with mild KFD (total lesion glycolysis: 473.5 ± 504.4 vs. 201.6 ± 363.5, p = 0.024). Multivariate logistic regression showed that myalgia (odds ratio [OR] 0.035; 95% confidence interval [CI] 0.001-0.792; p = 0.035), total lymph node SUVmax (cutoff 9.27; OR 24.734; 95% CI 1.323-462.407; p = 0.032), and spleen SUVmean (cutoff 1.79; OR 37.770; 95% CI 1.769-806.583; p = 0.020) were significantly associated with severe KFD. 18F-FDG PET/CT could be useful in assessing KFD severity.

Risk Factors for Mortality in Patients with Elizabethkingia Infection and the Clinical Impact of the Antimicrobial Susceptibility Patterns of Elizabethkingia Species.

Elizabethkingia species (spp.), which can colonize hospital environments, are emerging nosocomial pathogens presenting high mortality. Due to their intrinsic resistance to a broad range of antibiotics, optimal antibiotic dosage has yet to be determined against infections caused by Elizabethkingia spp. This study aimed to investigate the risk factors for the mortality of infections caused by Elizabethkingia spp. and assess the clinical implications of their antimicrobial susceptibility patterns. Data from 210 patients affected by Elizabethkingia-induced pneumonia and bacteremia between 1 November 2005 and 31 May 2016, were analyzed. Further antimicrobial susceptibility tests for moxifloxacin, rifampin, and vancomycin using Elizabethkingia isolates were performed to compensate for the Elizabethkingia spp. susceptibility panel in patients affected after 2013. The mean age of the patients was 66.5 ± 18 years and the 28-day mortality rate was 25.2% (53/210). In the univariate analysis, history of prior stay in an intensive care unit, central venous catheter use, presented thrombocytopenia, immunocompetent status, a high simplified acute physiology score II (SAPS II score), a high C-reactive protein (CRP)/albumin ratio on the day of isolation and seven days later, and a high minimum inhibitory concentration (MIC) value of rifampin were significantly associated with a higher mortality rate. In the multivariate logistic regression analysis, the MIC values of rifampin (odds ratio (OR): 1.045; 95% confidence interval (CI): 1.006-1.085; p = 0.023), SAPS II score (OR: 1.053; 95% CI: 1.022-1.084; p = 0.001), and initial CRP/albumin ratio (OR: 1.030; 95% CI: 1.009-1.051; p = 0.004) were significantly associated with 28-day mortality. To reduce the mortality associated with Elizabethkingia infections, prediction of the clinical course using initial CRP/albumin ratio and SAPS II and early intervention are essential. Rifampin is a promising candidate as the drug of choice in treating Elizabethkingia infections.

Viable SARS-CoV-2 in various specimens from COVID-19 patients.

OBJECTIVES: The aim was to determine whether various clinical specimens obtained from COVID-19 patients contain the infectious virus. METHODS: To demonstrate whether various clinical specimens contain the viable virus, we collected naso/oropharyngeal swabs and saliva, urine and stool samples from five COVID-19 patients and performed a quantitative polymerase chain reaction (qPCR) to assess viral load. Specimens positive with qPCR were subjected to virus isolation in Vero cells. We also used urine and stool samples to intranasally inoculate ferrets and evaluated the virus titres in nasal washes on 2, 4, 6 and 8 days post infection. RESULTS: SARS-CoV-2 RNA was detected in all naso/oropharyngeal swabs and saliva, urine and stool samples collected between days 8 and 30 of the clinical course. Notably, viral loads in urine, saliva and stool samples were almost equal to or higher than those in naso/oropharyngeal swabs (urine 1.08 ± 0.16-2.09 ± 0.85 log10 copies/mL, saliva 1.07 ± 0.34-1.65 ± 0.46 log10 copies/mL, stool 1.17 ± 0.32 log10 copies/mL, naso/oropharyngeal swabs 1.18 ± 0.12-1.34 ± 0.30 log10 copies/mL). Further, viable SARS-CoV-2 was isolated from naso/oropharyngeal swabs and saliva of COVID-19 patients, as well as nasal washes of ferrets inoculated with patient urine or stool. DISCUSSION: Viable SARS-CoV-2 was demonstrated in saliva, urine and stool samples from COVID-19 patients up to days 11-15 of the clinical course. This result suggests that viable SARS-CoV-2 can be secreted in various clinical samples and respiratory specimens.

Profiles of Extrapulmonary Nontuberculous Mycobacteria Infections and Predictors for Species: A Multicenter Retrospective Study.

