Antimicrobial activity of ceftazidime-avibactam against KPC-2-producing Enterobacterales: a cross-combination and dose-escalation titration study with relebactam and vaborbactam.

With the introduction of ceftazidime-avibactam worldwide, the antimicrobial activity of new ß-lactam/ß-lactamase inhibitors (BL/BLIs) needs to be investigated. From January 2020 to June 2023, Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales were collected. With a broth microdilution test of new BL/BLIs, cross-activity test with nine combinations of BLs and new BLIs and dose-escalation titration test for non-susceptible isolates were conducted to investigate inhibitory activities of new BLIs. A total of 188 isolates was collected and most isolates (186/188, 98.9%) carried the KPC-2 gene exclusively, while two isolates (1.1%) co-harbored NDM-1. Among the 186 KPC-2-producing isolates, 184 (98.9%) were susceptible to ceftazidime-avibactam, 173 (93.0%) to imipenem-relebactam, and 184 (98.9%) to meropenem-vaborbactam. All isolates non-susceptible to imipenem-relebactam or meropenem-vaborbactam became susceptible when avibactam replaced relebactam or vaborbactam, with 7 of 11 (63.6%) imipenem-relebactam non-susceptible isolates and both (100.0%) of the meropenem-vaborbactam non-susceptible isolates. When the minimum inhibitory concentrations (MICs) of BLs were compared using log2 scales, combinations with avibactam showed statistically significant efficacy in lowering MICs compared to relebactam and vaborbactam (all P < 0.05). In the dose-escalation test of new BLIs, increasing dose of all new BLIs corresponded to increased susceptibility to BLs. Ceftazidime-avibactam exhibited excellent susceptibility against KPC-2-producing Enterobacterales unless co-harboring metallo-ß-lactamase. The cross-combination test against non-susceptible isolates suggests that the inhibitory activity of avibactam was superior to those of relebactam or vaborbactam. Increasing the dose of new BLIs produced increased susceptibility to BLs, suggesting that high-concentration regimen need to be developed. IMPORTANCE: This study investigated 188 Klebsiella pneumoniae carbapenemase (KPC)-2-producing Enterobacterales collected from January 2020 to June 2023 in a tertiary care hospital of Korea. Most isolates were susceptible to ceftazidime-avibactam (98.9%) and meropenem-vaborbactam (98.9%), while susceptibility to imipenem-relebactam was lower (93.0%). The cross-combination test using nine combinations of the individual ß-lactams (BLs) and new ß-lactamase inhibitors (BLIs) showed that the inhibitory activity of avibactam was significantly superior to relebactam or vaborbactam when the Log2 MIC of BLs were compared for each combination with BLIs (all P < 0.05). The dose-escalation test of new BLIs demonstrated that increasing doses of new BLIs corresponded to increased susceptibility to BLs. Taken together, this study illustrates the excellent activity of ceftazidime-avibactam against KPC-2-producing Enterobacterales and suggests further investigation into high-concentration regimens for potentially non-susceptible clinical isolates.

Extensively drug-resistant Enterobacter ludwigii co-harbouring MCR-9 and a multicopy of blaIMP-1 in South Korea.

In this study, we describe an Enterobacter ludwigii clinical isolate that is resistant to both carbapenems and colistin in South Korea. Antimicrobial susceptibility testing revealed that E. ludwigii CRE2104-31 was non-susceptible to all tested antibiotics except fosfomycin. Whole genome sequencing identified a 323-kbp IncHI2 plasmid, pCRE2104-31a, that was co-harbouring mobile colistin resistance (mcr)-9.1 and blaIMP-1. In comparison with other full plasmids, pCRE2104-31a exhibited the closest similarity to a plasmid from the Klebsiella pneumoniae strain CNR48 from France, with 19.9% query coverage and 99% identity. Notably, we observed five tandem repeats of blaIMP-1 and aac(6')-Il genes, accompanied by multiple attCs within a class I integron on the Tn402-like transposon. The unit of blaIMP-1-attC-aac(6')-Il-attC might have accumulated due to multiple convergent events. In addition to mcr-9.1 and blaIMP-1, various other antibiotic resistance-associated genes were identified in the plasmid, as follows: blaTEM-1B, aph(3')-I, aph(3')-Ia, aac(6')-Il, aac(6')-IIc, aac(6')-IIa, aph(6)-Id, aph(3'')-Ib, aadA2b, aac(6')-Ib3, sul, dfrA19, qnrB2, aac(6')-Ib-cr, ere(A), and qacE. A conjugation assay showed that the mcr-9.1/blaIMP-1-co-bearing plasmid was self-transmissible to E. coli J53. However, colistin and carbapenem resistance could not be transferred to E. coli due to high incompatibility. The convergence of mcr and carbapenemase genes is thought to be host-dependent among Enterobacteriaceae. The emergence of extensively drug-resistant E. ludwigii co-harbouring MCR-9.1 and a multicopy of blaIMP-1 would pose a significant threat within the compatible Enterobacteriaceae.

