1.Comparison of Two Quinupristin–dalfopristin Susceptibility Testing Methods and Two Interpretive Criteria for Enterococcus faecium Bloodstream Isolates from Korean Hospitals
Yong Jun KWON ; Ha Jin LIM ; Soo Hyun KIM ; Seung A BYUN ; Ga Yeong LEE ; Ga-Gyeong KIM ; Seok Hoon JEONG ; Jeong Hwan SHIN ; Young Ah KIM ; Young UH ; Jong Hee SHIN
Annals of Laboratory Medicine 2025;45(6):630-634
Enterococcus faecium, particularly in its multidrug-resistant forms, causes invasive nosocomial infections. Given the limited data comparing the effectiveness of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the CLSI clinical breakpoints (CBPs) for quinupristin–dalfopristin (QD) resistance and the need to evaluate their practical application, we retrospectively investigated the susceptibility patterns of 287 E.faecium bloodstream isolates from Korean hospitals to QD using the updated EUCAST and CLSI CBPs and two antimicrobial susceptibility testing methods: disk diffusion (DD) and Sensititre broth microdilution (Sensititre). QD resistance rates were 5.9% (CLSI) and 18.8% (EUCAST) for DD and 22.6% (CLSI) and 28.2% (EUCAST) for Sensititre. The most prevalent QD resistance gene types among QD-resistant isolates were ermB+msrC+ or ermB– msrC+. Categorical agreement between DD and Sensititre ranged from 77.7% to 90.7%, depending on the testing method and CBPs applied. The EUCAST zone diameter CBPs more effectively help identify QD-resistant E. faecium isolates using the DD method than the CLSI zone diameter CBPs. In comparison, the CLSI minimum inhibitory concentration (MIC) CBPs provide more reliable results for resistance classification in the Sensititre method than EUCAST MIC CBPs. These findings would help improve clinical decision-making for treating multidrug-resistant E. faecium infections.
2.Diagnostic performance of quantitative ultrasonography for hepatic steatosis in a health screening program: a prospective single-center study
Jeung Hui PYO ; Soo Jin CHO ; Sung Chul CHOI ; Jae Hwan JEE ; Jeeyeong YUN ; Jeong Ah HWANG ; Goeun PARK ; Kyunga KIM ; Wonseok KANG ; Mira KANG ; Young hye BYUN
Ultrasonography 2024;43(4):250-262
Purpose:
This study compared the diagnostic performance of quantitative ultrasonography (QUS) with that of conventional ultrasonography (US) in assessing hepatic steatosis among individuals undergoing health screening using magnetic resonance imaging–derived proton density fat fraction (MRI-PDFF) as the reference standard.
Methods:
This single-center prospective study enrolled 427 participants who underwent abdominal MRI and US. Measurements included the attenuation coefficient in tissue attenuation imaging (TAI) and the scatter-distribution coefficient in tissue scatter-distribution imaging (TSI). The correlation between QUS and MRI-PDFF was evaluated. The diagnostic capabilities of QUS, conventional B-mode US, and their combined models for detecting hepatic fat content of ≥5% (MRI-PDFF ≥5%) and ≥10% (MRI-PDFF ≥10%) were compared by analyzing the areas under the receiver operating characteristic curves. Additionally, clinical risk factors influencing the diagnostic performance of QUS were identified using multivariate linear regression analyses.
Results:
TAI and TSI were strongly correlated with MRI-PDFF (r=0.759 and r=0.802, respectively; both P<0.001) and demonstrated good diagnostic performance in detecting and grading hepatic steatosis. The combination of QUS and B-mode US resulted in the highest areas under the ROC curve (AUCs) (0.947 and 0.975 for detecting hepatic fat content of ≥5% and ≥10%, respectively; both P<0.05), compared to TAI, TSI, or B-mode US alone (AUCs: 0.887, 0.910, 0.878 for ≥5% and 0.951, 0.922, 0.875 for ≥10%, respectively). The independent determinants of QUS included skinliver capsule distance (β=7.134), hepatic fibrosis (β=4.808), alanine aminotransferase (β=0.202), triglyceride levels (β=0.027), and diabetes mellitus (β=3.710).
