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.A Prospective Cross-sectional Screening Using Non-mydriatic Fundus Photography and Optical Coherence Tomography in Patients on Tamoxifen Therapy
Sang Cheol YANG ; Jun Young LEE ; Dong Seon KIM ; Tae Yeon KIM ; Young Hwan JEONG ; Bo Hyun PARK ; IkSoo BYON ; Sung Who PARK
Journal of Retina 2026;11(1):44-49
Purpose:
To determine the prevalence of tamoxifen retinopathy and assess the utility of a screening protocol using non-mydriatic fundus photography and optical coherence tomography (OCT).
Methods:
Between May and October 2024, patients on tamoxifen therapy at a breast surgery clinic were offered screening including non-mydriatic fundus photography and OCT. Among those who consented, 290 patients (580 eyes) were included after excluding other retinal diseases. We investigated tamoxifen duration, cumulative dose, central retinal thickness, BMI, underlying diseases, menopausal status, and history of chemotherapy, hormone therapy, or oral contraceptives.
Results:
All patients were taking 20 mg of tamoxifen daily. The mean treatment duration was 55.7 ± 29.5 months for those treated longer than two years (n = 193), with a mean BMI of 22.1 ± 3.0 kg/m2. Systemic comorbidities included dyslipidemia (n = 27, 14.0%), hypertension (n = 19, 9.8%), diabetes mellitus (n = 13, 6.7%), and cardiovascular disease (n = 4, 2.1%). Additionally, patient histories included chemotherapy (n = 84, 43.7%), postmenopausal status (n = 56, 29.1%), hormone therapy (n = 52, 27.0%), and oral contraceptive use (n = 14, 7.2%). Tamoxifen retinopathy was not observed in any of the patients.
Conclusions
In this cross-sectional study, the prevalence of tamoxifen retinopathy, as assessed by non-mydriatic fundus photography and OCT in this study, was 0%, which is lower than previously reported rates (0.9%–12%). Although specialized examination by an ophthalmologist, including a dilated fundus examination and OCT remains the diagnostic gold standard, practical constraints can limit its routine clinical use. Our study evaluated a screening protocol performed without ophthalmologist intervention. However, we found that limitations in image quality compromised the detection of subtle lesions, such as crystalline deposits. Consequently, this approach may be insufficient to serve as a primary screening strategy.
3.Topical Application of Probiotic-Derived EGF From Pediococcus pentosaceus Improves UVB-Induced Photoaging in Hairless Mice
Yoon Jin ROH ; Yoon Hwan LEE ; Sun Young YUH ; Hye Won SONG ; Do Yeon KWON ; Byung Chull AN ; Yongku RYU ; Myung Jun CHUNG ; Kui Young PARK
Annals of Dermatology 2026;38(3):191-201
Background:
Epidermal growth factor (EGF) is widely applied in dermatology for its regenerative effects; however, its clinical utility is limited by low stability and high production costs.To overcome these limitations, we developed a novel probiotic-derived epidermal growth factor (pEGF) by engineering Pediococcus pentosaceus CBT SL4 to express and secrete EGF.
Objective:
To investigate the anti-photoaging effects of topical pEGF in a ultraviolet B (UVB)-irradiated mice by assessing histological and molecular changes related to collagen synthesis, extracellular matrix (ECM) remodeling, oxidative stress, and inflammation.
Methods:
SKH1 hairless mice were exposed to UVB for twelve weeks to induce photoaging and treated with topical 10% pEGF cream from week 9 to 12. Skin samples were analyzed using dermoscopy, histology, immunohistochemistry, quantitative real-time polymerase chain reaction, western blotting, and proteomics to evaluate morphological and molecular alterations in ECM components and inflammatory markers.
Results:
Topical pEGF treatment improved skin texture and reduced wrinkles. Histological evaluation revealed that EGF significantly attenuated UVB-induced epidermal thickening and restored collagen density, with the strongest effects observed in the pEGF group. Molecular analysis showed downregulation of matrix metalloproteinases (MMPs; MMP-1, MMP-3), upregulation of collagen (type I collagen, type III collagen) and tissue inhibitors of metalloproteinases (TIMPs; TIMP-1, TIMP-2). Additionally, pEGF reduced pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-1β) and oxidative stress markers.
