The microbiology of periprosthetic joint infections as revealed by sonicate cultures in Korea: Routine use of fungal and mycobacterial cultures is necessary?

BACKGROUND: Although sonication is a valuable diagnostic tool for periprosthetic joint infections (PJI), it is not commonly utilized. We analyzed sonicate and intraoperative tissue culture results obtained from three hospitals to define the microbial etiology of PJIs in Korea. Furthermore, we investigated necessity of conducting regular fungal and mycobacterial cultures. METHODS: We retrospectively analyzed data for patients with suspected orthopedic-related infections between 2017 and 2022, who had undergone prostheses removal surgery. We included 193 patients with suspected PJIs, and bacterial (n = 193), fungal (n = 193), and mycobacterial (n = 186) cultures were conducted on both sonicate and intraoperative tissue samples. The diagnosis of PJI was based on the European Bone and Joint Infection Society (EBJIS) criteria. RESULTS: Out of 193 patients, 121 (62.7%) had positive sonicate cultures, while 112 (58.0%) had positive periprosthetic tissue cultures. According to EBJIS criteria, a total of 181 patients were diagnosed with PJI, and 141 patients received microbiological confirmation through sonicate fluid culture or tissue culture. Of the 181 patients, 28 were classified with acute PJI (within 3 months of implantation) and 153 with chronic PJI. Among 141 patients, staphylococci were the most common organisms, accounting for 51.8% of cases, followed by Gram-negative organisms (15.6%), fungus (8.5%), and mycobacteria (3.5%). Nearly 91.7% of fungal isolates were Candida species, which also grew in bacterial cultures. In total, 11 cases cultured positive only in tissue culture, whereas 20 cases cultured positive only in sonicate culture. The antibiotic treatment plans were adjusted according to culture results. CONCLUSIONS: Utilizing sonicate culture has greatly assisted in identifying pathogens responsible for chronic indolent PJIs, allowing suitable antimicrobial treatment. Based on few cases involving non-Candida and mycobacterial infections, it appears that routine fungal and mycobacterial cultures may not be necessary.

Comparative Study on the Immunogenicity of COVID-19 mRNA Vaccines in Patients Receiving Adjuvant and Palliative Chemotherapy.

This study was conducted to investigate potential differences in vaccine efficacy between patients undergoing palliative chemotherapy and receiving adjuvant chemotherapy. Additionally, the study proved the influence of vaccination timing on vaccine efficacy during active chemotherapy. Anti-receptor-binding domain (RBD) IgG binding antibody assays and surrogate neutralizing antibody assays were performed after BNT162b2 or mRNA-1273 vaccination in 45 solid cancer patients (23 adjuvant and 22 palliative chemotherapy) and in 24 healthy controls before vaccination (baseline), at every two to four weeks after the first (post-dose 1) and the second vaccination (post-dose 2). The levels of anti-RBD IgG and neutralizing antibodies increased significantly from baseline through post-dose 1 to post-dose 2 in all three groups. At the post-dose 1, the anti-RBD IgG and neutralizing antibody levels were significantly lower in cancer patients than in healthy controls. However, by post-dose 2, the seropositivity of anti-RBD IgG and neutralizing antibodies uniformly reached 100% across all groups, with no significant disparity in antibody levels among the three groups. Moreover, the antibody titers were not significantly different between patients with a vaccine and chemotherapy interval of more than 14 days or those with less than 14 days. This study demonstrated that after second doses of mRNA COVID-19 vaccines, humoral immune responses in patients receiving chemotherapy were comparable to those of healthy controls, regardless of whether the purpose of the anti-cancer treatment was palliative or adjuvant. Furthermore, the timing of vaccination did not affect the level of humoral immunity after the second vaccination.

Under-diagnosis of vector-borne diseases among individuals suspected of having Scrub Typhus in South Korea.