Conclusion
QUS is a useful and effective screening tool for detecting and grading hepatic steatosis during health checkups.
3.Noninferiority Outcomes of Besifovir Compared to Tenofovir Alafenamide in Treatment-Naïve Patients with Chronic Hepatitis B
Tae Hyung KIM ; Ji Hoon KIM ; Hyung Joon YIM ; Yeon Seok SEO ; Sun Young YIM ; Young-Sun LEE ; Young Kul JUNG ; Jong Eun YEON ; Soon Ho UM ; Kwan Soo BYUN
Gut and Liver 2024;18(2):305-315
Background/Aims:
Besifovir dipivoxil maleate (BSV) and tenofovir alafenamide fumarate (TAF) have been recently approved in Korea as the initial antiviral agents for chronic hepatitis B (CHB).However, the real-world outcome data for these drugs remain limited. Therefore, we conducted a noninferiority analysis using real-world data to compare the clinical outcomes of the two nucleotide analogs in treatment-naïve patients with CHB.
Methods:
We retrospectively investigated a cohort of patients with CHB who received BSV or TAF as first-line antiviral agents. The endpoints were virological response (VR) and liver-related clinical outcomes.
Results:
A total of 537 patients, consisting of 202 and 335 patients administered BSV and TAF, respectively, were followed up for 42 months. No significant difference was observed between the VRs of the patients from the two groups. The rates of biochemical response, virologic breakthrough, and incidence rates of hepatocellular carcinoma did not differ between the groups. However, the hepatitis B e antigen seroclearance rate was higher and the renal function declined less in the BSV group. Multivariable analysis indicated older age, alcohol abuse, cirrhosis and ascites, and lower serum HBV DNA level to be independently associated with increased hepatocellular carcinoma risk. The 1:1 propensity score-matched analysis with 400 patients showed VR rates of 85.0% and 88.7% in the BSV and TAF group patients, respectively, at 2 years. The absolute value of the 95% confidence interval for the difference (–0.04 to 0.12) satisfied the a priori limit of a noninferiority of 0.15.
Conclusions
BSV is noninferior to TAF in terms of VR, and their clinical outcomes are comparable to CHB.
4.Understanding Standard Procedure in Auditory Brainstem Response: Importance of Normative Data
Chanbeom KWAK ; Yuseon BYUN ; Sunghwa YOU ; Junghee SAGONG ; Do-Yun KIM ; Wan-Ho CHO ; Tae Hoon KONG ; Soo Hee OH ; In-Ki JIN ; Michelle J. SUH ; Hyo-Jeong LEE ; Seong Jun CHOI ; Dongchul CHA ; Kyung-Ho PARK ; Young Joon SEO
Journal of Audiology & Otology 2024;28(4):243-251
The auditory brainstem response (ABR) is a noninvasive test that measures neural activity in response to auditory stimuli. Racial differences in head shape have provided strong evidence for specific normative data and accurate device calibration. International standards emphasize the need for standardized procedures and references. This study aimed to outline the standard procedure and related normative ABR values. Standard procedures were performed according to International Electrotechnical Commission (IEC) standards. Five studies from two countries were included to compare the normative values of the ABR. The dataset from the National Standard Reference Data Center (NSRDC) was used as reference. Normative values were described in terms of stimuli, latency, and amplitude. For click stimuli, the latency of the ABR showed different patterns across populations, such as those from Korea and the USA. Although the latencies reported by the NSRDC and for Koreans were relatively short, those reported for USA populations were longer. Using clicks, it was shown that the USA population had the largest ABR amplitude compared to those reported for the other two datasets. For Wave V latency using tone bursts, a similar pattern was identified with click stimuli. Frequency-specific trends were also observed. Although there is a lack of ABR datasets, the information and insights of the present study could be utilized as standard guidelines in research on ABR.
