Background: Enzyme immunoassays (EIAs), which detect glutamate dehydrogenase (GDH) and toxin A/B, are widely used to screen for Clostridioides difficile infection (CDI); however, their sensitivity is lower than that of molecular assays. This study aimed to evaluate the performance of two EIAs, C. Diff Quik Chek Complete (QCC) and RIDASCREEN (RIDA), and investigate the cycle threshold (Ct) values from two real-time polymerase chain reaction (PCR) assays (Allplex GI–Bacteria(I) and Xpert C. difficile) in EIA-discordant samples. Methods: A total of 180 clinical stool samples were tested using QCC, RIDA, and Allplex GI– Bacteria(I) PCR assays. The Xpert C. difficile assay was used to analyze discordant results. Results: QCC and RIDA showed high sensitivities for GDH detection, 100.0% and 94.4%, respectively. QCC was significantly more sensitive than RIDA for toxin detection (51.4% vs. 28.6%, p = 0.007). In 25 EIA-discordant, Xpert positive samples, the Ct values of the toxin B gene ranged from 31.5 to 44.8 (mean, 38.1) for Allplex PCR and from 23.7 to 36.3 (mean, 30.4) for Xpert PCR. The Ct values of the two PCR assays were not significantly correlated (r = 0.201, p = 0.324). Conclusion QCC is a suitable initial immunological test for diagnosing CDI. The lack of correlation in the Ct values between the two real-time PCR assays suggests that assay-specific validation is necessary for cutoff level interpretation.

Background: Carbapenem-resistant Pseudomonas aeruginosa (CrPA) is a leading cause of healthcare-associated urinary tract infections (UTIs). Carbapenemase production is an important mechanism that significantly alters the efficacy of frequently used anti-pseudomonal agents. Reporting the current genotypic distribution of carbapenemase-producing P.aeruginosa (CPPA) isolates in relation to antimicrobial susceptibility, UTI risk factors, and mortality is necessary to increase the awareness and control of these strains. Methods: In total, 1,652 non-duplicated P. aeruginosa strains were isolated from hospitalized patients between 2015 and 2020. Antimicrobial susceptibility, carbapenemase genotypes, risk factors for UTI, and associated mortality were analyzed. Results: The prevalence of carbapenem-non-susceptible P. aeruginosa isolates showed a decreasing trend from 2015 to 2018 and then increased in the background of the emergence of New Delhi metallo-β-lactamase (NDM)-type isolates since 2019. The CPPA strains showed 100.0% non-susceptibility to all tested antibiotics, except aztreonam (94.5%) and colistin (5.9%). Carbapenems were identified as a risk and common predisposing factor for UTI (odds ratio [OR] = 1.943) and mortality (OR = 2.766). Intensive care unit (ICU) stay (OR = 2.677) and white blood cell (WBC) count (OR = 1.070) were independently associated with mortality. Conclusions The changing trend and genetic distribution of CPPA isolates emphasize the need for relentless monitoring to control further dissemination. The use of carbapenems, ICU stay, and WBC count should be considered risk factors, and aggressive antibiotic stewardship programs and monitoring may serve to prevent worse outcomes.

Background/Aims: The SAMe-TT2R2 score is used for assessing anticoagulation control (AC) quality with warfarin. However, it is hard to apply SAMe-TT2R2 score in Asian patients with atrial fibrillation (AF), because it has not been proven in those populations. This study aimed to validate the SAMe-TT2R2 score in Asian patients with AF and suggest a modified SAMe- TT2R2 score for this population. Methods: We analyzed 710 Korean patients with AF who were using warfarin. The AC quality was assessed as the mean time in therapeutic range (TTR). Each component of SAMe-TT2R2 score was evaluated for the relationship with AC. Further clinical factors that predict AC were analyzed. Identified factors were re-assorted and constructed as SA2Me-TTR scoring system. Results: Of the components of the SAMe-TT2R2 score, female, age, and rhythm control were associated with AC. Heart failure and renal insufficiency were newly identified factors associated with AC. The modified SA2Me-TTR score was reconstructed with the relevant risk factors (S, female gender, 1 point; A, age < 60 yr, 2 points; Me, medical history of heart failure, 1 point; T, treatment for rhythm control, 1 point; T, history of stroke or transient ischemic attack, 1 point; R, renal insufficiency, 1 point). The modified SA2Me-TTR score demonstrated an excellent relationship with the grading of AC. The modified SA2Me-TTR score ≤ 1 identified patients with good AC (hazard ratio 2.46, 95% CI 1.75–3.47). Conclusions The modified SA2Me-TTR score was useful for guiding oral anticoagulants selection in Asian patients with AF.

