Background: Since the emergence of hypervirulent strains of Clostridioides difficile, the incidence of C. difficile infections (CDI) has increased significantly. Methods: To assess the incidence of CDI in Korea, we conducted a prospective multicentre observational study from October 2020 to October 2021. Additionally, we calculated the incidence of CDI from mass data obtained from the Health Insurance Review and Assessment Service (HIRA) from 2008 to 2020. Results: In the prospective study with active surveillance, 30,212 patients had diarrhoea and 907 patients were diagnosed with CDI over 1,288,571 patient-days and 193,264 admissions in 18 participating hospitals during 3 months of study period; the CDI per 10,000 patientdays was 7.04 and the CDI per 1,000 admission was 4.69. The incidence of CDI was higher in general hospitals than in tertiary hospitals: 6.38 per 10,000 patient-days (range: 3.25–12.05) and 4.18 per 1,000 admissions (range: 1.92–8.59) in 11 tertiary hospitals, vs. 9.45 per 10,000 patient-days (range: 5.68–13.90) and 6.73 per 1,000 admissions (range: 3.18–15.85) in seven general hospitals. With regard to HIRA data, the incidence of CDI in all hospitals has been increasing over the 13-year-period: from 0.3 to 1.8 per 10,000 patient-days, 0.3 to 1.6 per 1,000 admissions, and 6.9 to 56.9 per 100,000 population, respectively. Conclusion The incidence of CDI in Korea has been gradually increasing, and its recent value is as high as that in the United State and Europe. CDI is underestimated, particularly in general hospitals in Korea.

Circulating microRNAs (miRNAs) are potential biomarkers for various kidney diseases. In this study, we aimed to identify a circulating miRNA signature for detecting acute kidney injury (AKI) in scrub typhus. Methods: We prospectively enrolled 40 patients with scrub typhus (20 with AKI, AKI group; 20 without AKI, non-AKI group) and 20 healthy volunteers (the HV group). Thereafter, we performed microarray analysis to assess the serum miRNA profiles of all the participants. Then, to identify miRNAs predictive of scrub typhus-associated AKI, we compared miRNA profiles among these three groups. Results: The proportions of miRNAs, small nucleolar RNAs, and small Cajal body-specific ribonucleoproteins were higher in patients with scrub typhus than in the HVs. Further, relative to the HVs, we identified 120 upregulated and 449 downregulated miRNAs in the non-AKI group and 101 upregulated and 468 downregulated miRNAs in the AKI group. We also identified 11 and 110 upregulated and downregulated miRNAs, respectively, in the AKI group relative to the non-AKI group, and among these miRNAs, we noted 14 miRNAs whose levels were significantly upregulated or downregulated in the AKI group relative to their levels in the HV and non-AKI groups. Biological pathway analysis of these 14 miRNAs indicated their potential involvement in various pathways associated with tumor necrosis factor alpha. Conclusion: We identified miRNAs associated with AKI in patients with scrub typhus that have predictive potential for AKI. Thus, they can be used as surrogate markers for the detection of scrub typhus-associated AKI.

Circulating microRNAs (miRNAs) are potential biomarkers for various kidney diseases. In this study, we aimed to identify a circulating miRNA signature for detecting acute kidney injury (AKI) in scrub typhus. Methods: We prospectively enrolled 40 patients with scrub typhus (20 with AKI, AKI group; 20 without AKI, non-AKI group) and 20 healthy volunteers (the HV group). Thereafter, we performed microarray analysis to assess the serum miRNA profiles of all the participants. Then, to identify miRNAs predictive of scrub typhus-associated AKI, we compared miRNA profiles among these three groups. Results: The proportions of miRNAs, small nucleolar RNAs, and small Cajal body-specific ribonucleoproteins were higher in patients with scrub typhus than in the HVs. Further, relative to the HVs, we identified 120 upregulated and 449 downregulated miRNAs in the non-AKI group and 101 upregulated and 468 downregulated miRNAs in the AKI group. We also identified 11 and 110 upregulated and downregulated miRNAs, respectively, in the AKI group relative to the non-AKI group, and among these miRNAs, we noted 14 miRNAs whose levels were significantly upregulated or downregulated in the AKI group relative to their levels in the HV and non-AKI groups. Biological pathway analysis of these 14 miRNAs indicated their potential involvement in various pathways associated with tumor necrosis factor alpha. Conclusion: We identified miRNAs associated with AKI in patients with scrub typhus that have predictive potential for AKI. Thus, they can be used as surrogate markers for the detection of scrub typhus-associated AKI.