Due to environmental and ecological changes and suitable habitats, the occurrence of vector-borne diseases is increasing. We investigated the seroprevalence of four major vector-borne pathogens in human patients with febrile illness who were clinically suspected of having Scrub Typhus (ST) caused by Orientia tsutsugamushi. A total of 187 samples (182 patient whole blood and sera samples, including 5 follow-up) were collected. Antibodies to Anaplasma phagocytophilum, Ehrlichia chaffeensis, Borrelia burgdorferi, and Bartonella henselae were tested by using indirect immunofluorescence assays. Molecular diagnoses were performed using real-time PCR. Of the 182 cases, 37 (20.3%) cases were designated as confirmed cases of ST, and the remaining 145 (79.7%) cases as other febrile diseases (OFDs). The seroprevalence of A. phagocytophilum, E. chaffeensis, B. burgdorferi, and B. henselae was 51.4% (19/37), 10.8% (4/37), 86.5% (32/37), and 10.8% (4/37) among the ST group, and 42.8% (62/145), 10.4% (19/145), 57.7% (105/145), and 15.9% (29/145) among the OFD group, respectively. There were no significant differences in the seroprevalence between the ST and the OFD groups. Considering the co-occurrence, 89.0% (162/182) had at least one antibody to tick-borne pathogens, 37.0% (60/162) were positive for two pathogens, 17.3% (28/162) for three pathogens, and 6.2% (10/162) for four pathogens. In real-time PCR, O. tsutsugamushi was positive in 16 cases [15 (40.5%) in ST group and 1 (2.2%) in OFD group], and the four other pathogens were negative in all cases except one confirmed as anaplasmosis. In evaluating the five follow-up samples, the appearance of new antibodies or an increase in the pre-existing antibody titers was detected. Our data highlighted that acute febrile illness and manifestations suggestive of a vector-borne infection must be recognized and further considered for coinfections in clinical practice and the laboratory.

Fosfomycin for Antibiotic Prophylaxis in Men Undergoing a Transrectal Prostate Biopsy: A Systematic Review and Meta-Analysis.

Background and Objectives: To assess the effects of fosfomycin compared with other antibiotics as a prophylaxis for urinary tract infections (UTIs) in men undergoing transrectal prostate biopsies. Materials and Methods: We searched multiple databases and trial registries without publication language or status restrictions until 4 January 2022. Parallel-group randomized controlled trials (RCTs) and non-randomized studies (NRS) were included. The primary outcomes were febrile UTI, afebrile UTI, and overall UTI. We used GRADE guidance to rate the certainty of evidence of RCTs and NRSs. The protocol was registered with PROSPERO (CRD42022302743). Results: We found data on five comparisons; however, this abstract focuses on the primary outcomes of the two most clinically relevant comparisons. Regarding fosfomycin versus fluoroquinolone, five RCTs and four NRSs with a one-month follow-up were included. Based on the RCT evidence, fosfomycin likely resulted in little to no difference in febrile UTIs compared with fluoroquinolone. This difference corresponded to four fewer febrile UTIs per 1000 patients. Fosfomycin likely resulted in little to no difference in afebrile UTIs compared with fluoroquinolone. This difference corresponded to 29 fewer afebrile UTIs per 1000 patients. Fosfomycin likely resulted in little to no difference in overall UTIs compared with fluoroquinolone. This difference corresponded to 35 fewer overall UTIs per 1000 patients. Regarding fosfomycin and fluoroquinolone combined versus fluoroquinolone, two NRSs with a one- to three-month follow-up were included. Based on the NRS evidence, fosfomycin and fluoroquinolone combined may result in little to no difference in febrile UTIs compared with fluoroquinolone. This difference corresponded to 16 fewer febrile UTIs per 1000 patients. Conclusions: Compared with fluoroquinolone, fosfomycin or fosfomycin and fluoroquinolone combined may have a similar prophylactic effect on UTIs after a transrectal prostate biopsy. Given the increasing fluoroquinolone resistance and its ease to use, fosfomycin may be a good option for antibiotic prophylaxis.

Thermally Managed, Injectable Optoelectronic Probe with Heat Dissipation Guide for Photodynamic Therapy.

