1.Molecular Epidemiology of Extended-spectrum β-Lactamase-producing Escherichia coli in South Korea: A Korean Global Antimicrobial Resistance Surveillance System Report
Dokyun KIM ; SungYoung LEE ; Jun Sung HONG ; Min Hyuk CHOI ; Hyun Soo KIM ; Young Ree KIM ; Young Ah KIM ; Young UH ; Kyeong Seob SHIN ; Jeong Hwan SHIN ; Jeong Su PARK ; Kyoung Un PARK ; Soo Hyun KIM ; Jong Hee SHIN ; Jungsik YU ; Seok Hoon JEONG
Annals of Laboratory Medicine 2026;46(1):72-82
Background:
Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is among the most important multidrug-resistant pathogens causing bloodstream infections (BSIs).Cefotaximase (CTX-M) enzymes are the most common and highly diverse ESBL family in E.coli. CTX-M-15 in group CTX-M-1 and CTX-M-14 in group CTX-M-9 are the most extensively disseminated enzymes. Multidrug-resistant E. coli strains complicate empirical therapy and increase healthcare burden globally and in Korea. We investigated the molecular epidemiology, sequence types (STs), and ESBL genotypes of E. coli bloodstream isolates in Korea and identified clinical risk factors for cefotaxime resistance.
Methods:
We collected all non-duplicated isolates of E. coli and related clinical information from patients with BSIs at eight sentinel hospitals in the Korean Global Antimicrobial Resistance Surveillance System (Kor-GLASS) collection network during 2017–2021. Duplicate isolates were removed to ensure representativeness of the data. Antimicrobial susceptibility was tested using disk diffusion tests, and multilocus sequence typing and betalactamase genotyping were performed.
Results:
Among 9,232 E. coli blood isolates, resistance rates to cefotaxime and ceftazidime were 36.4% and 11.4%, respectively. Among the clinical factors, age > 65 yrs (adjusted odds ratio [aOR], 1.36), hospital-origin infection (aOR, 2.55), and admission type (intensive care unit [ICU] vs. general ward; aOR, 1.34) were significant cefotaxime resistance risk factors. ST131 was the most prevalent among cefotaxime-resistant E. coli (64.8%, 2,180/3,363), followed by ST1193 (5.3%, N = 177), and ST69 (5.1%, N = 170).ST131, ST648, ST405, and ST410 cefotaxime-resistant E. coli isolates frequently harbored blaCTX-M-15, whereas ST1193 and ST68 showed a high proportion of blaCTX-M-27 carriers, and most ST457 and ST5150 isolates carried blaCTX-M-55.
Conclusions
Continuous monitoring of ESBL-producing E. coli is required to prevent further dissemination, guide empirical therapy, inform infection control policies, and ensure early detection of multidrug-resistant clones with the potential for widespread transmission.
2.Comparison of Broad-Spectrum Antibiotic Use According to Hospice Utilization Among Patients with Cancer at the End of Life in South Korea: A Nationwide Analysis
Ye Sul JEUNG ; Hak Jun KIM ; Jiwon YU ; Jeong-Han KIM ; Jin-Ah SIM ; Shin Hye YOO
Journal of Hospice and Palliative Care 2026;29(2):41-50
Purpose:
We aimed to compare broad-spectrum antibiotic use between hospice and nonhospice patients with cancer at the end of life using nationwide data from Korea.
Methods:
In this retrospective cohort study, we analyzed the Korean National Health Insurance Service data of adult patients with cancer who died between 2018 and 2021. Hospice users were defined as patients who received inpatient, home-based, or consultation-based hospice care before death. We applied propensity score matching (1:2) to balance the baseline characteristics of the hospice and non-hospice groups. Broad-spectrum antibiotic use, including anti-pseudomonal penicillins, anti-pseudomonal cephalosporins, carbapenems, and glycopeptides, was assessed during the last 3 months of life using prescription proportions and days of therapy per 1,000 patient-days.
Results:
After matching, 38,102 hospice and 75,736 non-hospice users were analyzed. During the last 3 months of life, 74.6% of hospiceand 79.0% of non-hospice users received at least one broad-spectrum antibiotic (P<0.001).The proportion of patients receiving broad-spectrum antibiotics was generally lower amonghospice users across all time intervals (P<0.001), and the number of days of therapy wasalso lower, with the largest differences observed during the final week and last 3 days of life.Subgroup analyses showed the highest antibiotic exposure among patients with hematologic and pancreatobiliary cancers, particularly in the non-hospice group.