Evolution of neutralizing antibodies through vaccination and breakthrough infections in the era of COVID-19 endemicity.

Despite a high vaccination rate, the COVID-19 pandemic continues with immune-evading Omicron variants. The success of additional antigenic stimulation through breakthrough infection (BI) and updated vaccination in overcoming antigenic imprinting needs to be determined. Participants in a long-term follow-up cohort of healthcare worker (HCW) vaccinee were categorized according to their infection/vaccination status. Anti-SARS-CoV-2 spike/nucleocapsid protein antibodies were measured, and plaque reduction neutralization tests (PRNTs) against wild-type (WT), BA.5, BN.1, and XBB.1.5 were conducted. The neutralization activity of intravenous immunoglobulin (IVIG) products was evaluated to assess the immune status of the general population. Ninety-five HCWs were evaluated and categorized into seven groups. The WT PRNT ND50 value was highest regardless of infection/vaccination status, and groups with recent antigenic stimulation showed high PRNT titers overall. Groups with double Omicron stimulation, either by BI plus BA.4/5 bivalent vaccination or repeated BI, exhibited significantly higher BA.5 and BN.1 PRNT to WT PRNT ratios than those with single Omicron stimulation. Overall group immunity was estimated to be boosted in January 2023, reflecting the effect of the BA.4/5 bivalent booster and additional BIs, but slightly declined in June 2023. A substantial increase in the antibody concentrations of IVIG products was noticed in 2022, and recently produced IVIG products exhibited a substantial level of cross-reactive neutralizing activity against emerging variants. Neutralizing activity against emerging variants could be enhanced by repeated antigenic stimulation via BI and/or updated vaccination. Overall group immunity was elevated accordingly, and IVIG products showed substantial activity against circulating strains.

Risk factors and clinical outcomes of cytomegalovirus diseases in hematologic malignancy patients without hematopoietic stem-cell transplantation.

PURPOSE: This study aims to evaluate the risk factors and prognosis for CMV diseases in hematologic malignancy patients without hematopoietic stem-cell transplantation (HSCT). METHODS: We performed a case-control study (1:2) between 2012 and 2022. Adults with pathologic-confirmed CMV diseases (n=60) among hematologic malignancy patients were matched and compared to whom without CMV disease. RESULTS: Lymphoma was the most common underlying malignancy, and gastrointestinal tract involvement was the most common CMV disease. In the case group, high-dose steroid administration and transfusion within one month before diagnosis were higher (p<0.001). Steroid administration (aOR=5.78; 95% confidence interval: 1.25-26.68, p=0.024), red blood cell transfusion within one month (aOR=14.63; 2.75-77.76, p=0.002), low BMI (aOR=13.46, 2.07-87.45, p=0.006), and hypoalbuminemia (aOR=26.48, 5.93-118.17, p<0.001) were independent risk factors associated with CMV disease. The 30-day mortality was higher in the case group and CMV disease was significantly associated with all-cause mortality (aOR=14.41, 3.23-64.31, p<0.001). CONCLUSION: In hematologic malignancy patients without HSCT, risk factors for CMV organ disease included high-dose steroid administration and RBC transfusion within one month, low BMI, and hypoalbuminemia. Overall mortality was significantly higher with CMV disease, and CMV disease occurrence was a significant risk factor for mortality.

False-positive Aspergillus galactomannan immunoassay in the glucose component of total parenteral nutrition products.