Conclusion
pEGF demonstrated potent anti-photoaging effects through ECM restoration, inflammation modulation, and barrier reinforcement. These findings support the therapeutic potential of pEGF as a stable, cost-effective alternative to conventional EGF in dermatological applications.
4.En bloc capsulectomy of a pseudocyst-like pocket after a massive filler injection into the buttocks: two case reports
Kyung Min KIM ; Jeong Hun AHN ; Ki Hyun KIM ; Sang Seok WOO ; Jun Won LEE ; Seong Hwan KIM ; Jai Koo CHOI ; Insuck SUH
Archives of Aesthetic Plastic Surgery 2026;32(2):26-31
Buttock augmentation is an increasingly popular cosmetic procedure designed to enhance buttock contour, size, and shape. However, the safety profile of this procedure remains insufficiently established, and it carries risks of complications, including foreign body reactions and infections. These complications may be exacerbated by filler migration, resulting in large soft-tissue cavities that resemble pseudocysts. In this study, we describe two patients who developed severe complications following massive filler injections to the buttocks. A 56-year-old female patient presented with a 6×5 cm soft-tissue defect associated with an extensive underlying dead space, sinus tract formation, and a large pocket extending across the buttock. Additionally, a 50-year-old female patient developed diffuse cellulitis and multiple abscesses secondary to migration of an infected filler-related pseudocyst. Both patients underwent successful en bloc capsulectomy, resulting in marked clinical improvement without recurrence or postoperative complications. These cases underscore the serious complications associated with large-volume filler injections and highlight the importance of comprehensive surgical management in addressing late-stage adverse outcomes.
5.Artificial intelligence-based personalized oncological outcome prediction model for upper urinary tract urothelial carcinoma after radical nephroureterectomy: A development and multicenter validation
Hyun Young LEE ; Hwanik KIM ; Bumjin LIM ; Dalsan YOU ; Cheryn SONG ; In Gab JEONG ; Jun Hyuk HONG ; Bumsik HONG ; Hanjong AHN ; Seung-hwan JEONG ; Ja Hyeon KU ; Jungyo SUH
Investigative and Clinical Urology 2026;67(1):15-23
Purpose:
To develop and validate an artificial intelligence (AI)-based personalized outcome prediction model for upper-urinary tract urothelial carcinoma patients undergoing radical nephroureterectomy.
Materials and Methods:
Data from patients who underwent radical nephroureterectomy between 2010 and 2020 across three hospitals were retrospectively analyzed. A model was developed using one tertiary center’s data and externally validated with data from two other hospitals. An AI model using XGBoost as risk estimator and bootstrapped Weibull Accelerated Failure Time model for 10-year survival probability was employed. Hyperparameter tuning used Optuna method. Model efficacy was assessed using concordance index, average Brier score, D-calibration, and six-month interval time-dependent area under the curve (AUC).
Results:
Of 1,039 patients, 627 qualified after excluding 50 with neoadjuvant chemotherapy. Model development used 564 patients (507 training, 57 test) with 9:1 stratified random split, plus 63 for internal validation and 362 for external validation. Significant parameters included preoperative glomerular filtration rate (p<0.001), hydroureteronephrosis (p=0.013), pathological N stage (p<0.001), concurrent carcinoma in situ (p<0.001), disease progression (p<0.001), and survival rate (p<0.001). Disease-free survival (DFS) model’s concordance index: internal validation 0.789, external validations 0.734 and 0.771. Overall survival (OS) model’s concordance index: internal validation 0.819, external validations 0.780 and 0.771. Mean time-dependent AUC was 0.66–0.77 for DFS and 0.67–0.80 for OS during 10-year periods.
Conclusions
AI-based model effectively predicts disease-free and OS outcomes for upper-urinary tract urothelial carcinoma patients with post-radical nephroureterectomy, showcasing robust performance across multicenter settings.