The development of fabrication technologies and appearance of new materials has resulted in dramatic increase in the performance of electronic devices, while the overall size has decreased. Recent electronic devices made of micro/nano-size components show high efficiency and outstanding performance with compact size, but these devices have revealed several fatal problems. In particular, the isolated heat that is generated by numerous components concentrated in a limited small area at high density, such as bio-integrated devices, is an issue that needs to be urgently addressed, because it is closely related to the performance and lifetime of electronic devices. To solve these problems, the microscale light emitting diode (µLED)-based neural probe is introduced on an injectable heat dissipation guide. The heat dissipation guide is made of boron nitride (BN) nanomaterials with high thermal conductivity. The heat management noticeably improves the optical output performance of the µLEDs, in which BN effectively dissipates heat, and allows enhanced lighting from the LEDs to be transmitted through brain tissue without thermal damage. Moreover, it shows remarkable improvement in the therapeutic effect of photodynamic therapy of mouse cancer cells.

A Double-Blind, Randomized, Placebo-Controlled, Phase II Clinical Study To Evaluate the Efficacy and Safety of Camostat Mesylate (DWJ1248) in Adult Patients with Mild to Moderate COVID-19.

Although several antiviral agents have become available for coronavirus disease 2019 (COVID-19) treatment, oral drugs are still limited. Camostat mesylate, an orally bioavailable serine protease inhibitor, has been used to treat chronic pancreatitis in South Korea, and it has an in vitro inhibitory potential against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study was a double-blind, randomized, placebo-controlled, multicenter, phase 2 clinical trial in mild to moderate COVID-19 patients. We randomly assigned patients to receive either camostat mesylate (DWJ1248) or placebo orally for 14 days. The primary endpoint was time to clinical improvement of subject symptoms within 14 days, measured using a subjective 4-point Likert scale. Three hundred forty-two patients were randomized. The primary endpoint was nonsignificant, where the median times to clinical improvement were 7 and 8 days in the camostat mesylate group and the placebo group, respectively (hazard ratio [HR] = 1.09; 95% confidence interval [CI], 0.84 to 1.43; P = 0.50). A post hoc analysis showed that the difference was greatest at day 7, without reaching significance. In the high-risk group, the proportions of patients with clinical improvement up to 7 days were 45.8% (50/109) in the camostat group and 38.4% (40/104) in the placebo group (odds ratio [OR] = 1.33; 95% CI, 0.77 to 2.31; P = 0.31); the ordinal scale score at day 7 improved in 20.0% (18/90) of the camostat group and 13.3% (12/90) of the placebo group (OR = 1.68; 95% CI, 0.75 to 3.78; P = 0.21). Adverse events were similar in the two groups. Camostat mesylate was safe in the treatment of COVID-19. Although this study did not show clinical benefit in patients with mild to moderate COVID-19, further clinical studies for high-risk patients are needed. (This trial was registered with ClinicalTrials.gov under registration no. NCT04521296).

Nosocomial Outbreak of COVID-19 from a Kidney Transplant Patient: Necessity of a Longer Isolation Period in Immunocompromised Patients.

BACKGROUND: Determination of the release from isolation for coronavirus disease 2019 (COVID-19) in immunocompromised patients who need additional hospitalization for treatment of non-COVID-19 related disease is important to prevent nosocomial transmission. However, there is insufficient evidence for an extended isolation period. MATERIALS AND METHODS: In September 2021, when the Delta variant was dominant, a nosocomial outbreak of COVID-19 occurred in the nephrology ward of a tertiary hospital in Gwangju, Korea. We conducted epidemiological investigations and whole-genome sequencing (WGS) of this virus. RESULTS: A man who underwent kidney transplantation was admitted to our hospital for the treatment of acute kidney injury. He was diagnosed with asymptomatic COVID-19 infection during a pre-admission screening test on September 1, 2021 and underwent isolation. After 10 days of isolation in the COVID-19-designated ward, he was transferred to the general nephrology ward. He underwent steroid pulse therapy (September 17 to September 23, >60 mg/day prednisolone) due to acute T-cell rejection. On September 28, 2021, the first patient with COVID-19 was identified in the nephrology ward, and a rapid-response team was activated to identify additional patients with COVID-19 and prevent the spread of COVID-19. Epidemiological investigations revealed that 12 patients, two caregivers, and three healthcare workers from the nephrology ward were diagnosed with COVID-19. The WGS of specimens from 14 nosocomial outbreak samples and released an index patient exhibited the same Delta variant originating from the B.1.617.2 lineage. This hospital-acquired COVID-19 outbreak in the nephrology ward resulted in two (11.7%) deaths in patients who underwent kidney transplantation. CONCLUSION: We demonstrated that an immunocompromised patient can cause a nosocomial outbreak due to the prolonged shedding of infectious viruses. Prolonged isolation in patients under active immunosuppressive therapy may be necessary to prevent transmission, especially in the hospital setting.

