Repositioning of ezetimibe for the treatment of idiopathic pulmonary fibrosis.

BACKGROUND: We previously identified ezetimibe, an inhibitor of Niemann-Pick C1-like intracellular cholesterol transporter 1 and European Medicines Agency-approved lipid-lowering agent, as a potent autophagy activator. However, its efficacy against pulmonary fibrosis has not yet been evaluated. This study aimed to determine whether ezetimibe has therapeutic potential against idiopathic pulmonary fibrosis. METHODS: Primary lung fibroblasts isolated from both humans and mice were employed for mechanistic in vitro experiments. mRNA sequencing of human lung fibroblasts and gene set enrichment analysis were performed to explore the therapeutic mechanism of ezetimibe. A bleomycin-induced pulmonary fibrosis mouse model was used to examine in vivo efficacy of the drug. Tandem fluorescent-tagged microtubule-associated protein 1 light chain 3 transgenic mice were used to measure autophagic flux. Finally, the medical records of patients with idiopathic pulmonary fibrosis from three different hospitals were reviewed retrospectively, and analyses on survival and lung function were conducted to determine the benefits of ezetimibe. RESULTS: Ezetimibe inhibited myofibroblast differentiation by restoring the mechanistic target of rapamycin complex 1-autophagy axis with fine control of intracellular cholesterol distribution. Serum response factor, a potential autophagic substrate, was identified as a primary downstream effector in this process. Similarly, ezetimibe ameliorated bleomycin-induced pulmonary fibrosis in mice by inhibiting mechanistic target of rapamycin complex 1 activity and increasing autophagic flux, as observed in mouse lung samples. Patients with idiopathic pulmonary fibrosis who regularly used ezetimibe showed decreased rates of all-cause mortality and lung function decline. CONCLUSION: Our study presents ezetimibe as a potential novel therapeutic for idiopathic pulmonary fibrosis.

A GLP-1/GLP-2 receptor dual agonist to treat NASH: Targeting the gut-liver axis and microbiome.

BACKGROUND AND AIMS: Currently there is no Food and Drug Administration-approved drug to treat NAFLD and NASH, the rates of which are increasing worldwide. Although NAFLD/NASH are highly complex and heterogeneous conditions, most pharmacotherapy pipelines focus on a single mechanistic target. Considering the importance of the gut-liver axis in their pathogenesis, we investigated the therapeutic effect of a long-acting dual agonist of glucagon-like peptide (GLP)-1 and GLP-2 receptors in mice with NAFLD/NASH. APPROACH AND RESULTS: C57BL/6J mice were fed a choline-deficient high-fat diet/high fructose and sucrose solution. After 16 weeks, mice were randomly allocated to receive vehicle, GLP1-Fc, GLP2-Fc, or GLP1/2-Fc fusion (GLP1/2-Fc) subcutaneously every 2 days for 4 weeks. Body weight was monitored, insulin/glucose tolerance tests were performed, feces were collected, and microbiome profiles were analyzed. Immobilized cell systems were used to evaluate direct peptide effect. Immunohistochemistry, quantitative PCR, immunoblot analysis, tunnel assay, and biochemical assays were performed to assess drug effects on inflammation, hepatic fibrosis, cell death, and intestinal structures. The mice had well-developed NASH phenotypes. GLP1/2-Fc reduced body weight, glucose levels, hepatic triglyceride levels, and cellular apoptosis. It improved liver fibrosis, insulin sensitivity, and intestinal tight junctions, and increased microvillus height, crypt depth, and goblet cells of intestine compared with a vehicle group. Similar effects of GLP1/2-Fc were found in in vitro cell systems. GLP1/2-Fc also changed microbiome profiles. We applied fecal microbiota transplantation (FMT) gain further insight into the mechanism of GLP1/2-Fc-mediated protection. We confirmed that FMT exerted an additive effect on GLP1-Fc group, including the body weight change, liver weight, hepatic fat accumulation, inflammation, and hepatic fibrosis. CONCLUSIONS: A long-acting dual agonist of GLP-1 and GLP-2 receptors is a promising therapeutic strategy to treat NAFLD/NASH.

Development of diagnostic tests for pathogen identification and detection of antimicrobial resistance on WHO global priority pathogens using modular real-time nucleic acid amplification test.