Conclusion
Hospice involvement was associated with lower use and reduced exposure to broad-spectrum antibiotics among patients with cancer near the end of life. These findings support the alignment of end-of-life treatment decisions with the comfort-oriented goals of hospice care.
3.DNA Damage and Nuclear Anaplasia Induced by Trastuzumab Deruxtecan in Cancer Cells with Variable HER2 Expression and Homologous Recombination Deficiency Status
So Hyeon KIM ; Yoonjung PARK ; Ahrum MIN ; Hye Yeon PARK ; Yu-Jin KIM ; Sujin HAM ; Jiwon KOH ; Seongyeong KIM ; Dae-Won LEE ; Han Suk RYU ; Jin-Soo KIM ; Kyung-Hun LEE ; Seock-Ah IM
Cancer Research and Treatment 2026;58(2):407-422
Purpose:
Human epidermal growth factor receptor 2 (HER2) is amplified or overexpressed in various malignancies, including breast and gastric cancers, and is associated with poor prognosis. Although HER2-targeted therapies, such as trastuzumab, improve outcomes in HER2-positive tumors, resistance often develops, and HER2-low tumors remain largely untargeted. Trastuzumab deruxtecan (T-DXd; DS-8201a) is a HER2-targeted antibody-drug conjugate with potent activity in HER2-positive and HER2-low tumors. This study evaluates its antitumor mechanisms and efficacy in HER2-positive, HER2-low, and homologous recombination deficiency (HRD)–associated models.
Materials and Methods:
Effects of T-DXd were assessed in cancer cell lines with diverse HER2 expression and HRD status. In vivo efficacy was evaluated using a xenograft model derived from HER2-low SNU-601 gastric cancer cells.
Results:
T-DXd reduced HER2 phosphorylation and downstream signaling (AKT, ERK) in HER2-positive cells. It induced DNA damage accumulation, as evidenced by increased γH2AX and p-Chk1 expression, and triggered apoptosis through cleaved poly(ADP-ribose) polymerase and caspase-3 activation, confirmed by annexin V staining. Similar effects were observed in HER2-low cells, with greater sensitivity in HRD cells. In xenografts, T-DXd reduced tumor volume by up to 80% at 4 mg/kg and 10 mg/kg. Histological analyses showed decreased Ki-67 and increased apoptosis. Furthermore, T-DXd induced G2/M cell cycle arrest and nuclear anaplasia, suggesting disruption of chromosomal stability as a potential antitumor mechanism. No significant toxicity, including body weight loss, was observed.
Conclusion
These findings highlight T-DXd’s effectiveness in HER2-low and HRD tumors, supporting its broader clinical application, including strategies targeting DNA damage repair pathways.
4.Elimusertib, a Novel ATR Inhibitor, Induces Anti-tumor Effects through Replication Catastrophe in Breast Cancers
Mudong KIM ; Ahrum MIN ; Sohyeon KIM ; Seongyeong KIM ; Yu-jin KIM ; Sujin HAM ; Miso LEE ; Eunice Yoojin LEE ; Jinyong KIM ; Dae-Won LEE ; Kyung-Hun LEE ; Seock-Ah IM
Cancer Research and Treatment 2026;58(1):159-174
Purpose:
Sustained cell proliferation and cell cycle acceleration in cancer cells inherently increase DNA damage, which interferes with homeostatic replication and transcription. Ataxia telangiectasia and Rad3-related (ATR) is crucial for initiation of the DNA damage response, and ATR inhibitors, such as elimusertib, induce increased replication stress and DNA damage. We investigated the anti-tumor effects of elimusertib and its mechanism of action in relation to replication stress.
Materials and Methods:
Anti-tumor effects were evaluated by MTT assay and colony formation assay in breast cancer cell lines in vitro, in breast cancer cell xenografts in vivo, and in patient-derived xenograft models. Cell cycle was assessed by flow cytometry and BrdU assay was used to measure replicating cells and S-phase progression. Alkaline and neutral comet assay was used to measure single and double-stranded DNA damages, respectively.
