Impact of Drug-Coated Balloon-Based Revascularization in Patients with Chronic Total Occlusions.

Background: Percutaneous coronary intervention (PCI) with a drug-eluting stent (DES) for chronic total coronary occlusions (CTOs) improves clinical symptoms and quality of life. However, data on drug-coated balloon (DCB)-based PCI in CTO lesions are limited. Methods: A total of 200 patients were successfully treated for CTO lesions, either with DCB alone or in combination with DES (DCB-based PCI). They were compared with 661 patients who underwent second-generation DES implantation for CTO from the PTRG-DES registry (DES-only PCI). The endpoint was major adverse cardiovascular events (MACEs), which included a composite of cardiac death, myocardial infarction, stent or target lesion thrombosis, target vessel revascularization, and major bleeding at 2 years. Results: In the DCB-based PCI group, 49.0% of patients were treated with DCB only and 51.0% underwent the hybrid approach combining DCB with DES. Bailout stenting was performed in seven patients (3.5%). The DCB-based PCI group exhibited fewer stents (1.0; IQR: 0.0-1.0 and 2.0; IQR: 1.0-3.0, p < 0.001), shorter stent lengths (6.5 mm; IQR: 0.0-38.0 mm and 42.0 mm; IQR: 28.0-67.0 mm, p < 0.001), and lower usage of small stents with a diameter of 2.5 mm or less (9.8% and 36.5%, p < 0.001). Moreover, the DCB-based PCI group had a lower rate of MACEs than the DES-only PCI group (3.1% and 13.2%, p = 0.001) at 2-year follow-up. Conclusions: The DCB-based PCI approach significantly reduced the stent burden, particularly in the usage of small stent diameters, and resulted in a lower risk of MACEs compared to DES-only PCI in CTO lesions.

Impact of Scoring Balloon Angioplasty on Lesion Preparation for DCB Treatment of Coronary Lesions.

OBJECTIVE: The aim of this study was to evaluate the efficacy of scoring balloon angioplasty for drug-coated balloon (DCB) treatment in percutaneous coronary intervention. BACKGROUND: The scoring balloon angioplasty may play a pivotal role in enhancing the outcomes of DCB treatment. METHODS: A total of 259 patients (278 lesions) with coronary artery disease successfully treated with DCB were retrospectively enrolled. The mean age of the patients was 62.2 ± 11.1 years, and the majority of patients were men (68.7%). The study's endpoint was defined as achieving an optimal angiographic result, which consisted of Thrombolysis in Myocardial Infarction (TIMI) flow grade 3, residual diameter stenosis ≤ 30%, and dissection less than type C after the procedure. RESULTS: Angioplasty was performed for 61 lesions with a scoring balloon and 217 lesions with a non-scoring balloon. All lesions were TIMI flow grade 3 except two lesions in the non-scoring balloon group. The scoring balloon group had a higher prevalence of residual diameter stenosis ≤ 30% (68.9% vs. 39.6%, p < 0.001), while severe dissection, defined as type C or greater, was observed less frequently (9.8% vs. 31.8%, p = 0.001). Moreover, the scoring balloon group achieved a superior rate of optimal angiographic results (60.7% vs. 28.6%, p < 0.001). In multivariable analysis, scoring balloon (OR: 3.08 [95% confidence interval, 1.47-6.58], p = 0.003) and DCB balloon-to-artery ratios (OR: 5.46 [95% confidence interval, 1.43-21.93], p = 0.014) were independent factors in the increasing rate of optimal angiographic result. CONCLUSIONS: The application of a scoring balloon catheter for lesion preparation, aiming to make them suitable for DCB treatment, was associated with a decreased risk of severe dissection and a greater occurrence of optimal angiographic outcomes compared with non-scoring balloon angioplasty.

Age- and Sex-Specific Disparities in Outcomes After Ticagrelor Versus Clopidogrel in East Asian Patients.