BACKGROUND: Concerns regarding antimicrobial resistance (AMR) have resulted in the World Health Organization (WHO) designating so-called global priority pathogens (GPPs). However, little discussion has focused on the diagnosis of GPPs. To enable the simultaneous identification of pathogens and AMR, we developed a modular real-time nucleic acid amplification test (MRT-NAAT). METHODS: Sequence-specific primers for each modular unit for MRT-NAAT pathogen identification and AMR sets were designed. The composition of the reaction mixture and the real-time PCR program were unified irrespective of primer type so to give MRT-NAAT modularity. Standard strains and clinical isolates were used to evaluate the performance of MRT-NAAT by real-time PCR and melting curve analysis. Probit analysis for the MRT-NAAT pathogen identification set was used to assess the limit of detection (LoD). RESULTS: The MRT-NAAT pathogen identification set was made up of 15 modular units 109-199 bp in product size and with a Tms of 75.5-87.5 °C. The LoD was < 15.548 fg/µL, and nine modular units successfully detected the target pathogens. The MRT-NAAT AMR set included 24 modular units 65-785 bp in product size with a Tms of 75.5-87.5 °C; it showed high performance for detecting GPP target genes and variants. CONCLUSIONS: MRT-NAAT enables pathogen identification and AMR gene detection and is time-effective. By unifying the reaction settings of each modular unit, the modularity where combinations of primers can be used according to need could be achieved. This would greatly help in reflecting the researcher's need and the AMR status of a certain region while successfully detecting pathogens and AMR genes.

Anti-Alpha-Toxin Antibody Responses and Clinical Outcomes of Staphylococcus aureus Bacteremia.

BACKGROUND: Alpha-toxin (AT), a major virulence factor of Staphylococcus aureus, is an important immunotherapeutic target to prevent or treat invasive S. aureus infections. Previous studies have suggested that anti-AT antibodies (Abs) may have a protective role against S. aureus bacteremia (SAB), but their function remains unclear. Therefore, we aimed to investigate the association between serum anti-AT Ab levels and clinical outcomes of SAB. METHODS: Patients from a prospective SAB cohort at a tertiary-care medical center (n = 51) were enrolled in the study from July 2016 to January 2019. Patients without symptoms or signs of infection were enrolled as controls (n = 100). Blood samples were collected before the onset of SAB and at 2- and 4-weeks post-bacteremia. Anti-AT immunoglobin G (IgG) levels were measured using an enzyme-linked immunosorbent assay. All clinical S. aureus isolates were tested for the presence of hla using polymerase chain reaction. RESULTS: Anti-AT IgG levels in patients with SAB before the onset of bacteremia did not differ significantly from those in non-infectious controls. Pre-bacteremic anti-AT IgG levels tended to be lower in patients with worse clinical outcomes (7-day mortality, persistent bacteremia, metastatic infection, septic shock), although the differences were not statistically significant. Patients who needed intensive care unit care had significantly lower anti-AT IgG levels at 2 weeks post-bacteremia (P = 0.020). CONCLUSION: The study findings suggest that lower anti-AT Ab responses before and during SAB, reflective of immune dysfunction, are associated with more severe clinical presentations of infection.

Evaluation of Vancomycin TDM Strategies: Prediction and Prevention of Kidney Injuries Based on Vancomycin TDM Results.

The current guidelines for therapeutic drug monitoring (TDM) of vancomycin suggest a target 24-hour area under the curve (AUC0-24) of 400 to 600 mg*h/L for serious methicillin-resistant Staphylococcus aureus infections. In this study, the predictabilities of acute kidney injury (AKI) of various TDM target parameters, target levels, and sampling methods were evaluated in patients who underwent TDM from January 2020 to December 2020. The AUC0-24 and trough values were calculated by both one- and two-point sampling methods, and were evaluated for the predictability of AKI. Among the AUC0-24 cutoff comparisons, the threshold value of 500 mg*h/L in the two sampling methods was statistically significant (P = 0.042) when evaluated for the predictability of AKI. Analysis by an receiver operating characteristic curve estimated an AUC0-24 cutoff value of 563.45 mg*h/L as a predictor of AKI, and was proposed as the upper limit of TDM target.

Zaluzanin C Alleviates Inflammation and Lipid Accumulation in Kupffer Cells and Hepatocytes by Regulating Mitochondrial ROS.