Replacement of the Dominant ST191 Clone by ST369 Among Carbapenem-Resistant Acinetobacter baumannii Bloodstream Isolates at a Tertiary Care Hospital in South Korea.

The clonal dissemination of carbapenem-resistant Acinetobacter baumannii (CRAB) bacteremia is a serious clinical problem worldwide. However, the factors related to the emergence and replacement of predominant CRAB clones in nosocomial settings are unclear. By multilocus sequence typing (MLST), we evaluated the genetic relatedness of CRAB bloodstream isolates at a tertiary care hospital over a 3.5-year period and investigated the clinical and microbiologic characteristics of the predominant sequence types (STs). One hundred and seventy-nine CRAB bloodstream isolates were collected from June 2016 to December 2019, and their MLSTs according to Oxford scheme and clinical data were obtained. The predominant STs were assessed for in vitro growth, competitive growth, and virulence in a mouse model of intraperitoneal infection. Two dominant clones-ST369 (n = 98) and ST191 (n = 48)-belonging to international clone 2 (IC2) were recovered from patients admitted to intensive care units (ICUs) or wards. ST191 predominated (61%, 27/43) from June 2016 to July 2017, whereas ST369 (72%, 98/136), which was first isolated from a patient admitted to the emergency room, replaced ST191 (15%, 21/136) after August 2017. In a multivariate analysis, leukopenia (OR = 3.62, 95% CI 1.04-12.6, p = 0.04) and ST191 or 369 (OR = 5.32, 95% CI 1.25-22.65, p = 0.02) were independent risk factors for 7-day mortality. Compared with non-ST369, ST369 was associated with a shorter time to bacteremia from ICU admission (7 vs. 11 days, p = 0.01), pneumonia as an origin of bacteremia (67 vs. 52%, p = 0.04), leukopenia (28 vs. 11%, p < 0.01), and a lower 7-day survival rate (41 vs. 70%, p < 0.01). In vitro, ST 369 isolates had significantly higher growth rates and enhanced competitive growth compared to ST191. Finally, ST369 had greater virulence and a higher mortality rate than other STs in a mouse infection model. We report almost-complete replacement of the predominant ST191 clone by ST369 within an 8-month period at our hospital. ST369 had a high incidence density rate of CRAB bacteremia, a short time to bacteremia after ICU admission, and a high early mortality rate, which may be in part explained by its faster competitive growth rate and higher virulence than ST191.

Weight Gain and Lipid Profile Changes in Koreans with Human Immunodeficiency Virus undergoing Integrase Strand Transfer Inhibitor-Based Regimens.