Previous studies have shown that tricuspid regurgitation (TR) can be developed in patients with atrial fibrillation (AF) due to annular dilatation. This study aimed to investigate the incidence and predictors of the progression of TR in patients with persistent AF. A total of 397 patients (66.9±11.4 years, 247 men; 62.2%) with persistent AF were enrolled between 2006 and 2016 in a tertiary hospital, and 287 eligible patients with follow-up echocardiography were analyzed. They were divided into two groups according to TR progression (progression group [n=68, 70.1±10.7 years, 48.5% men] vs. non-progression group [n=219, 66.0±11.3 years, 64.8% men]). Among 287 patients in the analysis, 68 had worsening TR severity (23.7%). Patients in the TR progression group were older and more likely to be female. Patients with left ventricular ejection fraction ＜50% were less frequent in the progression group than those in the non-progression group (7.4% vs. 19.6%, p=0.018). Patients with mitral valve disease were more frequent in the progression group. Multivariate analysis with COX regression demonstrated independent predictors of TR progression, including left atrial (LA) diameter ＞54 mm (HR 4.85, 95%CI 2.23-10.57, p＜0.001), E/e’ (HR 1.05, 95%CI 1.01-1.10, p=0.027), and no use of antiarrhythmic agents (HR 2.20, 95%CI 1.03-4.72, p=0.041). In patients with persistent AF, worsening TR was not uncommon. The independent predictors of TR progression turned out to be greater LA diameter, higher E/e’, and no use of antiarrhythmic agents.

Purpose: Deceased donor liver transplantation (DDLT) recipients in Korea are generally sicker due to an increasing organ shortage. In the present study, the risk factors for early 30-day liver graft failure after DDLT were identified. Methods: From August 2017 to February 2021, 265 adult DDLTs were performed. The characteristics of patients with and without 30-day graft failure were compared. Results: Liver graft failure occurred in 11 patients (17.7%) after DDLT. Baseline and perioperative characteristics of donors and recipients were not statistically significantly different between the 2 groups. The cumulative graft and overall survival rates at 6 months were 83.9% and 88.7%, respectively. Multivariate analysis showed ventilator support in the pretransplant period was a predisposing factor for 30-day graft failure after DDLT. Conclusion Present study indicates that cautious decision is required when allocating DDLT in critically ill patients on mechanical ventilatory support.

Background: Reference materials are essential for the quality assurance of molecular detection methods. We developed and characterized synthetic norovirus GI and GII RNA reference materials. Methods: Norovirus GI and GII RNA sequences including the ORF1–ORF2 junction region were designed based on 1,495 reported norovirus sequences and synthesized via plasmid preparation and in vitro transcription. The synthetic norovirus GI and GII RNAs were evaluated using six commercial norovirus detection kits used in Korea and subjected to homogeneity and stability analyses. A multicenter study involving five laboratories and using four commercial real-time PCR norovirus detection assays was conducted for synthetic norovirus RNA characterization and uncertainty measurements. Results: The synthetic norovirus GI and GII RNAs were positively detected using the six commercial norovirus detection kits and were homogeneous and stable for one year when stored at –20°C or –70°C. All data from the five laboratories were within a range of 1.0 log copies/μL difference for each RNA, and the overall mean concentrations for norovirus GI and GII RNAs were 7.90 log copies/μL and 6.96 log copies/μL, respectively. Conclusions The synthetic norovirus GI and GII RNAs are adequate for quality control based on commercial molecular detection reagents for noroviruses with high sequence variability. The synthetic RNAs can be used as reference materials in norovirus molecular detection methods.