5.Development of an Instrument for Slit-lamp Examination of Donor Corneas in Preservation Medium
Ga Hee NAM ; Da Ran KIM ; Young Chae YOON ; Soon Won YANG ; Woong Joo WHANG ; Yong-Soo BYUN ; Hyung Bin HWANG ; Kyung Sun NA ; Hyun Soo LEE ; So Hyang CHUNG ; Eun Chul KIM ; Yang Kyung CHO ; Hyun Seung KIM ; Ho Sik HWANG
Journal of the Korean Ophthalmological Society 2024;65(2):108-116
Purpose:
To evaluate the effectiveness of an instrument devised for slit-lamp examination of donor corneas suspended in preservation medium.
Methods:
The study examined two donor corneas received at Yeouido St. Mary's Hospital in February 2023 and March 2023. The instrument has three main components: a plastic holder to hold the preservation medium bottle, a cube with a mirror for reflecting the slit beam, and a stand to attach the device to the slit-lamp. Using the instrument, the donor corneas were examined via slit-lamp: microscopy with the endothelium facing upward and downward. Specular microscopy and anterior segment optical coherence tomography (OCT) were also performed on the preserved donor corneas.
Results:
Slit-lamp examination of donor corneas in preservation medium using the instrument showed overall corneal buttoning and optical sections of the donor cornea. Using specular reflection and retroillumination, the endothelial layer was partially visible. However, specular microscopy and anterior segment OCT could not examine the donor cornea in preservation medium using the instrument.
Conclusions
The devised instrument facilitates slit-lamp examination of donor corneas in preservation medium, enabling a qualitative assessment of donor corneas before corneal transplantation surgery.
6.Ten-year Trends in Infectious Keratitis in South Korea
Chanjoon PARK ; Hye Yeon YOON ; Young Sik YOO ; Hyun Soo LEE ; Hyung Bin HWANG ; Kyung Sun NA ; Yang Kyung CHO ; Eun Chul KIM ; So Hyang CHUNG ; Hyun Seung KIM ; Yong-Soo BYUN
Journal of the Korean Ophthalmological Society 2024;65(3):181-193
Purpose:
This study investigated the causative microorganisms, antibiotic susceptibility, and risk factors of infectious keratitis over the past 10 years.
Methods:
Data from patients with infectious keratitis who underwent microbial culture tests from 2012 to 2021, obtained from anonymized data systems, were analyzed. Microbial culture results and antibiotic susceptibility profiles were examined. A retrospective analysis of the medical records of patients with infectious keratitis during the same period was conducted to investigate the clinical characteristics and risk factors.
Results:
Data from 1,837 cases of infectious keratitis were extracted from anonymized records. The culture positive rate among patients was 46.0% (1,137/2,474), with coagulase-negative Staphylococcus (CoNS) being the most common causative organism (27.8%). Increased resistance to cefazolin and cefotaxime was observed in gram-negative bacteria, while there were no significant temporal changes in quinolone resistance in gram-positive or negative bacteria. A retrospective medical record analysis of 288 cases revealed that older patients, as well as those with an initial corrected visual acuity < 0.1, a history of ocular surgery, pre-existing ocular conditions, prior steroid eye drops, or glaucoma eye drops, had significantly higher rates of culture positivity. Multivariate analysis identified risk factors for severe keratitis requiring surgical intervention as a symptom-to-presentation period of 7 days or longer (p = 0.048) and pre-existing ocular conditions (p = 0.040).
Conclusions
CoNS was the most common microorganism causing infectious keratitis over the past decade. There has been an increase in resistance to cephalosporin antibiotics among gram-negative bacteria. Patients with pre-existing ocular conditions may require surgical intervention, so infectious keratitis in these patients requires greater attention.
