Showing papers in "Korean Journal of Laboratory Medicine in 2015"

Meta-Analysis of Genetic Association Studies

Abstract: The object of this review is to help readers to understand meta-analysis of genetic association study. Genetic association studies are a powerful approach to identify susceptibility genes for common diseases. However, the results of these studies are not consistently reproducible. In order to overcome the limitations of individual studies, larger sample sizes or meta-analysis is required. Meta-analysis is a statistical tool for combining results of different studies on the same topic, thus increasing statistical strength and precision. Meta-analysis of genetic association studies combines the results from independent studies, explores the sources of heterogeneity, and identifies subgroups associated with the factor of interest. Meta-analysis of genetic association studies is an effective tool for garnering a greater understanding of complex diseases and potentially provides new insights into gene-disease associations.

Inflammatory Cytokines and Their Prognostic Ability in Cases of Major Burn Injury

Abstract: Background: Major burn injuries induce inflammatory responses and changes in the levels of various cytokines. This study was conducted to assess early changes in the serum levels of inflammatory cytokines after burn injury, identify cytokines associated with mortality, and characterize correlations among cytokines. Methods: Blood samples of 67 burn patients were collected on days 1 and 3 after burn injury, and the concentrations of 27 cytokines were measured using the Bio-Plex Suspension Array System (Bio-Rad Laboratories, USA). Blood samples of 25 healthy subjects were used as controls. We analyzed statistical differences in the concentrations of each cytokine between the control and patient groups, between day 1 and day 3, and between survival and nonsurvival groups. Correlations among 27 cytokines were analyzed. Results: Median concentrations of granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin 1 receptor antagonist (IL1RA), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 10 (IL-10), interleukin 15 (IL-15), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein 1β (MIP-1β), and vascular endothelial growth factor (VEGF) were significantly higher in burn patients than in controls. IL-1RA, IL-6, and MCP-1 levels were significantly higher in the nonsurvival group than in the survival group on day 1 after burn injury. Correlation analysis of 27 cytokines showed different relationships with one another. Stronger correlations among interferon γ (IFN-γ), IL-2, IL-4, IL-7, IL-12p70, and IL-17 were found. Conclusions: IL-1RA, IL-6, and MCP-1 may be used as prognostic indicators of mortality in burn patients and the increase in cytokine concentrations is induced by interactions within a complex network of cytokine-related pathways.

Establishment of trimester-specific reference intervals for thyroid hormones in Korean pregnant women

Abstract: BACKGROUND Establishment of trimester- and assay-specific reference intervals for every population is recommended. The aim of this study was to establish a trimester- and assay-specific reference interval for thyroid-stimulating hormone (TSH) and free thyroxine (FT4) in Korean pregnant women. METHODS From April 2012 to December 2012, 531 pregnant women receiving prenatal care and 238 age-matched, non-pregnant women were enrolled in this study. After excluding patients with pregnancy-associated complications or thyroid-specific autoantibody, 465 pregnant and 206 non-pregnant women were included. Non-parametric analysis (2.5-97.5th percentile) was performed to determine the reference interval. Levels of TSH and FT4 were determined by electrochemiluminescence immunoassay (Elecsys thyroid tests, Roche Diagnostics, Germany). RESULTS The TSH reference intervals were 0.01-4.10, 0.01-4.26, and 0.15-4.57 mIU/L for the first, second, and third trimester, respectively. From the first trimester to the third trimester, the median TSH levels showed a significantly increasing trend (P<0.0001). The FT4 reference intervals were 0.83-1.65, 0.71-1.22, and 0.65-1.13 ng/dL for the first, second, and third trimester, respectively, showing a significantly decreasing trend (P<0.0001). CONCLUSIONS Establishing trimester-specific reference intervals in pregnant women is essential for accurate assessment of thyroid function. Our population-specific and method-specific reference intervals will be useful for screening Korean pregnant women for thyroid disease.

Influence of blood lipids on global coagulation test results.

Abstract: Background High levels of blood lipids have been associated with high levels of coagulation factors. We investigated whether blood lipids influence the results of global coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin generation assay (TGA).

The sul1 Gene in Stenotrophomonas maltophilia With High-Level Resistance to Trimethoprim/Sulfamethoxazole

Abstract: Emerging resistance to trimethoprim/sulfamethoxazole (SXT) poses a serious threat to the treatment of Stenotrophomonas maltophilia infections. We determined the prevalence and molecular characteristics of acquired SXT resistance in recent clinical S. maltophilia isolates obtained from Korea. A total of 252 clinical isolates of S. maltophilia were collected from 10 university hospitals in Korea between 2009 and 2010. Antimicrobial susceptibility was determined by using the CLSI agar dilution method. The sul1, sul2, and sul3 genes, integrons, insertion sequence common region (ISCR) elements, and dfrA genes were detected using PCR. The presence of the sul1 gene and integrons was confirmed through sequence analysis. Among the 32 SXT-resistant isolates, sul1 was detected in 23 isolates (72%), all of which demonstrated high-level resistance (≥64 mg/L) to SXT. The sul1 gene (varying in size and structure) was linked to class 1 integrons in 15 of the 23 isolates (65%) harboring this gene. None of the SXT-susceptible isolates or the SXT-resistant isolates with a minimum inhibitory concentration of 4 and 8 mg/L were positive for sul1. Moreover, the sul2, sul3, and dfrA genes or the ISCR elements were not detected. The sul1 gene may play an important role in the high-level SXT resistance observed in S. maltophilia.