Zaluzanin C (ZC), a sesquiterpene lactone isolated from Laurus nobilis L., has been reported to have anti-inflammatory and antioxidant effects. However, the mechanistic role of ZC in its protective effects in Kupffer cells and hepatocytes has not been elucidated. The purpose of this study was to elucidate the efficacy and mechanism of action of ZC in Kupffer cells and hepatocytes. ZC inhibited LPS-induced mitochondrial ROS (mtROS) production and subsequent mtROS-mediated NF-κB activity in Kupffer cells (KCs). ZC reduced mRNA levels of pro-inflammatory cytokines (Il1b and Tnfa) and chemokines (Ccl2, Ccl3, Ccl4, Cxcl2 and Cxcl9). Tumor necrosis factor (TNF)-α-induced hepatocyte mtROS production was inhibited by ZC. ZC was effective in alleviating mtROS-mediated mitochondrial dysfunction. ZC enhanced mitophagy and increased mRNA levels of fatty acid oxidation genes (Pparα, Cpt1, Acadm and Hadha) and mitochondrial biosynthetic factors (Pgc1α, Tfam, Nrf1 and Nrf2) in hepatocytes. ZC has proven its anti-lipid effect by improving lipid accumulation in hepatocytes by enhancing mitochondrial function to facilitate lipid metabolism. Therefore, our study suggests that ZC may be an effective compound for hepatoprotection by suppressing inflammation and lipid accumulation through regulating mtROS.

Clinical and molecular epidemiology of invasive group B Streptococcus infections in adults in a referral center in Korea.

Invasive group B Streptococcus (GBS) infections are increasing among adults with underlying health conditions; however, clinical manifestations and serotype distribution remain unclear. This study investigated the molecular characteristics and antimicrobial resistance of invasive GBS in Korean adults. GBS isolates from patients with invasive diseases during 2006-2015 were investigated for capsular serotype, multilocus sequence type (ST), antimicrobial susceptibility, and resistance genes. Among the 74 isolates analyzed, the most common serotype was Ib (31.1%), followed by III (21.6%), V (20.3%), Ia (12.2%), and VI (12.2%). Thirteen STs were detected, with ST1, ST10, ST19, and ST23 as the most prevalent. The dominant capsular serotype exhibited by ST1 was V, and those expressed by ST10, ST19, and ST23 were Ib, III, and Ia, respectively. Erythromycin and levofloxacin resistance were observed in 33.8% and 31.1% of the isolates, respectively. ST10-Ib (n = 11/11, 100%) and ST654-Ib (n = 3/3, 100%) were dominant levofloxacin-resistant strains. Serotypes Ib, III, and V were most common among adults, which is inconsistent with recent reports in Korea where III, V, and Ia were predominant in infants. The difference in the serotype distribution between adults and children may be associated with the selective pressure imparted by antibiotics.

Interspecies differences in clinical characteristics and risk factors for third-generation cephalosporin resistance between Escherichia coli and Klebsiella pneumoniae bloodstream infection in patients with liver cirrhosis.

This retrospective study aimed to clarify the interspecies differences in the clinical characteristics and risk factors of bloodstream infection (BSI) due to third-generation cephalosporin-resistant (3GC-R) Escherichia coli (EC) and Klebsiella pneumoniae (KP) in patients with liver cirrhosis (LC). KP BSI had more comorbidities and higher treatment failure rate than EC BSI. Non-alcoholic LC was a risk factor for treatment failure in EC, whereas it was not associated with KP. Risk factors for BSI due to 3GC-R strain were nosocomial infection in EC, and ß-lactam/fluoroquinolone treatment ≤ 30 days in KP. These results could help predict outcomes of BSI and improve clinical practice.

Nationwide Survey for Current Status of Laboratory Diagnosis of Clostridioides difficile Infection in Korea.

BACKGROUND: The interest in Clostridioides difficile infection (CDI) has increased, and the choice of assays became wider since the first national survey in Korea on CDI diagnosis in 2015. We conducted a survey of the domestic CDI assays with more varied questions to understand the current situation in Korea. METHODS: In April 2018, about 50 questions on the current status of CDI assays and details on implementation and perceptions were written, and a survey questionnaire was administered to laboratory medicine specialists in 200 institutions. RESULTS: One-hundred and fifty institutions responded to the questionnaire, of which 90 (60.0%) including one commercial laboratory, performed CDI assays. The toxin AB enzyme immunoassay (toxin AB EIA), nucleic acid amplification test (NAAT), and C. difficile culture, glutamate dehydrogenase assay, alone or in combination with other assays, were used in 75 (84.3%), 52 (58.4%), 35 (36.0%), and 23 (25.8%), respectively, and 65 (73.0%) institutions performed a combination of two or more assays. The sensitivity of toxin AB EIA was more negatively perceived, and that on specificity was more positively perceived. The perception of sensitivity and specificity of NAAT was mostly positive. Perception on the algorithm test projected it as useful but in need of countermeasures. Sixty-three (73.3%) institutions responded that they performed surveillance on CDI. CONCLUSION: This study provides useful evidence on the current status of CDI laboratory diagnosis in Korea as well as on items that require improvement and is thought to aid in standardizing and improving the CDI laboratory diagnosis in Korea.

