Comparison of Clinical Features according to FLG Mutation in Korean Atopic Dermatitis Patients / 대한피부과학회지

BACKGROUND: Mutation in the gene encoding filaggrin (FLG) is a major predisposing factor for atopic dermatitis (AD), in association with distinct features such as increased allergic sensitization, higher severity, and frequent skin infections. Genetic diversity in FLG mutations exists across ethnicities. OBJECTIVE: This study aimed to investigate the clinical features of AD according to the presence of FLG mutation in Korean individuals. METHODS: We performed reverse blot hybridization assay to detect FLG mutation in Korean patients with AD. Classifying subjects into AD with or without FLG mutation, clinical features of AD and patch test results were compared between the two groups. RESULTS: Among a total of 281 subjects, 39 (13.9%) were found to have FLG mutation. AD with FLG mutation was associated with higher risk of impetigo and eczema herpeticum but lower risk of prurigo nodularis. In the patch test, there was no difference in positive reactions of major contact allergens between the groups. CONCLUSION: In Korean patients with AD, FLG mutation was associated with more frequent skin infections but not with personal or family history of atopic diseases, allergic sensitization, contact allergy, and protracted course. It is important to consider other skin-barrier-related genes, such as KLK7 and SPINK5, and immune response-related genes in conjunction.

Detection of Rifampicin- and Isoniazid-Resistant Mycobacterium tuberculosis Using the Quantamatrix Multiplexed Assay Platform System

BACKGROUND: The increasing prevalence of drug-resistant tuberculosis (TB) infection represents a global public health emergency. We evaluated the usefulness of a newly developed multiplexed, bead-based bioassay (Quantamatrix Multiplexed Assay Platform [QMAP], QuantaMatrix, Seoul, Korea) to rapidly identify the Mycobacterium tuberculosis complex (MTBC) and detect rifampicin (RIF) and isoniazid (INH) resistance-associated mutations. METHODS: A total of 200 clinical isolates from respiratory samples were used. Phenotypic anti-TB drug susceptibility testing (DST) results were compared with those of the QMAP system, reverse blot hybridization (REBA) MTB-MDR assay, and gene sequencing analysis. RESULTS: Compared with the phenotypic DST results, the sensitivity and specificity of the QMAP system were 96.4% (106/110; 95% confidence interval [CI] 0.9072–0.9888) and 80.0% (72/90; 95% CI 0.7052–0.8705), respectively, for RIF resistance and 75.0% (108/144; 95% CI 0.6731–0.8139) and 96.4% (54/56; 95% CI 0.8718–0.9972), respectively, for INH resistance. The agreement rates between the QMAP system and REBA MTB-MDR assay for RIF and INH resistance detection were 97.6% (121/124; 95% CI 0.9282–0.9949) and 99.1% (109/110; 95% CI 0.9453–1.0000), respectively. Comparison between the QMAP system and gene sequencing analysis showed an overall agreement of 100% for RIF resistance (110/110; 95% CI 0.9711–1.0000) and INH resistance (124/124; 95% CI 0.9743–1.0000). CONCLUSIONS: The QMAP system may serve as a useful screening method for identifying and accurately discriminating MTBC from non-tuberculous mycobacteria, as well as determining RIF- and INH-resistant MTB strains.

Differences in Genetic Variations Between Treatable and Recalcitrant Atopic Dermatitis in Korean

PURPOSE: Variations in barrier- or immune response-related genes are closely related to the development of atopic dermatitis (AD). This study was designed to identify genetic variations and clinical features to predict ‘recalcitrant AD.’ METHODS: AD patients were classified as treatable and recalcitrant. Treatable AD patients showed satisfactory clinical improvement with basic and topical treatments. Recalcitrant AD patients used systemic immune-suppressants for over 4 weeks as they had not shown clinical improvement with basic and topical treatments. The frequency of gene variations in barrier- (FLG 3321delA, FLG K4022X, KLK7, SPINK 1156, SPINK 1188, SPINK 2475) and immune response- (DEFB1, KDR, IL-5RA, IL-9, and IL-12RB1a, b) related genes were compared between each AD group and the controls. RESULTS: Of all, 249 treatable AD and 32 recalcitrant AD were identified. Heterozygous mutations (Hetero) in KLK7 was more frequent in recalcitrant AD patients than treatable AD, without statistical significance. Hetero in DEFB1 was more frequent in treatable AD patients. However, no other significant genetic differences between treatable and recalcitrant AD was observed. Instead, higher initial Eczema Area Severity Index (EASI) score, serum immunoglobulin E (IgE) level, allergen specific IgE for house dust mites, and family history of atopic diseases were associated with recalcitrant AD with statistical significance. CONCLUSIONS: According to our study, no genetic variation to predict recalcitrant AD was identified, suggesting that clinical manifestation, rather than genetic variations of AD patients is more likely to be an important factor in predicting the prognosis of AD. Further large-scale studies on the correlation between genetic variation and recalcitrant AD are needed.