Distribution of β-Lactamase Genes Among Carbapenem-Resistant Klebsiella pneumoniae Strains Isolated From Patients in Turkey

Abstract: Background The emergence of carbapenem-resistant Klebsiella pneumoniae poses a serious problem to antibiotic management. We investigated the β-lactamases in a group of carbapenem-resistant K. pneumoniae clinical isolates from Turkey.

Direct Identification of Urinary Tract Pathogens From Urine Samples Using the Vitek MS System Based on Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

Abstract: Background We evaluated the coincidence rate between Vitek MS system (bioMerieux, France) and Vitek 2 in identifying uropathogens directly from urine specimens. Methods Urine specimens submitted to our microbiology laboratory between July and September 2013 for Gram staining and bacterial culture were analyzed. Bacterial identification was performed by using the conventional method. Urine specimens showing a single morphotype by Gram staining were processed by culturing and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Of 2,370 urine specimens, 251 showed a single morphotype on Gram staining, and among them, 202 were available for MALDI-TOF MS. Results In these 202 specimens, colony growth was observed in 189 specimens, and 145 specimens had significant growth of single-colony morphotype in culture. One hundred and ten (75.9%) of them had colony counts of ≥10(5) colony-forming units (CFU)/mL and included 71 enteric gram-negative bacteria (GNB), 5 glucose-non-fermenting GNB, 9 gram-positive cocci (GPC), and 25 yeasts. Furthermore, 70 (98.6%), 3 (60.0%), 4 (44.4%), and 5 (20.0%), respectively, of these were correctly identified by Vitek MS. Thirty-one specimens (21.4%; 11 GNB, 7 GPC, 12 yeasts, and 1 gram-positive bacillus) had colony counts of 10(4)-10(5) CFU/mL. Four specimens (2.8%) yielded colony counts of 10(3)-10(4) CFU/mL. Conclusions Vitek MS showed high rate of accuracy for the identification of GNB in urine specimens (≥10(5) CFU/mL). This could become a rapid and accurate diagnostic method for urinary tract infection caused by GNB. However, for the identification of GPC and yeasts, further studies on appropriate pre-treatment are warranted.

Species-specific difference in antimicrobial susceptibility among viridans group streptococci.

Abstract: BACKGROUND Viridans group streptococci (VGS) are both commensal microbes and potential pathogens Increasing resistance to penicillin in VGS is an ongoing issue in the clinical environment We investigated the difference in susceptibility and resistance to penicillin among various VGS species METHODS In total 1,448 VGS isolated from various clinical specimens were analyzed over a two-yr period Identification and antimicrobial susceptibility test was performed by the automated VITEK 2 system (bioMerieux, France) or the MicroScan MICroSTREP system (Siemens, Germany) RESULTS Among the 1,448 isolates, 412 were isolated from blood (284%) Streptococcus mitis group was the most frequently isolated (589 isolates, 407%), followed by the S anginosus group (290 isolates, 200%), S sanguinis group (179 isolates, 124%) and S salivarius group (57 isolates, 39%) In total, 314 isolates could not be identified up to the species level The overall non-susceptibility to penicillin was observed to be 400% (resistant, 112% and intermediately resistant, 288%) with uneven distribution among groups; 402% in S sanguinis group (resistant, 50% and intermediately resistant, 352%), 603% in S mitis group (resistant, 209% and intermediately resistant, 394%), 789% in S salivarius group (resistant, 88% and intermediately resistant, 701%), and 62% in S anginosus group (resistant, 17% and intermediately resistant, 45%) CONCLUSIONS Antimicrobial resistance patterns towards penicillin show differences among various VGS; this should be considered while devising an effective antimicrobial treatment against VGS

Quantitative measurement of serum microRNA-21 expression in relation to breast cancer metastasis in Chinese females.

Abstract: BACKGROUND Breast cancer is the most common type of cancer in females. Aberrant expression of microRNA-21 (miR-21) has previously been reported in breast cancer tissue. The aim of this study was to investigate expression levels of serum miR-21 in breast cancer patients and evaluate its prognostic value in Chinese females. METHODS Real-time quantitative (RQ)-PCR was used to analyze miR-21 expression in archived serum, tumor tissue, and adjacent normal tissue from 549 participants (326 with breast cancer, 223 without breast cancer). We also analyzed associations between serum miR-21 expression and breast cancer subtypes and patient prognosis. Recurrence and survival were analyzed by using the multivariate Cox proportional hazards model. RESULTS Expression of miR-21 was significantly higher in breast cancer tissues compared with normal adjacent breast tissues (P<0.001). The 2(-ΔΔCt) values for serum miR-21 in breast cancer patients versus healthy controls were 9.12±3.43 and 2.96±0.73, respectively. Multivariate Cox proportional hazards model suggested that serum miR-21 expression was an independent poor prognostic factor for both recurrence (hazard ratio [HR]= 2.942; 95% confidence interval [CI]=1.420-8.325; P=0.008) and disease-free survival (HR=2.732; 95% CI=1.038-7.273, P=0.003) in breast cancer. CONCLUSIONS Increased serum miR-21 expression level was correlated with poor prognosis of breast cancer patients, indicating that serum miR-21 may be a novel prognostic marker for recurrence and survival of breast cancer patients before resection.