Background and objectives: This study aimed to identify the characteristics and clinical outcomes of cancer patients who developed constrictive physiology (CP) after percutaneous pericardiocentesis. Methods: One-hundred thirty-three cancer patients who underwent pericardiocentesis were divided into 2 groups according to follow-up echocardiography (CP vs. non-CP). The clinical history, imaging findings, and laboratory results, and overall survival were compared. Results: CP developed in 49 (36.8%) patients after pericardiocentesis. The CP group had a more frequent history of radiation therapy. Pericardial enhancement and malignant masses abutting the pericardium were more frequently observed in the CP group. Fever and ST segment elevation were more frequent in the CP group, with higher C-reactive protein levels (6.6±4.3mg/dL vs. 3.3±2.5mg/dL, p<0.001). Pericardial fluid leukocytes counts were significantly higher, and positive cytology was more frequent in the CP group. In baseline echocardiography before pericardiocentesis, medial e′ velocity was significantly higher in the CP group (8.6±2.1cm/s vs. 6.5±2.3cm/s, p<0.001), and respirophasic ventricular septal shift, prominent expiratory hepatic venous flow reversal, pericardial adhesion, and loculated pericardial fluid were also more frequent. The risk of all-cause death was significantly high in the CP group (hazard ratio, 1.53; 95% confidence interval,1.10–2.13; p=0.005). Conclusions CP frequently develops after pericardiocentesis, and it is associated with poor survival in cancer patients. Several clinical signs, imaging, and laboratory findings suggestive of pericardial inflammation and/or direct malignant pericardial invasion are frequently observed and could be used as predictors of CP development.

Background: To assess the clinical efficacy of intravenous immunoglobulin G (IVIG) administration combined with low-dose aspirin in women with unexplained recurrent pregnancy loss (RPL). Methods: We retrospectively analyzed the medical records of patients who had been diagnosed with unexplained RPL and treated with IVIG and low-dose aspirin between January 2000 and March 2020 at Asan Medical Center. We analyzed pregnancy outcomes and their association with the percentage of natural killer (NK) cells. Results: The study analyzed a total of 93 patients and 113 natural and assisted reproductive technology pregnancy cycles. The live birth rate per cycle was 73.5% (83/113), and the term delivery rate was 86.7% (72/83). The live birth rate was high regardless of the type of RPL, method of pregnancy, timing of IVIG treatment, and presence or absence of autoantibodies.In addition, the live birth rate was significantly higher in patients who received IVIG more than once, compared with patients who received IVIG only once (77.8% vs. 42.9%, P = 0.006). There was no significant association between the NK cell counts and live birth rate (65.5% in the group with NK cell < 12%, and 69.7% in that with NK cell ≥ 12%, P = 0.725). Among all patients, 87.6% had no complications, and there were no congenital malformation among newborn babies. Conclusion IVIG combined with low-dose aspirin treatment showed favorable pregnancy outcomes regardless of the patient’s NK cell counts (%).

Background: The risk of secondhand smoke (SHS) is gradually becoming apparent, and as smoking cessation zones are expanding, the exposure to SHS in workplaces, homes, and public places is decreasing. The objective of this study was to evaluate the actual exposure to SHS in nonsmokers. Methods: This study used data from 2008 to 2011 and 2014 to 2018 from the Korean National Health and Nutrition Examination Survey (KNHANES). The urine cotinine concentration values were compared by the geometric mean according to sex, age group, and rurality for non-smokers aged 19 years or older who were tested for urine cotinine. Results: The overall trend of urine cotinine concentration in Korean adult non-smokers have shown a decline since 2011. It gradually decreased from 2.82 ng/mL in 2010 to 0.50 ng/mL in 2016 but slightly increased to 0.79 ng/mL in 2018. Both male and female showed this trend. The decline tended to be lower in those aged 60 years and older, with higher urine cotinine concentrations in the recent 3 years in the rural than in urban residents. Conclusion The urinary cotinine concentration levels in Korean non-smokers increased from 2008 to 2010, then decreased till 2016, but gradually increased thereafter. This is possibly due to limiting the exposure to SHS through expanding the smoking area. Furthermore, a policy to lower the smoking rate with strict implementation and monitoring of the existing policy will be needed.

Background: Despite the increasing number of syphilis cases, there has been a considerable lack of recent data comparing the efficacy and duration of benzathine penicillin G, ceftriaxone, and tetracycline in Korean patients. Objective: To compare the efficacy and duration of benzathine penicillin, ceftriaxone, and tetracycline in Korean patients with syphilis. Methods: We retrospectively reviewed 145 cases of syphilis from 2004 to 2019 and statistically analyzed the treatment efficacy and duration. Results: Patients in the benzathine penicillin, ceftriaxone, and tetracycline treatment groups showed no significant statistical difference in terms of treatment rate (chi-square test, p=0.962). Similarly, treatment duration among groups was not statistically significant (one-way analysis of variance, p=0.792). Co-infection with human immunodeficiency virus resulted in reduced treatment rate (p=0.016) and increased treatment duration (p=0.007). Conclusion This retrospective study showed no significant difference between penicillin, ceftriaxone, and tetracycline in terms of treatment rate and duration. However, a difference in treatment rate and duration was evident between the non-infection and HIV co-infection groups.ng