It is unknown whether there are age- and gender-related differences in the safety and efficacy of potent P2Y12 inhibitors in East Asian populations with a different bleeding or ischemic propensity. Using data from the TICAKOREA (Ticagrelor Versus Clopidogrel in Asian/Korean Patients with ACS Intended for Invasive Management) trial comparing ticagrelor versus clopidogrel for 800 Korean patients with acute coronary syndrome, the safety and efficacy outcomes were compared according to age (<75 vs ≥75 years) and gender (men vs women). The primary bleeding end point was clinically significant bleeding, and the primary ischemic end point was a major adverse cardiovascular event (MACE) at 12 months. The incidences of clinically significant bleeding were significantly higher after ticagrelor than after clopidogrel in patients aged <75 years (adjusted hazard ratio [HR] 2.56, 95% confidence interval [CI] 1.40 to 4.67) but not in patients aged ≥75 years (adjusted HR 1.1, 95% CI 0.40 to 3.38). The incidences of MACEs were significantly higher after ticagrelor than after clopidogrel in patients aged ≥75 years (adjusted HR 6.14, 95% CI 1.40 to 26.90) but not in patients aged <75 years (adjusted HR 0.93, 95% CI 0.50 to 1.73). The incidences of clinically significant bleeding were significantly higher after ticagrelor than after clopidogrel in men (adjusted HR 2.69, 95% CI 1.38 to 5.24) but not in women (adjusted HR 1.49, 95% CI 0.64 to 3.46). The adjusted risks of MACEs after ticagrelor or clopidogrel were not significantly different between men and women. In conclusion, there were substantial age- and gender-related differences in bleeding and ischemic outcomes after ticagrelor or clopidogrel in Korean patients with acute coronary syndrome. Clinical Trial Registration: URL: https://www.clinicaltrials.gov Unique identifier: NCT02094963.

Impact of leaflet thrombosis on valve haemodynamic status after transcatheter aortic valve replacement.

OBJECTIVES: The effect of subclinical leaflet thrombosis, characterised by hypoattenuated leaflet thickening (HALT), on the valve haemodynamic function and durability of the bioprosthetic valve, is not yet determined. We determined the impact of HALT on valve haemodynamics after transcatheter aortic valve replacement (TAVR) and the predictors of haemodynamic structural valve deterioration (SVD). METHODS: The Anticoagulation vs Dual Antiplatelet Therapy for Prevention of Leaflet Thrombosis and Cerebral Embolization after Transcatheter Aortic Valve Replacement(ADAPT-TAVR) trial is a multicenter, randomised trial that compared edoxaban and dual antiplatelet therapy in patients who had undergone successful TAVR. The presence of HALT was evaluated by four-dimensional CT at 6 months and serial echocardiography performed at baseline, immediately post-TAVR and after 6 months. SVD was defined as at least one of the following: (1) mean transprosthetic gradient ≥20 mm Hg, (2) change in the mean gradient ≥10 mm Hg from baseline, or (3) new or increase in intraprosthetic aortic regurgitation of at least ≥1 grade, resulting in moderate or greater regurgitation. RESULTS: At 6 months, HALT was found in 30 of 211 (14.2%) patients. The presence of HALT did not significantly affect aortic valve mean gradients (with vs without HALT; 14.0±4.8 mm Hg vs 13.7±5.5 mm Hg; p=0.74) at 6 months. SVD was reported in 30 of 206 patients (14.6%) at 6-month follow-up echocardiography. Older age (OR: 1.138; 95% CI: 1.019 to 1.293; p=0.033), use of aortic valve size ≤23 mm (OR: 6.254; 95% CI: 2.230 to 20.569; p=0.001) and mean post-TAVR pressure gradient (OR: 1.233; 95% CI: 1.123 to 1.371; p<0.001) were independent predictors of haemodynamic SVD; however, the presence of HALT was not identified as a predictor of SVD. CONCLUSIONS: In patients who had undergone successful TAVR, aortic valve haemodynamic status was not influenced by the presence of HALT. Although HALT was not a predictor of haemodynamic SVD at 6 months, it warrants further longer-term follow-up to evaluate the effect on long-term valve durability. TRIAL REGISTRATION NUMBER: NCT03284827 (https://www. CLINICALTRIALS: gov).

Clinical Impact of Supraclavicular Lymph Node Involvement of Stage IIIC Non-Small Cell Lung Cancer Patients.