BACKGROUND: This study explored the relationship between integrase strand transfer inhibitor (INSTI)-based anti-retroviral agents and weight gain over time, and the risk factors for weight gain in Korean people living with human immunodeficiency virus (PLWH). MATERIALS AND METHODS: The study was conducted retrospectively in PLWHs 18 years of age or older who took one of three INSTI-based single-tablet regimens (STRs) (tenofovir disoproxil fumarate/emtricitabine/elvitegravir/cobicistat [TDF/F/EVG/c], tenofovir alafenamide/emtricitabine/elvitegravir/cobicistat [TAF/F/EVG/c], and abacavir/lamivudine/dolutegravir [ABC/3TC/DTG]) for more than 2 years at three university-affiliated hospitals in South Korea from May 2014 to December 2020. Analysis was performed in the treatment-naïve and treatment-experienced groups, respectively. RESULTS: Individual INSTI-based STRs were associated with weight gain at the 24-month follow up in both treatment-naïve (n = 179) and treatment-experienced (n = 290) groups. Body mass index (BMI) categories changed over time for TAF/F/EVG/c and ABC/3TC/DTG, with significant increases in the rates of overweight and obesity in treatment-naïve patients, whereas there was no change for TDF/F/EVG/c. TAF/F/EVG/c significantly increased total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) compared to other regimens over 24 months. In the treatment-naïve group, a baseline CD4+ T cell count <100 cells/mm3, human immunodeficiency virus (HIV) viral load (VL) ≥100,000 copies/mL, no physical exercise, and TAF/F/EVG/c (vs. TDF/F/EVF/c) were risk factors for ≥10% weight gain. In the treatment-experienced group, age <45 years, BMI <25 kg/m², and no physical exercise were risk factors for ≥5% weight gain. CONCLUSION: INSTI-based STR continued to increase body weight at the 24-month follow up in treated and untreated Korean PLWH. Exercise, together with demographic-, HIV-, and anti-retroviral therapy-related factors, influenced weight gain. Therefore, when prescribing an INSTI-based STR, weight gain and metabolic changes should be closely monitored in PLWH with these risk factors.

Positivity rates of mycobacterial culture in patients with tuberculous spondylitis according to methods and sites of biopsies: An analysis of 206 cases.

OBJECTIVES: We aimed to evaluate the mycobacterial culture positivity rates according to biopsy methods and sites in patients with tuberculous spondylitis (TS) and identify which tissues are the best sites for the diagnosis of TS. METHODS: We retrospectively identified and reviewed medical records of all patients with TS in three university-affiliated hospitals in the Republic of Korea from January 2003 to December 2020. TS was diagnosed by culture or histopathologic examination of vertebral bodies or paraspinal tissues and characteristic clinical and radiologic features. Patients with TS who received a needle biopsy or underwent surgical biopsy were investigated. The sites of needle biopsy were classified as vertebral bodies or paraspinal tissues. RESULTS: During the study period, 206 tissues from 200 patients with TS were included in the analysis. The culture positivity rates of vertebral bodies obtained by needle biopsy, paraspinal tissues obtained by needle biopsy, and tissues obtained by surgery were 69.0%, 85.3%, and 83.2%, respectively. Multivariate logistic regression identified that paraspinal tissues as biopsy sites were independently associated with mycobacterial culture positivity in TS undergoing needle biopsy (adjusted odds ratio, 3.68; 95% confidence interval: 1.13-11.99, P = 0.030). CONCLUSIONS: We demonstrated that the positivity rates of mycobacterial culture in TS were 69.0-85.3%. Paraspinal tissues as biopsy sites were significantly associated with culture positivity in needle biopsy, suggesting that targeting paraspinal tissues during needle biopsy may be the best method for diagnosing TS.

Performance of Severe Acute Respiratory Syndrome Coronavirus 2 Serological Diagnostic Tests and Antibody Kinetics in Coronavirus Disease 2019 Patients.