IMPORTANCE: This manuscript describes an occurrence of false-positive GM tests in patients receiving TPN products from a manufacturer who had recently changed the supplier of the glucose component. We describe the clinical presentation of nine false-positive cases and the results of serologic and microbiological investigations of the TPN products suspected of contamination with GM. Attempts to detect GM in parenteral nutrition products were made since the detection of GM in sodium gluconate-containing solutions in 2007, but none of them identified the source of elevated GM indexes in TPN products. However, the present study demonstrated that the glucose component of the TPN products contained a high level of GM antigen, which caused false-positive GM assay results. The source of GM was glucoamylase, which was derived from A. niger in the manufacturing process. Physicians and clinical microbiology laboratories should be aware of this issue to improve interpretation and patient care.

Longitudinal kinetics of neutralizing antibodies against circulating SARS-CoV-2 variants and estimated level of group immunity of booster-vaccinated individuals during omicron-dominated COVID-19 outbreaks in the Republic of Korea, 2022.

The coronavirus disease 2019 pandemic persisted for 3 years and is now transitioning to endemicity. We illustrated the change in group immunity induced by vaccination (monovalent vaccines) and breakthrough infections (BIs) in a healthcare worker (HCW) cohort. Five sampling points were analyzed: before the third dose and 1, 3, 5, and 8 months after the vaccination. The last two points corresponded roughly to 1 and 4 months after omicron BA.1/BA.2 BI. A semi-quantitative anti-spike binding antibody (Sab) assay and plaque reduction neutralization test (PRNT) against circulating variants were conducted. A linear regression model was utilized to deduce correlation equations. Baseline characteristics and antibody titers after the third dose were not different between 106 HCWs with or without BI (54/52). One month after the third dose, BA.1 PRNT increased with wild-type (WT), but 3 months after the third dose, it decreased more rapidly than WT PRNT. After BI, BA.1 PRNT increased robustly and waned slower than WT. A linear equation of waning kinetics was deduced between log10Sab and months, and the slope became gradual after BI. The estimated BA.5 PRNT titers at the beginning of the BA.5 outbreak were significantly higher than the BA.1 PRNT titers of the initial BA.1/BA.2 wave, which might be associated with the smaller size of the BA.5 wave. BA.1/BA.2 BI after the third dose elicited robust and broad neutralizing activity, preferentially maintaining cross-neutralizing longevity against BA.1 and BA.5. The estimated kinetics provide an overview of group immunity through the third vaccination and BA.1/BA.2 BI, correlating with the actual outbreaks. IMPORTANCE This study analyzed changes in group immunity induced by coronavirus disease 2019 (COVID-19) vaccination and BA.1/BA.2 breakthrough infections (BIs) in a healthcare worker cohort. We investigated the longitudinal kinetics of neutralizing antibodies against circulating variants and confirmed that BA.1/BA.2 BIs enhance the magnitude and durability of cross-neutralization against BA.1 and BA.5. Correlation equations between semi-quantitative anti-spike antibody and plaque reduction neutralization test titers were deduced from the measured values using a linear regression model. Based on the equations, group immunity was estimated to last up to 11 months following the third dose of the COVID-19 vaccine. The estimated group immunity suggests that the augmented immunity and flattened waning slope through BI could correlate with the overall outbreak size. Our findings could provide a better understanding to establish public health strategies against future endemicity.

Loss of Neutralizing Activity of Tixagevimab/Cilgavimab (Evusheld™) Against Omicron BN.1, a Dominant Circulating Strain Following BA.5 During the Seventh Domestic Outbreak in Korea in Early 2023.

Tixagevimab/cilgavimab is a monoclonal antibody used to prevent coronavirus disease 2019 among immunocompromised hosts and maintained neutralizing activity against early omicron variants. Omicron BN.1 became a dominant circulating strain in Korea early 2023, but its susceptibility to tixagevimab/cilgavimab is unclear. We conducted plaque reduction neutralization test (PRNT) against BN.1 in a prospective cohort (14 patients and 30 specimens). BN.1 PRNT was conducted for one- and three-months after tixagevimab/cilgavimab administration and the average PRNT ND50 of each point was lower than the positive cut-off value of 20 (12.9 ± 4.5 and 13.2 ± 4.2, respectively, P = 0.825). In the paired analyses, tixagevimab/cilgavimab-administered sera could not actively neutralize BN.1 (PRNT ND50 11.5 ± 2.9, P = 0.001), compared with the reserved activity against BA.5 (ND50 310.5 ± 180.4). Unlike virus-like particle assay, tixagevimab/cilgavimab was not active against BN.1 in neutralizing assay, and would not be effective in the present predominance of BA.2.75 sublineages.