7.The Use of High-Speed Burr in Minimally Invasive Surgery for Button Osteoma of the Skull: An Institutional Review
Ji Soo PARK ; Bo-Bin CHA ; Sung Joo BYUN ; Ji Hye MOON ; Won-Serk KIM ; Young-Jun CHOI
Korean Journal of Dermatology 2024;62(7):391-399
Background:
In a previous study, rhinoplasty rasp was shown an effective method for removal of button osteoma (BO) of the skull.
Objective:
In the present study, our experience was presented and surgical outcome using high-speed burr in surgery for BO evaluated.
Methods:
The register-based surgery reports of patients who underwent local excision of BO (2010∼2023) at a single institution were reviewed. Demographics, photodocumentation, radiologic examinations, pathology reports, data of scar prevention, and surgical outcome in the BO study cohort were analyzed.
Results:
A total of 20 BO lesions in 18 patients (14 females and four males; mean age of 52.4±14.3 years) who underwent surgery using high-speed burr were assessed. The mean size of BO was 9.3 mm (range, 5∼17 mm).Most of the BOs were located on the forehead (19/20, 95.0%), which was associated with the course of the supratrochlear (n=13) or supraorbital nerve (n=6). Minimal hematoma was complicated in three patients (16.7%).Delayed complications, recurrence, and severe scarring during the mean follow-up of 3.1±3.5 months were not reported.
Conclusion
The use of high-speed burr for surface smoothening may provide good surgical results in minimally invasive BO surgery.
8.Categorization of Meibomian Gland Dysfunction Using Lipid Layer Thickness and Meibomian Gland Dropout in Dry Eye Patients: A Retrospective Study
Phil Kyu LEE ; Jae Lim CHUNG ; Da Ran KIM ; Young Chae YOON ; SoonWon YANG ; Woong-Joo WHANG ; Yong-Soo BYUN ; HyungBin HWANG ; Kyung Sun NA ; HyunSoo LEE ; So Hyang CHUNG ; Eun Chul KIM ; YangKyung CHO ; Hyun Seung KIM ; Ho Sik HWANG
Korean Journal of Ophthalmology 2024;38(1):64-70
Purpose:
In the present study, we determined the prevalence of obstructive meibomian gland dysfunction (MGD), hyposecretory MGD, grossly normal MG, and hypersecretory MGD in patients with dry eye syndrome using lipid layer thickness (LLT) and MG dropout.
Methods:
Eighty-eight patients with dry eye syndrome were included in the study. Patients were categorized into four groups according to the LLT and weighted total meiboscore. The proportion of patients in each group was calculated. The age, sex, Ocular Surface Disease Index, LLT, Schirmer, tear film breakup time, cornea stain, weighted total meiboscore, expressibility, and quality of meibum were compared between the four groups.
Results:
Fifteen eyes (17.0%) had obstructive MGD, two eyes (2.3%) had hyposecretory MGD, 40 eyes (45.5%) had grossly normal MG, and 17 eyes (19.3%) had hypersecretory MGD. The obstructive MGD group was younger than the grossly normal MG group. In obstructive MGD, the ratio of men to women was higher than that of the other groups. However, Ocular Surface Disease Index, Schirmer, tear film breakup time, and corneal stain did not show statistically significant differences between the four groups. The meibum expressibility of the hyposecretoy MGD group was worse than those of the other groups. The meibum expressibility of the hyposecretoy MGD group was poor than those of the obstructive and hypersecretory MGD group.
Conclusions
This categorization was expected to help determine the best treatment method for dry eye syndrome, according to the MG status.