Background and Objective: Investigations on the clinical impact of supraclavicular lymph node (SCN) involvement in stage IIIC non-small cell lung cancer (NSCLC) remain scarce. We evaluated the oncological outcomes of definitive radiochemotherapy and the clinical significance of SCN involvement. Materials and Methods: Between November 2009 and June 2019, a total of 40 patients with N3-positivity and NSCLC were evaluated. Most patients received concomitant chemotherapy, but six patients who received radiotherapy (RT) alone were also included. Twenty-one patients (52.5%) received 3D-conformal RT (3DCRT), and the remainder received intensity-modulated RT (IMRT). Results: The median follow-up duration was 10.7 months (range: 1.7-120.6 months). Median overall survival (OS) and cause-specific survival (CSS) times were 10.8 months and 16.3 months, respectively. Among the 40 patients, 17 (42.5%) had SCN involvement. SCN involvement negatively affected progression-free survival (hazard ratio (HR): 2.08, 95% confidence interval (CI): 1.04-4.17, p = 0.039) and local control (HR: 3.05, 95% CI: 1.09-8.50, p = 0.034). However, IMRT use was correlated with higher local control (HR: 0.28, 95% CI: 0.09-0.86, p = 0.027). Grade ≥3 esophagitis and pneumonitis accounted for 7.5% and 15.0% of all cases, respectively. A higher RT dose (mean dose: 66.6 vs. 61.7 Gy) was significantly correlated with grade ≥3 pneumonitis (p = 0.001). RT modality was a significant factor (p = 0.042, five of six cases occurred in the IMRT group). Conclusions: SCN involvement could negatively affect oncologic outcomes of stage IIIC NSCLC patients. High-dose irradiation with IMRT could increase local control but may cause lung toxicities.

Clinical efficacy of external beam radiotherapy complementing incomplete transarterial chemoembolization for hepatocellular carcinoma.

PURPOSE: External beam radiotherapy (EBRT) has been commonly applied as salvage or a combination locoregional modality after transarterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). This study reports oncologic outcomes and feasibility after application of the two modalities in our center. METHODS: Forty consecutive patients who underwent EBRT due to incomplete responses of TACE were evaluated. Fourteen patients (35.0%) received stereotactic body radiotherapy (SBRT) and the remaining patients received conventionally fractionated radiotherapy (RT). A majority of patients who underwent SBRT received doses of 27 to 48 Gy in 3-4 fractions [median EQD2 (Equivalent dose in 2 Gy per fraction radiotherapy): 57.0 Gy]. Conventionally fractionated RT was performed with a median EQD2 of 47.8 Gy. RESULTS: The median follow-up duration was 14.4 months (range: 2.6-83.0 months). A majority (77.5%) of patients were regarded as having Child-Pugh grade A. The median tumor size was 3.4 cm (range: 0.8-20.1 cm). Ten patients (25.0%) had thrombosis at a main portal branch. The 1- and 2-year overall survival (OS) and progression-free survival (PFS) rates were 82.2% and 42.1% and 55.8% and 32.1%, respectively. The local control rates were 89.1% and 89.1% at 1 and 2 years, respectively. The albumin level was a significant factor affecting OS (p = .002), and the BCLC stage significantly affected PFS (p = .001). Intrahepatic, out-of-field recurrence was the main cause of disease progression (60.0%), and distant metastasis developed in 12 patients (30.0%) during follow-up. Non-classic radiation-induced liver disease was seen in five (12.5%) patients, and two (5%) patients experienced grade ≥3 hepatic toxicities. CONCLUSIONS: EBRT after incomplete TACE was feasible and yielded favorable oncologic outcomes. However, disease progression related to intrahepatic failure remained a hindrance.

Atherogenic index of plasma and the risk of advanced subclinical coronary artery disease beyond traditional risk factors: An observational cohort study.

BACKGROUND: Atherogenic lipoprotein profile of plasma is an important risk factor for atherosclerosis. The atherogenic index of plasma (AIP) has been suggested as a novel marker for atherosclerosis. HYPOTHESIS: AIP is a useful marker of advanced subclinical coronary artery disease (CAD) in subjects without overt renal dysfunction. METHODS: A total of 6928 subjects with estimated glomerular filtration rate > 60 mL/minutes/1.73 m2 evaluated by coronary computed tomography angiography (CCTA) for health check-up were included. The relation of AIP to advanced CAD (heavy coronary calcification, defined as coronary artery calcium score [CACS] >100 or obstructive coronary plaque [OCP], defined as plaque with >50% stenosis) was evaluated. RESULTS: All participants were stratified into four groups based on AIP quartiles. The prevalence of CACS >100 (group I [lowest] 4.7% vs group II 7.0% vs group III 8.8% vs group IV 10.0%) and OCP (group I 3.7% vs group II 6.4% vs group III 8.8% vs group IV 10.9%) (all P < .001) increased with elevating AIP quartiles. Higher AIP (per 0.1 unit increase) was associated with an increased risk of CACS >100 (odds ratio [OR] 1.057, 95% confidence interval (CI) 1.010 to 1.106, P = .017; relative risk (RR) 1.048, 95% CI 1.009-1.089, and P = .015) and OCP (OR 1.079, 95% CI 1.033-1.127, P = .001; RR 1.069, 95% CI 1.031-1.108, P < .001) after adjusting for age > 60 years, male sex, hypertension, diabetes mellitus, dyslipidaemia, obesity, and proteinuria. CONCLUSION: AIP is independently associated with advanced subclinical CAD beyond traditional risk factors.