Impact of Public Health Interventions on Seasonal Influenza Activity During the COVID-19 Outbreak in Korea.

BACKGROUND: Coronavirus disease 2019 (COVID-19) was introduced in Korea early with a large outbreak in mid-February. We reviewed the public health interventions used during the COVID-19 outbreak and describe the impact on seasonal influenza activity in Korea. METHODS: National response strategies, public health interventions and daily COVID-19-confirmed cases in Korea were reviewed during the pandemic. National influenza surveillance data were compared between 7 sequential seasons. Characteristics of each season, including rate of influenza-like illness (ILI), duration of epidemic, date of termination of epidemic, distribution of influenza virus strain, and hospitalization, were analyzed. RESULTS: After various public health interventions including enforced public education on hand hygiene, cough etiquette, staying at home with respiratory symptoms, universal mask use in public places, refrain from nonessential social activities, and school closures the duration of the influenza epidemic in 2019/2020 decreased by 6-12 weeks and the influenza activity peak rated 49.8 ILIs/1000 visits compared to 71.9-86.2 ILIs/1000 visits in previous seasons. During the period of enforced social distancing from weeks 9-17 of 2020, influenza hospitalization cases were 11.9-26.9-fold lower compared with previous seasons. During the 2019/2020 season, influenza B accounted for only 4%, in contrast to previous seasons in which influenza B accounted for 26.6-54.9% of all cases. CONCLUSIONS: Efforts to activate a high-level national response not only led to a decrease in COVID-19 but also a substantial decrease in seasonal influenza activity. Interventions applied to control COVID-19 may serve as useful strategies for prevention and control of influenza in upcoming seasons.

Ezetimibe ameliorates lipid accumulation during adipogenesis by regulating the AMPK-mTORC1 pathway.

Adipogenesis, a critical process that converts adipocyte precursors into adipocytes, is considered a potential therapeutic target for the treatment of obesity. Ezetimibe, a drug approved by the United States Food and Drug Administration, is used for the treatment of hypercholesterolemia. Recently, it was reported to ameliorate high fat diet-induced dyslipidemia in mice and reduce lipid accumulation in hepatocytes through the activation of AMPK. However, the anti-adipogenic effects of ezetimibe and the underlying molecular mechanism have not yet been elucidated. Here, we found that ezetimibe reduced lipid accumulation via activating AMPK during the early phase of adipogenesis. We also observed that ezetimibe inhibited peroxisome proliferator-activated receptor γ, which is a major transcription factor of adipogenesis. Furthermore, ezetimibe-mediated AMPK activation reduced lipid accumulation by inhibiting mTORC1 signaling, leading to the downregulation of lipogenesis-related genes. Mitotic clonal expansion, required for adipogenesis, accelerates cell cycle progression and cell proliferation. We additionally observed that ezetimibe prevented the progression of mitotic clonal expansion by arresting the cell cycle at the G0/G1 phase, which was followed by the inhibition of cell proliferation. Collectively, ezetimibe-mediated inhibition of adipogenesis is dependent on the AMPK-mTORC1 pathway. Thus, we suggest that ezetimibe might be a promising drug for the treatment of obesity.

Molecular cloning and characterization of chemokine C-C motif ligand 34 (CCL34) genes from olive flounder (Paralichthys olivaceus).