6.Delayed Retroperitoneal Hematoma Following Intradiscal Electrothermal Therapy: A Case Report of a Rare Complication
Jun-Yong CHA ; Yun-Young PARK ; Jin-Uk KIM ; Jun-Ho LEE ; Seong-Hwan MUN ; Gun AHN ; Il-Tae JANG
The Nerve 2026;12(1):36-40
Intradiscal electrothermal therapy (IDET) is a minimally invasive procedure used to treat discogenic back pain and offers an alternative to surgical intervention in selected patients. Although it is generally considered safe, rare but significant complications can occur and may be difficult to diagnose because their symptoms overlap with those of other spinal conditions. We describe the case of a 69-year-old woman who presented with severe lower back and left buttock pain that was unresponsive to conservative treatment. Magnetic resonance imaging revealed disc bulging with a high-intensity zone at the L4–5 and L5–S1 levels. IDET was performed at the L4–5 level, resulting in initial pain relief. However, the patient returned 7 days later with recurrent pain. Despite undergoing percutaneous epidural neuroplasty at the left L5–S1 level, a medial branch block, and a piriformis muscle block, her symptoms persisted. Further evaluation with spinal computed tomography revealed a retroperitoneal hematoma near the left psoas muscle. Referred pain from the hematoma mimicked discogenic pain, resulting in delayed diagnosis and unnecessary interventions. The patient remained hemodynamically stable and gradually improved with conservative management alone. This case highlights retroperitoneal hematoma as a rare complication of IDET and emphasizes the importance of accurate and timely diagnosis in patients with persistent or worsening symptoms after spinal procedures. Clinicians should consider non-discogenic sources of pain when treatment outcomes deviate from expected patterns.
7.When Fire Meets Ice: a Case of Silent Clinical Course after Massive Levothyroxine and Sedative Co-Ingestion
Kyung-Hun SUNG ; Jaekyung LEE ; Seung-Hwan LEE ; Dong-Jun LIM
International Journal of Thyroidology 2026;19(1):110-113
Levothyroxine overdose is uncommon in adults and often presents with variable clinical severity, ranging from overt thyrotoxicosis to an entirely asymptomatic course. We report the case of a 47-year-old woman with a history of total thyroidectomy who intentionally ingested 10 mg of levothyroxine along with supratherapeutic doses of zolpidem and clonazepam at once in a suicide attempt. She presented three days later without adrenergic or gastrointestinal symptoms. Laboratory tests revealed markedly elevated free thyroxine and total triiodothyronine with suppressed thyroid stimulating hormone. She was treated with propranolol for heart rate control and empirical hydrocortisone in case of adrenal insufficiency. She remained asymptomatic with gradual biochemical improvement and normalization of thyroid function on follow-up. The protective effect of co-ingested supratherapeutic doses of gamma-aminobutyric acid (GABA)-ergic agents suggests a potential role for anti-anxiety medications in mitigating severe adrenergic symptoms in endogenous thyrotoxicosis, such as Graves’ disease.
8.Germline Mutations Related to Complete Remission After Neoadjuvant Chemotherapy in Patients With Triple-negative Breast Cancer
Jee Hyun AHN ; Ji Soo PARK ; Dongju WON ; Seung-Tae LEE ; Suk Jun LEE ; Seung Hye YANG ; Jee Ye KIM ; Seho PARK ; Seung Il KIM ; Byeong-Woo PARK ; Min Hwan KIM ; Gun Min KIM ; Joohyuk SOHN ; Hyung Seok PARK
Journal of Breast Cancer 2026;29(2):118-127
Purpose:
Triple-negative breast cancer (TNBC) is a frequent phenotype of BRCA-mutanttumors. Tumors with BRCAness may show characteristics of BRCA-mutant tumors and respond to similar treatments. Next-generation sequencing is an efficient and cost-effective method for simultaneously sequencing multiple cancer susceptibility genes, surpassing conventional Sanger testing.
Methods:
A total of 148 women with TNBC were recruited from December 2015 to November 2018, as part of a sub-analysis based on the PEARLY trial data. Of them, 103 patients received neoadjuvant chemotherapy (NCT). The targeted genes related to hereditary cancers were sequenced using the 65-gene germline next-generation sequencing (gNGS) panel pathogenic and likely pathogenic variants (P&LPs) were determined by Sanger sequencing. We examined the occurrence of pathologic complete remission (ypCR) in patients with P&LPs.
