Clinical and microbiological analyses of colistin-resistant strains among carbapenem-resistant complex clinical isolates.

Carbapenem-resistant complex (CR-ECC), which is rapidly increasing as the cause of nosocomial infections, has limited treatment options. The aim of this study is to investigate the microbiological and clinical traits and molecular epidemiology of isolates of CR-ECC and provide guidance for antibiotic selection in clinical practice. Clinical CR-ECC isolates (ertapenem MIC ≥ 2 mg/L) were collected from 2021 to 2022.

Synergistic effects of colistin-rifampin-based triple antimicrobial combination therapy against Carbapenem-resistant Pseudomonas aeruginosa: a time-kill assay.

Background: Our research aimed to investigate the potential of in vitro triple antimicrobial synergism against carbapenem-resistant Pseudomonas aeruginosa (CRPA) as a strategy to overcome antimicrobial resistance.

Methods: We used 12 CRPA blood isolates stocked in the Asian Bacterial Bank between 2016 and 2018. All isolates were tested by multi-locus sequencing and carbapenemase multiplex PCR.

Overcoming the age-dependent SARS-CoV-2 vaccine response through hybrid immunity: analysis of humoral and cellular immunity with mass cytometry profiling.

Background: Age-dependent immune responses to coronavirus disease 2019 (COVID-19) vaccinations and breakthrough infections (BIs) in young and middle-aged individuals are unclear.

Methods: This nationwide multicenter prospective cohort study analyzed immune responses in participants of the ChAdOx1 (ChAd)-ChAd-mRNA vaccine group using cytometry by time-of-flight, anti-spike protein antibody (Sab) and anti-nucleocapsid antibody (Nab) titers, plaque reduction neutralization tests (PRNTs), and interferon-gamma (IFN-γ) release assays at various time points.

Results: We evaluated 347 participants with an average age of 38.

Risk Factors for Impaired Cellular or Humoral Immunity after Three Doses of SARS-CoV-2 Vaccine in Healthy and Immunocompromised Individuals.

We aimed to identify the risk factors for impaired cellular and humoral immunity after three doses of the SARS-CoV-2 vaccine. Six months after the third vaccine dose, T-cell immunity was evaluated using interferon-gamma release assays (IGRAs) in 60 healthy and 139 immunocompromised (IC) individuals, including patients with hematologic malignancy (HM), solid malignancy (SM), rheumatic disease (RD), and kidney transplantation (KT). Neutralizing antibody titers were measured using the plaque reduction neutralization test (PRNT) and surrogate virus neutralization test (sVNT).

Longitudinal multiomic profiling and corticosteroid modulation of the immediate innate immune response to an adenovirus-vector vaccine.

Among new vaccine technologies contributed to the control of the COVID-19 pandemic, ChAdOx1 nCoV-19, a chimpanzee adenovirus (ChAd)-vector vaccine expressing the SARS-CoV-2 spike protein, could be administered globally owing to its low production cost and lack of a requirement for frozen storage. Despite its benefits, most recipients have reported immediate inflammatory reactions after the initial dose vaccination. We comprehensively examined the immune landscape following ChAdOx1 nCoV-19 vaccination based on the single-cell transcriptomes of immune cells and epigenomic profiles of monocytes.

Persistent differences in the immunogenicity of the two COVID-19 primary vaccines series, modulated by booster mRNA vaccination and breakthrough infection.

Introduction: The long-term impact of initial immunogenicity induced by different primary COVID-19 vaccine series remains unclear.

Methods: A prospective cohort study was conducted at 10 tertiary hospitals in Korea from March 2021 to September 2022. Immunogenicity assessments included anti-spike protein antibody (Sab), SARS-CoV-2-specific interferon-gamma releasing assay (IGRA), and multiplex cytokine assays for spike protein-stimulated plasma.

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

Unlabelled: With the introduction of ceftazidime-avibactam worldwide, the antimicrobial activity of new β-lactam/β-lactamase inhibitors (BL/BLIs) needs to be investigated. From January 2020 to June 2023, 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.

Omicron BA.2 breakthrough infection elicits CD8 T cell responses recognizing the spike of later Omicron subvariants.

Here, we examine peripheral blood memory T cell responses against the SARS-CoV-2 BA.4/BA.5 variant spike among vaccinated individuals with or without Omicron breakthrough infections.

Extensively drug-resistant Enterobacter ludwigii co-harbouring MCR-9 and a multicopy of bla 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.

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.

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.

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.

COVID-19 Vaccination Alters NK Cell Dynamics and Transiently Reduces HBsAg Titers Among Patients With Chronic Hepatitis B.

Coronavirus disease 2019 (COVID-19) vaccination may non-specifically alter the host immune system. This study aimed to evaluate the effect of COVID-19 vaccination on hepatitis B surface Ag (HBsAg) titer and host immunity in chronic hepatitis B (CHB) patients. Consecutive 2,797 CHB patients who had serial HBsAg measurements during antiviral treatment were included in this study.

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

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.

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.

Clinical Utility of Sero-Immunological Responses Against SARS-CoV-2 Nucleocapsid Protein During Subsequent Prevalence of Wild-Type, Delta Variant, and Omicron Variant.

As nucleocapsid protein of severe acute respiratory syndrome coronavirus 2 is immunogenic but not targeted in vaccines, it could be useful in distinguishing natural infection from vaccination. We aimed to investigate the clinical utility of sero-immunological responses against the nucleocapsid protein. Nucleocapsid antibody immunoassay study with 302 coronavirus disease 2019 (COVID-19) patients showed lower titers in immunocompromised patients ( < 0.

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.

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.

Trend of immunity against measles and varicella zoster virus in healthcare workers in Korea.

Objective: To examine the seroprevalence of measles and varicella zoster virus (VZV) among healthcare workers (HCW) and evaluate the concordance between self-reported history of previous disease or vaccination and seropositivity.

Design: A seroprevalence study and survey.

Setting: A university-affiliated tertiary care hospital.

Effectiveness of regdanvimab treatment for SARS-CoV-2 delta variant, which exhibited decreased activity: a nationwide real-world multicenter cohort study.

Background: Immune-evading severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are emerging continuously. The clinical effectiveness of monoclonal antibody agents that exhibit decreased activity against SARS-CoV-2 variants needs to be elucidated.

Methods: A nationwide, multicenter, retrospective cohort study was designed to evaluate the effectiveness of regdanvimab, an anti-SARS-CoV-2 monoclonal antibody agent.

Impact of vancomycin resistance in Enterococcus faecium bloodstream infection on mortality: A retrospective analysis of nationwide surveillance data.

Objectives: It is unclear whether the poor outcome of patients with severe vancomycin-resistant enterococci (VRE) infection is attributable to vancomycin resistance or to Enterococcus faecium (Efm), which predominates among VRE.

Methods: Retrospective study of a prospectively identified cohort from nationwide surveillance. A cohort of consecutive, nonduplicate episodes of monomicrobial bloodstream infections (BSIs) caused by Efm in 2016 was selected.