Circulating microRNAs (miRNAs) are potential biomarkers for various kidney diseases. In this study, we aimed to identify a circulating miRNA signature for detecting acute kidney injury (AKI) in scrub typhus. Methods: We prospectively enrolled 40 patients with scrub typhus (20 with AKI, AKI group; 20 without AKI, non-AKI group) and 20 healthy volunteers (the HV group). Thereafter, we performed microarray analysis to assess the serum miRNA profiles of all the participants. Then, to identify miRNAs predictive of scrub typhus-associated AKI, we compared miRNA profiles among these three groups. Results: The proportions of miRNAs, small nucleolar RNAs, and small Cajal body-specific ribonucleoproteins were higher in patients with scrub typhus than in the HVs. Further, relative to the HVs, we identified 120 upregulated and 449 downregulated miRNAs in the non-AKI group and 101 upregulated and 468 downregulated miRNAs in the AKI group. We also identified 11 and 110 upregulated and downregulated miRNAs, respectively, in the AKI group relative to the non-AKI group, and among these miRNAs, we noted 14 miRNAs whose levels were significantly upregulated or downregulated in the AKI group relative to their levels in the HV and non-AKI groups. Biological pathway analysis of these 14 miRNAs indicated their potential involvement in various pathways associated with tumor necrosis factor alpha. Conclusion: We identified miRNAs associated with AKI in patients with scrub typhus that have predictive potential for AKI. Thus, they can be used as surrogate markers for the detection of scrub typhus-associated AKI.

Circulating microRNAs (miRNAs) are potential biomarkers for various kidney diseases. In this study, we aimed to identify a circulating miRNA signature for detecting acute kidney injury (AKI) in scrub typhus. Methods: We prospectively enrolled 40 patients with scrub typhus (20 with AKI, AKI group; 20 without AKI, non-AKI group) and 20 healthy volunteers (the HV group). Thereafter, we performed microarray analysis to assess the serum miRNA profiles of all the participants. Then, to identify miRNAs predictive of scrub typhus-associated AKI, we compared miRNA profiles among these three groups. Results: The proportions of miRNAs, small nucleolar RNAs, and small Cajal body-specific ribonucleoproteins were higher in patients with scrub typhus than in the HVs. Further, relative to the HVs, we identified 120 upregulated and 449 downregulated miRNAs in the non-AKI group and 101 upregulated and 468 downregulated miRNAs in the AKI group. We also identified 11 and 110 upregulated and downregulated miRNAs, respectively, in the AKI group relative to the non-AKI group, and among these miRNAs, we noted 14 miRNAs whose levels were significantly upregulated or downregulated in the AKI group relative to their levels in the HV and non-AKI groups. Biological pathway analysis of these 14 miRNAs indicated their potential involvement in various pathways associated with tumor necrosis factor alpha. Conclusion: We identified miRNAs associated with AKI in patients with scrub typhus that have predictive potential for AKI. Thus, they can be used as surrogate markers for the detection of scrub typhus-associated AKI.

Purpose: Notable effectiveness of trastuzumab deruxtecan in patients with human epidermal growth factor receptor 2 (HER2)–low advanced breast cancer (BC) has focused pathologists’ attention. We studied the incidence and clinicopathologic characteristics of HER2-low BC, and the effects of immunohistochemistry (IHC) associated factors on HER2 IHC results. Materials and Methods: The Breast Pathology Study Group of the Korean Society of Pathologists conducted a nationwide study using real-world data on HER2 status generated between January 2022 and December 2022. Information on HER2 IHC protocols at each participating institution was also collected. Results: Total 11,416 patients from 25 institutions included in this study. Of these patients, 40.7% (range, 6.0% to 76.3%) were classified as HER2-zero, 41.7% (range, 10.5% to 69.1%) as HER2-low, and 17.5% (range, 6.7% to 34.0%) as HER2-positive. HER2-low tumors were associated with positive estrogen receptor and progesterone receptor statuses (p < 0.001 and p < 0.001, respectively). Antigen retrieval times (≥ 36 minutes vs. < 36 minutes) and antibody incubation times (≥ 12 minutes vs. < 12 minutes) affected on the frequency of HER2 IHC 1+ BC at institutions using the PATHWAY HER2 (4B5) IHC assay and BenchMark XT or Ultra staining instruments. Furthermore, discordant results between core needle biopsy and subsequent resection specimen HER2 statuses were observed in 24.1% (787/3,259) of the patients. Conclusion The overall incidence of HER2-low BC in South Korea concurs with those reported in previously published studies. Significant inter-institutional differences in HER2 IHC protocols were observed, and it may have impact on HER2-low status. Thus, we recommend standardizing HER2 IHC conditions to ensure precise patient selection for targeted therapy.