Comparison of the Clinical Outcomes Between Early and Delayed Transplantation After SARS-CoV-2 Infection

Our study analyzed 95 solid organ transplant (SOT) and 78 hematopoietic stem cell transplant (HSCT) recipients with prior coronavirus disease 2019 (COVID-19). Patients who underwent transplantation within 30 days of COVID-19 infection comprised the early group, and those who underwent transplantation post-30 days of COVID-19 infection comprised the delayed group. In the early transplantation group, no patient, whether undergoing SOT and HSCT, experienced COVID-19-associated complications. In the delayed transplantation group, one patient each from SOT and HSCT experienced COVID-19-associated complications. Additionally, among early SOT and HSCT recipients, two and six patients underwent transplantation within seven days of COVID-19 diagnosis, respectively. However, no significant differences were observed in the clinical outcomes of these patients compared to those in other patients. Early transplantation following severe acute respiratory syndrome coronavirus 2 infection can be performed without increased risk of COVID-19-associated complications. Therefore, transplantation needs not be delayed by COVID-19 infection.

Clinical safety of remdesivir therapy in COVID-19 patients with renal insufficiency

Though remdesivir benefits COVID-19 patients, its use in those with renal dysfunction is currently limited due to concerns about possible toxic effects of accumulated sulfobutylether-β-cyclodextrin (SBECD) on liver and kidney. We examined renal and hepatic function for a month in renally-impaired COVID-19 patients who were treated or not treated with remdesivir to assess the safety of the drug. A retrospective study was performed in adult COVID-19 patients with glomerular filtration rates of <30 ml/min/1.73 m2 at admission to a tertiary care hospital between November 2020 and March 2022. Data on serum creatinine and liver chemistry were collected serially. A total of 101 patients with impaired renal function were analyzed, comprising 64 remdesivir-treated patients and 37 who did not receive any antiviral agent. Although remdesivir-treated patients were more likely to be infected with the Omicron variant (79.7% vs. 48.6%), baseline characteristics did not differ significantly between the two groups. Among patients who initially did not require dialysis, 18.4% (7/38) of remdesivir-treated patients developed acute kidney injury (AKI) at days 4-6, compared with 51.7% (15/29) of non-remdesivir-treated patients. Liver injury severity worsened in 3.1% (2/64) of remdesivir-treated patients and 5.4% (2/37) of non-remdesivir-treated patients at days 4-6. In addition, there was no significant increase in AKI and liver injury over time in remdesivir-treated patients, and there were no cases of discontinuation of remdesivir due to adverse reactions. Concerns regarding the safety of SBECD should not lead to hasty withholding of remdesivir treatment in renally-impaired COVID-19 patients.

The origin of sequence type 72 community-associated methicillin-resistant Staphylococcus aureus (MRSA) and fusidic acid (FA) resistant sequence type 5 MRSA: Analysis of FA resistance and spa type in a single center in South Korea

INTRODUCTION

We investigated the prevalence of fusidic acid (FA) resistance in MSSA and MRSA stratified by sequence (ST) and spa types, and determined the prevalence of FA resistance mechanisms.

METHODS

From August 2014 to April 2020, S. aureus blood isolates were collected in Asan Medical Center, Seoul, South Korea. Antimicrobial susceptibility tests were performed using broth microdilution and interpreted according to EUCAST's FA criteria. We performed spa typing for fusA mutation presence and acquired FA resistance determinants (fusB, fusC, and fusD) by PCR.

RESULTS

Of the 590 MRSA isolates, 372 were FA resistant, and among 425 MSSA isolates, 136 were resistant. Of the 380 ST5-MRSA isolates, 350 were FA resistant, whereas only 1 of 14 ST5-MSSA isolates was FA resistant. Conversely, of the 163 ST72-MRSA isolates, only 8 were resistant, whereas 37 of 42 ST72-MSSA were resistant. The fusA mutation (80%) was the most common determinant. The one FA resistant ST5-MSSA isolate belonged to the t2460 spa type, the most common spa type (24 of 35 isolates) of FA resistant ST5-MRSA. In addition, t324 and t148, which are minor spa types of ST72-MSSA, were susceptible to FA, in contrast to other ST72-MSSA spa types, and the major spa type of ST72-MRSA (110 of 163 isolates).

CONCLUSIONS

FA resistance was common in ST5-MRSA and ST72-MSSA, and rare in ST5-MSSA and ST72-MRSA. Our findings suggest that minor clones of ST5-MSSA isolates, with the fusA mutation and minor clones of ST72-MSSA susceptible to FA, may have evolved to harbor the mecA gene.

Assisted reproductive techniques and subsequent risk of asthma and allergic rhinitis in offspring: a nationwide birth cohort study in South Korea

OBJECTIVE

The relationship between assisted reproductive techniques (ART) and the risk of asthma and allergic rhinitis (AR) is controversial. Thus, we aimed to investigate the relationship between ART and the risk of asthma and AR in a nationwide, large-scale birth cohort.

PATIENTS AND METHODS

This study utilized the National Health Insurance Service data in South Korea to conduct a nationwide, large-scale, population-based birth cohort. We included all infants born between 2017 and 2018. AR, asthma, food allergies, and atopic dermatitis were defined using the International Classification of Diseases tenth edition codes. Asthma was classified as allergic or non-allergic based on accompanying allergic diseases (AR, food allergy, or atopic dermatitis). Using 1:10 propensity score matching, we compared infants conceived through ART with those conceived naturally (non-ART). After matching, logistic regression was used to compare the hazard ratio for asthma and AR between the two groups.

RESULTS

We included 543,178 infants [male infants, 280,194 (51.38%)]. After matching, 8,925 and 74,229 infants were selected for the ART and non-ART groups, respectively. The ART group showed a decreased risk of asthma in the offspring [adjusted hazard ratio (aHR), 0.45; 95% confidence interval (CI), 0.41-0.48]. Similarly, for AR, being conceived by ART was associated with a decreased risk of AR (aHR, 0.25; 95% CI, 0.12-0.37). ART offspring showed a decreased risk of asthma and AR in offspring compared to that observed in non-ART offspring.

CONCLUSIONS

Our study offers important insights for clinicians, researchers, and parents regarding the health outcomes of ART-conceived infants and enhances our understanding of ART's impact on respiratory health.

Ameliorating effect of 2'-Fucosyllactose and 6'-Sialyllactose on lipopolysaccharide-induced intestinal inflammation

Human milk oligosaccharides (HMO) affect gut microbiota during neonatal development, particularly with respect to the immune system. Bovine milk-based infant formulas have low oligosaccharide contents. Thus, efforts to fortify infant formulas with HMO are being undertaken. Two major HMO, 2'-fucosyllactose (2'-FL) and 6'-sialyllactose (6'-SL), exert anti-inflammatory effects; however, the associations between anti-inflammatory effects induced by 2'-FL and 6'-SL co-treatment and gut microbiota composition and metabolite modulation remain unclear. Therefore, in this study, we evaluated the effects of a mixture of these HMO. To determine the optimal HMO ratio for anti-inflammatory effects and elucidate its mode of action, LPS-induced inflammatory HT-29 epithelial cells and intestinal inflamed suckling mice were treated with various mixtures of 2'-FL and 6'-SL. 2'-FL:6'-SL ratio of 5:1 was identified as the most effective pre-treatment HMO mixture in vitro; thus, this ratio was selected and used for low, middle, and high-dose treatments for subsequent in vivo studies. In vivo, high-dose HMO treatment restored LPS-induced inflammation symptoms, such as body weight loss, colon length reduction, histological structural damage, and intestinal gene expression related to inflammatory responses. High-dose HMO was the only treatment that modulated the major phyla Bacteroidetes and Firmicutes and the genera Ihubacter, Mageeibacillus, and Saccharofermentans. These changes in microbial composition were correlated with intestinal inflammation-related gene expression and short-chain fatty acid production. To our knowledge, our study is the first to report the effects of Ihubacter, Mageeibacillus, and Saccharofermentans on short chain fatty acid levels, which can subsequently affect inflammatory cytokine and tight junction protein levels. Conclusively, the HMO mixture exerted anti-inflammatory effects through changes in microbiota and metabolite production. These findings suggested that supplementation of infant formula with HMO may benefit formula-fed infants by forming unique microbiota contributing to neonatal development.