NDM-5 and OXA-48 Co-producing Uropathogenic Escherichia coli Isolate: First Case in Korea

No abstract available.

Skin Barrier Function Is Not Impaired and Kallikrein 7 Gene Polymorphism Is Frequently Observed in Korean X-linked Ichthyosis Patients Diagnosed by Fluorescence in Situ Hybridization and Array Comparative Genomic Hybridization

X-linked ichthyosis (XLI) is a recessively inherited ichthyosis. Skin barrier function of XLI patients reported in Western countries presented minimally abnormal or normal. Here, we evaluated the skin barrier properties and a skin barrier-related gene mutation in 16 Korean XLI patients who were diagnosed by fluorescence in situ hybridization and array comparative genomic hybridization analysis. Skin barrier properties were measured, cytokine expression levels in the stratum corneum (SC) were evaluated with the tape stripped specimen from skin surface, and a genetic test was done on blood. XLI patients showed significantly lower SC hydration, but normal basal trans-epidermal water loss and skin surface pH as compared to a healthy control group. Histopathology of ichthyosis epidermis showed no acanthosis, and levels of the pro-inflammatory cytokines in the corneal layer did not differ between control and lesional/non-lesional skin of XLI patients. Among the mutations in filaggrin (FLG), kallikrein 7 (KLK7), and SPINK5 genes, the prevalence of KLK7 gene mutations was significantly higher in XLI patients (50%) than in controls (0%), whereas FLG and SPINK5 prevalence was comparable. Korean XLI patients exhibited unimpaired skin barrier function and frequent association with the KLK7 gene polymorphism, which may differentiate them from Western XLI patients.

Skin Barrier Function Is Not Impaired and Kallikrein 7 Gene Polymorphism Is Frequently Observed in Korean X-linked Ichthyosis Patients Diagnosed by Fluorescence in Situ Hybridization and Array Comparative Genomic Hybridization

X-linked ichthyosis (XLI) is a recessively inherited ichthyosis. Skin barrier function of XLI patients reported in Western countries presented minimally abnormal or normal. Here, we evaluated the skin barrier properties and a skin barrier-related gene mutation in 16 Korean XLI patients who were diagnosed by fluorescence in situ hybridization and array comparative genomic hybridization analysis. Skin barrier properties were measured, cytokine expression levels in the stratum corneum (SC) were evaluated with the tape stripped specimen from skin surface, and a genetic test was done on blood. XLI patients showed significantly lower SC hydration, but normal basal trans-epidermal water loss and skin surface pH as compared to a healthy control group. Histopathology of ichthyosis epidermis showed no acanthosis, and levels of the pro-inflammatory cytokines in the corneal layer did not differ between control and lesional/non-lesional skin of XLI patients. Among the mutations in filaggrin (FLG), kallikrein 7 (KLK7), and SPINK5 genes, the prevalence of KLK7 gene mutations was significantly higher in XLI patients (50%) than in controls (0%), whereas FLG and SPINK5 prevalence was comparable. Korean XLI patients exhibited unimpaired skin barrier function and frequent association with the KLK7 gene polymorphism, which may differentiate them from Western XLI patients.

Evaluation of PCR-Reverse Blot Hybridization Assay, REBA Sepsis-ID Test, for Simultaneous Identification of Bacterial Pathogens and mecA and van Genes from Blood Culture Bottles