Clinical Characteristics and Risk Factors for Mortality in Critical COVID-19 Patients Aged 50 Years or Younger During Omicron Wave in Korea: Comparison With Patients Older Than 50 Years of Age.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has caused the death of thousands of patients worldwide. Although age is known to be a risk factor for morbidity and mortality in COVID-19 patients, critical illness or death is occurring even in the younger age group as the epidemic spreads. In early 2022, omicron became the dominant variant of the COVID-19 virus in South Korea, and the epidemic proceeded on a large scale. Accordingly, this study aimed to determine whether young adults (aged ≤ 50 years) with critical COVID-19 infection during the omicron period had different characteristics from older patients and to determine the risk factors for mortality in this specific age group. METHODS: We evaluated 213 critical adult patients (high flow nasal cannula or higher respiratory support) hospitalized for polymerase chain reaction-confirmed COVID-19 in nine hospitals in South Korea between February 1, 2022 and April 30, 2022. Demographic characteristics, including body mass index (BMI) and vaccination status; underlying diseases; clinical features and laboratory findings; clinical course; treatment received; and outcomes were collected from electronic medical records (EMRs) and analyzed according to age and mortality. RESULTS: Overall, 71 critically ill patients aged ≤ 50 years were enrolled, and 142 critically ill patients aged over 50 years were selected through 1:2 matching based on the date of diagnosis. The most frequent underlying diseases among those aged ≤ 50 years were diabetes and hypertension, and all 14 patients who died had either a BMI ≥ 25 kg/m² or an underlying disease. The total case fatality rate among severe patients (S-CFR) was 31.0%, and the S-CFR differed according to age and was higher than that during the delta period. The S-CFR was 19.7% for those aged ≤ 50 years, 36.6% for those aged > 50 years, and 38.1% for those aged ≥ 65 years. In multivariate analysis, age (odds ratio [OR], 1.084; 95% confidence interval [CI], 1.043-1.127), initial low-density lipoprotein > 600 IU/L (OR, 4.782; 95% CI, 1.584-14.434), initial C-reactive protein > 8 mg/dL (OR, 2.940; 95% CI, 1.042-8.293), highest aspartate aminotransferase > 200 IU/L (OR, 12.931; 95% CI, 1.691-98.908), and mechanical ventilation implementation (OR, 3.671; 95% CI, 1.294-10.420) were significant independent predictors of mortality in critical COVID-19 patients during the omicron wave. A similar pattern was shown when analyzing the data by age group, but most had no statistical significance owing to the small number of deaths in the young critical group. Although the vaccination completion rate of all the patients (31.0%) was higher than that in the delta wave period (13.6%), it was still lower than that of the general population. Further, only 15 (21.1%) critically ill patients aged ≤ 50 years were fully vaccinated. Overall, the severity of hospitalized critical patients was significantly higher than that in the delta period, indicating that it was difficult to find common risk factors in the two periods only with a simple comparison. CONCLUSION: Overall, the S-CFR of critically ill COVID-19 patients in the omicron period was higher than that in the delta period, especially in those aged ≤ 50 years. All of the patients who died had an underlying disease or obesity. In the same population, the vaccination rate was very low compared to that in the delta wave, indicating that non-vaccination significantly affected the progression to critical illness. Notably, there was a lack of prescription for Paxlovid for these patients although they satisfied the prescription criteria. Early diagnosis and active initial treatment was necessary, along with the proven methods of vaccination and personal hygiene. Further studies are needed to determine how each variant affects critically ill patients.

TRAF3-EWSR1 signaling axis acts as a checkpoint on germinal center responses.