Mitochondrial DNA aberrations and pathophysiological implications in hematopoietic diseases, chronic inflammatory diseases, and cancers.

Abstract: Mitochondria are important intracellular organelles that produce energy for cellular development, differentiation, and growth. Mitochondrial DNA (mtDNA) presents a 10- to 20-fold higher susceptibility to genetic mutations owing to the lack of introns and histone proteins. The mtDNA repair system is relatively inefficient, rendering it vulnerable to reactive oxygen species (ROS) produced during ATP synthesis within the mitochondria, which can then target the mtDNA. Under conditions of chronic inflammation and excess stress, increased ROS production can overwhelm the antioxidant system, resulting in mtDNA damage. This paper reviews recent literature describing the pathophysiological implications of oxidative stress, mitochondrial dysfunction, and mitochondrial genome aberrations in aging hematopoietic stem cells, bone marrow failure syndromes, hematological malignancies, solid organ cancers, chronic inflammatory diseases, and other diseases caused by exposure to environmental hazards.

Highly Sensitive and Novel Point-of-Care System, aQcare Chlamydia TRF Kit for Detecting Chlamydia trachomatis by Using Europium (Eu) (III) Chelated Nanoparticles

Abstract: Background The bacterium Chlamydia trachomatis is one of the leading causes of sexually transmitted diseases worldwide. Since no simple and effective tool exists to diagnose C. trachomatis infections, we evaluated a novel point-of-care (POC) test, aQcare Chlamydia TRF kit, which uses europium-chelated nanoparticles and a time-resolved fluorescence reader.

Combined use of the modified Hodge test and carbapenemase inhibition test for detection of carbapenemase-producing Enterobacteriaceae and metallo-β-lactamase-producing Pseudomonas spp.

Abstract: Background: We evaluated the combined use of the modified Hodge test (MHT) and carbapenemase inhibition test (CIT) using phenylboronic acid (PBA) and EDTA to detect carbapenemase-producing Enterobacteriaceae (CPE) and metallo-β-lactamase (MBL)-producing Pseudomonas spp. Methods: A total of 49 isolates of CPE (15 Klebsiella pneumoniae carbapenemase [KPC], 5 Guiana extended-spectrum β-lactamase [GES]-5, 9 New Delhi metallo-β-lactamase [NDM]1, 5 Verona integron-encoded metallo-β-lactamase [VIM]-2, 3 imipenem-hydrolyzing β-lactamase [IMP], and 12 oxacillinase [OXA]-48-like), 25 isolates of MBL-producing Pseudomonas spp. (14 VIM-2 and 11 IMP), and 35 carbapenemase-negative controls were included. The MHT was performed for all isolates as recommended by the Clinical and Laboratory Standards Institute. Enhanced growth of the indicator strain was measured in mm with a ruler. The CIT was performed by directly dripping PBA and EDTA solutions onto carbapenem disks that were placed on Mueller-Hinton agar plates seeded with the test strain. Results: Considering the results of the MHT with the ertapenem disk in Enterobacteriaceae and Pseudomonas spp., the CIT with the meropenem disk in Enterobacteriaceae, and the imipenem disk in Pseudomonas spp., three combined disk tests, namely MHT-positive plus PBA-positive, EDTA-positive, and MHT-positive plus PBA-negative plus EDTA-negative, had excellent sensitivity and specificity for the detection of KPC- (100% sensitivity and 100% specificity), MBL- (94% sensitivity and 100% specificity), and OXA-48-like-producing isolates (100% sensitivity and 100% specificity), respectively. Conclusions: Combined use of the MHT and CIT with PBA and EDTA, for the detection of CPE and MBL-producing Pseudomonas spp., is effective in detecting and characterizing carbapenemases in routine laboratories.

Calreticulin Exon 9 Mutations in Myeloproliferative Neoplasms

Abstract: Results: CALR mutations were detected in 21.9% of ET and 16.7% of PMF patients, which accounted for 58.5% and 33.3% of ET and PMF patients without Janus kinase 2 (JAK2) or myeloproliferative leukemia virus oncogenes (MPL) mutations, respectively. A total of five types of mutation were detected, among which, L367fs*46 (53.6%) and K385fs*47 (35.7%) were found to be the most common. ET patients with CALR mutation had lower leukocyte counts and ages compared with JAK2-mutated ET patients. Conclusion: Genotyping for CALR could be a useful diagnostic tool for JAK2-or MPL-negative ET or PMF patients. CALR mutation may be a distinct disease group, with different hematological characteristics than that of JAK2-positive patients.