Extrapulmonary nontuberculous mycobacteria (NTM) infections contribute to morbidity and mortality worldwide. However, studies about extrapulmonary NTM infections have been limited. Therefore, we aim to describe the diversity of extrapulmonary NTM infections and identify predictors for species. Information regarding diversity of NTM isolates, antimicrobial susceptibility testing, treatment regimens, and outcomes were collected from four tertiary care centers in South Korea. Comparisons were made between patients with rapidly growing mycobacteria (RGM) and slowly growing mycobacteria (SGM) infections. A total of 117 patients (46 males vs. 71 females) were included. Skin and soft tissue infections (SSTIs) predominated (34.2%), followed by bone and joint infections (28.2%). In SSTIs, RGM species were predominantly identified (26/28, 92.9%), whereas SGM species were mainly identified in bone and joint infections (18/26, 69.2%), and the difference of isolated sites was verified by a post hoc test (p < 0.001). Multivariable regression analysis revealed that male sex (vs. female sex; OR 5.30, CI 1.35-24.26, p = 0.020) and bone and joint infections (vs. SSTIs; OR 18.10, CI 3.28-157.07, p = 0.002) were predictors of SGM infections, whereas the opposite was observed for RGM infections. Bone and joint infections and male sex were predictors for SGM infections, whereas SSTIs and female sex were predictors for RGM infections.

Cost-effectiveness analysis of pre-exposure prophylaxis for the prevention of HIV in men who have sex with men in South Korea: a mathematical modelling study.

In February 2018, the Ministry of Food and Drug Safety in Korea approved tenofovir disoproxil fumarate and emtricitabine (TDF/FTC) co-formulate for use in pre-exposure prophylaxis (PrEP) for the prevention of human immunodeficiency virus (HIV) infection. This study aimed to estimate the cost-effectiveness of PrEP in men who have sex with men (MSM), a major risk group emerging in Korea. A dynamic compartmental model was developed for HIV transmission and progression in MSM aged 15-64 years. With a combined model including economic analysis, we estimated averted HIV infections, changes in HIV prevalence, discounted costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). PrEP was evaluated in both the general MSM and high-risk MSM populations and was assumed to reduce infection risk by 80%. Implementing PrEP in all MSM would avert 75.2% HIV infections and facilitate a gain of 37,372 QALYs at a cost of $274,822 per QALY gained over 20 years relative to the status quo. Initiating PrEP in high-risk MSM with an average of eight partners per year (around 20% of MSM) would improve the cost-effectiveness, averting 78.0% HIV infections and add 29,242 QALYs at a cost of $51,597 per QALY gained, which is within the willingness-to-pay threshold for Korea of $56,000/QALY gained. This result was highly sensitive to annual PrEP costs, quality-of-life for people who are on PrEP, and initial HIV prevalence. Initiating PrEP in a larger proportion of MSM in Korea would prevent more HIV infections, but at an increasing cost per QALY gained. Focusing PrEP on higher risk MSM and any reduction in PrEP cost would improve cost-effectiveness.

Comparison of Characteristics and Survival between Prospective and Retrospective Korea Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome Cohort Studies.

By comparing the data of prospectively and retrospectively enrolled cohorts, we evaluated whether the prospective cohort represented all patients in the retrospective cohort. The prospectively enrolled subjects were older and had lower CD4+ T cell counts, higher viral load. In addition, the initial antiretroviral treatment regimen of the prospective cohort consisted of less integrase strand transfer inhibitor-containing regimens. The 20-year survival rate was 51.8% in the prospective cohort and 84.6% in the retrospective cohort, respectively (P = 0.844). This study suggests the prospective cohort study may not represent all patients.

Characteristics of Faecal Microbiota in Korean Patients with Clostridioides difficile-associated Diarrhea.

BACKGROUND: The intestinal microbiota plays an important role in the pathogenesis of Clostridioides difficile-associated diarrhea, and regional and racial characteristics influence the microbiome composition and diversity. We investigated the intestinal microbiome characteristics of patients with C. difficile colitis (CD+) compared to those of patients with colitis not due to C. difficile (CD-), patients with vancomycin-resistant enterococci (VRE) colonization, and healthy controls, in Korea. MATERIALS AND METHODS: We collected stool samples from 24, 18, 11 and 13 subjects within CD+, CD-, VRE and healthy control groups, respectively. The microbial communities were evaluated by 454-pyrosequencing of bacterial 16s rRNA. RESULTS: The species richness and microbial diversity were significantly lower in the CD+ group compared to those in healthy controls, but not compared to those in CD- and VRE groups. Phylum-level analysis showed that the proportion of Actinobacteria in the CD+ group was significantly lower than in the healthy control, but was unchanged compared to that in CD- and VRE groups. At the genus level, compared to the healthy group, the CD+ group showed significantly lower proportions of Blautia, Bifidobacterium, Faecalibacterium et al. Compared to the VRE group, the CD+ group showed a significantly higher proportion of Anaerostipes. CONCLUSIONS: We could identify the intestinal microbiome characteristics of Koreans with C. difficile colitis. It might help to develop microbiome based diagnostic and treatment modalities.