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.Changes in Candidemia during the COVID-19 Pandemic: Species Distribution, Antifungal Susceptibility, Initial Antifungal Usage, and Mortality Trends in Two Korean Tertiary Care Hospitals
Ahrang LEE ; Minji KIM ; Sarah KIM ; Hae Seong JEONG ; Sung Un SHIN ; David CHO ; Doyoung HAN ; Uh Jin KIM ; Jung Ho YANG ; Seong Eun KIM ; Kyung-Hwa PARK ; Sook-In JUNG ; Seung Ji KANG
Chonnam Medical Journal 2025;61(1):52-58
This study aimed to investigate changes in candidemia incidence, species distribution, antifungal susceptibility, initial antifungal use, and mortality trends in Korea before and during the COVID-19 pandemic. A retrospective analysis was conducted on candidemia cases from two tertiary care hospitals in Korea between 2017 and 2022. Data were compared between the pre-pandemic (2017-2019) and pandemic (2020-2022) periods. Statistical methods included incidence rate ratios (IRRs) and multivariate Cox regression to assess 30-day mortality risk factors. A total of 470 candidemia cases were identified, with 48.7% occurring pre-pandemic and 51.3% during the pandemic. While the overall incidence of candidemia remained similar across the two periods (IRR 1.15;p=0.13), the incidence in intensive care units (ICUs) significantly increased during the pandemic (IRR 1.50; p<0.01). The distribution of Candida species did not differ significantly between the two periods. Fluconazole non-susceptibility in C. albicans markedly decreased (10.0% vs. 0.9%, p<0.01), whereas C. glabrata exhibited a significant rise in caspofungin non-susceptibility during the pandemic (0% vs. 22.4%, p<0.01).Echinocandin use increased (21.8% vs. 34.4%; p<0.01), while fluconazole use declined (48.0% vs. 32.8%; p<0.01). Although the 30-day mortality rate was higher during the pandemic (60.2% vs. 57.2%), the difference was not statistically significant (p=0.57).The findings highlight the need for region-specific surveillance and tailored management strategies to improve candidemia outcomes, especially during healthcare disruptions like the COVID-19 pandemic.
3.Changes in Candidemia during the COVID-19 Pandemic: Species Distribution, Antifungal Susceptibility, Initial Antifungal Usage, and Mortality Trends in Two Korean Tertiary Care Hospitals
Ahrang LEE ; Minji KIM ; Sarah KIM ; Hae Seong JEONG ; Sung Un SHIN ; David CHO ; Doyoung HAN ; Uh Jin KIM ; Jung Ho YANG ; Seong Eun KIM ; Kyung-Hwa PARK ; Sook-In JUNG ; Seung Ji KANG
Chonnam Medical Journal 2025;61(1):52-58
This study aimed to investigate changes in candidemia incidence, species distribution, antifungal susceptibility, initial antifungal use, and mortality trends in Korea before and during the COVID-19 pandemic. A retrospective analysis was conducted on candidemia cases from two tertiary care hospitals in Korea between 2017 and 2022. Data were compared between the pre-pandemic (2017-2019) and pandemic (2020-2022) periods. Statistical methods included incidence rate ratios (IRRs) and multivariate Cox regression to assess 30-day mortality risk factors. A total of 470 candidemia cases were identified, with 48.7% occurring pre-pandemic and 51.3% during the pandemic. While the overall incidence of candidemia remained similar across the two periods (IRR 1.15;p=0.13), the incidence in intensive care units (ICUs) significantly increased during the pandemic (IRR 1.50; p<0.01). The distribution of Candida species did not differ significantly between the two periods. Fluconazole non-susceptibility in C. albicans markedly decreased (10.0% vs. 0.9%, p<0.01), whereas C. glabrata exhibited a significant rise in caspofungin non-susceptibility during the pandemic (0% vs. 22.4%, p<0.01).Echinocandin use increased (21.8% vs. 34.4%; p<0.01), while fluconazole use declined (48.0% vs. 32.8%; p<0.01). Although the 30-day mortality rate was higher during the pandemic (60.2% vs. 57.2%), the difference was not statistically significant (p=0.57).The findings highlight the need for region-specific surveillance and tailored management strategies to improve candidemia outcomes, especially during healthcare disruptions like the COVID-19 pandemic.