The formation of germinal centers (GCs) is crucial for humoral immunity and vaccine efficacy. Constant stimulation through microbiota drives the formation of constitutive GCs in Peyer's patches (PPs), which generate B cells that produce antibodies against gut antigens derived from commensal bacteria and infectious pathogens. However, the molecular mechanism that regulates this persistent process is poorly understood. We report that Ewing Sarcoma Breakpoint Region 1 (EWSR1) is a brake to constitutive GC generation and immunoglobulin G (IgG) production in PPs, vaccination-induced GC formation, and IgG responses. Mechanistically, EWSR1 suppresses Bcl6 upregulation after antigen encounter, thereby negatively regulating induced GC B cell generation and IgG production. We further showed that tumor necrosis factor receptor-associated factor (TRAF) 3 serves as a negative regulator of EWSR1. These results established that the TRAF3-EWSR1 signaling axis acts as a checkpoint for Bcl6 expression and GC responses, indicating that this axis is a therapeutic target to tune GC responses and humoral immunity in infectious diseases.

Breakthrough invasive fungal infection in patients with myeloid malignancy receiving posaconazole tablet prophylaxis: Clinical features, risk factors, and posaconazole profiles.

Posaconazole (PSC) delayed-release tablet prophylaxis is the standard of care for preventing invasive fungal infection (IFI) in patients with acute myeloid leukemia undergoing myelosuppressive chemotherapy. The clinical features, risk factors, and PSC profiles of breakthrough IFI (bIFI) in patients receiving PSC tablet prophylaxis were investigated. A single-center retrospective cohort study was conducted, including adult patients with myeloid malignancy who received prophylactic PSC tablets while undergoing chemotherapy from June 2016 to June 2021. Logistic regression analysis was used to identify risk factors for bIFI. A receiver operating characteristic curve was used to predict the relationship between PSC trough level at steady state and bIFI. A total of 434 patients with myeloid malignancy who received PSC tablets were screened. A total of 10 patients with bIFI were compared with 208 non-IFI patients. There were four proven and six probable IFI cases, nine due to Aspergillus, and one due to Fusarium species. The bIFI patients had higher in-hospital mortality (30.0%) than the non-IFI patients (1.9%; P < 0.001). History of allogeneic hematopoietic stem cell transplantation (odds ratio [OR] 6.27; 95% confidence interval [CI] 1.63-24.09), prolonged neutropenia ≥28 days (OR 4.33; 95% CI 1.20-15.70), and low plasma PSC concentration <0.7 µg/ml (OR 16.33; 95% CI 4.15-64.26) were risk factors for bIFI. The optimal cutoff value of plasma PSC concentration predicting bIFI was 0.765 µg/ml (sensitivity, 60.0%; specificity, 91.3%; area under the curve, 0.746). bIFI was not uncommon in patients with myeloid malignancy receiving PSC tablet prophylaxis and associated with poor outcomes. Therapeutic drug monitoring may still be necessary, even in patients receiving PSC tablets.

Invasive fungal infections increase mortality in acute myeloid leukemia patients. This study investigated breakthrough invasive fungal infection cases in patients receiving posaconazole tablet prophylaxis. Our results will contribute to improving the outcome of patients with myeloid malignancy.

Neutralizing activity against Omicron BA.5 after tixagevimab/cilgavimab administration comparable to those after Omicron BA.1/BA.2 breakthrough infections.

Introduction: The effect of tixagevimab/cilgavimab (Evusheld™; AstraZeneca, UK) should be evaluated in the context of concurrent outbreak situations. Methods: For serologic investigation of tixagevimab/cilgavimab during the BA.5 outbreak period, sera of immunocompromised (IC) hosts sampled before and one month after tixagevimab/cilgavimab administration and those of healthcare workers (HCWs) sampled one month after a 3rd shot of COVID-19 vaccines, five months after BA.1/BA.2 breakthrough infection (BI), and one month after BA.5 BI were investigated. Semi-quantitative anti-spike protein antibody (Sab) test and plaque reduction neutralizing test (PRNT) against BA.5 were performed. Results: A total of 19 IC hosts (five received tixagevimab/cilgavimab 300 mg and 14 received 600 mg) and 41 HCWs (21 experienced BA.1/BA.2 BI and 20 experienced BA.5 BI) were evaluated. Baseline characteristics did not differ significantly between IC hosts and HCWs except for age and hypertension. Sab significantly increased after tixagevimab/cilgavimab administration (median 130.2 BAU/mL before tixagevimab/cilgavimab, 5,665.8 BAU/mL after 300 mg, and 10,217 BAU/mL after 600 mg; both P < 0.001). Sab of one month after the 3rd shot (12,144.2 BAU/mL) or five months after BA.1/BA.2 BI (10,455.8 BAU/mL) were comparable with that of tixagevimab/cilgavimab 600 mg, while Sab of one month after BA.5 BI were significantly higher (22,216.0 BAU/mL; P < 0.001). BA.5 PRNT ND50 significantly increased after tixagevimab/cilgavimab administration (median ND50 29.6 before tixagevimab/cilgavimab, 170.8 after 300 mg, and 298.5 after 600 mg; both P < 0.001). The ND50 after tixagevimab/cilgavimab 600 mg was comparable to those of five months after BA.1 BI (ND50 200.9) while ND50 of one month after the 3rd shot was significantly lower (ND50 107.6; P = 0.019). The ND50 of one month after BA.5 BI (ND50 1,272.5) was highest among tested groups, but statistical difference was not noticed with tixagevimab/cilgavimab 600 mg. Conclusion: Tixagevimab/cilgavimab provided a comparable neutralizing activity against the BA.5 with a healthy adult population who were vaccinated with a 3rd shot and experienced BA.1/BA.2 BI.