Validation of the Conversion between the Mini-Mental State Examination and Montreal Cognitive assessment in Korean Patients with Parkinson's Disease.

OBJECTIVE: Two conversion tables between the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) have recently been established for Parkinson's disease (PD). This study aimed to validate them in Korean patients with PD and to evaluate whether they could be influenced by educational level. METHODS: A total of 391 patients with PD who undertook both the Korean MMSE and the Korean MoCA during the same session were retrospectively assessed. The mean, median, and root mean squared error (RMSE) of the difference between the true and converted MMSE scores and the intraclass correlation coefficient (ICC) were calculated according to educational level (6 or fewer years, 7-12 years, or 13 or more years). RESULTS: Both conversions had a median value of 0, with a small mean and RMSE of differences, and a high correlation between the true and converted MMSE scores. In the classification according to educational level, all groups had roughly similar values of the median, mean, RMSE, and ICC both within and between the conversions. CONCLUSION: Our findings suggest that both MMSE-MoCA conversion tables are useful instruments for transforming MoCA scores into converted MMSE scores in Korean patients with PD, regardless of educational level. These will greatly enhance the utility of the existing cognitive data from the Korean PD population in clinical and research settings.

Dry facts are not always inviting: a content analysis of Korean videos regarding Parkinson's disease on YouTube.

This study aimed to evaluate the accuracy of Korean videos regarding Parkinson's disease (PD) on YouTube and viewers' responses to them. YouTube search was performed using the search term "Parkinson disease" in Korean language on March 28, 2017. Two independent neurologists categorized the videos into "reliable", "misleading" or "patient experiences". The number of views, days since upload, video length, number of "likes" and "dislikes", and upload source were collected for each video. A total of 138 videos were included in this study. Of these, 91 videos (65.9%) were reliable; 31 (22.5%) were misleading, and 16 (11.6%) were of patient experiences. The videos with patient experiences had the highest number of mean views with 9710.4±3686.9, followed by misleading videos with 5075.0±1198.6, and reliable videos with 2146.8±353.4 (ANOVA, p<0.001). The number of mean views per day was 4.0±0.6 for the reliable videos, which was significantly lower than the misleading videos (9.7±3.4, p=0.020) and the videos of patient experiences (11.3±4.6, p=0.023). The reliable videos were mostly uploaded by university hospitals (46.2%) and misleading videos by health-related commercial entities (74.2%). The misleading videos as well as the videos of patient experiences advocated "diet" asa treatment of PD. The current study found that only two-thirds of the Korean videos regarding PD on YouTube provide reliable information. More importantly, the videos with reliable contents were less popular than videos with misleading contents. Further efforts are warranted to effectively increase the dissemination of accurate and scientifically proven PD information to YouTube users.

Moutan Cortex Protects Hepatocytes against Oxidative Injury through AMP-Activated Protein Kinase Pathway.

Moutan Cortex, the root bark of Paeonia suffruticosa ANDREWS in Ranunculaceae, has widely demonstrated analgesic, anti-spasmodic, and anti-inflammatory effects in various cancer and immune cell lines. Oxidative stress is associated with development of several diseases, including liver disease. We prepared the water extract of Moutan Cortex (MCE) to investigate the cytoprotective activities and its mechanism. MCE protected hepatocytes from arachidonic acid (AA)+iron induced oxidative stress, as indicated by reactive oxygen species (ROS) production and cell viability analysis. MCE also suppressed mitochondrial dysfunction in AA+iron-treated human hepatocyte-derived hepatocellular carcinoma cell line, HepG2 cells. In addition, MCE treatment induces AMP-activated protein kinase (AMPK) and liver kinase B1 phosphorylation, which play a role in inhibition of oxidative stress induced cell death. Moreover, one of the MCE compounds, chlorogenic acid, exerted protective effects against oxidative stress and apoptosis. Taken together, MCE protected hepatocytes against AA+iron-induced oxidative stress through AMPK activation, and may be a candidate for the treatment of liver disease.