The First Klebsiella pneumoniae Isolate Co-Producing OXA-48 and NDM-1 in Turkey

Abstract: the test results were interpreted by using the CLSI criteria. The Modified Hodge test (MHT) was used to screen for the production of carbapenemase, and carbapenem-resistant isolates were examined by using real-time polymerase chain reaction for the expression of blaKPC, blaNDM-1, and blaOXA-48 [5, 6]. The nucleotide sequences were then analyzed by using an Applied Biosystems sequencer (ABI Prism 310 genetic analyzer; PE Applied Biosystems, Foster City, CA, USA). Multiple alignments were performed by using DNAMAN 4.1 software (Lynnon BioSoft, Quebec, Canada) for isolates producing NDM-1. Forty-nine of the 887 Enterobacteriaceae isolates (5.52%) were resistant to ≥1 of the three carbapenems (imipenem, meropenem, and ertapenem), and MHT revealed that all 49isolates were strong carbapenemase producers. No isolates harbored blaKPC, although 48 harbored blaOXA-48, and 1 K. pneumoniae isolate that was recovered from a patient’s urine sample was positive for both blaOXA-48 and blaNDM-1. This patient was a 75-yr-old woman who was living in Sanliurfa (on the southeastern border of Turkey) and was diagnosed as having chronic obstructive pulmonary disease, pneumonia, and hypotension. In 2013, she was transferred to the Pulmonary Diseases Department of a hospital in the central region of Turkey with severe shortness of breath, sluggishness, reduced consciousness, and weakness in her legs and arms. On the day after her admission, she developed severe respiratory fail

Soluble ST2 Has a Prognostic Role in Patients With Suspected Sepsis

Abstract: Background: Soluble suppression of tumorigenicity 2 (sST2) has emerged as a novel biomarker for heart failure, and serum sST2 concentrations could be increased in inflammatory diseases. We explored whether sST2 is related to cardiac dysfunction/failure and has a prognostic role in patients with suspected sepsis. Methods: In a total of 397 patients with suspected sepsis, sST2 concentrations were measured by using the Presage ST2 Assay (Critical Diagnostics, USA). sST2 concentrations were analyzed according to procalcitonin (PCT) concentrations, cardiovascular subscores of the sepsis-related organ failure assessment (SOFA) score, and clinical outcomes. Results: sST2 concentrations were increased significantly according to the five groups of PCT concentrations and cardiovascular subscores of the SOFA score (P <0.000001 and P =0.036, respectively). In-hospital mortality was significantly higher among patients with sST2 concentrations above 35 ng/mL (P =0.0213) and among patients with increased concentrations of both sST2 and PCT (P =0.0028). Conclusions: sST2 seems to be related to both cardiac dysfunction/failure and severity in sepsis. Measurement of sST2 and PCT in combination would be useful for risk stratification and prognosis prediction in patients with suspected sepsis.

Allele and Haplotype Frequencies of Human Leukocyte Antigen-A, -B, -C, -DRB1, and -DQB1 From Sequence-Based DNA Typing Data in Koreans.

Abstract: Background Data on allele frequencies (AFs) and haplotype frequencies (HFs) of HLA-C and -DQB1 are limited in Koreans. We investigated AFs and HFs of HLA-A, -B, -C, -DRB1, and -DQB1 in Koreans by high-resolution sequence-based typing (SBT).

Evaluation of VITEK Mass Spectrometry (MS), a Matrix-Assisted Laser Desorption Ionization Time-of-Flight MS System for Identification of Anaerobic Bacteria

Abstract: BACKGROUND By conventional methods, the identification of anaerobic bacteria is more time consuming and requires more expertise than the identification of aerobic bacteria. Although the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems are relatively less studied, they have been reported to be a promising method for the identification of anaerobes. We evaluated the performance of the VITEK MS in vitro diagnostic (IVD; 1.1 database; bioMerieux, France) in the identification of anaerobes. METHODS We used 274 anaerobic bacteria isolated from various clinical specimens. The results for the identification of the bacteria by VITEK MS were compared to those obtained by phenotypic methods and 16S rRNA gene sequencing. RESULTS Among the 249 isolates included in the IVD database, the VITEK MS correctly identified 209 (83.9%) isolates to the species level and an additional 18 (7.2%) at the genus level. In particular, the VITEK MS correctly identified clinically relevant and frequently isolated anaerobic bacteria to the species level. The remaining 22 isolates (8.8%) were either not identified or misidentified. The VITEK MS could not identify the 25 isolates absent from the IVD database to the species level. CONCLUSIONS The VITEK MS showed reliable identifications for clinically relevant anaerobic bacteria.

Clinical usefulness of bronchoalveolar lavage cellular analysis and lymphocyte subsets in diffuse interstitial lung diseases.