9.In Vivo Human Lacrimal Gland Imaging Using an Ultrasound Biomicroscopy
Chanjoon PARK ; Da Ran KIM ; Young Chae YOON ; Soonwon YANG ; Woong-Joo WHANG ; Yong-Soo BYUN ; Hyung Bin HWANG ; Kyung Sun NA ; Hyun Soo LEE ; So Hyang CHUNG ; Eun Chul KIM ; Yang Kyung CHO ; Hyun Seung KIM ; Hosik HWANG
Korean Journal of Ophthalmology 2024;38(3):227-235
Purpose:
In the present study, we introduce human lacrimal gland imaging using an ultrasound biomicroscopy (UBM) with a soft cover and show their findings
Methods:
The representative UBM findings of palpebral lobes in seven subjects (four with non-Sjögren dry eye syndrome, one with Sjögren syndrome, and two healthy subjects) were described in this study. To prolapse the palpebral lobe, the examiner pulled the temporal part of the upper eyelid in the superotemporal direction and directed the subject to look in the inferonasal direction. We scanned the palpebral lobes longitudinally and transversely using UBM. We used an Aviso UBM with a 50 MHz linear probe and ClearScan.
Results:
In UBM of two healthy subjects, the echogenicity of the lacrimal gland was lower than that of the sclera and homogeneous. But the parenchyma of a patient with Sjögren dry eye syndrome was quite inhomogeneous compared to the healthy subjects. In two patients with dry eye syndrome, we were able to observe some lobules in the parenchyma. We could find excretory ducts running parallel at the surface of the longitudinal section in some subjects. In the longitudinal UBM scan of a subject, we observed a tubular structure at a depth of 1,500 μm that was considered a blood vessel. It ran from the superonasal to the inferotemporal direction. In a subject, we observed a large cyst beneath the conjunctiva.
Conclusions
Lacrimal gland imaging using UBM has both advantages of optical coherence tomography and sonography, and could be useful for evaluating dry eye syndrome.
10.Diagnostic performance of quantitative ultrasonography for hepatic steatosis in a health screening program: a prospective single-center study
Jeung Hui PYO ; Soo Jin CHO ; Sung Chul CHOI ; Jae Hwan JEE ; Jeeyeong YUN ; Jeong Ah HWANG ; Goeun PARK ; Kyunga KIM ; Wonseok KANG ; Mira KANG ; Young hye BYUN
Ultrasonography 2024;43(4):250-262
Purpose:
This study compared the diagnostic performance of quantitative ultrasonography (QUS) with that of conventional ultrasonography (US) in assessing hepatic steatosis among individuals undergoing health screening using magnetic resonance imaging–derived proton density fat fraction (MRI-PDFF) as the reference standard.
Methods:
This single-center prospective study enrolled 427 participants who underwent abdominal MRI and US. Measurements included the attenuation coefficient in tissue attenuation imaging (TAI) and the scatter-distribution coefficient in tissue scatter-distribution imaging (TSI). The correlation between QUS and MRI-PDFF was evaluated. The diagnostic capabilities of QUS, conventional B-mode US, and their combined models for detecting hepatic fat content of ≥5% (MRI-PDFF ≥5%) and ≥10% (MRI-PDFF ≥10%) were compared by analyzing the areas under the receiver operating characteristic curves. Additionally, clinical risk factors influencing the diagnostic performance of QUS were identified using multivariate linear regression analyses.
Results:
TAI and TSI were strongly correlated with MRI-PDFF (r=0.759 and r=0.802, respectively; both P<0.001) and demonstrated good diagnostic performance in detecting and grading hepatic steatosis. The combination of QUS and B-mode US resulted in the highest areas under the ROC curve (AUCs) (0.947 and 0.975 for detecting hepatic fat content of ≥5% and ≥10%, respectively; both P<0.05), compared to TAI, TSI, or B-mode US alone (AUCs: 0.887, 0.910, 0.878 for ≥5% and 0.951, 0.922, 0.875 for ≥10%, respectively). The independent determinants of QUS included skinliver capsule distance (β=7.134), hepatic fibrosis (β=4.808), alanine aminotransferase (β=0.202), triglyceride levels (β=0.027), and diabetes mellitus (β=3.710).
Conclusion
QUS is a useful and effective screening tool for detecting and grading hepatic steatosis during health checkups.

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