Usefulness of the Rapid Antigen Test in Detecting SARS-CoV-2 for Infection Control in Hospitals

BACKGROUND

We aimed at evaluating the diagnostic performance of rapid antigen test (RAT) compared to polymerase chain reaction (PCR) for severe acute respiratory syndrome coronavirus 2 and the possible transmission of infection to close contacts from patients with negative RAT and positive PCR results.

MATERIALS AND METHODS

Patients/guardians urgently requiring admission to the ward on the same day had been hospitalized with RAT-negative result before the PCR results were available. We performed an epidemiologic investigation of the close contacts of those with negative RAT but positive PCR results after hospitalization.

RESULTS

A total of 4,237 RATs were performed from March to August 2022. When the PCR test was used as the reference, RAT had a sensitivity of 28.8% (17/59; 95% confidence interval [CI], 17.8 - 42.1), a specificity of 100% (4,220/4,220; 95% CI, 99.9 - 100.0), a positive predictive value of 100.0% (17/17; 95% CI, 100.0 - 100.0), and a negative predictive value of 99.0% (4,178/4,220; 95% CI, 99.3 - 99.8). The epidemiologic investigation revealed that among the 32 patients with negative RAT and subsequent positive PCR results after admission into multi-patient room, two (6.3%) showed secondary coronavirus disease 2019.

CONCLUSION

The secondary transmission rate from patients with negative RAT and positive PCR results was low. Our data suggest that RAT may be useful for rapid exclusion of high transmissible cases. However, further evaluation using whole genome sequencing is needed to determine the potential for transmissibility in cases showing a negative RAT but a positive PCR result.

Validation of a new risk stratification system-based management for methicillin-resistant Staphylococcus aureus bacteraemia: analysis of a multicentre prospective study

PURPOSE

Distinguishing between complicated and uncomplicated Staphylococcus aureus bacteraemia (SAB) is therapeutically essential. However, this distinction has limitations in reflecting the heterogeneity of SAB and encouraging targeted diagnostics. Recently, a new risk stratification system for SAB metastatic infection, involving stepwise approaches to diagnosis and treatment, has been suggested. We assessed its applicability in methicillin-resistant SAB (MRSAB) patients.

METHODS

We retrospectively analysed data of a 3-year multicentre, prospective cohort of hospitalised patients with MRSAB. We classified the patients into three risk groups: low, indeterminate, and high, based on the new system and compared between-group management and outcomes.

RESULTS

Of 380 patients with MRSAB, 6.3% were classified as low-, 7.6% as indeterminate-, and 86.1% as high-risk for metastatic infection. No metastatic infection occurred in the low-, 6.9% in the indeterminate-, and 19.6% in the high-risk groups (P < 0.001). After an in-depth diagnostic work-up, patients were finally diagnosed as 'without metastatic infection (6.3%)', 'with metastatic infection (17.4%)', and 'uncertain for metastatic infection (76.3%)'. 30-day mortality increased as the severity of diagnosis shifted from 'without metastatic infection' to 'uncertain for metastatic infection' and 'with metastatic infection' (P = 0.09). In multivariable analysis, independent factors associated with metastatic complications were suspicion of endocarditis in transthoracic echocardiography, clinical signs of metastatic infection, Pitt bacteraemia score ≥ 4, and persistent bacteraemia.

CONCLUSIONS

The new risk stratification system shows promise in predicting metastatic complications and guiding work-up and management of MRSAB. However, reducing the number of cases labelled as 'high-risk' and 'uncertain for metastatic infection' remains an area for improvement.

PPIB/Cyclophilin B expression associates with tumor progression and unfavorable survival in patients with pulmonary adenocarcinoma

Cyclophilin B (CypB), encoded by peptidylprolyl isomerase B (PPIB), is involved in cellular transcriptional regulation, immune responses, chemotaxis, and proliferation. Recent studies have shown that PPIB/CypB is associated with tumor progression and chemoresistance in various cancers. However, the clinicopathologic significance and mechanism of action of PPIB/CypB in non-small cell lung cancer (NSCLC) remain unclear. In this study, we used RNA in situ hybridization to examine PPIB expression in 431 NSCLC tissue microarrays consisting of 295 adenocarcinomas (ADCs) and 136 squamous cell carcinomas (SCCs). Additionally, Ki-67 expression was evaluated using immunohistochemistry. The role of PPIB/CypB was assessed in five human NSCLC cell lines. There was a significant correlation between PPIB/CypB expression and Ki-67 expression in ADC (Spearman correlation r=0.374, P<0.001) and a weak correlation in SCC (r=0.229, P=0.007). In ADCs, high PPIB expression (PPIBhigh) was associated with lymph node metastasis (P=0.023), advanced disease stage (P=0.014), disease recurrence (P=0.013), and patient mortality (P=0.015). Meanwhile, high Ki-67 expression (Ki-67high) was correlated with male sex, smoking history, high pT stage, lymph node metastasis, advanced stage, disease recurrence, and patient mortality in ADC (all P<0.001). However, there was no association between either marker or clinicopathological factors, except for old age and PPIBhigh (P=0.038) in SCC. Survival analyses revealed that the combined expression of PPIBhigh/Ki-67high was an independent prognosis factor for poor disease-free survival (HR 1.424, 95% CI 1.177-1.723, P<0.001) and overall survival (HR 1.266, 95% CI 1.036-1.548, P=0.021) in ADC, but not in SCC. Furthermore, PPIB/CypB promoted the proliferation, colony formation, and migration of NSCLC cells. We also observed the oncogenic properties of PPIB/CypB expression in human bronchial epithelial cells. In conclusion, PPIB/CypB contributes to tumor growth in NSCLC, and elevated PPIB/Ki-67 levels are linked to unfavorable survival, especially in ADC.

Saturation of Fishbone Instability by Self-Generated Zonal Flows in Tokamak Plasmas

Gyrokinetic simulations of the fishbone instability in DIII-D tokamak plasmas find that self-generated zonal flows can dominate the nonlinear saturation by preventing coherent structures from persisting or drifting in the energetic particle phase space when the mode frequency down-chirps. Results from the simulation with zonal flows agree quantitatively, for the first time, with experimental measurements of the fishbone saturation amplitude and energetic particle transport. Moreover, the fishbone-induced zonal flows are likely responsible for the formation of an internal transport barrier that was observed after fishbone bursts in this DIII-D experiment. Finally, gyrokinetic simulations of a related ITER baseline scenario show that the fishbone induces insignificant energetic particle redistribution and may enable high performance scenarios in ITER burning plasma experiments.

Biporous silica nanostructure-induced nanovortex in microfluidics for nucleic acid enrichment, isolation, and PCR-free detection

Efficient pathogen enrichment and nucleic acid isolation are critical for accurate and sensitive diagnosis of infectious diseases, especially those with low pathogen levels. Our study introduces a biporous silica nanofilms-embedded sample preparation chip for pathogen and nucleic acid enrichment/isolation. This chip features unique biporous nanostructures comprising large and small pore layers. Computational simulations confirm that these nanostructures enhance the surface area and promote the formation of nanovortex, resulting in improved capture efficiency. Notably, the chip demonstrates a 100-fold lower limit of detection compared to conventional methods used for nucleic acid detection. Clinical validations using patient samples corroborate the superior sensitivity of the chip when combined with the luminescence resonance energy transfer assay. The enhanced sample preparation efficiency of the chip, along with the facile and straightforward synthesis of the biporous nanostructures, offers a promising solution for polymer chain reaction-free detection of nucleic acids.

The association between antibody responses and prolonged viable SARS-CoV-2 shedding in immunocompromised patients: a prospective cohort study

Immunocompromised COVID-19 patients were prospectively enrolled from March to November 2022 to understand the association between antibody responses and SARS-CoV-2 shedding. A total of 62 patients were analyzed and the results indicated a faster decline in genomic and subgenomic viral RNA in patients with higher neutralizing and S1-specific IgG antibodies (both P < 0.001). Notably, high neutralizing antibody levels were associated with a significantly faster decrease in viable virus cultures (P = 0.04). Our observations suggest the role of neutralizing antibodies in prolonged virus shedding in immunocompromised patients, highlighting the potential benefits of enhancing their humoral immune response through vaccination or monoclonal antibody treatments.