Abstract: Background: Diffuse interstitial lung diseases (DILDs) form a part of a heterogeneous group of respiratory diseases. Bronchoalveolar lavage (BAL) analysis has been used for differential diagnosis of DILDs, but their clinical usefulness is controversial. The aim of this study was to investigate the clinical usefulness of BAL cellular analysis with lymphocyte subsets for the differential diagnosis of DILDs. Methods: A total of 69 patients diagnosed with DILDs were enrolled. Basic demographic data, BAL cellular analysis with lymphocyte subsets, histology, and high resolution computed tomogram (HRCT) findings were analyzed and compared as per disease subgroup. Results: Significant differences were found between groups in the proportion of neutrophils (P =0.0178), eosinophils (P =0.0003), T cells (P =0.0305), CD4 cells (P =0.0002), CD8 cells (P <0.0001), and CD4/CD8 ratio (P <0.0001). These findings were characteristic features of eosinophilic pneumonia and sarcoidosis. Other parameters were not significantly different between groups. At the cut-off value of 2.16 for sarcoidosis, CD4/CD8 ratio showed sensitivity of 91.7% (95% CI, 61.5-98.6%) and specificity of 84.2% (95% CI, 72.1-92.5%).

Association Between High Platelet Indices and Proteinuria in Patients With Hypertension

Abstract: plateletcrit (PCT), mean platelet volume (MPV), platelet distribution width (PDW), and proteinuria associated with hypertension (HT) as well as the relative power of each to predict proteinuria. Methods: The study included 223 patients (68 men and 155 women) with primary HT. PCT, MPV, PDW, and proteinuria levels were measured. The patients were divided into two groups according to proteinuria status based on 24-hr urinary protein excretion: proteinuria (+) group (15 men and 40 women) and proteinuria (-) group (53 men and 115 women). Results: The mean and SD of platelet count, PDW, PCT, and MPV were 278.8 ±49.6 ×10 9 /L, 13.5 ±1.8%, 0.31 ±0.07%, and 11.3 ±2.6 fL, respectively. The mean platelet count, PCT, MPV, and PDW were significantly higher in the proteinuria (+) group than in the proteinuria (-) group (P <0.05); there were no significant differences in the other blood parameters between the two groups. The platelet count, PCT, MPV, and PDW were independent risk factors predictive of proteinuria according to a stepwise regression analysis of PDW, PCT, and MPV. PCT was the strongest independent predictor of proteinuria. Conclusions: The platelet indices PCT, PDW, and MPV were significantly higher in patients with proteinuria than in those without it. Among these three indices, PCT was the strongest predictor of proteinuria.

Molecular Identification and Amphotericin B Susceptibility Testing of Clinical Isolates of Aspergillus From 11 Hospitals in Korea

Abstract: Background We investigated the species distribution and amphotericin B (AMB) susceptibility of Korean clinical Aspergillus isolates by using two Etests and the CLSI broth microdilution method.

Multicenter study of antimicrobial susceptibility of anaerobic bacteria in Korea in 2012.

Abstract: Background Periodic monitoring of regional or institutional resistance trends of clinically important anaerobic bacteria is recommended, because the resistance of anaerobic pathogens to antimicrobial drugs and inappropriate therapy are associated with poor clinical outcomes. There has been no multicenter study of clinical anaerobic isolates in Korea. We aimed to determine the antimicrobial resistance patterns of clinically important anaerobes at multiple centers in Korea.

Phenotypic and genotypic analysis of anti-tuberculosis drug resistance in Mycobacterium tuberculosis isolates in Myanmar.

Abstract: Background Tuberculosis (TB) is one of the most serious health problems in Myanmar. Because TB drug resistance is associated with genetic mutation(s) relevant to responses to each drug, genotypic methods for detecting these mutations have been proposed to overcome the limitations of classic phenotypic drug susceptibility testing (DST). We explored the current estimates of drug-resistant TB and evaluated the usefulness of genotypic DST in Myanmar. Methods We determined the drug susceptibility of Mycobacterium tuberculosis isolated from sputum smear-positive patients with newly diagnosed pulmonary TB at two main TB centers in Myanmar during 2013 by using conventional phenotypic DST and the GenoType MTBDRplus assay (Hain Lifescience, Germany). Discrepant results were confirmed by sequencing the genes relevant to each type of resistance (rpoB for rifampicin; katG and inhA for isoniazid). Results Of 191 isolates, phenotypic DST showed that 27.7% (n=53) were resistant to at least one first-line drug and 20.9% (n=40) were resistant to two or more, including 18.3% (n=35) multidrug-resistant TB (MDR-TB) strains. Monoresistant strains accounted for 6.8% (n=13) of the samples. Genotypic assay of 189 isolates showed 17.5% (n=33) MDR-TB and 5.3% (n=10) isoniazid-monoresistant strains. Genotypic susceptibility results were 99.5% (n=188) concordant and agreed almost perfectly with phenotypic DST (kappa=0.99; 95% confidence interval 0.96-1.01). Conclusions The results highlight the burden of TB drug resistance and prove the usefulness of the genotypic DST in Myanmar.