Serological testing is recommended to support the detection of undiagnosed coronavirus disease 2019 (COVID-19) cases. However, the performance of serological assays has not been sufficiently evaluated. Hence, the performance of six severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binding antibody assays [three chemiluminescence (CLIAs) and three lateral flow immunoassays (LFIAs)] and a surrogate virus neutralization test (sVNT) was analyzed in a total of 988 serum samples comprising 389 COVID-19-positives and 599 COVID-19-negatives. The overall diagnostic sensitivities of CLIAs and LFIAs ranged from 54.2 to 56.6% and from 56.3 to 64.3%, respectively. The overall diagnostic specificities of CLIAs and LFIAs ranged from 98.2 to 99.8% and from 97.3 to 99.0%, respectively. In the symptomatic group (n = 321), the positivity rate increased by over 80% in all assays > 14 days after symptom onset. In the asymptomatic group (n = 68), the positivity rate increased by over 80% in all assays > 21 days after initial RT-PCR detection. In LFIAs, negatively interpreted trace bands accounted for the changes in test performance. Most false-positive results were weak or trace reactions and showed negative results in additional sVNT. For six binding antibody assays, the overall agreement percentages ranged from 91.0 to 97.8%. The median inhibition activity of sVNT was significantly higher in the symptomatic group than in the asymptomatic group (50.0% vs. 29.2%; p < 0.0001). The median times to seropositivity in the symptomatic group were 9.7 days for CLIA-IgG, 9.2 and 9.8 days for two CLIAs-Total (IgM + IgG), 7.7 days for LFIA-IgM, 9.2 days for LFIA-IgG, and 8.8 days for sVNT-IgG, respectively. There was a strong positive correlation between the quantitative results of the four binding antibody assays and sVNT with Spearman ρ-values ranging from 0.746 to 0.854. In particular, when using LFIAs, we recommend using more objective interpretable assays or establishing a band interpretation system for each laboratory, accompanied by observer training. We also anticipate that sVNT will play an essential role in SARS-CoV-2 antibody testing and become the practical routine neutralizing antibody assay.

Measles susceptibility of marriage migrant women in Korea.

International migrants could be considered a risk group susceptible to vaccine-preventable diseases. We conducted a measles seroprevalence study among 419 marriage migrant women living in Sinan-gun and Wando-gun, South Jeolla Province, located in the southwestern part of Korea. The overall seroimmunity was 92.8%. The seroimmunity varied considerably according to the country of origin and increased with age. Our current analysis could be valuable in the context of discussions concerning vaccination policies for immigrants in Korea.

In vivo imaging of invasive aspergillosis with 18F-fluorodeoxysorbitol positron emission tomography.

Invasive aspergillosis is a critical complication in immunocompromised patients with hematologic malignancies or with viral pneumonia caused by influenza virus or SARS­CoV­2. Although early and accurate diagnosis of invasive aspergillosis can maximize clinical outcomes, current diagnostic methods are time-consuming and poorly sensitive. Here, we assess the ability of 2-deoxy-2-18F-fluorosorbitol (18F-FDS) positron emission tomography (PET) to specifically and noninvasively detect Aspergillus infections. We show that 18F-FDS PET can be used to visualize Aspergillus fumigatus infection of the lungs, brain, and muscles in mouse models. In particular, 18F-FDS can distinguish pulmonary aspergillosis from Staphylococcus aureus infection, both of which induce pulmonary infiltrates in immunocompromised patients. Thus, our results indicate that the combination of 18F-FDS PET and appropriate clinical information may be useful in the differential diagnosis and localization of invasive aspergillosis.

Rifamycin resistance, rpoB gene mutation and clinical outcomes of Staphylococcus species isolates from prosthetic joint infections in Republic of Korea.