Chemokines are a superfamily of chemotactic cytokines that regulate the migration and immune responses of leukocytes. Depending on the arrangement of the first two cysteine residues, chemokines are divided into four groups: CXC (α), CC (ß), C (γ), and CX3C (δ). Chemokine C-C motif ligand 34 (CCL34) is a member of the CC chemokine family and is known as a fish-specific CC chemokine. In this experiment, we analyzed the molecular cloning and characterization of the PoCCL34 gene in olive flounder (Paralichthys olivaceus), including CCL34a.3 (PoCCL34a.3) and CCL34b.3 (PoCCL34b.3). The amino acid sequence of PoCCL34 has four highly conserved cysteine residues and it has a C-C motif. Phylogenetic analysis revealed that PoCCL34 was phylogenetically clustered in the fish CCL34 subcluster. Recombinant PoCCL34 induced chemotaxis of head kidney leukocytes in a dose-dependent manner. Head kidney leukocytes stimulated with PoCCL34 also exhibited significant respiratory burst activity and increased expression of pro-inflammatory cytokines (IL-1ß, IL-6, and CXCL8), but the overall expression of interferon-related genes (IFN-α/ß, IFN-γ, Mx, and ISG15) did not increase. Olive flounder injected with recombinant PoCCL34 demonstrated increased expression of pro-inflammatory cytokines (IL-1ß and IL-6) in the head kidney. However, there was no increase in the expression of interferon-related genes (IFN-α/ß, IFN-γ, Mx, and ISG15). Additionally, recombinant PoCCL34 induced high lysozyme activity in the serum of the flounder. These results indicate that although PoCCL34 is not involved in the antiviral response, it may play a significant role in the overall immune response of the flounder, particularly in mediating the inflammatory response.

Removal of chemical hazardous compounds using CATACOAT, a nano-platinum thermal catalyst system.

The performance of CATACOAT, a nano-platinum thermal catalyst system, was evaluated for the removal of chemical hazardous compounds from air. Xylene, benzene, styrene, and toluene were selected as standard volatile organic compounds (VOCs) in this study. In addition, formaldehyde was tested as a chemical hazardous compound. Each VOC, or formaldehyde, was evaporated in a 4,000 L chamber under controlled environments. At the maximum concentration point, CATACOAT was turned on and the concentrations of the chemical hazardous compounds were recorded for 5 h. The air purifier based on H-13-grade high-efficiency particulate air (HEPA) filter was tested in the same way to compare the effects of CATACOAT. Compared with the HEPA filter system, every VOC concentration was significantly decreased with the CATACOAT system only 0.025 h after turning on the air purifier (P values for xylene, benzene, styrene, and toluene are 0.00488, 0.01508, 0.00014, and 0.04690, respectively). After running the air cleaners for 5 h, every VOC and formaldehyde demonstrated significantly decreased concentrations with the CATACOAT system, compared with HEPA filter system (P values for xylene, benzene, styrene, toluene, and formaldehyde are 0.00034, 0.00009, 0.00008, 0.00001, and 0.00571, respectively). In conclusion, the CATACOAT may be a viable solution to control indoor air pollution.

Fifteen new nucleotide substitutions in variants of human papillomavirus 18 in Korea : Korean HPV18 variants and clinical manifestation.

High-risk human papillomavirus (HPV) infection is an essential factor for the development of cervical cancer. HPV18 is the second most common carcinogenic HPV type following HPV16, but the lineages of HPV18 have been less well studied than those of HPV 16. The purpose of this study was to analyze the nucleotide variants in the E6, E7, and L1 genes of HPV18, to assess the prevalence of HPV18 variants in Korea and to explore the relationship between HPV18 genetic variants and the risk for cervical cancer.A total of 170 DNA samples from HPV18-positive cervical specimens were collected from women admitted to a secondary referral hospital located in Seoul. Among them, the lineages of the 97 samples could be successfully determined by historical nomenclature.All the studied HPV 18 variants were lineage A. Sublineages A1 and A4 comprised 91.7% (89/97) and 1.0% (1/97), respectively. Sublineages other than A1 or A4 comprised 7.2% (7/97). We identified 15 new nucleotide substitutions among 44 nucleotide substitutions: C158T, T317G, T443G, A560G, A5467G, A5560C, A5678C, A6155G, G6462A, T6650G, G6701A, T6809C, A6823G, T6941C and T6953C. Among them, 6 substitutions at positions 317, 443, 5467, 5560, 6462, and 6823 resulted in amino acid changes (E6: F71L and N113K; L1: H13R, H44P, A345T, and N465S, respectively). The pathologic results were classified as normal in 25.8% (25/97) of the women, atypical squamous cells of undermined significance (ASCUS) in 7.2% (7/97), cervical intraepithelial neoplasia (CIN) 1 in 36.1% (35/97), CIN2/3 in 19.6% (18/97), and carcinoma in 12.4% (12/97). There was no significant association between the HPV18 sublineages and the severity of pathologic lesion or the disease progression.This study is the first to analyze the distribution of HPV18 variants in Korean and to associate the results with pathologic findings. Although the HPV18 variants had no significant effect on the degree and progression of the disease, the newly discovered nonsynonymous mutation in L1 might serve as a database to determine vaccine efficacy in Korean women.