Results:
Elimusertib delayed S-phase progression in MDA-MB-453 and MDA-MB-231 cells and induced caspase-7–dependent apoptosis. Furthermore, the increase in sub-G1 population in the fluorescence-activated cell sorting analysis and Annexin V assay also confirmed apoptotic cell death. In the BrdU assay, single-stranded DNA (ssDNA) increased in sensitive cells and aberrant ssDNA induced DNA damage in S-phase and eventually caused replication catastrophe. Finally, these anti-tumor effects were proven in in vivo xenograft and patient-derived xenograft models.
Conclusion
Elimusertib had anti-tumor effects and induced replication catastrophe in breast cancer cells with a high replication rate. Moreover, cells under high DNA replication stress were sensitive to elimusertib. Further studies and treatment strategies with elimusertib are warranted for cancers with a high replication rate.
5.Associated factors of osteoporosis and the impact of osteoporosis on all-cause mortality in incident hemodialysis older patients
Seunghye LEE ; Yoomee KANG ; Yu Ah HONG ; Sung Joon SHIN ; Soon Hyo KWON ; Sungjin CHUNG ; Young Youl HYUN ; Sang Heon SONG ; Jae Won YANG ; Won Min HWANG ; Jang-Hee CHO ; Kyung Don YOO ; In O SUN ; Gang-Jee KO ; Byung Chul YU ; Hyunsuk KIM ; Woo Yeong PARK ; Tae Won LEE ; Dong Jun PARK ; Eunjin BAE ;
Kidney Research and Clinical Practice 2026;45(1):110-119
Background:
With the aging population and advancements in medical care worldwide, the number of older patients with end-stage kidney disease continues to rise. This study aimed to identify factors associated with osteoporosis and osteopenia in older patients undergoing incident hemodialysis and assess their impact on mortality.
Methods:
We analyzed a large multicenter retrospective cohort of patients aged ≥70 years undergoing incident hemodialysis to identify factors associated with osteoporosis using logistic regression analysis and to assess the association of death with osteoporosis and osteopenia using Cox multivariable analysis.
Results:
Among 710 patients, 39.0% and 19.6% had osteoporosis and osteopenia, respectively. Osteoporosis was significantly associated with female sex, a history of fractures, and the absence of phosphate binder use. During a median follow-up of 36.8 months, 348 participants (58.8%) died. Mortality rates were the highest in the osteoporosis group (79.8%), followed by the osteopenia (77.2%) and normal bone mineral density (BMD) groups (35.2%). Cox regression analysis revealed that even after adjusting for covariates, the osteoporosis group was significantly associated with a higher mortality risk than the normal BMD group. Osteoporosis at the start of hemodialysis was significantly associated with higher mortality.
Conclusion
We should consider the importance of bone health in patients undergoing incident hemodialysis and pay attention to the use of phosphate binders and fracture prevention.
6.Impact of obesity on renal function in elderly Korean adults: a national population-based cohort study
Jihyun YANG ; Hui Seung LEE ; Chi-Yeon LIM ; Hyunsuk KIM ; Sungjin CHUNG ; Soon Hyo KWON ; Jang-Hee CHO ; Kyung Don YOO ; Woo Yeong PARK ; In O SUN ; Byung Chul YU ; Gang-Jee KO ; Jae Won YANG ; Won Min HWANG ; Sang Heon SONG ; Sung Joon SHIN ; Yu Ah HONG ; Eunjin BAE ; Young Youl HYUN
Kidney Research and Clinical Practice 2026;45(1):65-76
Background:
Obesity is a well-known risk factor for chronic kidney disease and its progression. However, the impact of obesity on the renal function of the elderly population is uncertain. We investigated the association between obesity and renal outcomes in the elderly.
Methods:
We analyzed 130,504 participants from the Korean National Health Insurance Service-Senior cohort. Obesity was classified according to body mass index (BMI), sex-specific waist circumference (WC), and the presence of metabolic syndrome. The primary outcome was renal function decline, defined as a decline in the estimated glomerular filtration rate (eGFR) of at least 50% from baseline or new-onset end-stage renal disease.