Cytokine and Chemokine Profiles in Acute Severe Fever with Thrombocytopenia Syndrome and Scrub Typhus in South Korea

In East Asia, severe fever with thrombocytopenia syndrome (SFTS) and scrub typhus, which are common endemic tick- and mite-mediated diseases sharing common clinical manifestations, are becoming public health concerns. However, there are limited data on the comparative immunopathogenesis between the two diseases. We compared the cytokine profiles of SFTS and scrub typhus to further elucidate immune responses that occur during the disease courses. We prospectively enrolled 44 patients with confirmed SFTS and 49 patients with scrub typhus from July 2015 to December 2020. In addition, 10 healthy volunteers were enrolled as healthy controls. A cytometric bead array was used to analyze plasma samples for 16 cytokines. A total of 68 plasma samples, including 31 (45.6%) from patients with SFTS and 37 (54.4%) from patients with scrub typhus, were available for cytokine measurement. There were three cytokine expression patterns: increased levels in both SFTS and scrub typhus (interleukin 6 [IL-6], IL-10, interferon gamma induced protein 10 [IP-10], and granulocyte-macrophage colony-stimulating factor [GM-CSF]), highest levels in SFTS (interferon alpha [IFN-α], IFN-γ, granulocyte-CSF [G-CSF], monocyte chemotactic protein 1 [MCP-1], macrophage inflammatory protein 1α [MIP-1α], and IL-8), and distinct levels in scrub typhus (IL-12p40, tumor necrosis factor alpha [TNFα], IL-1β, regulated on activation and normally T-cell expressed and secreted [RANTES], IL-17A, and vascular endothelial growth factor [VEGF]). Although patients with acute SFTS and scrub typhus exhibited partly shared expression patterns of cytokines related to disease severity, the different profiles of cytokines and chemokines might contribute to higher mortality in SFTS than in scrub typhus. Discrete patterns of helper T cell-related cytokines and VEGF might reflect differences in CD4 T-cell responses and vascular damage between these diseases.

Clinical utility of quantitative immunoassays and surrogate virus neutralization tests for predicting neutralizing activity against the SARS-CoV-2 Omicron BA.1 and BA.5 variants

Developing new antibody assays for emerging SARS-CoV-2 variants is challenging. SARS-CoV-2 surrogate virus neutralization tests (sVNT) targeting Omicron BA.1 and BA.5 have been devised, but their performance needs to be validated in comparison with quantitative immunoassays. First, using 1749 PRNT-positive sera, we noticed that log-transformed optical density (OD) ratio of wild-type (WT) sVNT exhibited better titer-correlation with plaque reduction neutralization test (PRNT) than % inhibition value. Second, we tried 798 dilutional titration tests with 103 sera, but nonlinear correlation between OD ratio and antibody concentration limited titration of sVNT. Third, the titer-correlations of two sVNT kits for BA.1 and two quantitative immunoassays for WT were evaluated with BA.1 and BA.5 PRNT. All tested kits exhibited a linear correlation with PRNT titers, but the sVNT kits exhibited high false-negative rates (cPass-BA.1 kit, 45.4% for BA.1 and 44.2% for BA.5; STANDARD F-BA.1 kit, 1.9% for BA.1 and 2.2% for BA.5), while quantitative immunoassays showed 100% sensitivity. Linear mixed-effects model suggested superior titer-correlation with PRNT for quantitative immunoassays compared to sVNT kits. Taken together, the use of quantitative immunoassays for WT, rather than rapid development of new kits, would be practical for predicting neutralizing activities against emerging new variants.

Clinical impact of metformin exposure during Staphylococcus aureus bacteremia in patients with diabetes mellitus

PURPOSE

Increasing evidence has suggested that metformin may play positive roles in a wide range of infectious diseases. This study aimed to investigate the clinical impact of metformin exposure during Staphylococcus aureus bacteremia (SAB) in patients with diabetes.

METHODS

A 3-year observational cohort study of 452 patients (aged ≥ 16 years) with SAB was performed at a tertiary care hospital. Metformin exposure was defined as receiving metformin during SAB, regardless of metformin use before the onset of bacteremia.

RESULTS

Of 452 patients, 51 (11.3%) were classified in Group A (diabetes with metformin exposure), 115 (25.4%) in Group B (diabetes without metformin exposure), and 286 (63.3%) in Group C (no diabetes). The 30-day mortality rate in Group A was significantly lower than that in Group B (3.9% [2/51] versus 14.8% [17/115]; p = 0.04) and lower than that in Group C (3.9% [2/51] versus 17.1% [49/286]; p = 0.02). The mortality rates did not differ between Group B and Group C (14.8% [17/115] versus 17.1% [49/286]; p = 0.57). The rates of persistent and recurrent bacteremia were comparable among the three groups. Multivariate analysis indicated that metformin exposure was significantly associated with reduced mortality (adjusted odds ratio, 0.20; 95% confidence interval, 0.04-0.88; p = 0.03).

CONCLUSIONS

Metformin exposure during SAB appears to be an independent predictor of survival in patients with diabetes.

Search for Boosted Dark Matter in COSINE-100

We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.7  kg·yr exposure, we set limits on BDM interactions under a variety of hypotheses. Notably, we explored the dark photon parameter space, leading to competitive limits compared to direct dark photon search experiments, particularly for dark photon masses below 4 MeV and considering the invisible decay mode. Furthermore, by comparing our results with a previous BDM search conducted by the Super-Kamionkande experiment, we found that the COSINE-100 detector has advantages in searching for low-mass dark matter. This analysis demonstrates the potential of the COSINE-100 detector to search for MeV electron recoil signals produced by the dark sector particle interactions.

Routine ophthalmologic examination in Klebsiella pneumoniae bacteremia is not necessary: incidence of and risk factors for ocular involvement

Klebsiella pneumoniae bacteremia is known to present a virulent clinical course, including multiple metastatic infections, which is not uncommon in Asia. However, there are limited data on the incidence and risk factors for ocular involvement in K. pneumoniae bacteremia. We retrospectively reviewed the medical records of all patients with K. pneumoniae bacteremia who underwent ophthalmologic examination in a tertiary center in Seoul, Korea, from February 2012 to December 2020. Two retinal specialists reviewed the findings of the ophthalmologic examinations and classified them as endophthalmitis, chorioretinitis, and no ocular involvement. Of 689 patients, 56 [8.1%; 95% confidence interval (CI) 6.2-10.4] had ocular involvement, and 9 (1.3%; 95% CI 0.6-2.5) were diagnosed with endophthalmitis. Of 47 patients with chorioretinitis, 45 (95.7%) improved with systemic antibiotic therapy alone. Community-onset bacteremia (100% vs 62.1% vs 57.4%, P = 0.04), cryptogenic liver abscess (55.6% vs 11.8% vs 8.5%, P = 0.003), and metastatic infection (66.7% vs 5.8% vs 10.6%, P < 0.001) were more common in endophthalmitis than in no ocular involvement or chorioretinitis. In the multivariable analysis, cryptogenic liver abscess [adjusted odds ratio (aOR), 6.63; 95% CI 1.44-35.20] and metastatic infection (aOR, 17.52; 95% CI 3.69-96.93) were independent risk factors for endophthalmitis. Endophthalmitis was not associated with 30-day mortality. Endophthalmitis is rare in Asian patients with K. pneumoniae bacteremia. Targeted ophthalmologic examination in those with cryptogenic liver abscess, metastatic infection, or ocular symptoms may be more appropriate than routine examination of all patients.

Clinical Characteristics of and Risk Factors for Subsequent Carbapenemase-producing Enterobacterales (CPE) Bacteraemia in Rectal CPE Carriers

BACKGROUND

Due to high mortality and limited treatment options, the rise in carbapenemase-producing Enterobacterales (CPE) has become a major concern. This study aimed to evaluate the incidence and characteristics of subsequent CPE bacteraemia in rectal CPE carriers and investigate the risk factors for CPE bacteraemia compared with non-carbapenemase-producing (non-CP) Enterobacterales bacteraemia.

METHODS

A retrospective analysis was conducted on adult patients who were confirmed to have CPE colonisation by stool surveillance culture at a tertiary hospital from January 2018 to February 2022. All episodes of Enterobacterales bacteraemia up to 6 months after CPE colonisation were identified.

RESULTS

Of 1174 patients identified as rectal CPE carriers, 69 (5.8%; 95% CI 4.6-7.3%) experienced subsequent CPE bacteraemia during the 6 months after the diagnosis of CPE colonisation. Colonisation by a Klebsiella pneumoniae carbapenemase (KPC) producer (or CP-K. pneumoniae), colonisation by multiple CPE species, chronic kidney disease and haematological malignancy were independently associated with CPE bacteraemia in CPE carriers. When CPE carriers developed Enterobacterales bacteraemia, the causative agent was more frequently non-CP Enterobacterales than CPE (63.6% vs. 36.4%). Among these patients, colonisation with a KPC producer, CPE colonisation at multiple sites, shorter duration from colonisation to bacteraemia (< 30 days) and recent intraabdominal surgery were independent risk factors for CPE bacteraemia rather than non-CP Enterobacterales bacteraemia.