OBJECTIVES: We conducted an in vitro investigation of the activity of rifamycins against planktonic and biofilm states of Staphylococcus aureus and Staphylococcus epidermidis isolates from patients with prosthetic joint infections (PJIs), characterised their rpoB gene mutations, and analysed the clinical outcomes of rifampicin-resistant isolates. METHODS: A total of 110 staphylococcal isolates were collected from patients with PJI. Antimicrobials tested using the broth microdilution method included rifampicin, rifabutin, rifapentine and rifaximin. We evaluated rpoB gene mutations to identify rifampicin resistance mechanisms. Clinical outcomes were assessed in rifampicin-resistant isolates. RESULTS: The 110 staphylococcal isolates included 85 S. aureus (55% methicillin-resistant) and 25 S. epidermidis (100% methicillin-resistant). Seven S. aureus isolates and two S. epidermidis isolates were resistant to rifampicin [minimum inhibitory concentration (MIC) ≥2 µg/mL] and these isolates exhibited rpoB gene mutations. Among the 78 rifampicin-susceptible S. aureus isolates and 23 S. epidermidis isolates, 76 S. aureus isolates (97.4%) and all S. epidermidis isolates (100%) were highly susceptible (MIC ≤ 0.06 µg/mL) to other rifamycins. The minimum biofilm bactericidal concentrations for ≥50% of isolates (MBBC50) to rifampicin, rifabutin, rifapentine and rifaximin were 4, 1, 2 and 4 µg/mL for S. aureus and 1, 0.125, 0.25 and 0.5 µg/mL for S. epidermidis, respectively, among rifampicin-susceptible isolates. Among nine patients bearing rifampicin-resistant isolates, only three (33%) had successful outcomes. CONCLUSION: Rifamycins other than rifampicin show promising antistaphylococcal activity, including antibiofilm activity. Rifamycin-resistant staphylococci exhibit rpoB gene mutations.

Genomic characterization of nine Clostridioides difficile strains isolated from Korean patients with Clostridioides difficile infection.

BACKGROUND: Clostridioides difficile infection (CDI) is an infectious nosocomial disease caused by Clostridioides difficile, an opportunistic pathogen that occurs in the intestine after extensive antibiotic regimens. RESULTS: Nine C. difficile strains (CBA7201-CBA7209) were isolated from nine patients diagnosed with CDI at the national university hospital in Korea, and the whole genomes of these strains were sequenced to identify their genomic characteristics. Comparative genomic analysis was performed using 51 reference strains and the nine isolated herein. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that all 60 C. difficile strains belong to the genus Clostridioides, while core-genome tree indicated that they were divided into five groups, which was consistent with the results of MLST clade analysis. All strains were confirmed to have a clindamycin antibiotic resistance gene, but the other antibiotic resistance genes differ depending on the MLST clade. Interestingly, the six strains belonging to the sequence type 17 among the nine C. difficile strains isolated here exhibited unique genomic characteristics for PaLoc and CdtLoc, the two toxin gene loci identified in this study, and harbored similar antibiotic resistance genes. CONCLUSION: In this study, we identified the specific genomic characteristics of Korean C. difficile strains, which could serve as basic information for CDI prevention and treatment in Korea.

Associations Between COVID-19 Symptoms and Psychological Distress.

Background: Hospital isolation for COVID-19 may cause significant psychological stress. The association between COVID-19 symptoms and psychological symptoms has not been systematically studied. We investigated the effects of telephonic intervention on the relationship between psychological symptoms and COVID-19 symptoms at the time of hospitalization and 1 week later. Method: We screened 461 patients with COVID-19 for psychiatric symptoms from February 29, 2020, to January 3, 2021. In total, 461 patients were evaluated 2 days after admission, and 322 (69.8%) were followed 1 week later. To assess anxiety and depressive symptoms, the Hospital Anxiety and Depression Scale (HADS) was administered to patients once per week. The Insomnia Severity Index (ISI) and item 9 of the Beck Depression Inventory (BDI-9) were used weekly to assess insomnia and suicidal ideation. Results: Of 461 enrolled patients, we observed clinically meaningful psychological anxiety symptoms (in 75/16.3% of patients), depression (122/26.5%), insomnia (154/33.4%), and suicidal ideation (54/11.7%). Commonly reported COVID-19 symptoms are cough/sputum/sneezing (244, 52.9%), headache/dizziness (98, 21.3%), myalgia (113, 24.5%), and sore throat (89, 19.3%). Compared to baseline, significant improvements were found in anxiety, depression, and suicidal ideation at 1 week. No significant group differences in ISI score were observed. Conclusions: COVID-19 symptoms at baseline had a significant and persistent negative impact on anxiety and depression at admission and at 1 week after hospitalization. Early intervention is essential to improve the outcomes of patients with mental illness.

Successful control of COVID-19 outbreak through tracing, testing, and isolation: Lessons learned from the outbreak control efforts made in a metropolitan city of South Korea.

