Kyoung-Ho Song

Jeong EJ, et al. J Korean Med Sci. 2027 Jan;42:e23. https://doi.org/10.3346/jkms.2027.42.e23

Panton – Valentine leukocidin (PVL) is a leukocyte-lytic toxin produced by Staphylococcus aureus , which is primarily associated with skin and soft tissue infections. Notably, there has been an increase in the number of cases caused by the USA300 lineage in Japan. However, the reported prevalence of USA300 is limited in other Asian countries, including Korea. This study investigated the prevalence of PVL-positive methicillin-resistant S. aureus (MRSA) in Korea and Japan and compared their molecular epidemiological characteristics. A total of 463 MRSA strains were analyzed, comprising 283 strains from patients visiting two hospitals in Seongnam and Seoul, Korea, and 180 strains from six hospitals in Tokyo, Japan, between 2018 and 2019. The PVL-encoding genes lukS/F-PV were detected using PCR. Molecular epidemiological and phylogenetic analyses were performed using next-generation sequencing. Overall, 27 (9.5%) PVL-positive MRSA strains were detected among strains isolated from Korea, and 16 (8.9%) were detected among those isolated from Japan. Genotyping of PVL-positive strains revealed that 85.2% of Korean and 81.3% of Japanese strains belonged to USA300. Most USA300 strains from Japan and Korea formed distinct clusters in phylogenetic analyses. Meanwhile, ΨUSA300 and ST22-PT, clones that are prevalent in Japan, were isolated in Korea. This study showed that USA300 strains, which are becoming more prevalent in Japan, are also present in Korea. Furthermore, this study suggests that ΨUSA300 and ST22-PT may be spreading between these two countries. Therefore, it is necessary to continue monitoring the epidemiological trends of PVL-positive MRSA clones both domestically and internationally. IMPORTANCE: Panton–Valentine leukocidin (PVL) is a major toxin produced by Staphylococcus aureus . Although a rapid increase in PVL-positive strains has been reported in Japan, data on PVL-positive strains in Korea remain limited. In this study, we performed a comparative analysis of PVL-positive S. aureus isolates from Korea and Japan. The results showed that the clinical backgrounds and genetic profiles of PVL-positive strains isolated in Korea and Japan were highly similar. Furthermore, we confirmed for the first time that clones circulating in Japan, including ΨUSA300 and ST22-PT, were also isolated in Korea. These findings provide valuable insights into the epidemiological status of PVL-positive S. aureus in East Asia.

Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is a serious clinical challenge due to limited treatments and high mortality. We conducted both preclinical and clinical studies to assess the potential role of delpazolid in combination with vancomycin. Synergistic effects of delpazolid with vancomycin or daptomycin were evaluated in vitro using checkerboard and time-kill assays, and in vivo using a Galleria mellonella model. A multicenter, double-blind, randomized, Phase IIa trial was conducted at six Korean hospitals between 26 April 2022 and 18 March 2024. Patients with MRSA bacteremia were randomized 1:1 to receive vancomycin monotherapy or vancomycin plus delpazolid for 14 to 42 days. The primary outcome was overall cure at day 14 (microbiological clearance and symptom resolution). Secondary endpoints included safety, adverse events, and delpazolid pharmacokinetics. In vitro checkerboard assays showed no interaction between delpazolid and vancomycin or daptomycin, while time-kill assays revealed antagonism only when delpazolid was combined with vancomycin. In the Galleria mellonella model, combination therapy improved survival over monotherapy. In the clinical study, 40 patients were enrolled, 38 received ≥1 dose (safety set), and 34 (monotherapy: 19; combination: 15) were included in the full analysis set. On day 14, overall cure was 52.6% in the monotherapy and 60.0% in the combination group ( P = 0.6675). Adverse event rates were similar across groups, with no significant safety concerns. In pharmacokinetic analyses, delpazolid showed favorable plasma levels when co-administered. These preliminary findings warrant further investigation in adequately powered trials to define the role of delpazolid plus vancomycin in the treatment of MRSA bacteremia. CLINICAL TRIALS: The study is registered with ClinicalTrial.gov as NCT05225558 . IMPORTANCE: Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia presents a serious clinical challenge due to limited treatments and high mortality. This study evaluated the potential role of delpazolid, an oral oxazolidinone, in combination with vancomycin for MRSA bacteremia. Preclinical studies demonstrated delpazolid’s antimicrobial activity comparable to vancomycin and daptomycin, and in the Galleria mellonella infection model, combination therapy significantly improved survival rates over monotherapy. The early-terminated Phase IIa clinical study showed that the combination regimen had an acceptable safety profile, with no apparent increase in adverse events compared to vancomycin monotherapy. While overall cure rates and bacteremia clearance were numerically higher in the combination group, these differences were not statistically significant. These preliminary findings underscore the need for larger, adequately powered clinical trials to clarify the clinical role of delpazolid combination therapy in MRSA infections.