CONCLUSIONS

In CPE carriers, non-CP Enterobacterales were more often responsible for bacteraemia than CPE. Empirical antibiotic therapy for CPE should be considered when sepsis is suspected in a CPE carrier with risk factors for CPE bacteraemia.

Virological characteristics and the rapid antigen test as deisolation criteria in immunocompromised patients with COVID-19: A prospective cohort study

There are limited data supporting current Centers for Disease Control and Prevention guidelines for the isolation period in moderate to severely immunocompromised patients with coronavirus disease 2019 (COVID-19). Adult COVID-19 patients who underwent solid organ transplantation (SOT) or received active chemotherapy against hematologic malignancy were enrolled and weekly respiratory samples were collected. Samples with positive genomic real-time polymerase chain reaction results underwent virus culture and rapid antigen testing (RAT). A total of 65 patients (40 with hematologic malignancy and 25 SOT) were enrolled. The median duration of viable virus shedding was 4 weeks (interquartile range: 3-7). Multivariable analysis revealed that B-cell depletion (hazard ratio [HR]: 4.76) was associated with prolonged viral shedding, and COVID-19 vaccination (≥3 doses) was negatively associated with prolonged viral shedding (HR: 0.22). The sensitivity, specificity, positive predictive value, and negative predictive value of RAT for viable virus shedding were 79%, 76%, 74%, and 81%, respectively. The negative predictive value of RAT was only 48% (95% confidence interval [CI]: 33-65) in the samples from those with symptom onset ≤20 days, but it was as high as 92% (95% CI: 85-96) in the samples from those with symptom onset >20 days. About half of immunocompromised COVID-19 patients shed viable virus for ≥4 weeks from the diagnosis, and virus shedding was prolonged especially in unvaccinated patients with B-cell-depleting therapy treatment. RAT beyond 20 days in immunocompromised patients had a relatively high negative predictive value for viable virus shedding.

Synaptic Activity Causes Minute-scale Changes in BAF Complex Composition and Function

Genes encoding subunits of the SWI/SNF or BAF ATP-dependent chromatin remodeling complex are among the most enriched for deleterious de novo mutations in intellectual disabilities and autism spectrum disorder, but the causative molecular pathways are not fully known 1,2 . Synaptic activity in neurons is critical for learning and memory and proper neural development 3 . Neural activity prompts calcium influx and transcription within minutes, facilitated in the nucleus by various transcription factors (TFs) and chromatin modifiers 4 . While BAF is required for activity-dependent developmental processes such as dendritic outgrowth 5-7 , the immediate molecular consequences of neural activity on BAF complexes and their functions are unknown. Here we mapped minute-scale biochemical consequences of neural activity, modeled by membrane depolarization of embryonic mouse primary cortical neurons, on BAF complexes. We used acute chemical perturbations of BAF ATPase activity and kinase signaling to define the activity-dependent effects on BAF complexes and activity-dependent BAF functions. Our studies found that BAF complexes change in subunit composition and are selectively phosphorylated within 10 minutes of depolarization. Increased levels of the core PBAF subunit Baf200/ Arid2 , uniquely containing an RFX-like DNA-binding domain, are concurrent with ATPase-dependent opening of chromatin at RFX/X-box motifs. Changes in BAF composition and phosphorylation lead to the regulation of chromatin accessibility for critical neurogenesis TFs. These biochemical effects are a convergent phenomenon downstream of multiple growth factor signaling pathways in mouse neurons and fibroblasts suggesting that BAF integrates signaling information from the membrane. In support of such a membrane-to-nucleus signaling cascade, we also identified a BAF-interacting kinase, Dclk2, whose inhibition attenuates BAF phosphorylation selectively. Our findings support a direct role of BAF complexes in responding to synaptic activity to regulate TF binding and transcription.

Molecular Characteristics and Prevalence of Rifampin Resistance in Staphylococcus aureus Isolates from Patients with Bacteremia in South Korea

Rifampin resistance (RIF-R) in Staphylococcus aureus (S. aureus) with rpoB mutations as one of its resistance mechanisms has raised concern about clinical treatment and infection prevention strategies. Data on the prevalence and molecular epidemiology of RIF-R S. aureus blood isolates in South Korea are scarce. We used broth microdilution to investigate RIF-R prevalence and analyzed the rpoB gene mutation in 1615 S. aureus blood isolates (772 methicillin-susceptible and 843 methicillin-resistant S. aureus (MRSA)) from patients with bacteremia, between 2008 and 2017. RIF-R prevalence and antimicrobial susceptibility were determined. Multilocus sequence typing was used to characterize the isolate's molecular epidemiology; Staphylococcus protein A (spa), staphylococcal cassette chromosome mec (SCCmec), and rpoB gene mutations were detected by PCR. Among 52 RIF-R MRSA isolates out of 57 RIF-R S. aureus blood isolates (57/1615, 0.4%; 5 methicillin-susceptible and 52 MRSA), ST5 (44/52, 84.6%), SCCmec IIb (40/52, 76.9%), and spa t2460 (27/52, 51.9%) were predominant. rpoB gene mutations with amino acid substitutions showed that A477D (17/48, 35.4%) frequently conferred high-level RIF resistance (MIC > 128 mg/L), followed by H481Y (4/48, 8.3%). RIF-R S. aureus blood isolates in South Korea have unique molecular characteristics and are closely associated with rpoB gene mutations. RIF-R surveillance through S. aureus-blood isolate epidemiology could enable effective therapeutic management.

Protracted course of SARS-CoV-2 pneumonia in moderately to severely immunocompromised patients

There have been few studies comparing the clinical characteristics and outcomes of SARS-CoV-2 pneumonia in individuals with and without moderately to severely immunocompromised conditions. We reviewed adult patients with SARS-CoV-2 infection who had radiologic evidence of pneumonia at a tertiary hospital in Seoul, South Korea, from February 2020 to April 2022. Moderately to severely immunocompromised status was defined as medical conditions or treatments that resulted in increased risk of severe COVID-19 and weakened immune response to COVID-19 vaccine as recommended by Centers for Disease Control and Prevention. The time to pneumonia development was defined as the time from symptom onset to the time when radiologic evidence of pneumonia was obtained. Viral clearance was defined as a Ct value > 30. COVID-19-related death was defined as 90-day death following imaging-confirmed pneumonia without any other plausible cause of death. A total of 467 patients with SARS-CoV-2 pneumonia were analyzed. Of these, 102 (22%) were moderately to severely immunocompromised. The median (IQR) time to pneumonia development was significantly longer in moderately to severely immunocompromised patients (9.5 [6-14] days) than the comparator (6 [3-8] days), p < 0.001), as was the median time to viral clearance (21 versus 12 days, p < 0.001). Moderately to severely immunocompromised status (aOR, 18.39; 95% CI, 5.80-58.30; p < 0.001) was independently associated with COVID-19-related death. Patients with moderately to severely immunocompromised conditions are likely to experience a more protracted course of SARS-CoV-2 pneumonia and a worse outcome than those without these conditions.

Clinical characteristics of COVID-19 rebound after nirmatrelvir-ritonavir or molnupiravir therapy: A prospective cohort study

The clinical characteristics of the rebound phenomenon after antiviral therapy in patients with Coronavirus disease-2019 (COVID-19) are largely unknown. There are few data comparing the rebound phenomenon after molnupiravir therapy to that after nirmatrelvir-ritonavir therapy. We investigated the incidence and risk factors associated with COVID-19 rebound after nirmatrelvir-ritonavir or molnupiravir therapy during the Omicron era. This prospective cohort study enrolled patients with mild-to-moderate COVID-19 who received nirmatrelvir-ritonavir or molnupiravir. We conducted weekly questionnaires of symptom scores from day 0 to day 28, with an additional day when patients experienced reappearing symptoms. We defined COVID-19 rebound as when patients experienced a 50% increase in symptom scores compared to the lowest symptom score between days 0 and 14. Among the 150 patients, 93 (62%) and 57 (38%) received nirmatrelvir-ritonavir therapy and molnupiravir, respectively. Of these, 11 patients (7.3%; 95% CI, 3.1-11.5) experienced COVID-19 rebound. The median duration from antiviral therapy to rebound was 12 days. Patients with clinical rebound had a higher symptom score at antiviral therapy initiation than those without (median, 5 vs 4; P = .02). There was no significant difference in the clinical rebounds associated with nirmatrelvir-ritonavir and molnupiravir therapy (5.4% vs 10.5%; P = .39). Approximately one-tenth of patients with mild-to-moderate COVID-19 who received antiviral therapy experienced rebound phenomena after treatment. Regardless of antiviral therapy type, high initial symptom scores were associated with a more frequent rebound phenomenon.