Stretchable and Skin-Mountable Temperature Sensor Array Using Reduction-Controlled Graphene Oxide for Dermatological Thermography.

Since thermometry of human skin is critical information that provides important aspects of human health and physiology, accurate and continuous temperature measurement is required for the observation of physical abnormalities. However, conventional thermometers are uncomfortable because of their bulky and heavy features. In this work, we fabricated a thin, stretchable array-type temperature sensor using graphene-based materials. Furthermore, we controlled the degree of graphene oxide reduction and enhanced the temperature sensitivity. The sensor exhibited an excellent sensitivity of 2.085% °C-1. The overall device was designed in a wavy meander shape to provide stretchability for the device so that precise detection of skin temperature could be performed. Furthermore, polyimide film was coated to secure the chemical and mechanical stabilities of the device. The array-type sensor enabled spatial heat mapping with high resolution. Finally, we introduced some practical applications of skin temperature sensing, suggesting the possibility of skin thermography and healthcare monitoring.

Augmented humoral and cellular immunity against severe acute respiratory syndrome coronavirus 2 after breakthrough infection in kidney transplant recipients who received 3 doses of coronavirus disease 2019 vaccine.

Diminished immune response to coronavirus disease 2019 (COVID-19) vaccines and breakthrough infection (BI) is a major concern for solid organ transplant recipients. Humoral and cellular immune responses of kidney transplant (KT) recipients after a third COVID-19 vaccination were investigated compared to matched health care workers. Anti-severe acute respiratory syndrome coronavirus 2 spike protein antibody and severe acute respiratory syndrome coronavirus 2 specific interferon-gamma releasing assay (IGRA) were assessed. A total of 38 KT recipients, including 20 BI and 18 noninfection, were evaluated. In the KT BI group, antibody titers were significantly increased (median 5 to 724, binding antibody units/mL (P = 0.002) after the third vaccination, but IGRA responses were negligible. After BI, antibody titers increased (median 11 355 binding antibody unit/mL; P < 0.001) and there was a significant increase of IGRA responses to spike proteins (Spike1-Nil, median 0.05 to 0.41 IU/mL; P = 0.009). Antibody titers and IGRA responses were significantly higher in the BI than in the noninfection group after 6 months. Immune responses were stronger in the health care worker than in the KT cohort, but the gap became narrower after BI. In conclusion, KT recipients who experienced BI after 3 COVID-19 vaccinations acquired augmented humoral and cellular immune responses.

Biometabolites of Citrus unshiu Peel Enhance Intestinal Permeability and Alter Gut Commensal Bacteria.