Hypertriglyceridemia is a Major Factor Associated With Elevated Levels of Small Dense LDL Cholesterol in Patients With Metabolic Syndrome

Abstract: Results: A comparison of the median values of the sdLDL-C concentration between subgroups, divided according to whether subjects met or did not meet the criteria for each MetS component in patients with MetS, revealed a significant difference in the sdLDL-C concentration only between subgroups divided according to whether subjects met or did not meet the triglyceride (TG) criteria (P <0.05 for each gender). The TG level showed a good correlation with sdLDL-C concentration (correlation coefficients [r]=0.543 for men; 0.653 for women) and the sdLDL-C/LDL-C ratio (r=0.789 for men; 0.745 for women). Multiple linear regression analyses conducted for the MetS group concordantly identified TG as one of the most significant contributors to sdLDL-C concentration (β=0.1747±0.0105, P <0.0001) and the sdLDL-C/LDL-C ratio (β=6.9518±0.3011, P <0.0001). Conclusions: Among five MetS components, only the abnormal TG level was a differentiating factor for sdLDL-C concentration and sdLDL-C/LDL-C ratio. These results were reproducible in both genders, with or without MetS.

Dried Blood Spot Testing for Seven Steroids Using Liquid Chromatography-Tandem Mass Spectrometry With Reference Interval Determination in the Korean Population

Abstract: Background Conventional screening for congenital adrenal hyperplasia (CAH) using immunoassays generates a large number of false-positive results. A more specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been introduced to minimize unnecessary follow-ups. However, because of limited data on its use in the Korean population, LC-MS/MS has not yet been incorporated into newborn screening programs in this region. The present study aims to develop and validate an LC-MS/MS method for the simultaneous determination of seven steroids in dried blood spots (DBS) for CAH screening, and to define age-specific reference intervals in the Korean population. Methods We developed and validated an LC-MS/MS method to determine the reference intervals of cortisol, 17-hydroxyprogesterone, 11-deoxycortisol, 21-deoxycortisol, androstenedione, corticosterone, and 11-deoxycorticosterone simultaneously in 453 DBS samples. The samples were from Korean subjects stratified by age group (78 full-term neonates, 76 premature neonates, 89 children, and 100 adults). Results The accuracy, precision, matrix effects, and extraction recovery were satisfactory for all the steroids at three concentrations; values of intra- and inter-day precision coefficients of variance, bias, and recovery were 0.7-7.7%, -1.5-9.8%, and 49.3-97.5%, respectively. The linearity range was 1-100 ng/mL for cortisol and 0.5-50 ng/mL for other steroids (R²>0.99). The reference intervals were in agreement with the previous reports. Conclusions This LC-MS/MS method and the reference intervals validated in the Korean population can be successfully applied to analyze seven steroids in DBS for the diagnosis of CAH.

Primary anti-D alloimmunization induced by "Asian type" RHD (c.1227G>A) DEL red cell transfusion.

Abstract: The Rh blood group system is the second most clinically significant blood group system after the ABO blood group system [1]. Extremely weak D variants known as DEL, which are weaker than Du, are hardly detectable by basic serologic typing except absorption-elution techniques and frequently require molecular studies for confirmation [2]. According to the previous review, the 678 DELs found by elution or DNA detection were genotyped, and more than 98% (667/678) presented the RHD (c.1227G>A) allele, which predominates in East Asians [3]. Thus, it is known as the "Asian type". Here, we present a case of primary anti-D alloimmunization induced by the transfusion of packed red blood cells (RBCs) from two Korean donors, both of whom coincidentally had DEL phenotypes. A 64-yr-old Caucasian male was admitted to our hospital for surgery for prostate adenocarcinoma. His blood type was group A, D-negative. The patient had no history of transfusion. Two days after admission, two units of crossmatch-compatible blood group A, D-negative packed RBCs from two separate donors were administered. The result of a pre-transfusion antibody screening test (BioVue, Ortho Clinical Diagnostics, Raritan, NJ, USA), an indirect antiglobulin test with column agglutination, was negative. No initial adverse effect of transfusion was observed. At day 12, the antibody screening test became positive and anti-D was identified in the recipient's serum (Resolve Panel A, Ortho Clinical Diagnostics). An autocontrol and a direct antiglobulin test (DAT) showed no visible agglutination. Anti-D development after transfusion in this patient was unexplainable, and possible analytical errors were ruled out. An antibody screening test performed by using previously taken blood samples yielded strongly positive results (4+) on days 7, 9, and 12 and a negative result on day 5. This implied that anti-D developed between day 5 and day 7. The remaining pre-sealed portions of two transfused RBC units were sent to the Korean Rare Blood Program Reference Laboratory (Seoul National University Bundang Hospital) for confirmation of the RHD variants. The RHD genotype was analyzed according to the previously described methods [4]. Surprisingly, the RhD genotype results for both donors were RHD (c.1227G>A). They presented the Ccee and CCEe phenotypes (Table 1). The two RHD (c.1227G>A)-positive RBC units were transfused at day 2 after admission, and the above observations suggest that anti-D alloimmunization caused anti-D to be detected more than 3 days later. Table 1 Blood group immunogenetic results of two donors DEL can cause anti-D alloimmunization despite small amounts of D antigens on RBCs. Several cases of anti-D alloimmunization caused by transfusion from DEL donors have been reported [4,5,6] (Table 2). Although 16% of serologically D-negative Korean blood donors were known to be DEL, only one patient of anti-D alloimmunization has been reported in Korea [4]. In our case, the patient received serologically D-negative RBCs from two donors, who were later shown to have the DEL phenotype by RHD genotyping. Two separate serologically D-negative RBC units with a DEL phenotype may not be a coincidence. In Germany and Upper Austria, RHD genotyping of D-negative donors is routinely performed as a screening method at first-time donation [7,8]. The prevalence of RHD gene carriers was 0.21% for six years, and approximately a half of them had a DEL phenotype, according to the data from Germany [7]. In Upper Austria, of 23,330 serologically D-negative samples, 94 showed one or more RHD markers from among 20 RHD markers located in exons 4, 7, and 10 [8]. However, according to the national transfusion guidelines from South Korea, serologically D-negative units are not tested for true D-negative and DEL phenotypes. Therefore, it is possible for DEL-type packed RBC units to be transfused to D-negative recipients. If RHD PCR is adopted as an initial screening method for D-negative blood, the number of cases with DEL phenotypes being serologically mistyped as general D-negative will decrease. However, it would increase costs and require additional time. Table 2 Characteristics of anti-D immunization by the DEL RBCs in literature Previous investigations reported that the presence of RHD genes was strongly related to RhC phenotype, with a high frequency of RhC(+) in serologically RhD-negative blood [9,10]. In an earlier study of D-negative Koreans, all except one (97.6%) of 42 "Asian type (c.1227G>A)" individuals showed a RhC phenotype [9]. Our study also showed the RhC(+) phenotype in both donors, who have Ccee and CCEe phenotypes. Thus, we agree with Wang et al. [10] that a laboratory protocol for blood banks that includes RhC phenotyping and confirmatory RHD PCR would be helpful for detecting DEL RBCs. Additional nationwide Korean data concerning the incidence of the RhC(+) phenotype in DEL individuals needs to be collected.