Deep Learning Assisted Surface-Enhanced Raman Spectroscopy (SERS) for Rapid and Direct Nucleic Acid Amplification and Detection: Toward Enhanced Molecular Diagnostics

Surface-enhanced Raman scattering (SERS) has evolved into a robust analytical technique capable of detecting a variety of biomolecules despite challenges in securing a reliable Raman signal. Conventional SERS-based nucleic acid detection relies on hybridization assays, but reproducibility and signal strength issues have hindered research on directly amplifying nucleic acids on SERS surfaces. This study introduces a deep learning assisted ZnO-Au-SERS-based direct amplification (ZADA) system for rapid, sensitive molecular diagnostics. The system employs a SERS substrate fabricated by depositing gold on uniformly grown ZnO nanorods. These nanorods create hot spots for the amplification of the target nucleic acids directly on the SERS surface, eliminating the need for postamplification hybridization and Raman reporters. The limit of detection of the ZADA system was superior to those of the conventional amplification methods. Clinical validation of the ZADA system with coronavirus disease 2019 (COVID-19) samples from human patients yielded a sensitivity and specificity of 92.31% and 81.25%, respectively. The integration of a deep learning program further enhanced sensitivity and specificity to 100% and reduced SERS analysis time, showcasing the potential of the ZADA system for rapid, label-free disease diagnosis via direct nucleic acid amplification and detection within 20 min.

False positive Aspergillus galactomannan assay results caused by specific parenteral nutrition

In September 2022, the proportion of clinically false positive results with high index values for the galactomannan (GM) assay increased dramatically in our hospital and remained high until November 2022. We aimed to identify the possible causative agent that led to the dramatic increase in false positivity in GM assay. A case-control-control study was conducted, and patients admitted to two intensive care units between September and November 2022 were included. We defined each time point at which the GM assay was conducted in a patient as an episode and classified episodes into strong-positive (≥10.0 index; case), positive (control), and negative (<0.5 index; control) groups. We compared the medications administered in three groups and measured GM levels in relevant medications, including parenteral nutrition (PN). In total, 118 episodes in 33 patients were classified into three groups. There were 46 negative, 23 positive, and 49 strong-positive episodes, and there was a significant difference in the use of Winuf® PNs (P < .001) between the three groups. Forty episodes (82%) in the strong-positive group received Winuf®, compared with three (6.5%) in the negative group and one (4.3%) in the positive group (P < .001). All samples of Winuf® PNs used in the five patients whose GM results were repeatedly strong-positive were strongly positive for GM. False positivity in GM assay can be caused by the administration of specific PNs. A thorough investigation of prescribed medications should be considered when there is an abrupt increase in the proportion of strong-positive or positive GM results.

Causes of a Low Measles Seroprevalence among Young Healthcare Workers in Korea

BACKGROUND

Sporadic measles outbreaks have continued to occur in Korea, mainly in adults in their 20s and 30s, most notably in 2014 and 2019. We here evaluated the possible causes of a low seroprevalance of measles by testing young healthcare workers (HCWs).

MATERIALS AND METHODS

This study was conducted in a 2,743-bed tertiary-care hospital in Seoul between 2020 and 2021. We performed a measles antibody test (chemiluminescence immunoassay), measured the IgM/IgG index ratio, and conducted an avidity test at 1-month after Measles-Mumps-Rubella (MMR) vaccination in HCWs who had been seronegative for measles. Measles vaccination histories were obtained from the national vaccine registry.

RESULTS

Of the 3,173 HCWs newly employed in our hospital during the study period, 54 with a negative measles IgG at commencement were enrolled. Thirty six (67%) of these subjects were female, and the median age was 25 years (interquartile range [IQR]: 24 - 27). Fourty nine (91%) showed seroconversion at 1 month after the first vaccination. Of these individuals, 38 received both measles IgM and IgG test, and all had an IgM/IgG index <1. Of the 49 seroconverters, all HCWs showed a high avidity index. According to the national immunization registry, 45 (83%) received at least 2 doses of an MMR vaccination.

CONCLUSION

Secondary vaccine failure may underlie vaccine failure in young Korean adults. HCWs born after 1985 with a negative measles antibody may need only a single dose booster vaccination rather than a 2-dose vaccination regimen.

Clinical Characteristics and Vertical Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Pregnant Women and Their Neonates in Korea

BACKGROUND

There are limited data on the clinical characteristics and the vertical transmission rate of pregnant women with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and their neonates in Korea.

MATERIALS AND METHODS

Pregnant women who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were retrospectively reviewed in Asan Medical Center from September 1, 2020, to April 26, 2022. All neonates and infected women underwent a polymerase chain reaction test for severe acute respiratory syndrome corona virus 2 within 24 hours of birth and at 48-hour interval if they stayed in the hospital.

RESULTS

A total of 60 pregnant women gave birth by cesarean section (n = 40, 66.7%) or vaginal delivery (n = 20, 33.3%). Among them, 3 women gave birth to twins. Delivery occurred, on average, at 38+2 weeks (± 2+0) of gestational age, and 9 patients (15.0%) had underlying diseases. Of these 60 patients, 9 (15.0%) received coronavirus disease 2019 vaccinations. Pneumonia was confirmed by a chest radiograph in 7 patients (11.7%), and 2 patients (3.3%) required supplemental oxygen therapy, both of whom eventually recovered. The mean birthweight of the neonates was 3,137 g (± 557.6). Further, 8 neonates (12.7%) were of low-birth weight (< 2,500 g), and 11 neonates (17.5%) were preterm (<37 weeks of gestation). Apgar score was median 8 (8 - 9) at 1 minute and 9 (9 - 9.5) at 5 minutes. Four neonates (6.3%) required invasive mechanical ventilation. All neonates had negative SARS-CoV-2 test results. Therefore, there was no vertical transmission in 63 of the neonates (0%, 95% confidence interval [CI]: 0 - 6).

CONCLUSION

Pregnant Korean women with SARS-CoV-2-infection had favorable obstetric outcomes, and the risk of vertical transmission to their neonates was low. Managing the infection risks of pregnant women and their neonates during the coronavirus disease 2019 pandemic are required.

Clinical Manifestation of Ralstonia mannitolilytica Infection in Pediatric Patients and Epidemiological Investigation of Outbreaks

BACKGROUND

Ralstonia mannitolilytica is a causative organism of nosocomial infections, particularly associated with contaminated water, and resistant to various antibiotics, including carbapenems. Several clusters of R. mannitolilytica infections appeared in children at our institute from August 2018 to November 2019.

METHODS

From March 2009 to March 2023, all patients admitted to Asan Medical Center Children's Hospital in Seoul, Korea, with culture-confirmed R. mannitolilytica and corresponding clinical signs of infection were identified. Epidemiological and environmental investigations were conducted. Polymerase chain reaction (PCR) was performed for the genes of OXA-443 and OXA-444 on R. mannitolilytica isolates.

RESULTS

A total of 18 patients with R. mannitolilytica infection were included in this study, with 94.4% (17/18) and 5.6% (1/18) being diagnosed with pneumonia and central line-associated bloodstream infection, respectively. All-cause 30-day mortality rate was 61.1% (11/18), and seven of the fatal cases were caused by R. mannitolilytica infection itself. The resistance rates to meropenem and imipenem werew 94.4% (17/18) and 5.6% (1/18), respectively. Although four out of nine meropenem-resistant R. mannitolilytica isolates had positive PCR results for OXA-443 and OXA-444 genes, there were no significant differences in antimicrobial susceptibility patterns. Environmental sampling identified R. mannitolylica at two sites: a cold-water tap of a water purifier and an exhalation circuit of a patient mechanical ventilator. After implementing and improving adherence to infection control policies, no additional R. mannitolilytica infection cases have been reported since December 2019.