Results:
During a follow-up period of 559,531.1 person-years (median, 4.3 years), 2,486 participants (19.0%; incidence rate of 4.44 per 1,000 person-years) showed renal function decline. A multivariate Cox proportional hazards model revealed that BMI/WC was not associated with renal function decline. However, the group with metabolic syndrome had a significantly increased risk of renal function decline compared to the group without metabolic syndrome (adjusted hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.13–1.36). Compared with the non-metabolic syndrome group, the adjusted HRs (95% CI) for participants with one through five components were 0.96 (0.84–1.11), 1.10 (0.96–1.27), 1.24 (1.06–1.45), 1.37 (1.12–1.66), and 1.99 (1.42–2.79), respectively (p for trend < 0.001).
Conclusion
In elderly Korean adults, metabolic syndrome and the number of its components were associated with a higher risk of renal function decline, but BMI or WC was not significant.
7.Impact of neuromuscular blockade depth on postoperative systemic cytokine release: a systematic review and meta-analysis
Soowon LEE ; Jung-Hee RYU ; Chang-Hoon KOO ; Yu Kyung BAE ; Ah-Young OH
Korean Journal of Anesthesiology 2026;79(1):56-68
Background:
Deep neuromuscular blockade (NMB) optimizes surgical conditions, particularly during laparoscopic procedures. However, its effects on systemic cytokines associated with anesthesia-related complications, including postoperative delirium and cognitive dysfunction, remain unclear. In this review, we quantified the impact of deep NMB on serum cytokine levels.
Methods:
PubMed, EMBASE, CENTRAL, CINAHL, Scopus, Web of Science, and Google Scholar databases were searched to identify randomized controlled trials (RCTs) evaluating serum cytokine levels in surgical patients under deep or moderate NMB.
Results:
Eight RCTs, including 661 patients undergoing laparoscopic and orthopedic surgeries, met the inclusion criteria. Immediately postoperatively, meta-analysis suggested a potential reduction in tumor necrosis factor-α (TNF-α, standardized mean difference: −0.46, 95% CI [−0.87 to −0.06], P = 0.03), with no significant differences in interleukin-1β (IL-1β) or interleukin-6 (IL-6) levels. At 24-h and 48-h postoperatively, no significant differences were observed in IL-1β, IL-6, TNF-α, or C-reactive protein levels. Meta-regression analysis indicated that inhalational anesthesia was associated with high IL-1β (estimate = 1.2135, 95% CI [0.5107–1.9162], P < 0.01) and TNF-α levels (estimate = 0.6271, 95% CI [0.0544–1.1997], P = 0.032) immediately postoperatively; however, younger patients exhibited elevated IL-1β levels under moderate NMB at 24-h postoperatively (estimate = 0.0242, 95% CI [0.0065–0.0419], P < 0.01).
Conclusions
Deep NMB may be associated with reduced TNF-α levels immediately postoperatively. Inhalational anesthesia and younger age may contribute more to higher serum cytokine levels compared with total intravenous anesthesia and older age, respectively, suggesting a potential immunomodulatory effect of deep NMB. Further studies should clarify its clinical relevance.
8.A New Agenda for Optimizing Roles and Infrastructure in a Mental Health Service Model for South Korea
Eunsoo KIM ; Hyeon-Ah LEE ; Yu-Ri LEE ; In Suk LEE ; Kyoung-Sae NA ; Seung-Hee AHN ; Chul-Hyun CHO ; Hwoyeon SEO ; Soo Bong JUNG ; Sung Joon CHO ; Hwa-Young LEE
Psychiatry Investigation 2025;22(1):26-39
Objective:
As the demand for community mental health services continues to grow, the need for well-equipped and organized services has become apparent. This study aimed to optimize the roles and infrastructure of mental health services, by establishing, among other initiatives, standardized operating models.
Methods:
The study was conducted in multiple phases from May 12, 2021, to December 29, 2021. Stakeholders within South Korea and metropolitan mental health welfare centers were targeted, but addiction management support centers, including officials, patients, and their families, were integrated as well. A literature review and survey, focus group interviews, a Delphi survey, and expert consultation contributed to comprehensive revisions and improvements of the mental health service model.
Results:
The proposed model for community mental health welfare centers emphasizes the expansion of personnel and infrastructure, with a focus on severe mental illnesses and suicide prevention. The model for metropolitan mental health welfare centers delineates essential tasks in areas such as project planning and establishment, community research, and education about severe mental illnesses. The establishment of a 24-hour emergency intervention center was a crucial feature. In the integrated addiction support center model, the need to promote addiction management is defined as an essential task and the establishment of national governance for addiction policies is recommended.