C1q/TNF-α-Related Protein 1 (CTRP1) Maintains Blood Pressure Under Dehydration Conditions.

RATIONALE: Circulating CTRP1 (C1q/TNF-α [tumor necrosis factor-α]-related protein 1) levels are increased in hypertensive patients compared with those in healthy subjects. Nonetheless, little is known about the molecular and physiological function of CTRP1 in blood pressure (BP) regulation. OBJECTIVE: To investigate the physiological/pathophysiological role of CTRP1 in BP regulation. METHODS AND RESULTS: CTRP1 production was increased to maintain normotension under dehydration conditions, and this function was impaired in inducible CTRP1 KO (knockout) mice (CTRP1 ΔCAG). The increase in CTRP1 under dehydration conditions was mediated by glucocorticoids, and the antagonist mifepristone prevented the increase in CTRP1 and attenuated BP recovery. Treatment with a synthetic glucocorticoid increased the transcription, translation, and secretion of CTRP1 from skeletal muscle cells. Functionally, CTRP1 increases BP through the stimulation of the AT1R (Ang II [angiotensin II] receptor 1)-Rho (Ras homolog gene family)/ROCK (Rho kinase)-signaling pathway to induce vasoconstriction. CTRP1 promoted AT1R plasma membrane trafficking through phosphorylation of AKT and AKT substrate of 160 kDa (AS160). In addition, the administration of an AT1R blocker, losartan, recovered the hypertensive phenotype of CTRP1 TG (transgenic) mice. CONCLUSIONS: For the first time, we provide evidence that CTRP1 contributes to the regulation of BP homeostasis by preventing dehydration-induced hypotension.

Recommendations Regarding Practical DEL Typing Strategies for Serologically D-Negative Asian Donors.

BACKGROUND: DEL, the weakest D variant, is mistyped as D-negative by routine serological assays. Transfusion of red blood cells expressing the DEL phenotype has the potential to elicit anti-D alloimmunization in D-negative recipients. The goal of this study was to recommend DEL typing strategies for serologically D-negative Asian donors. METHODS: RhCE phenotyping and the adsorption-elution test were performed on 674 serologically D-negative samples. RHD genotyping using real-time polymerase chain reaction and melting curve analysis were also undertaken to identify DEL alleles. Costs and turnaround time of RhCE phenotyping, the adsorption-elution test, and RHD genotyping were estimated. RESULTS: Sensitivity and specificity of the adsorption-elution test for serologically D-negative samples were 94.9% (93/98) and 91.5% (527/576), respectively. C+ phenotypes were detected in all 98 samples with DEL alleles. Despite comparable costs, RHD genotyping was more accurate and rapid than the adsorption-elution test. CONCLUSIONS: Two practical DEL typing strategies using RhCE phenotyping as an initial screening method were recommended for serologically D-negative Asian donors. Compared with DEL typing using RHD genotyping, serological DEL typing using adsorption-elution test is predicted to increase the incidence of anti-D alloimmunization and decrease the D-negative donor pool without having any cost-competitiveness but can be used in laboratories where molecular methods are not applicable.

Pharmacokinetic Characteristics and Limited Sampling Strategies for Therapeutic Drug Monitoring of Colistin in Patients With Multidrug-Resistant Gram-Negative Bacterial Infections.

BACKGROUND: Colistin is increasingly used as the last therapeutic option for the treatment of multidrug-resistant, Gram-negative bacterial infections. To ensure safe and efficacious use of colistin, therapeutic drug monitoring (TDM) is needed due to its narrow therapeutic window. This study aimed to evaluate the pharmacokinetic (PK) characteristics of colistin and to guide TDM in colistin-treated patients in Korea. METHODS: In a prospective study, we analyzed PK characteristics in 15 patients who intravenously received colistin methanesulfonate twice per day. Colistin methanesulfonate doses were adjusted based on renal function of the subjects. The appropriate blood sampling points for TDM were evaluated by analyzing the correlations between the PK parameters and the plasma concentrations at each time point. RESULTS: The mean values for the minimum, maximum, and average concentrations (Cmin, Cmax, and Caverage) of colistin at steady state were 2.29, 5.5, and 3.38 mg/L, respectively. The dose-normalized Cmin, Cmax, Caverage, and area under the plasma concentration-time curve from 0 to the last measurable concentration (AUClast) showed negative correlations with the creatinine clearance. The combination of the 0- and 2-hour post-dose plasma concentrations was evaluated as the appropriate sampling point for TDM. Two patients reported nephrotoxic adverse events during colistin administration. CONCLUSIONS: Our study clarifies the PK characteristics of successful colistin treatment using TDM. Further evaluations in a larger patient population are needed to confirm the clinical usefulness of colistin TDM.