In vitro activity of tedizolid against gram-positive bacteria in patients with skin and skin structure infections and hospital-acquired pneumonia: a Korean multicenter study.

Abstract: We compared the activities of tedizolid to those of linezolid and other commonly used antimicrobial agents against gram-positive cocci recovered from patients with skin and skin structure infections (SSSIs) and hospital-acquired pneumonia (HAP) in Korean hospitals. Gram-positive isolates were collected from 356 patients with SSSIs and 144 patients with HAP at eight hospitals in Korea from 2011 to 2014. SSSIs included impetigo, cellulitis, erysipelas, furuncles, abscesses, and infected burns. Antimicrobial susceptibility was tested by using the CLSI agar dilution method. All of the gram-positive isolates were inhibited by ≤1 μg/mL tedizolid. The minimum inhibitory concentration [MIC]₉₀ of tedizolid was 0.5 μg/mL for methicillin-resistant Staphylococcus aureus, which was 4-fold lower than that of linezolid. Tedizolid may become a useful option for the treatment of SSSIs and HAP caused by gram-positive bacteria.

Comparison of AdvanSure TB/NTM PCR and COBAS TaqMan MTB PCR for Detection of Mycobacterium tuberculosis Complex in Routine Clinical Practice

Abstract: The AdvanSure tuberculosis/non-tuberculous mycobacterium (TB/NTM) PCR (LG Life Science, Korea) and COBAS TaqMan Mycobacterium tuberculosis (MTB) PCR (Roche Diagnostics, USA) are commonly used in clinical microbiology laboratories. We aimed to evaluate these two commercial real-time PCR assays for detection of MTB in a large set of clinical samples over a two-year period. AdvanSure TB/NTM PCR and COBAS TaqMan MTB PCR were performed on 9,119 (75.2%) and 3,010 (24.8%) of 12,129 (9,728 respiratory and 2,401 non-respiratory) MTB specimens, with 361 (4.0%) and 102 (3.4%) acid-fast bacilli (AFB)-positive results, respectively. In MTB culture, 788 (6.5%) MTB and 514 (4.2%) NTM were identified. The total sensitivity and specificity of the AdvanSure assay were 67.8% (95% confidence interval [CI], 63.9-71.6) and 98.3% (95% CI, 98.0-98.6), while those of the COBAS TaqMan assay were 67.2% (95% CI, 60.0-73.8) and 98.4% (95% CI, 97.9-98.9), respectively. The sensitivities and specificities of the AdvanSure and COBAS TaqMan assays for AFB-positive and AFB-negative samples were comparable. Furthermore, the AdvanSure assay showed fewer invalid results compared with the COBAS TaqMan assay (5.0 vs. 20.4 invalid results/1,000 tests, P<0.001). AdvanSure assay represents a comparable yet more reliable method than COBAS TaqMan for the identification of mycobacteria in routine clinical microbiology.