Liqustri lucidi Fructus inhibits hepatic injury and functions as an antioxidant by activation of AMP-activated protein kinase in vivo and in vitro.

Medicinal herbs are used to treat or prevent various diseases, and function to regulate protective mechanisms as nutraceuticals. Fructus Ligustri lucidi is the fruit of Ligustrum lucidum and has been used for its tonic effects on the liver. This study was designed to examine the effects of Fructus Ligustri lucidi water extract (FLL) against severe oxidative stress and mitochondrial impairment in vivo and in vitro and to elucidate its cellular mechanisms of action. Treatment of HepG2 cells with arachidonic acid (AA) + iron successfully induced oxidative stress and apoptosis, as indicated by depletion of glutathione, formation of ROS, decreses in mitochondrial membrane potential (Δψm), and altered expression of apoptosis-related proteins, such as procaspase-3 and Bcl-xL. FLL treatment significantly blocked these pathological changes and the mitochondrial dysfunction caused by AA + iron, which were similar with the effect of aminoimidazole-carboxamide-ß-d-ribofuranoside (AICAR). Moreover, FLL induced the activation of AMP-activated protein kinase (AMPK), which was mediated by its upstream kinase LKB1. Inhibition or activation of AMPK revealed the role of AMPK in cellular protection conferred by FLL in LKB1-deficient cells. In mice, oral administration of 100 mg/kg FLL activated AMPK in the liver, and protected against oxidative stress and liver injury induced by CCl4 injection. Among the components of FLL, chlorogenic acid was found to be responsible for the protection of hepatocytes against AA + iron-induced cellular damage. Overall, our results confirmed that FLL has the ability to protect hepatocytes against oxidative injury through regulation of the AMPK signaling pathway.

Modified Surgical Intervention for Extensive Mitral Valve Endocarditis and Posterior Mitral Annular Calcification.

The concomitant presence of posterior mitral annular calcification and infectious mitral valve lesions poses a technical challenge with considerable perioperative risk when using previously proposed techniques for mitral valve surgery. Herein, we report a case of the use of a modified surgical technique to successfully treat a patient with mitral infective endocarditis complicated by a subendocardial abscess and extensive posterior mitral annular calcification.

Optimization of Expression Conditions Enhances Production of Sepiapterin, a Precursor for Tetrahydrobiopterin Biosynthesis, in Recombinant Escherichia coli.

Sepiapterin is a precursor for the synthesis of tetrahydrobiopterin (BH4), which is a wellknown cofactor for aromatic amino acid hydroxylation and nitric oxide synthesis in higher mammals. In this study, a recombinant Escherichia coli BL21(DE3) strain harboring cyanobacterial guanosine 5'-triphosphate cyclohydrolase 1 (GCH1) and human 6- pyruvoyltetrahydropterin synthase (PTPS) genes was constructed to produce sepiapterin. The optimum conditions for T7 promoter-driven expression of GCH1 and PTPS were 30°C and 0.1 mM isopropyl-ß-D-thioglucopyranoside (IPTG). The maximum sepiapterin concentration of 88.1 ± 2.4 mg/l was obtained in a batch cultivation of the recombinant E. coli, corresponding to an 18-fold increase in sepiapterin production compared with the control condition (37°C and 1 mM IPTG).

Atypical Anterior Spinal Artery Infarction due to Left Vertebral Artery Occlusion Presenting with Bilateral Hand Weakness.

BACKGROUND: Infarct of the anterior spinal artery is the most common subtype of spinal cord infarct, and is characterized by bilateral motor deficits with spinothalamic sensory deficits. We experienced a case with atypical anterior-spinal-artery infarct that presented with bilateral hand weakness but without sensory deficits. CASE REPORT: A 29-year-old man presented with sudden neck pain and bilateral weakness of the hands. Magnetic resonance imaging (MRI) of the brain did not reveal any lesion. His motor symptoms improved rapidly except for mild weakness in his left wrist and fingers. Magnetic resonance angiography showed proximal occlusion of the left vertebral artery; a spine MRI revealed left cervical cord infarction. CONCLUSIONS: Bilateral or unilateral hand weakness can be the sole symptom of a cervical cord infarct.