Objective The incidence of psychiatric illnesses might be higher in individuals people living with human immunodeficiency virus (PLWH) than in individuals without human immunodeficiency virus (HIV). We aimed to investigate whether PLWH had different risks of psychiatric morbidities in comparison to non-HIV-infected individuals.Methods This study included all PLWH in South Korea between January 1, 2017 and December 31, 2017. The control group, which had never been diagnosed with HIV, was selected using a 1:10 stratified random sampling technique, considering age and sex. The endpoint of this study was new diagnosis of psychiatric morbidities which were diagnosed from January 1, 2018 to December 31, 2022.Results After conducting a 1:5 propensity score (PS) matching process, the final analysis comprised a group of 17,815 PLWH and 78,021 control subjects. In the PS-matched cohort, the incidence rate of psychiatric morbidity in PLWH was 5,677.7 per 100,000 per year, whereas that in the controls was 4,926.3 per 100,000 per year. In Cox regression in the PS-matched cohort, PLWH showed 17% (hazard ratio, 1.17; 95% confidence interval, 1.14–1.21; p<0.001) higher risk of psychiatric morbidity than controls. Specifically, PLWH showed higher risk of depression, mania, bipolar disorder, insomnia disorder, substance use disorder, and schizophrenia compared to controls.Conclusion PLWH had a greater likelihood of experiencing psychiatric morbidities compared to those without HIV in South Korea. Our research findings indicate the importance of public health policy in addressing the declining mental health of individuals living with HIV.

Kim SA, et al. J Korean Med Sci. 2026 Dec;41:e330. https://doi.org/10.3346/jkms.2026.41.e330

[This corrects the article DOI: 10.1017/ash.2024.75.].

Although large language models (LLMs) have demonstrated impressive reasoning capabilities across general domains, their effectiveness in real-world clinical practice remains limited. This is likely due to their insufficient exposure to real-world clinical data during training, as such data is typically not included due to privacy concerns. To address this, we propose enhancing the clinical reasoning capabilities of LLMs by leveraging real-world clinical data. We constructed reasoning-intensive questions from a nationwide sepsis registry and fine-tuned Phi-4 on these questions using reinforcement learning, resulting in C-Reason. C-Reason exhibited strong clinical reasoning capabilities on the in-domain test set, as evidenced by both quantitative metrics and expert evaluations. Furthermore, its enhanced reasoning capabilities generalized to a sepsis dataset involving different tasks and patient cohorts, an open-ended consultations on antibiotics use task, and other diseases. Future research should focus on training LLMs with large-scale, multi-disease clinical datasets to develop more powerful, general-purpose clinical reasoning models.

Our objective was to perform a systematic review of individual patient data comparing immunodiagnostic test sensitivity in patients with localized versus disseminated tuberculosis who are from high- and less-than-high-income countries. In a systematic review of individual patient data, we compared IGRA results and characteristics of patients with disseminated tuberculosis with IGRA results and characteristics of patients with localized tuberculosis. Data were extracted from Pubmed, EMBASE and the Cochrane Library, analyzed and presented following the PRISMA-IPD and STROBE statements. We identified 52 patients with localized and 105 with disseminated tuberculosis. Immunodiagnostic tests in localized tuberculosis from high-income countries were positive in 88.8% and in 67.3% of patients with disseminated tuberculosis (p = 0.034). In patients from less-than-high-income countries, the sensitivity of immunodiagnostic tests was not significantly lower with disseminated tuberculosis. Patients with disseminated tuberculosis were significantly younger and had a higher rate of microbiological confirmation. Multivariate logistic regression analysis revealed that rate of microbiological confirmation was associated with a negative IGRA. Disseminated tuberculosis may be associated with a reduced sensitivity of IGRA in high-income countries and this may be related to a higher bacterial load with a negative IGRA.

Lee R, et al. Infect Chemother. 2025 Jan;57:e4. https://doi.org/10.3947/ic.2024.0148