Multidrug-Resistant Corynebacterium striatum Bacteremia: First Case in Korea

Abstract: Dear Editor Corynebacteria are aerobic, non-spore forming, and gram-positive bacilli that are commensal organisms of skin and mucosal membranes. C. striatum, like other Corynebacterium species, is a part of the normal human skin flora; therefore, it has been frequently dismissed as a blood and airway sample contaminant in the past. However, C. striatum is emerging as a cause of bloodstream infections and endocarditis [1]. Moreover, C. striatum infection outbreaks have been reported in long-stay patients with underlying disease [2]. We report a case of C. striatum bacteremia in a patient who had undergone gastrostomy. To our knowledge, there has been no report of C. striatum bacteremia in Korea so far. A 64-yr-old quadriplegic man visited the outpatient rehabilitation clinic for gastrostomy tube change. Before visiting our hospital, he was admitted to a secondary hospital and had hypertension and diabetes mellitus. Nine months before this visit, quadriplegia developed because of hypoxic ischemic encephalopathy; he underwent tracheostomy and gastrostomy tube placement. He was admitted to our hospital owing to persistent low-grade fever with blood pressure of 156/89 mmHg. The white blood cell count was 6.02×109/L (86% segmented neutrophils), and C-reactive protein level was 3.34 mg/dL (reference range: 128 µg/mL), and erythromycin (>128 µg/mL). At first, the physician assumed that C. striatum was a contaminant and the fever was caused by a urinary tract infection on the basis of the past history. Thus, only intravenous piperacillin/tazobactam was administered for the possible urinary tract infection. Culture for medical devices such as the gastrostomy or tracheostomy tubes was not performed. However, fever did not subside and C-reactive protein level was elevated; follow-up blood cultures performed on the 6th day of admission revealed C. striatum growth. The patient was continuously given intravenous piperacillin/tazobactam. As the fever subsided, he was transferred to a provincial medical center. The patient was readmitted for check-up a month after discharge and showed no sign of infection. It is difficult to distinguish simple colonization from real infection when Corynebacterium spp. are recovered from specimens [4]. C. striatum are commonly isolated in patients with significant underlying illnesses [2] and has close association with various medical devices such as prosthetic valve/joint and central venous catheter [5] and long hospitalization. In this case, the patient suffered from diabetes, hypertension, tracheostomy, and gastrostomy. Additionally, he had stayed at a secondary health care center before being admitted to our hospital. These factors probably increased the patient's risk of C. striatum infection. Additionally, each of the blood culture sets was collected at regularly spaced intervals with adequate blood volumes, and turned positive within 24 hr. One of the recent issues related to C. striatum is the emergence and spread of multidrug resistance. Generally, most of the reported C. striatum isolates were susceptible to a wide range of antibiotics [6]; however, recent studies showed the emergence of multi-drug resistant strains with increasing use of broad-spectrum antibiotics (Table 1) [1, 4, 6, 7]. When invasive C. striatum infection is suspected, most initial therapies should include vancomycin, because in vitro resistance to vancomycin has not been reported in any of the Corynebacterium species [5]. If the patient is allergic to vancomycin, daptomycin may be an alternative. Fernandez et al. [1] reported successful treatment of a case of multidrug-resistant C. striatum endocarditis with daptomycin. Table 1 Multidrug resistant Corynebacterium striatum in the literature In conclusion, with increasing numbers of immunosuppressed patients and indwelling medical devices, C. striatum infections will be more commonly found and should never be overlooked as a contaminant. This report suggests the need to increase awareness of C. striatum as a pathogen causing bloodstream infections.

Mutation Analysis of the TGFBI Gene in Consecutive Korean Patients With Corneal Dystrophies

Abstract: Background Mutations in the transforming growth factor β-induced gene (TGFBI) are major causes of genetic corneal dystrophies (CDs), which can be grouped into TGFBI CDs. Although a few studies have reported the clinical and genetic features of Korean patients with TGFBI CD, no data are available regarding the frequency and spectrum of TGFBI mutations in a consecutive series of Korean patients with clinically diagnosed CDs.

Comparison of Quantitation of Cytomegalovirus DNA by Real-Time PCR in Whole Blood with the Cytomegalovirus Antigenemia Assay

Abstract: Background: Quantitation of cytomegalovirus (CMV) DNA using real-time PCR has been utilized for monitoring CMV infection. However, the CMV antigenemia assay is still the ‘gold standard’ assay. There are only a few studies in Korea that compared the efficacy of use of real-time PCR for quantitation of CMV DNA in whole blood with the antigenemia assay, and most of these studies have been limited to transplant recipients. Method: 479 whole blood samples from 79 patients, falling under different disease groups, were tested by real-time CMV DNA PCR using the Q-CMV real-time complete kit (Nanogen Advanced Diagnostic S.r.L., Italy) and CMV antigenemia assay (CINA Kit, ArgeneBiosoft, France), and the results were compared. Repeatedly tested patients were selected and their charts were reviewed for ganciclovir therapy. Results: The concordance rate of the two assays was 86.4% (Cohen’s kappa coefficient value=0.659). Quantitative correlation between the two assays was a moderate (r=0.5504, P <0.0001). Among 20 patients tested repeatedly with the two assays, 13 patients were transplant recipients and treated with ganciclovir. Before treatment, CMV was detected earlier by real-time CMV DNA PCR than the antigenemia assay, with a median difference of 8 days. After treatment, the antigenemia assay achieved negative results earlier than real-time CMV DNA PCR with a median difference of 10.5 days. Conclusions: Q-CMV real-time complete kit is a useful tool for early detection of CMV infection in whole blood samples in transplant recipients.