4.Changes in Candidemia during the COVID-19 Pandemic: Species Distribution, Antifungal Susceptibility, Initial Antifungal Usage, and Mortality Trends in Two Korean Tertiary Care Hospitals
Ahrang LEE ; Minji KIM ; Sarah KIM ; Hae Seong JEONG ; Sung Un SHIN ; David CHO ; Doyoung HAN ; Uh Jin KIM ; Jung Ho YANG ; Seong Eun KIM ; Kyung-Hwa PARK ; Sook-In JUNG ; Seung Ji KANG
Chonnam Medical Journal 2025;61(1):52-58
This study aimed to investigate changes in candidemia incidence, species distribution, antifungal susceptibility, initial antifungal use, and mortality trends in Korea before and during the COVID-19 pandemic. A retrospective analysis was conducted on candidemia cases from two tertiary care hospitals in Korea between 2017 and 2022. Data were compared between the pre-pandemic (2017-2019) and pandemic (2020-2022) periods. Statistical methods included incidence rate ratios (IRRs) and multivariate Cox regression to assess 30-day mortality risk factors. A total of 470 candidemia cases were identified, with 48.7% occurring pre-pandemic and 51.3% during the pandemic. While the overall incidence of candidemia remained similar across the two periods (IRR 1.15;p=0.13), the incidence in intensive care units (ICUs) significantly increased during the pandemic (IRR 1.50; p<0.01). The distribution of Candida species did not differ significantly between the two periods. Fluconazole non-susceptibility in C. albicans markedly decreased (10.0% vs. 0.9%, p<0.01), whereas C. glabrata exhibited a significant rise in caspofungin non-susceptibility during the pandemic (0% vs. 22.4%, p<0.01).Echinocandin use increased (21.8% vs. 34.4%; p<0.01), while fluconazole use declined (48.0% vs. 32.8%; p<0.01). Although the 30-day mortality rate was higher during the pandemic (60.2% vs. 57.2%), the difference was not statistically significant (p=0.57).The findings highlight the need for region-specific surveillance and tailored management strategies to improve candidemia outcomes, especially during healthcare disruptions like the COVID-19 pandemic.
5.First Reported Case of Prosthetic Joint Infection Caused by Lomentospora prolificans in an Immunocompetent Host
Yoonjung LEE ; Soosung KIM ; Hong Yeol YANG ; Ahrang LEE ; Minji KIM ; Hae Seong JEONG ; Sung Un SHIN ; Uh Jin KIM ; Kyung-Hwa PARK ; Sook-In JUNG ; Seung Ji KANG
Korean Journal of healthcare-associated Infection Control and Prevention 2025;30(1):76-80
Lomentospora prolificans is a rare opportunistic mold with high intrinsic resistance to most antifungal agents. It causes disseminated infections in immunocompromised patients and localized infections in immunocompetent hosts, often involving the bones, joints, or skin. However, prosthetic joint infections (PJI) due to L. prolificans have not been previously reported.Here, we describe the first case of L. prolificans PJI in an immunocompetent 51-year-old male patients, who had no significant comorbidities other than hypertension. The patient presented with right knee pain and swelling one year after total knee arthroplasty. Cultures of the joint fluid and periprosthetic tissue yielded L. prolificans, as confirmed by matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI-TOF MS) and rRNA gene sequencing. Susceptibility testing showed high minimum inhibitory concentrations for most currently available antifungal agents, including azoles, amphotericin B, echinocandins, and terbinafine. Despite prosthesis removal, multiple surgical debridements, and prolonged antifungal therapy, including voriconazole and terbinafine, the infection persisted over a five-year period.Amputation was discussed as a potential curative measure; however, no consensus has been reached due to its long-term impact. This case highlights the clinical challenges of managing L. prolificans PJI and underscores the need for novel antifungal therapies to treat rare drugresistant fungal infections.
6.Aging with HIV: The Burden of Comorbidities, Polypharmacy, and Drug Interactions in Korean People Living withHIV Aged ≥50 Years
Jin KIM ; Hyun-Ju NAM ; Ji-Yeon KIM ; Mi-Kyung HEO ; Sung Un SHIN ; Uh Jin KIM ; Seong Eun KIM ; Seung-Ji KANG ; Jihwan BANG ; Jin-Soo LEE ; Mi-Ok JANG ; Kyung-Hwa PARK
Infection and Chemotherapy 2024;56(4):534-543
Background:
The life expectancy of people living with human immunodeficiency virus (PLWH) has significantly improved with advancements in antiretroviral therapy (ART). However, aging PLWH face a growing burden of noncommunicable diseases (NCDs), polypharmacy, and drug-drug interactions (DDIs), which pose challenges in their management. This study investigates the prevalence of NCDs, polypharmacy, and DDIs among PLWH aged ≥50 years in Korea and their impact on quality of life (QOL).
Materials and Methods:
A cross-sectional study was conducted among 243 PLWH aged ≥50 years receiving ART for at least three months at three university hospitals in Korea between January and July 2022. Data were collected through electronic medical records and personal interviews, assessing demographics, comorbidities, polypharmacy, ART adherence, and QOL using the Korean version of WHOQOL-HIV BREF scale. Potential DDIs were analyzed using the University of Liverpool HIV Drug Interaction Database, and potentially inappropriate medications (PIMs) were identified using the 2023 American Geriatrics Society Beers Criteria. We classified participants into three age groups:50–<65 years, 65–<75 years, and ≥75 years.