CONCLUSION

R. mannitolilytica can cause life-threatening infections with high mortality in fragile pediatric populations. To prevent outbreaks, healthcare workers should be aware of R. mannitolilytica infections and strive to comply with infection control policies.

Risk and Outcome of Infective Endocarditis in Streptococcal Bloodstream Infections according to Streptococcal Species

This study aimed to identify which streptococcal species are closely associated with infective endocarditis (IE) and to evaluate risk factors for mortality in patients with streptococcal IE. We performed a retrospective cohort study of all patients with streptococcal bloodstream infection (BSI) from January 2010 to June 2020 in a tertiary hospital in South Korea. We compared clinical and microbiological characteristics of streptococcal BSIs according to the diagnosis of IE. We performed multivariate analysis to evaluate the risk of IE according to streptococcal species and risk factors for mortality in streptococcal IE. A total of 2,737 patients were identified during the study period, and 174 (6.4%) were diagnosed with IE. The highest IE prevalence was in patients with Streptococcus mutans BSI (33% [9/27]) followed by S. sanguinis (31% [20/64]), S. gordonii (23% [5/22]), S. gallolyticus (16% [12/77]), and S. oralis (12% [14/115]). In multivariate analysis, previous IE, high-grade BSI, native valve disease, prosthetic valve, congenital heart disease, and community-onset BSI were independent risk factors for IE. After adjusting for these factors, S. sanguinis (adjusted OR [aOR], 7.75), S. mutans (aOR, 5.50), and S. gallolyticus (aOR, 2.57) were significantly associated with higher risk of IE, whereas S. pneumoniae (aOR, 0.23) and S. constellatus (aOR, 0.37) were associated with lower risk of IE. Age, hospital-acquired BSI, ischemic heart disease, and chronic kidney disease were independent risk factors for mortality in streptococcal IE. Our study points to significant differences in the prevalence of IE in streptococcal BSI according to species. IMPORTANCE Our study of risk of infective endocarditis in patients with streptococcal bloodstream infection demonstrated that Streptococcus sanguinis, S. mutans, and S. gallolyticus were significantly associated with higher risk of infective endocarditis. However, when we evaluated the performance of echocardiography in patients with streptococcal bloodstream infection, patients with S. mutans and S. gordonii bloodstream infection had a tendency of low performance in echocardiography. There are significant differences in the prevalence of infective endocarditis in streptococcal bloodstream infection according to species. Therefore, performing echocardiography in streptococcal bloodstream infection with a high prevalence of, and significant association with, infective endocarditis is desirable.

Observation of Collider Muon Neutrinos with the SND@LHC Experiment

We report the direct observation of muon neutrino interactions with the SND@LHC detector at the Large Hadron Collider. A dataset of proton-proton collisions at sqrt[s]=13.6  TeV collected by SND@LHC in 2022 is used, corresponding to an integrated luminosity of 36.8  fb^{-1}. The search is based on information from the active electronic components of the SND@LHC detector, which covers the pseudorapidity region of 7.2<η<8.4, inaccessible to the other experiments at the collider. Muon neutrino candidates are identified through their charged-current interaction topology, with a track propagating through the entire length of the muon detector. After selection cuts, 8 ν_{μ} interaction candidate events remain with an estimated background of 0.086 events, yielding a significance of about 7 standard deviations for the observed ν_{μ} signal.

Immune Response Kinetics Following a Third Heterologous BNT162b2 Booster Dose After Primary 2-Dose ChAdOx1 Vaccination in Relation to Omicron Breakthrough Infection: A Prospective Nationwide Cohort Study in South Korea

Background

Immune responses to each vaccine must be investigated to establish effective vaccination strategies for the ongoing coronavirus disease (COVID-19) pandemic. We investigated the long-term kinetics of immune responses after heterologous booster vaccination in relation to Omicron breakthrough infection (BI).

Methods

Our study included 373 healthcare workers who received primary ChAdOx1 vaccine doses and a third BNT162b2 vaccine dose. BIs that occurred after the third vaccine were investigated. Blood specimens were collected before and 3 months after the booster dose from participants without BI and 1, 4, and 6 months after BI from participants who experienced BI. Spike-specific binding and neutralizing antibody levels against the wild-type virus, Omicron BA.1, and Omicron BA.5, as well as cellular responses, were analyzed.

Results

A total of 346 participants (82 in the no BI group; 192 in the BI group during the BA.1/BA.2 period; 72 in the BI group during the BA.5 period) were included in the analysis. Participants without BI exhibited the highest binding and neutralizing antibody concentrations and greatest cellular response 1 month after the third vaccination, which reached a nadir by the ninth month. Antibody and cellular responses in participants who experienced BI substantially increased postinfection. Neutralizing antibody titers in individuals who experienced BI during the BA.1/BA.2 period showed more robust increase against wild-type virus than against BA.1 and BA.5.

Conclusions

Our findings provide evidence of antigenic imprinting in participants who received a heterologous booster vaccination, thereby serving as a foundation for further studies on the impact of BIs on immune responses.

Clinical Sensitivity of the (1-3)-β-D-glucan Test for Predicting Candidemia

The sensitivity of the (1-3)-β-D-glucan (BDG) diagnostic test for candidemia varies in different clinical settings, and its usefulness in early diagnosis of candidemia is suboptimal. We evaluated the sensitivity of the test for early candidemia prediction. All adult patients with culture-proven candidemia who underwent a serum Goldstream Fungus (1-3)-β-D-Glucan Test within seven days prior to candidemia onset at a tertiary referral hospital between January 2017 and May 2021 were included. Any-positive BDG results within seven days prior to candidemia onset were obtained in 38 out of 93 (40.9%) patients. The positive rate increased when the test was performed near the day of candidemia onset (P=0.04) but reached only 52% on the day of candidemia onset. We observed no significant differences between BDG-positive and -negative groups in terms of underlying disease, risk factors for candidemia, clinical presentation, origin of candidemia, and 30-day mortality. Candida albicans was significantly associated with positive BDG results than with all-negative BDG results (P=0.04). The Goldstream BDG test is unreliable for candidemia prediction because of its low sensitivity. Negative BDG results in patients with a high risk of invasive candidiasis should be interpreted with caution.

First Observation of the β3αp Decay of ^{13}O via β-Delayed Charged-Particle Spectroscopy

The β-delayed proton decay of ^{13}O has previously been studied, but the direct observation of β-delayed 3αp decay has not been reported. Rare 3αp events from the decay of excited states in ^{13}N^{⋆} provide a sensitive probe of cluster configurations in ^{13}N. To measure the low-energy products following β-delayed 3αp decay, the Texas Active Target (TexAT) time projection chamber was employed using the one-at-a-time β-delayed charged-particle spectroscopy technique at the Cyclotron Institute, Texas A&M University. A total of 1.9×10^{5} ^{13}O implantations were made inside the TexAT time projection chamber. A total of 149 3αp events were observed, yielding a β-delayed 3αp branching ratio of 0.078(6)%. Four previously unknown α-decaying excited states were observed in ^{13}N at 11.3, 12.4, 13.1, and 13.7 MeV decaying via the 3α+p channel.

Triple immune modulator therapy for aberrant hyperinflammatory responses in severe COVID-19

A dysregulated hyperinflammatory response is a key pathogenesis of severe COVID-19, but optimal immune modulator treatment has not been established. To evaluate the clinical effectiveness of double (glucocorticoids and tocilizumab) and triple (plus baricitinib) immune modulator therapy for severe COVID-19, a retrospective cohort study was conducted. For the immunologic investigation, a single-cell RNA sequencing analysis was performed in serially collected PBMCs and neutrophil specimens. Triple immune modulator therapy was a significant factor in a multivariable analysis for 30-day recovery. In the scRNA-seq analysis, type I and II IFN response-related pathways were suppressed by GC, and the IL-6-associated signature was additionally downregulated by TOC. Adding BAR to GC and TOC distinctly downregulated the ISGF3 cluster. Adding BAR also regulated the pathologically activated monocyte and neutrophil subpopulation induced by aberrant IFN signals. Triple immune modulator therapy in severe COVID-19 improved 30-day recovery through additional regulation of the aberrant hyperinflammatory immune response.