Early detection of mycobacteria using a novel hydrogel culture method.

BACKGROUND: Early laboratory detection of Mycobacterium tuberculosis is crucial for controlling tuberculosis. We developed a hydrogel mycobacterial culture method that retains the advantages of both solid and liquid methods in terms of speed, cost, and efficiency. METHODS: Mycobacterium bovis bacillus Calmette-Guérin (BCG) suspensions and 200 acid-fast bacilli (AFB)-positive clinical specimens were inoculated in Middlebrook 7H9 liquid media (Becton-Dickinson and Company, USA) and mixed with 75 µL of 9-fluorenylmethoxycarbonyl (Fmoc)-Phe-Phe-OH hydrogel stock solution in an Eppendorf tube just before culture incubation. The mixtures were cultured at 37℃ for as long as 14 days to monitor culture status. RESULTS: The number of M. bovis BCG increased with time. For 200 AFB smear-positive specimens, 155 of 158 conventional culture-positive specimens and 4 culture-negative or contaminated specimens yielded positive cultures within 14 days. For 128 specimens positive with the liquid culture method, the time to positive culture using the hydrogel method (mean, 12.6 days; range, 7 to 14 days) was significantly shorter than that for conventional liquid culture (mean, 16.2 days; range, 6 to 31 days; P<0.0001). CONCLUSIONS: The hydrogel scaffold culture system is useful for timely, economical, and efficient detection of mycobacteria in clinical specimens.

Neurologic outcomes of preoperative acute silent cerebral infarction in patients with cardiac surgery.

BACKGROUND: Acute cerebral infarction is a major risk factor for postoperative neurologic complications in cardiac surgery. However, the outcomes associated with acute silent cerebral infarction (ASCI) have not been not well established. Few studies have reported the postoperative outcomes of these patients in light of preoperative Diffusion-weighted magnetic resonance imaging (DWI). We studied the postoperative neurologic outcomes of patients with preoperative ASCI detected by DWI. METHODS: We retrospectively studied 32 patients with preoperative ASCI detected by DWI. None of the patients had preoperative neurologic symptoms. The mean age at operation was 68.8±9.5 years. Five patients had previous histories of stroke. Four patients had been diagnosed with infective endocarditis. Single cerebral infarct lesions were detected in 16 patients, double lesions in 13, and multiple lesions (>5) in three. The median size of the infarct lesions was 4 mm (range, 2 to 25 mm). The operations of three of the 32 patients were delayed pending follow-up DWI studies. RESULTS: There were two in-hospital mortalities. Neurologic complications also occurred in two patients. One patient developed extensive cerebral infarction unrelated to preoperative infarct lesions. One patient showed sustained delirium over one week but recovered completely without any neurologic deficits. In two patients, postoperative DWI confirmed that no significant changes had occurred in the lesions. CONCLUSION: Patients with preoperative ASCI showed excellent postoperative neurologic outcomes. Preoperative ASCI was not a risk factor for postoperative neurologic deterioration.

Comparison of modified multiple-locus variable-number tandem-repeat fingerprinting with pulsed-field gel electrophoresis for typing clinical isolates of Staphylococcus aureus.

BACKGROUND: Multiple-locus variable-number tandem-repeat fingerprinting (MLVF) is based on multiplex PCR, utilizing variable number tandem repeat. Our goal was to compare the performance of MLVF in distinguishing clinical Staphylococcus aureus isolates with that of pulsed-field gel electrophoresis (PFGE), which has traditionally been the gold standard. METHODS: Sixty-three clinically significant S. aureus isolates were tested using both PFGE and MLVF. Multiplex PCR for MLVF was performed using PCR primers for clfA, clfB, sdrCDE, sspA, and spa. PFGE was performed with genomic DNA fragments generated by SmaI endonuclease digestion. Banding patterns of MLVF or PFGE were analyzed using InfoQuestFP software. RESULTS: The hands-on time of our modified method was about 3 h, on average, for each of 18 isolates. PFGE (80% cutoff) or MLVF (75% cutoff) separated all of the 63 isolates into 13 and 12 types, respectively. Three types generated by PFGE were identical to those generated by MLVF. PFGE and MLVF yielded similar Simpson's diversity indices, indicating similar discriminatory power. The overall concordance between PFGE and MLVF was low, as represented by adjusted Rand indices (0.266-0.278). PFGE predicted MLVF type better than MLVF predicted PFGE type, as reflected by Wallace coefficients (PFGE cutoff 80% vs. MLVF cutoff 75%, 0.389 vs. 0.233). Analysis of the relationship between a pair of isolates showed 91.0% concordance between the PFGE (80% cutoff) and MLVF (75% cutoff). CONCLUSIONS: Our simple, low-cost, modified MLVF protocol can effectively discriminate between S. aureus clinical isolates. MLVF can replace PFGE for the hospital infection control of S. aureus.