BACKGROUND: The aim of this study was to evaluate a newly developed PCR-based reverse blot hybridization assay (PCR-REBA), REBA Sepsis-ID (M&D, Wonju, Korea), to rapidly detect the presence of bacteremia and antimicrobial resistance gene in blood culture samples. METHODS: One thousand four hundred consecutive blood culture samples from patients with a delta neutrophil index greater than 2.7% were selected from March to July in 2013. Three hundred positive and 1,100 negative for bacterial growth in blood culture bottles samples were tested by conventional and real-time PCR-REBA, respectively. RESULTS: The overall agreement between the conventional identification test and the REBA Sepsis-ID test was 95.3% (286/300). Agreement for gram-positive bacteria, gram-negative bacteria, fungi, and polymicrobials was 94.5% (190/201), 97.3% (71/73), 100% (14/14), and 91.7% (11/12), respectively. The detection rate of the mecA gene from methicillin-resistant Staphylococcus isolates was 97.8% (90/92). The vanA gene was detected in one blood culture sample from which vancomycin-resistant Enterococcus was isolated. When the cycle threshold for real-time PCR was defined as 30.0, 2.4% (26/1,100) of negative blood culture samples tested positive by real-time PCR. CONCLUSIONS: The REBA Sepsis-ID test is capable of simultaneously and quickly detecting both causative agents and antimicrobial resistance genes, such as mecA and van, in blood culture positive samples.

Evaluation of MolecuTech Real MTB-ID for MTB/NTM Detection Using Direct Specimens / 대한임상미생물학회지

BACKGROUND: The differentiation of Mycobacterium tuberculosis (MTB) from nontuberculous mycobacteria (NTM) is of primary importance for infection control and choice of antimicrobial therapy. The diagnosis of diseases caused by NTM is difficult because NTM are prevalent in the environment and have fastidious properties. In this study, we evaluated the real-time PCR-based MTB/NTM detection kit for its usefulness in discrimination of MTB and NTM species. METHODS: A total of 155 sputum specimens whose AFB staining smear and culture were positive were used for this study. Among them, 59 and 96 samples had been identified as MTB and NTM, respectively. DNA obtained from sputum specimens was subjected to analysis with MolecuTech Real MTB-ID(R) (M&D, Korea) real-time PCR-based MTB/NTM detection kit. Subsequently, the results of MolecuTech Real MTB-ID(R) were compared with AFB staining smear and culture results. RESULTS: The positive rate of MolecuTech Real MTB-ID(R) to detect MTB and NTM was 98.3% (58/59) and 97.9 (94/96), respectively, using sputum specimens. CONCLUSION: For detection of MTB/NTM, the sensitivity and specificity of MolecuTech Real MTB-ID(R) were comparable to those of conventional methods. Therefore, this study suggests the usefulness of real-time PCR-based MolecuTech Real MTB-ID(R) for rapid detection of MTB/NTM from direct specimens.

PCR-reverse Blot Hybridization Assay for Species Identification of Dermatophytes / 대한의진균학회지

BACKGROUND: Dermatophytes (Trichophyton, Microsporum, and Epidermophyton) cause cutaneous mycoses called dermatophytosis. Forproper anti-dermatophytosis therapy, accurate and early diagnosis of dermatophytes is important. Laboratory diagnosis of dermatophytosis for dermatophytes still relies on microscopic and macroscopic examination of in vitro cultures and some physiological tests. These methods (conventional methods) are time-consuming (2~4 weeks) and yet, still have low sensitivity and specificity. Recently, in order to overcome such limitations of conventional methods, molecular-based methods have been developed to identify dermatophytes. The polymerase chain reaction-reverse blot hybridization assay (PCR-REBA) allows sensitive and specific identification of dermatophytes species. OBJECTIVE: This study was aimed to develop a new PCR-REBA with higher sensitivity using less amount of probe concentration, so the assay can be more practical in clinical settings. METHODS: For this, PCR primers and species-specific oligonucleotide probes were designed within the internal transcribed sequences 1 region between 5.8S and 18S rRNA. The species-specific probes designed in this study was to identify 6 species (T. rubrum, T. mentagrophytes, T. tonsurans, M. canis, M. gypseum, and E. floccosum) comprised 99% of dermatophytes isolatedin Korea. RESULTS: The detection efficiency of the PCR-REBA was compared with the microscopic method, and the results showed that the sensitivity of the PCR-REBA developed in this study is 100 times higher than previously developed one. Subsequently, the results of PCR-REBA were evaluated using clinical isolates. DNAs from a total of 68 clinical isolates were analyzed by PCR-REBA, and the inconsistent results between PCR-REBA and conventional microscopic identification results were confirmed by sequence analysis. CONCLUSION: In brief, the results showed that results of sequence analysis were identical with PCR-REBA implying newly developed PCR-REBA is very useful method for accurate and rapid identification of dermatophytes and would provide higher simplicity, specificity, sensitivity than conventional method.