Flavanones in Citrus unshiu peel (CUP) have been used as therapeutic agents to reduce intestinal inflammation; however, the anti-inflammatory effects of their biometabolites remain ambiguous. Here, we identified aglycone-type flavanones, such as hesperetin and naringenin, which were more abundant in the bioconversion of the CUP than in the ethanol extracts of the CUP. We found that the bioconversion of the CUP induced the canonical nuclear factor-κB pathway via degradation of IκB in Caco-2 cells. To check the immune suppressive capacity of the aglycones of the CUP in vivo, we orally administered the bioconversion of the CUP (500 mg/kg) to mice for two weeks prior to the 3% dextran sulfate sodium treatment. The CUP-pretreated group showed improved body weight loss, colon length shortage, and intestinal inflammation than the control mice. We also found a significant decrease in the population of lamina propria Th17 cells in the CUP-pretreated group following dextran sodium sulfate (DSS) treatment and an increase in mRNA levels of occludin in CUP-treated Caco-2 cells. Pyrosequencing analysis revealed a decreased abundance of Alistipes putredinis and an increased abundance of Muribaculum intestinale in the feces of the CUP-pretreated mice compared to those of the control mice. Overall, these findings suggest that the pre-administration of CUP biometabolites may inhibit the development of murine colitis by modulating intestinal permeability and the gut microbiome.

Can nirmatrelvir/ritonavir treatment shorten the duration of COVID-19 isolation?

Background: The impact of nirmatrelvir/ritonavir treatment on shedding of viable virus in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. Methods: A prospective cohort study evaluating mildly ill COVID-19 patients was conducted. Virologic responses were compared between nirmatrelvir/ritonavir-treatment and supportive care groups. Risk factors and relevant clinical factors for shedding of viable virus were investigated. Results: A total of 80 COVID-19 patients were enrolled and 222 sputum specimens were collected. Ten patients were dropped during follow-up, and 33 patients in the nirmatrelvir/ritonavir and 37 in the supportive care groups were compared. The median age was 67 years, and 67% were male. Clinical characteristics were similar between groups. Viral loads decreased significantly faster in the nirmatrelvir/ritonavir group compared with the supportive care group (P < 0.001), and the slope was significantly steeper (-2.99 ± 1.54 vs. -1.44 ± 1.52; P < 0.001). The duration of viable virus shedding was not statistically different between groups. In the multivariable analyses evaluating all collected specimens, male gender (OR 2.51, 95% CI 1.25-5.03, P = 0.010), symptom score (OR 1.41, 95% CI 1.07-1.87, P = 0.015), days from symptom onset (OR 0.72, 95% CI 0.59-0.88, P = 0.002), complete vaccination (OR 0.09, 95% CI 0.01-0.87, P = 0.038), and BA.2 subtype (OR 0.49, 95% CI 0.26-0.91, P = 0.025) were independently associated with viable viral shedding, while nirmatrelvir/ritonavir treatment was not. Conclusion: Nirmatrelvir/ritonavir treatment effectively reduced viral loads of SARS-CoV-2 Omicron variants but did not decrease the duration of viable virus shedding.

Förster Resonance Energy Transfer-Based Single-Cell Imaging Reveals Piezo1-Induced Ca2+ Flux Mediates Membrane Ruffling and Cell Survival.

A mechanosensitive ion channel, Piezo1 induces non-selective cation flux in response to various mechanical stresses. However, the biological interpretation and underlying mechanisms of cells resulting from Piezo1 activation remain elusive. This study elucidates Piezo1-mediated Ca2+ influx driven by channel activation and cellular behavior using novel Förster Resonance Energy Transfer (FRET)-based biosensors and single-cell imaging analysis. Results reveal that extracellular Ca2+ influx via Piezo1 requires intact caveolin, cholesterol, and cytoskeletal support. Increased cytoplasmic Ca2+ levels enhance PKA, ERK, Rac1, and ROCK activity, which have the potential to promote cancer cell survival and migration. Furthermore, we demonstrate that Piezo1-mediated Ca2+ influx upregulates membrane ruffling, a characteristic feature of cancer cell metastasis, using spatiotemporal image correlation spectroscopy. Thus, our findings provide new insights into the function of Piezo1, suggesting that Piezo1 plays a significant role in the behavior of cancer cells.

Severity-Adjusted Dexamethasone Dosing and Tocilizumab Combination for Severe COVID-19.