Comparison of an automated repetitive sequence-based PCR microbial typing system with IS6110-restriction fragment length polymorphism for epidemiologic investigation of clinical Mycobacterium tuberculosis isolates in Korea.

Tuberculosis remains a severe public health problem worldwide. Presently, genotyping is used for conducting epidemiologic and clinical studies on tuberculosis cases. We evaluated the efficacy of the repetitive sequence-based PCR (rep-PCR)-based DiversiLab™ system (bioMérieux, France) over the IS6110-restriction fragment length polymorphism analysis for detecting Mycobacterium tuberculosis. In all, 89 clinical M. tuberculosis isolates collected nationwide from Korea were used. The DiversiLab system allocated the 89 isolates to 8 groups with 1 unique isolate when a similarity level of 95% was applied. Seventy-six isolates of the Beijing family and 13 isolates of non-Beijing family strains were irregularly distributed regardless of rep-PCR groups. The DiversiLab system generated a rapid, sensitive, and standardized result. It can be used to conduct molecular epidemiologic studies to identify clinical M. tuberculosis isolates in Korea.

Application of single-nucleotide polymorphism and mycobacterial interspersed repetitive units-variable number of tandem repeats analyses to clinical Mycobacterium tuberculosis isolates from Korea.

BACKGROUND: Single-nucleotide polymorphism (SNP) analysis is a powerful strategy for large-scale molecular population studies examining phylogenetic relationships among bacterial strains. Mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) can be easily digitized to share data among laboratories. This study applied SNP and MIRU-VNTR analyses for molecular strain typing of Mycobacterium tuberculosis isolates collected throughout Korea. METHODS: We studied 102 clinical M. tuberculosis isolates, including 6 paired strains, collected from 11 university hospitals in Korea in 2008 and 2009. SNPs were detected using hairpin primer assays, and then, MIRU-VNTR analysis was performed. RESULTS: Thirty-five SNPs contained polymorphisms that helped differentiate the 96 tested isolates. The isolates were classified into 15 clusters. The Beijing family strains were distributed within closely related clusters in the SNP dendrogram. For MIRU-VNTR analysis, the 96 isolates were divided into 12 groups. The discriminatory index in 8 of these groups (MIRU-10, -23, -26, and -31; ETR-A, -B, -C, and -F) was high (Hunter-Gaston diversity index > 0.6). Unlike the SNP method, MIRU-VNTR analysis did not identify any notable localizations of Beijing or non-Beijing family isolates in specific clusters. CONCLUSIONS: SNP and MIRU-VNTR analyses are surrogate molecular strain-typing methods for M. tuberculosis in Korea where Beijing family isolates are predominant.

IS6110-restriction fragment length polymorphism and spoligotyping analysis of Mycobacterium tuberculosis clinical isolates for investigating epidemiologic distribution in Korea.

The Beijing family of Mycobacterium tuberculosis has been emerging in the world. However, there are few nationwide data of genotypic distribution in Korea. This study aimed to identify the genotypic diversity of clinical isolates of M. tuberculosis and to demonstrate the population of Beijing family in Korea. We collected 96 clinical M. tuberculosis isolates from 11 university hospitals nationwide in Korea from 2008 to 2009. We observed 24 clusters in IS6110-RFLP analysis and 19 patterns in spoligotyping. Seventy-five isolates were confirmed to be Beijing family. Two isolates of the K strain and 12 isolates of the K family strain were also found. We found that drug resistance phenotypes were more strongly associated with Beijing family than non-Beijing family (P=0.003). This study gives an overview of the distribution of genotypes of M. tuberculosis in Korea. These findings indicate that we have to pay more attention to control of M. tuberculosis strains associated with the Beijing family.