Results:
The patients’ median age was 47 years (range, 27–69 years). Twenty (13.7%) of 148 patients had P&LP in six genes, including BARD1 (n = 2), BRCA1 (n = 9), BRCA2 (n = 5), CHEK2 (n = 1), RAD51C (n = 1), and RAD51D (n = 2). Among the 103 patients with NCT, 43 (41.7%) achieved ypCR (P&LPs; 9 individuals vs. non-variants; 34 individuals). Among the 103 patients with NCT, 14 (9.3%) had P&LPs. Nine of 14 patients with P&LPs, including BARD1 (n = 2), BRCA1 (n = 4), BRCA2 (n = 1), RAD51C (n = 1), and RAD51D (n = 1), achieved ypCR, showing a trend toward statistical significance (p = 0.066).
Conclusion
Germline P&LP mutations in TNBC patients can be detected by gNGS. This panel test can identify BRCA and BRCAness mutations that may predict ypCR in TNBC.
9.Medical disputes involving lower gastrointestinal endoscopies: cases from the Korean Medical Dispute Mediation and Arbitration Agency
Eun Hye OH ; Jeong Eun SHIN ; Jun Yong BAE ; Yoon Suk LEE ; Yehyun PARK ; Yong Hwan KWON ; Chang Nyol PAIK ; Jun Kyu LEE ; Tae Hee LEE
The Korean Journal of Internal Medicine 2025;40(3):404-426
Background/Aims:
As the number of lower gastrointestinal endoscopies and high-risk examinees increases, the incidence of adverse events associated with these endoscopies has also increased. Medical disputes and lawsuits related to adverse events are rapidly increasing.
Methods:
Medical disputes related to lower gastrointestinal endoscopy that had been filed in Korean Medical Dispute Mediation and Arbitration Agency (K-medi) from April 2012 to August 2020 were evaluated with the corresponding medical records and written appraisal. Facilities, patients, procedures, adverse events, and outcome-related variables related to medical disputes were analyzed.
Results:
As the number of lower gastrointestinal endoscopies in Korea increases each year, the number of medical disputes related to lower gastrointestinal endoscopy appraised by K-medi has also increased yearly during the same period. Among the 121 cases analyzed, 86 (71.1%) were conciliated and 35 (28.9%) were cosigned by prosecution. Perforations accounted for the largest proportion of cases (93 cases, 76.9%). Most patients (n = 119, 98.3%) underwent non-emergent procedures, and only 10 (8.3%) underwent them for therapeutic purposes. Approximately one-fifth of the patients (n = 25, 20.7%) died.
Conclusions
The number of medical disputes related to lower gastrointestinal endoscopy are increasing. To prevent this, it is important to review the data on existing cases and establish specific response guidelines.
10.Association of Nutritional Intake with Physical Activity and Handgrip Strength in Individuals with Airflow Limitation
I Re HEO ; Tae Hoon KIM ; Jong Hwan JEONG ; Manbong HEO ; Sun Mi JU ; Jung-Wan YOO ; Seung Jun LEE ; Yu Ji CHO ; Yi Yeong JEONG ; Jong Deog LEE ; Ho Cheol KIM
Tuberculosis and Respiratory Diseases 2025;88(1):120-129
Background:
We investigated whether nutritional intake is associated with physical activity (PA) and handgrip strength (HGS) in individuals with airflow limitation.
Methods:
This study analyzed data from the 2014 and 2016 Korean National Health and Nutrition Examination Survey. We assessed total protein intake (g/day), caloric intake (kcal/day), and other nutritional intakes, using a 24-hour dietary recall questionnaire. HGS was measured three times for each hand using a digital grip strength dynamometer, and PA was assessed as health-enhancing PA. Airflow limitation was defined as a forced expiratory volume/forced vital capacity ratio of 0.7 in individuals over 40 years of age. Participants were categorized into groups based on their PA levels and HGS measurements: active aerobic PA vs. non-active aerobic PA, and normal HGS vs. low HGS.
Results:
Among the 622 individuals with airflow limitation, those involved in active aerobic PA and those with higher HGS had notably higher total food, calorie, water, protein, and lipid intake. The correlations between protein and caloric intake with HGS were strong (correlation coefficients=0.344 and 0.346, respectively). The forest plots show that higher intakes of food, water, calories, protein, and lipids are positively associated with active aerobic PA, while higher intakes of these nutrients are inversely associated with low HGS. However, in the multivariate logistic regression analysis, no significant associations were observed between nutritional intake and active aerobic PA or HGS.
Conclusion
Nutritional intake was found to not be an independent factor associated with PA and HGS. However, the observed correlations suggest potential indirect effects that warrant further investigation.

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