Conclusion
This study proposed standard operating models for three types of mental health service centers. To meet the increasing need for community care, robust mental health service delivery systems are of primary importance.
9.Reduction of Low-Density Lipoprotein Cholesterol by Mesenchymal Stem Cells in a Mouse Model of Exogenous Cushing’s Syndrome
Yu-Hee KIM ; Seonghee JEONG ; Kyung-Ah CHO ; So-Youn WOO ; Seung-Ho HAN ; Kyung-Ha RYU
Tissue Engineering and Regenerative Medicine 2025;22(2):237-248
BACKGROUND:
Exogenous Cushing’s syndrome, which results from prolonged glucocorticoid treatment, is associated with metabolic abnormalities. Previously, we reported the inhibitory effect of tonsil-derived mesenchymal stem cell conditioned medium (T-MSC CM) on glucocorticoid signal transduction. In this study, we investigated the therapeutic efficacy of T-MSCs in a mouse model of exogenous Cushing’s syndrome.
METHODS:
Exogenous Cushing’s syndrome model mice was generated by corticosterone administration in the drinking water for 5 weeks, and T-MSCs were injected intraperitoneally twice during the third week. Serum lipid profiles were measured using a chemistry analyzer. HepG2 cells were treated with dexamethasone and co-cultured with T-MSCs.Expression levels of genes involved in cholesterol metabolism were examined using real-time PCR. Low-density lipoprotein receptor (LDLR) protein levels were determined using western blotting and immunohistochemistry. Liver RNA extracted from the CORT and CORT ? MSC mouse groups was used for transcriptome sequencing analysis and protein– protein interaction analysis.
RESULTS:
Weight reduction and improvements in dyslipidemia by T-MSC administration were observed only in female mice. T-MSCs reduce circulating LDL cholesterol levels by downregulating liver X receptor a (LXRa) and inducible degrader of LDLR (IDOL) expression, thereby stabilizing LDLRs in the liver. Transcriptome analysis of liver tissue revealed pathways that are regulated by T-MSCs administration.
CONCLUSION
Administration of MSCs to female mice receiving chronic corticosterone treatment reduced the circulating LDL cholesterol level by downregulating the LXRa–IDOL axis in hepatocytes. These results suggest that T-MSCs may offer a novel therapeutic strategy for managing exogenous Cushing’s syndrome by regulating cholesterol metabolism.
10.Reducing Healing Period with DDM/rhBMP-2 Grafting for Early Loading in Dental Implant Surgery
Jeong-Kui KU ; Jung-Hoon LIM ; Jung-Ah LIM ; In-Woong UM ; Yu-Mi KIM ; Pil-Young YUN
Tissue Engineering and Regenerative Medicine 2025;22(2):261-271
Background:
Traditionally, dental implants require a healing period of 4 to 9 months for osseointegration, with longer recovery times considered when bone grafting is needed. This retrospective study evaluates the clinical efficacy of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) during dental implant placement to expedite the osseointegration period for early loading.
Methods:
Thirty patients (17 male, 13 female; mean age 55.0 ± 8.8 years) requiring bone grafts due to implant fixture exposure (more than four threads; ≥ 3.2 mm) were included, with a total of 96 implants placed. Implants were inserted using a two-stage protocol with DDM/rhBMP-2 grafts. Early loading was initiated at two months postoperatively in the mandible and three months in the maxilla. Clinical outcomes evaluated included primary and secondary stability (implant stability quotient values), healing period, bone width, and marginal bone level assessed via cone-beam computed tomography.
Results:
All implants successfully supported final prosthetics with a torque of 50Ncm, without any osseointegration failures. The average healing period was 69.6 days in the mandible and 90.5 days in the maxilla, with significantly higher secondary stability in the mandible (80.7 ± 6.7) compared to the maxilla (73.0 ± 9.2, p < 0.001). Histological analysis confirmed new bone formation and vascularization.
Conclusion
DDM/rhBMP-2 grafting appears to significantly reduce the healing period, enabling early loading with stable and favorable clinical outcomes.

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