Results:
The prevalence of comorbidities was 71.6%, with older participants (≥75 years) showing a significantly higher burden, including bone diseases, osteoarthritis, and dementia (P<0.001). Polypharmacy was observed in 28.4% of participants and increased with age, with 53.3% of those aged ≥75 years taking ≥10 pills daily.Polypharmacy was associated with poorer QOL (71.6 vs. 76.6, P=0.010). Amber-flag DDIs were found in 81 participants (33.3%), most commonly involving metformin and divalent cations. No red-flag DDIs were identified.PIMs were observed in 6.6% of participants aged ≥65 years.
Conclusion
Aging PLWH in Korea face significant challenges from comorbidities, polypharmacy, and DDIs, which negatively impact QOL. Integrated, age-specific, and multidisciplinary care strategies are urgently needed to improve outcomes and ensure the well-being of older PLWH.
7.Aging with HIV: The Burden of Comorbidities, Polypharmacy, and Drug Interactions in Korean People Living withHIV Aged ≥50 Years
Jin KIM ; Hyun-Ju NAM ; Ji-Yeon KIM ; Mi-Kyung HEO ; Sung Un SHIN ; Uh Jin KIM ; Seong Eun KIM ; Seung-Ji KANG ; Jihwan BANG ; Jin-Soo LEE ; Mi-Ok JANG ; Kyung-Hwa PARK
Infection and Chemotherapy 2024;56(4):534-543
Background:
The life expectancy of people living with human immunodeficiency virus (PLWH) has significantly improved with advancements in antiretroviral therapy (ART). However, aging PLWH face a growing burden of noncommunicable diseases (NCDs), polypharmacy, and drug-drug interactions (DDIs), which pose challenges in their management. This study investigates the prevalence of NCDs, polypharmacy, and DDIs among PLWH aged ≥50 years in Korea and their impact on quality of life (QOL).
Materials and Methods:
A cross-sectional study was conducted among 243 PLWH aged ≥50 years receiving ART for at least three months at three university hospitals in Korea between January and July 2022. Data were collected through electronic medical records and personal interviews, assessing demographics, comorbidities, polypharmacy, ART adherence, and QOL using the Korean version of WHOQOL-HIV BREF scale. Potential DDIs were analyzed using the University of Liverpool HIV Drug Interaction Database, and potentially inappropriate medications (PIMs) were identified using the 2023 American Geriatrics Society Beers Criteria. We classified participants into three age groups:50–<65 years, 65–<75 years, and ≥75 years.
Results:
The prevalence of comorbidities was 71.6%, with older participants (≥75 years) showing a significantly higher burden, including bone diseases, osteoarthritis, and dementia (P<0.001). Polypharmacy was observed in 28.4% of participants and increased with age, with 53.3% of those aged ≥75 years taking ≥10 pills daily.Polypharmacy was associated with poorer QOL (71.6 vs. 76.6, P=0.010). Amber-flag DDIs were found in 81 participants (33.3%), most commonly involving metformin and divalent cations. No red-flag DDIs were identified.PIMs were observed in 6.6% of participants aged ≥65 years.
Conclusion
Aging PLWH in Korea face significant challenges from comorbidities, polypharmacy, and DDIs, which negatively impact QOL. Integrated, age-specific, and multidisciplinary care strategies are urgently needed to improve outcomes and ensure the well-being of older PLWH.
8.IFITM3-mediated activation of TRAF6/MAPK/AP-1pathways induces acquired TKI resistance in clear cell renal cell carcinoma
Se Un JEONG ; Ja-Min PARK ; Sun Young YOON ; Hee Sang HWANG ; Heounjeong GO ; Dong-Myung SHIN ; Hyein JU ; Chang Ohk SUNG ; Jae-Lyun LEE ; Gowun JEONG ; Yong Mee CHO
Investigative and Clinical Urology 2024;65(1):84-93
Purpose:
Vascular endothelial growth factor tyrosine kinase inhibitors (TKIs) have been the standard of care for advanced and metastatic clear cell renal cell carcinoma (ccRCC). However, the therapeutic effect of TKI monotherapy remains unsatisfactory given the high rates of acquired resistance to TKI therapy despite favorable initial tumor response.
Materials and Methods:
To define the TKI-resistance mechanism and identify new therapeutic target for TKI-resistant ccRCC, an integrative differential gene expression analysis was performed using acquired resistant cohort and a public dataset. Sunitinib-resistant RCC cell lines were established and used to test their malignant behaviors of TKI resistance through in vitro and in vivo studies. Immunohistochemistry was conducted to compare expression between the tumor and normal kidney and verify expression of pathway-related proteins.