The first surge of coronavirus disease 2019 (COVID-19) cases began on June 27, 2020 in Gwangju metropolitan city, located in the southwestern part of South Korea, with a population of 1,501,000. Local governments and the Korean Center for Disease Control and Prevention immediately started an epidemiologic investigation and traced the contacts of patients using a wide variety of data sources, including location data from mobile devices, credit card transaction, and closed-circuit television footage. Until July 16, 2020, 138 community transmission cases and 10 infection clusters were identified across the city. Through contact tracing, epidemiologic relatedness was found in 136 (98.6%) of 138 cases. Our investigation showed how the extensive and meticulous contact tracing suppressed COVID-19 outbreak in a populated city.

Veno-arterial extracorporeal membrane oxygenation for severe fever with thrombocytopenia syndrome with fulminant myocarditis: a case report.

BACKGROUND: The clinical spectrum of severe fever with thrombocytopenia syndrome (SFTS) is wide, which can range from fever to multiple organ failure. Conservative therapy plays a key role in the treatment of SFTS. However, severe cases of SFTS, such as fulminant myocarditis, may require mechanical hemodynamic support. CASE PRESENTATION: This report presents a case of a 59-year old woman diagnosed with SFTS by reverse-transcription polymerase chain reaction. The patient had no initial symptoms of cardiac involvement and rapidly developed hemodynamic instability 3 days after hospitalization. She suffered from chest pain and had elevated cardiac enzymes. In the absence of atrio-ventricular conduction abnormalities, left ventricular dysfunction, and coronary artery abnormalities by coronary angiography, she was diagnosed with fulminant myocarditis. At that time, her pulse rate nearly dropped to 0 bpm and she developed near complete akinesia of the heart despite vasopressor administration. Veno-arterial extracorporeal membrane oxygenation (ECMO) was initiated with other supportive measures and she fully recovered after 21 days. CONCLUSIONS: This case indicates that SFTS can cause fulminant myocarditis even without evidence of cardiac involvement at presentation. When symptoms and/or signs of acute heart failure develop in patients with SFTS, myocarditis should be suspected and the patient should be promptly evaluated. Additionally, mechanical hemodynamic support like ECMO can be a lifesaving tool in the treatment of fulminant myocarditis.

Circulating Plasmacytoid and Conventional Dendritic Cells Are Numerically and Functionally Deficient in Patients With Scrub Typhus.

Background: Dendritic cells (DCs) are specialized antigen-presenting cells known to bridge innate and adaptive immune reactions. However, the relationship between circulating DCs and Orientia tsutsugamushi infection is unclear. Therefore, this study aimed to examine the level and function of plasmacytoid DCs (pDCs) and conventional DCs (cDCs), two subsets of circulating DCs, in scrub typhus patients. Methods: The study included 35 scrub typhus patients and 35 healthy controls (HCs). pDC and cDC levels, CD86 and CD274 expression, and cytokine levels were measured using flow cytometry. Results: Circulating pDC and cDC levels were found to be significantly reduced in scrub typhus patients, which were correlated with disease severity. The patients displayed increased percentages of CD86+ pDCs, CD274+ pDCs, and CD274+ cDCs in the peripheral blood. The alterations in the levels and surface phenotypes of pDCs and cDCs were recovered in the remission state. In addition, the production of interferon (IFN)-α and tumor necrosis factor (TNF)-α by circulating pDCs, and interleukin (IL)-12 and TNF-α by circulating cDCs was reduced in scrub typhus patients. Interestingly, our in vitro experiments showed that the percentages of CD86+ pDCs, CD274+ pDCs, and CD274+ cDCs were increased in cultures treated with cytokines including IFN-γ, IL-12, and TNF-α. Conclusions: This study demonstrates that circulating pDCs and cDCs are numerically deficient and functionally impaired in scrub typhus patients. In addition, alterations in the expression levels of surface phenotypes of pDCs and cDCs could be affected by pro-inflammatory cytokines.