PURPOSE: Real-world experience with tocilizumab in combination with dexamethasone in patients with severe coronavirus disease (COVID-19) needs to be investigated. MATERIALS AND METHODS: A retrospective cohort study was conducted to evaluate the effect of severity-adjusted dosing of dexamethasone in combination with tocilizumab for severe COVID-19 from August 2020 to August 2021. The primary endpoint was 30-day clinical recovery, which was defined as no oxygen requirement or referral after recovery. RESULTS: A total of 66 patients were evaluated, including 33 patients in the dexamethasone (Dexa) group and 33 patients in the dexamethasone plus tocilizumab (DexaToci) group. The DexaToci group showed a statistically significant benefit in 30-day clinical recovery, compared to the Dexa group (p=0.024). In multivariable analyses, peak FiO2 within 3 days and tocilizumab combination were consistently significant for 30-day recovery (all p<0.05). The DexaToci group showed a significantly steeper decrease in FiO2 (-4.2±2.6) than the Dexa group (-2.7±2.6; p=0.021) by hospital day 15. The duration of oxygen requirement was significantly shorter in the DexaToci group than the Dexa group (median, 10.0 days vs. 17.0 days; p=0.006). Infectious complications and cellular and humoral immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the convalescence stage were not different between the two groups. CONCLUSION: A combination of severity-adjusted dexamethasone and tocilizumab for the treatment of severe COVID-19 improved clinical recovery without increasing infectious complications or hindering the immune response against SARS-CoV-2.

Characterization of Edwardsiella piscicida CK108 flagellin genes and evaluation of their potential as vaccine targets in the zebrafish model.

The control of bacterial pathogens, including Edwardsiella piscicida, in the aquaculture industry has high economic importance. This study aimed to identify a potential live vaccine candidate against E. piscicida infection to minimize the side effects and elicit immunity in the host. This study evaluated the virulence factors of E. piscicida CK108, with a special focus on the flagella. E. piscicida has two important homologous flagellin genes, namely flagellin-associated protein (fap) and flagellin domain-containing protein (fdp). CK226 (Δfap), CK247 (Δfdp) and CK248 (Δfap, fdp) mutant strains were constructed. Both CK226 and CK247 displayed decreased length and thickness of flagellar filaments, resulting in reduced bacterial swimming motility, while CK248 was non-motile as it lacked flagella. The loss of flagella and decreased motility was expected to decrease the pathogenicity of CK248. However, the median lethal dose (LD50 ) of CK248 against zebrafish was lower than those of the wild-type, CK226 and CK247 strains. The protective immunity and cytokine gene expression levels in the CK248-infected zebrafish were lower than those in the wild type-infected zebrafish. In conclusion, Fap and Fdp are essential for flagella formation and motility, and for stimulating fish immune response, which can be utilized as a potential adjuvants for E. piscicida vaccination.

Effects of Short-Term Corticosteroid Use on Reactogenicity and Immunogenicity of the First Dose of ChAdOx1 nCoV-19 Vaccine.

The effects of corticosteroid use on the reactogenicity and immunogenicity of ChAdOx1 nCoV-19 (ChAd) vaccine were evaluated. Healthcare workers (HCWs) who took low-dose corticosteroid agents around the time of the first dose of ChAd (ChAdPd group) were recruited and the reactogenicity and immunogenicity were compared with those of ChAd (ChAd group) and BNT162b2 vaccination (BNT group) of HCWs without corticosteroid exposure. The immunogenicity was measured three weeks after vaccination using quantitative anti-SARS-CoV-2 spike protein (S) antibody electrochemiluminescence immunoassay and interferon gamma (IFN-γ) release assay. A total of 67 HCWs comprising 24 ChAd, 29 BNT, and 14 ChAdPd was included. The median total corticosteroid dose of the ChAdPd group was 30 mg prednisolone equivalents (interquartile range (IQR) 20-71.3 mg). HCWs in the ChAdPd group experienced significantly milder reactogenicity (median total score 7.5, IQR 4.0-18.0) compared to those in the ChAd group (median 23.0, IQR 8.0-43.0, P=0.012) but similar to that in the BNT group (median 5.0, IQR 3.0-9.0, P=0.067). The S antibody concentration of the ChAdPd group (62.4 ± 70.0 U/mL) was higher than that of the ChAd group, though without statistical significance (3.45 ± 57.6 U/mL, P=0.192). The cellular immune response was most robust in the ChAdPd group, with significantly higher IFN-γ concentration (5.363 ± 4.276 IU/mL), compared to the ChAd (0.978 ± 1.181 IU/mL, P=0.002) and BNT (1.656 ± 1.925 IU/mL, P=0.009) groups. This finding suggest that short-term corticosteroid reduces reactogenicity of the first dose of ChAd without hindering immunogenicity.