Results:
Integrated differential gene expression analysis revealed increased interferon-induced transmembrane protein 3 (IFITM3) expression in post-TKI samples. IFITM3 expression was increased in ccRCC compared with the normal kidney. TKI-resistant RCC cells showed high expression of IFITM3 compared with TKI-sensitive cells and displayed aggressive biologic features such as higher proliferative ability, clonogenic survival, migration, and invasion while being treated with sunitinib. These aggressive features were suppressed by the inhibition of IFITM3 expression and promoted by IFITM3 overexpression, and these findings were confirmed in a xenograft model. IFITM3-mediated TKI resistance was associated with the activation of TRAF6 and MAPK/AP-1 pathways.
Conclusions
These results demonstrate IFITM3-mediated activation of the TRAF6/MAPK/AP-1 pathways as a mechanism of acquired TKI resistance, and suggest IFITM3 as a new target for TKI-resistant ccRCC.
9.Aging with HIV: The Burden of Comorbidities, Polypharmacy, and Drug Interactions in Korean People Living withHIV Aged ≥50 Years
Jin KIM ; Hyun-Ju NAM ; Ji-Yeon KIM ; Mi-Kyung HEO ; Sung Un SHIN ; Uh Jin KIM ; Seong Eun KIM ; Seung-Ji KANG ; Jihwan BANG ; Jin-Soo LEE ; Mi-Ok JANG ; Kyung-Hwa PARK
Infection and Chemotherapy 2024;56(4):534-543
Background:
The life expectancy of people living with human immunodeficiency virus (PLWH) has significantly improved with advancements in antiretroviral therapy (ART). However, aging PLWH face a growing burden of noncommunicable diseases (NCDs), polypharmacy, and drug-drug interactions (DDIs), which pose challenges in their management. This study investigates the prevalence of NCDs, polypharmacy, and DDIs among PLWH aged ≥50 years in Korea and their impact on quality of life (QOL).
Materials and Methods:
A cross-sectional study was conducted among 243 PLWH aged ≥50 years receiving ART for at least three months at three university hospitals in Korea between January and July 2022. Data were collected through electronic medical records and personal interviews, assessing demographics, comorbidities, polypharmacy, ART adherence, and QOL using the Korean version of WHOQOL-HIV BREF scale. Potential DDIs were analyzed using the University of Liverpool HIV Drug Interaction Database, and potentially inappropriate medications (PIMs) were identified using the 2023 American Geriatrics Society Beers Criteria. We classified participants into three age groups:50–<65 years, 65–<75 years, and ≥75 years.
Results:
The prevalence of comorbidities was 71.6%, with older participants (≥75 years) showing a significantly higher burden, including bone diseases, osteoarthritis, and dementia (P<0.001). Polypharmacy was observed in 28.4% of participants and increased with age, with 53.3% of those aged ≥75 years taking ≥10 pills daily.Polypharmacy was associated with poorer QOL (71.6 vs. 76.6, P=0.010). Amber-flag DDIs were found in 81 participants (33.3%), most commonly involving metformin and divalent cations. No red-flag DDIs were identified.PIMs were observed in 6.6% of participants aged ≥65 years.
Conclusion
Aging PLWH in Korea face significant challenges from comorbidities, polypharmacy, and DDIs, which negatively impact QOL. Integrated, age-specific, and multidisciplinary care strategies are urgently needed to improve outcomes and ensure the well-being of older PLWH.
10.A Case of Acantholytic Squamous Cell Carcinoma on a Male Areola:An Uncommon Histologic Variant at a Rare Location
Joong Ho KIM ; Ji An UH ; Ho Sung KIM ; Soo Kyung LEE ; Myoung Shin KIM ; Geumhee GWAK ; Un Ha LEE
Korean Journal of Dermatology 2023;61(5):308-312
The areola is a rare location for squamous cell carcinoma (SCC) because sunlight exposure, the main risk factor for SCC, is unusual on it. Acantholytic SCC (ASCC) is a rare histologic variant of SCC, characterized by pseudoglandular appearance with acantholytic tumor cells. A 59-year-old male presented a painful erythematous papule on his right areola. He had a history of psoralen ultraviolet A phototherapy for psoriasis in his 20s. Biopsy revealed an epithelial tumor and pseudoglandular structures with acantholytic tumor cells. In immunohistochemistry, cytokeratin 5/6, epithelial membrane antigen, and p63 were positive, while cytokeratin 7, carcinoembryonic antigen, S-100, and estrogen and progesterone receptors were negative. Periodic acid-Schiff stain was negative. Ki-67 labeling index was 79.7%. The final diagnosis was ASCC of the areola. After wide local excision, recurrence have not been reported. Here, we report a case of ASCC on the areola, focusing on its rare histologic variant and uncommon location.

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