Fermented whey protein supplementation improves muscular strength, muscle parameters, and physical performance in middle-aged Korean adults: An 8-week double blind randomized controlled trial

The present study evaluated the effects of fermented whey protein using kimchi lactic acid bacteria Lactobacillus casei DK211 on skeletal muscle mass, muscle strength, and physical performance in healthy middle-aged males performing regular resistance exercises. Effective protein supplementation and regular exercise are two important factors for improving muscle health. Therefore, in this study, the effects of consuming fermented whey protein twice a day were investigated and compared with that of non-fermented supplementation. Forty-eight males (average age 44.8) were randomly assigned to two groups: Fermented whey protein supplementation (FWPS) and non-fermented whey protein concentration supplementation (WPCS) groups. Each group ingested 37 g of FWPS or WPCS twice a day for eight weeks. Body composition, muscle strength, and physical performance were assessed pre- and post-intervention. Independent t-tests or chi-square tests for the categorical variables were performed for analyzing the observations. FWPS was effective in promoting the physical performance in dynamic balance measurement and muscle health, indicated through the increment in grip strength (left), upper arm circumference, and flat leg circumference from the baseline. However, similar improvements were not observed in the WPCS group. These results imply that whey protein fermented by L. casei DK211 is an effective protein supplement for enhancing muscle health in males performing regular resistance exercises.

Lupus anticoagulants as a prospective independent predictor in COVID-19 patients

OBJECTIVE

Lupus anticoagulant (LA) are commonly detected during SARS-CoV-2 infection. However, the relationship between LA and clinical significance is still unclear.

METHODS

A retrospective chart analysis was performed on COVID-19 patients who were tested for LA at our hospital from March 2020 to November 2021. We analyzed the patient's characteristics based on the result of the LA test. In addition, subgroup analysis performed the LA-positive group who had undergone serial LA tests.

RESULTS

A total of 219 COVID-19 patients were enrolled in the study, 148 patients (67.6%) were positive for LA test. The LA-positive group received more treatment of high flow nasal cannula (LA-positive 73.0%, LA-negative 57.7%, p = 0.024). The LA-positive group showed prolonged aPTT, higher levels of CRP and fibrinogen (all p's < 0.05). Among 148 LA-positive patients, 127 patients (86.5%) were found to be LA-positive within 10 days of SARS-CoV-2 positive, and LA-positive group confirmed a median time to LA loss of 10 days. However, there was a group that was negative for LA in the early stages of infection and became positive about 13 days later. A subgroup analysis showed that these patients had different characteristics due to their longer hospital stays and higher D-dimer levels.

CONCLUSIONS

In COVID-19 patients, LA is expected to be associated to disease severity. Since the clinical significance of LA is different depending on the onset time of LA positivity, the LA test is suggested to be done at diagnosis of SARS-CoV-2 infection, even if LA is negative, follow-up test should be considered within 10 days.

The relationship between organising pneumonia and invasive mould disease in patients with haematologic malignancy

BACKGROUND

Organising pneumonia (OP) is reported in patients with haematologic malignancy suspected of having invasive mould disease, yet little is known about this relationship.

OBJECTIVE

To investigate molecular evidence of invasive mould pneumonia in paraffin-embedded lung tissues from histologically diagnosed OP patients with suspected invasive mould pneumonia.

PATIENTS/METHODS

Patients with haematologic malignancy suspected to have invasive pulmonary mould disease who underwent lung biopsy at a tertiary hospital, Seoul, South Korea, between 2008 and 2020, were retrospectively reviewed. To find molecular evidence of fungal infection, PCR assay was used to detect Aspergillus- and Mucorales-specific DNA within OP lung tissue sections.

RESULTS

Forty-seven patients with suspected invasive mould pneumonia underwent lung biopsy and 15 (32%) were histologically diagnosed as OP without any evidence of fungal hyphae. Of these 15 patients, 3 (20%) received allogenic haematopoietic stem cell transplantation prior to developing OP. Before biopsy, 2 and 13 patients had probably and possible invasive mould disease, respectively. The median antifungal treatment length was 81 [8-114] days, and the median steroid treatment dosage was 0.35 mg/kg/day for 36 days (methylprednisolone equivalent doses), respectively. After biopsy, three patients with possible invasive mould infection revealed probable invasive pulmonary aspergillosis. From the 15 paraffin-embedded lung tissues, 6 (40%) exhibited positive PCR assay results for detecting Aspergillus- and Mucorales-specific DNA.

CONCLUSIONS

More than one third of OP cases in patients with suspected invasive mould pneumonia exhibited molecular evidence of invasive mould infection by fungus-specific PCR in lung tissues, likely associated with concurrent or prior fungal infection.

Corticosteroids reduce pathologic interferon responses by downregulating STAT1 in patients with high-risk COVID-19

We do not yet understand exactly how corticosteroids attenuate hyperinflammatory responses and alleviate high-risk coronavirus disease 2019 (COVID-19). We aimed to reveal the molecular mechanisms of hyperinflammation in COVID-19 and the anti-inflammatory effects of corticosteroids in patients with high-risk COVID-19. We performed single-cell RNA sequencing of peripheral blood mononuclear cells (PBMCs) from three independent COVID-19 cohorts: cohort 1 was used for comparative analysis of high-risk and low-risk COVID-19 (47 PBMC samples from 28 patients), cohort 2 for longitudinal analysis during COVID-19 (57 PBMC samples from 15 patients), and cohort 3 for investigating the effects of corticosteroid treatment in patients with high-risk COVID-19 (55 PBMC samples from 13 patients). PBMC samples from healthy donors (12 PBMC samples from 12 donors) were also included. Cohort 1 revealed a significant increase in the proportion of monocytes expressing the long noncoding RNAs NEAT1 and MALAT1 in high-risk patients. Cohort 2 showed that genes encoding inflammatory chemokines and their receptors were upregulated during aggravation, whereas genes related to angiogenesis were upregulated during improvement. Cohort 3 demonstrated downregulation of interferon-stimulated genes (ISGs), including STAT1, in monocytes after corticosteroid treatment. In particular, unphosphorylated STAT-dependent ISGs enriched in monocytes from lupus patients were selectively downregulated by corticosteroid treatment in patients with high-risk COVID-19. Corticosteroid treatment suppresses pathologic interferon responses in monocytes by downregulating STAT1 in patients with high-risk COVID-19. Our study provides insights into the mechanisms underlying COVID-19 aggravation and improvement and the effects of corticosteroid treatment.

Epidemiology and characteristics of respiratory syncytial virus pneumonia in critically ill adults

Background

Severe RSV-associated pneumonia in adults has been rarely addressed. We investigated the burden and clinical characteristics of severe RSV-associated pneumonia in critically ill adult patients.

Methods

We analyzed a prospective cohort of 2,865 adults with severe pneumonia who were admitted to the intensive care unit in a 2,700-bed tertiary care hospital from 2010–2019. The epidemiology, characteristics, and outcomes of 92 cases of severe RSV-associated pneumonia and 163 cases of severe influenza virus (IFV)-associated pneumonia were compared.

Results

Of 1,589 cases of severe community-acquired pneumonia, the incidence of RSV-associated pneumonia was less than half that of IFV-associated pneumonia (3.4% vs. 8.1%). However, among 1,276 cases of severe hospital-acquired pneumonia (HAP), there were slightly more cases of RSV-associated than IFV-associated pneumonia (3.8% vs. 3.5%). During the nine epidemic seasons, RSV-A (five seasons) and RSV-B (four seasons) predominated alternately. Structural lung disease, diabetes mellitus, and malignancy were common underlying diseases in both groups. Immunocompromise (57.6% vs. 34.4%, p&lt;0.001) and hospital acquisition (47.8% vs. 23.9%, p&lt;0.001) were significantly more common in the RSV group. Co-infection with Streptococcus pneumoniae (3.3% vs. 9.8%, p=0.08) and methicillin-susceptible Staphylococcus aureus (1.1% vs. 6.8%, p=0.06) tended to be less frequent in the RSV group. The 90-day mortalities were high in both groups (39.1% vs. 40.5%, p=0.89).

Conclusion

RSV infection was associated with substantial morbidity and mortality in critically ill adult patients, similar to IFV. The relatively higher incidence of RSV in severe HAP suggests that the transmissibility of RSV can exceed that of IFV in a hospital setting.

Active surveillance testing to reduce transmission of carbapenem-resistant, gram-negative bacteria in intensive care units: a pragmatic, randomized cross-over trial

BACKGROUND

In intensive care unit (ICU) settings, the transmission risk of carbapenem-resistant, gram-negative bacteria (CRGNB) is high. There is a paucity of data regarding the effectiveness of interventions, including active screening, preemptive isolation, and contact precautions, to reduce transmission of CRGNB.