Cluster of Lymphadenitis due to Nontuberculous Mycobacterium in Children and Adolescents 8-15 Years of Age.

BACKGROUND: Nontuberculous mycobacteria (NTM) lymphadenitis is an under-recognized entity, and data of the true burden in children are limited. Without a high index of suspicion, diagnosis may be delayed and microbiological detection is challenging. Here, we report a cluster of NTM lymphadenitis experienced in Korean children. METHODS: Subjects under 19 years of age diagnosed with NTM lymphadenitis during November 2016-April 2017 and April 2018 were included. Electronic medical records were reviewed for clinical, laboratory and pathological findings. Information regarding underlying health conditions and environmental exposure factors was obtained through interview and questionnaires. RESULTS: A total of ten subjects were diagnosed during 18 months. All subjects were 8-15 years of age, previously healthy, male and had unilateral, nontender, cervicofacial lymphadenitis for more than 3 weeks with no significant systemic symptoms and no response to empirical antibiotics. Lymph nodes involved were submandibular (n = 8), preauricular (n = 6) and submental (n = 1). Five patients had two infected nodes and violaceous discoloration was seen in seven subjects. Biopsy specimens revealed chronic granulomatous inflammation and acid-fast bacteria culture identified Mycobacterium haemophilum in two cases and NTM polymerase chain reaction was positive in two cases. Survey revealed various common exposure sources. CONCLUSION: NTM lymphadenitis is rare but increasing in detection and it may occur in children and adolescents. Diagnosis requires high index of suspicion and communication between clinicians and the laboratory is essential for identification of NTM.

Spatiotemporal Expression of Anticoagulation Factor Antistasin in Freshwater Leeches.

Antistasin, which was originally discovered in the salivary glands of the Mexican leech Haementeria officinalis, was newly isolated from Helobdella austinensis. To confirm the temporal expression of antistasin during embryogenesis, we carried out semi-quantitative RT-PCR. Hau-antistasin1 was uniquely expressed at stage 4 of the cleavage and was strongly expressed in the late stages of organogenesis, as were other antistasin members. In order to confirm the spatial expression of antistasin, we performed fluorescence in situ hybridization in the late stages of organogenesis. The expression of each antistasin in the proboscis showed a similar pattern and varied in expression in the body. In addition, the spatial expression of antistasin orthologs in different leeches showed the possibility of different function across leech species. Hau-antistasin1 was expressed in the same region as hedgehog, which is a known mediator of signal transduction pathway. Hau-antistasin1 is probably a downstream target of Hedgehog signaling, involved in segment polarity signal pathway.

Impact of Vancomycin MIC on Treatment Outcomes in Invasive Staphylococcus aureus Infections.

There are conflicting data on the association of vancomycin MIC (VAN-MIC) with treatment outcomes in Staphylococcus aureus infections. We investigated the relationship between high VAN-MIC and 30-day mortality and identified the risk factors for mortality in a large cohort of patients with invasive S. aureus (ISA) infections, defined as the isolation of S. aureus from a normally sterile site. Over a 2-year period, 1,027 adult patients with ISA infections were enrolled in 10 hospitals, including 673 (66%) patients with methicillin-resistant S. aureus (MRSA) infections. There were 200 (19.5%) isolates with high VAN-MIC (≥1.5 mg/liter) by Etest and 87 (8.5%) by broth microdilution (BMD). The all-cause 30-day mortality rate was 27.4%. High VAN-MIC by either method was not associated with all-cause 30-day mortality, and this finding was consistent across MIC methodologies and methicillin susceptibilities. We conclude that high VAN-MIC is not associated with increased risk of all-cause 30-day mortality in ISA infections. Our data support the view that VAN-MIC alone is not sufficient evidence to change current clinical practice.