METHODS

We conducted a pragmatic, cluster-randomized, non-blinded cross-over study in 6 adult ICUs in a tertiary care center in Seoul, South Korea. ICUs were randomly assigned to perform active surveillance testing with preemptive isolation and contact precautions (intervention) or standard precautions (control) during the initial 6-month study period, followed by a 1-month washout period. During a subsequent 6-month period, departments that used standard precautions switched to using interventional precautions and vice versa. The incidence rates of CRGNB were compared between the two periods using Poisson regression analysis.

RESULTS

During the study period, there were 2268 and 2224 ICU admissions during the intervention and control periods, respectively. Because a carbapenemase-producing Enterobacterales outbreak occurred in a surgical ICU (SICU), we excluded admissions to the SICU during both the intervention and control periods and performed a modified intention-to-treat (mITT) analysis. In mITT analysis, a total of 1314 patients were included. The acquisition rate of CRGNB was 1.75 cases per 1000 person-days during the intervention period versus 3.33 cases per 1000 person-days during the control period (IRR, 0.53 [95% confidence interval (CI) 0.23-1.11]; P = 0.07).

CONCLUSIONS

Although this study was underpowered and showed borderline significance, active surveillance testing and preemptive isolation could be considered in settings with high baseline prevalence of CRGNB. Trial registration Clinicaltrials.gov Identifier: NCT03980197.

A heterologous AZD1222 priming and BNT162b2 boosting regimen more efficiently elicits neutralizing antibodies, but not memory T cells, than the homologous BNT162b2 regimen

BACKGROUND

Comparative analyses of SARS-CoV-2-specific immune responses elicited by diverse prime-boost regimens are required to establish efficient regimens for the control of COVID-19.

METHOD

In this prospective observational cohort study, spike-specific immunoglobulin G (IgG) and neutralizing antibodies (nAbs) alongside spike-specific T-cell responses in age-matched groups of homologous BNT162b2/BNT162b2 or AZD1222/AZD1222 vaccination, heterologous AZD1222/BNT162b2 vaccination, and prior wild-type SARS-CoV-2 infection/vaccination were evaluated.

RESULTS

Peak immune responses were achieved after the second vaccine dose in the naïve vaccinated groups and after the first dose in the prior infection/vaccination group. Peak titers of anti-spike IgG and nAb were significantly higher in the AZD1222/BNT162b2 vaccination and prior infection/vaccination groups than in the BNT162b2/BNT162b2 or AZD1222/AZD1222 groups. However, the frequency of interferon-γ-producing CD4⁺ T cells was highest in the BNT162b2/BNT162b2 vaccination group. Similar results were observed in the analysis of polyfunctional T cells. When nAb and CD4⁺T-cell responses against the Delta variant were analyzed, the prior infection/vaccination group exhibited higher responses than the groups of other homologous or heterologous vaccination regimens.

CONCLUSION

nAbs are efficiently elicited by heterologous AZD1222/BNT162b2 vaccination, as well as prior infection/vaccination, whereas spike-specific CD4⁺T-cell responses are efficiently elicited by homologous BNT162b2 vaccination. Variant-recognizing immunity is more efficiently generated by prior infection/vaccination than the other homologous or heterologous vaccination regimens.

Self-directed molecular diagnostics (SdMDx) system for COVID-19 via one-pot processing

Rapid, sensitive, and specific detection of the severe acute respiratory syndrome coronavirus (SARS-CoV)- 2 during early infection is pivotal in controlling the spread and pathological progression of Coronavirus Disease 2019 (COVID-19). Thus, highly accurate, affordable, and scalable point-of-care (POC) diagnostic technologies are necessary. Herein, we developed a rapid and efficient self-directed molecular diagnostic (SdMDx) system for SARS-CoV-2. This system combines the sample preparation step, including virus enrichment and extraction processes, which involve dimethyl suberimidate dihydrochloride and diatomaceous earth functionalized with 3-aminopropyl(diethoxy)methylsilane, and the detection step using loop-mediated isothermal amplification-lateral flow assay (LAMP-LFA). Using the SdMDx system, SARS-CoV-2 could be detected within 47 min by hand without the need for any larger instruments. The SdMDx system enabled detection as low as 0.05 PFU in the culture fluid of SARS-CoV-2-infected VeroE6 cells. We validated the accuracy of the SdMDx system on 38 clinical nasopharyngeal specimens. The clinical utility of the SdMDx system for targeting the S gene of SARS-CoV-2 showed 94.4% sensitivity and 100% specificity. This system is more sensitive than antigen and antibody assays, and it minimizes the use of complicated processes and reduces contamination risks. Accordingly, we demonstrated that the SdMDx system enables a rapid, accurate, simple, efficient, and inexpensive detection of SARS-CoV-2 at home, in emergency facilities, and in low-resource sites as a pre-screening platform and POC testing through self-operation and self-diagnosis.

Clinical characteristics and outcomes of invasive and non-invasive fusariosis in South Korea

BACKGROUND

Invasive fusariosis mainly affects immunocompromised patients including haematopoietic stem cell transplant recipients and those with haematologic malignancy. There are limited studies on invasive fusariosis in the Asia-Pacific region.

OBJECTIVE

To describe the clinical characteristics and outcomes of invasive and non-invasive fusariosis in South Korea.

PATIENTS/METHODS

From 2005 to 2020, patients with fusariosis who met the revised European Organisation for Research and Treatment of Cancer and the Mycoses Study Group criteria for the definition of proven or probable invasive fusariosis, and those with non-invasive fusariosis were retrospectively reviewed in a tertiary medical centre in Seoul, South Korea.

RESULTS

Overall, 26 and 75 patients had invasive and non-invasive fusariosis, respectively. Patients with invasive fusariosis commonly had haematologic malignancy (62%), were solid organ transplant recipients (23%), and had a history of immunosuppressant usage (81%). In non-invasive fusariosis, diabetes mellitus (27%) and solid cancer (20%) were common underlying conditions. Disseminated fusariosis (54%) and invasive pulmonary disease (23%) were the most common clinical manifestations of invasive fusariosis; skin infection (48%) and keratitis (27%) were the most common manifestations of non-invasive fusariosis. Twenty-eight-day and in-hospital mortalities were high in invasive fusariosis (40% and 52%, respectively). In multivariate analysis, invasive fusariosis (adjusted odds ratio, 9.6; 95% confidence interval 1.3-70.8; p = .03) was an independent risk factor for 28-day mortality.

CONCLUSIONS

Patients with invasive fusariosis were frequently immunocompromised, and more than half had disseminated fusariosis. Invasive fusariosis was associated with poor prognosis.

Waning of humoral immunity depending on the types of COVID-19 vaccine

BACKGROUND

There are limited data on the rates of the waning of antibody levels after two-dose and booster vaccination according to the different platforms of COVID-19 vaccines.

METHODS

We enrolled healthcare workers (HCWs) in a tertiary care hospital who received homologous two-dose vaccination, followed by a homologous or heterologous booster mRNA vaccine. SARS-CoV-2 S1-specific IgG was measured using ELISA. A linear mixed regression model was used to compare the slope from the peak antibody titre to the lowest antibody titres 3 months after vaccination.

RESULTS

A total of 113 HCWs (BNT162b2 (n = 48 [42%]), ChAdOx1 nCoV-19 (n = 52 [46%]) or mRNA-1273 (n = 13 [12%])) were enrolled in this prospective cohort study. More gradual antibody waning was observed over 3 months with the two-dose ChAdOx1 nCoV-19 (ChAdOx1) than with the two-dose BNT162b2 or mRNA-1273 (p < 0.001 and p = 0.001, respectively). In addition, homologous mRNA-1273 booster induced a more durable antibody response than homologous BNT162b2 booster (p < 0.001) or heterologous ChAdOx1-BNT162b2 booster (p < 0.001).

CONCLUSIONS

Two-dose homologous ChAdOx1 vaccination or homologous mRNA-1273 booster appears to induce more-durable antibody responses than 2-dose homologous mRNA vaccination, homologous BNT162b2 booster, or 2-dose ChAdOx1 followed by BNT62b2 booster, although our findings are based on the relatively short term (3-month) follow-up after the vaccinations and the evaluation of the slopes from different antibody peak levels. Further studies on long-term durability depending on the types of vaccines are needed.