Changing Epidemiology of Pathogenic Bacteria Over the Past 20 Years in Korea

Background@#The epidemiology of pathogenic bacteria varies according to the socioeconomic status and antimicrobial resistance status. However, longitudinal epidemiological studies to evaluate the changes in species distribution and antimicrobial susceptibility of pathogenic bacteria nationwide are lacking. We retrospectively investigated the nationwide trends in species distribution and antimicrobial susceptibility of pathogenic bacteria over the last 20 years in Korea. @*Methods@#From 1997 to 2016, annual cumulative antimicrobial susceptibility and species distribution data were collected from 12 university hospitals in five provinces and four metropolitan cities in South Korea. @*Results@#The prevalence of Staphylococcus aureus was the highest (13.1%) until 2012 but decreased to 10.3% in 2016, consistent with the decrease in oxacillin resistance from 76.1% in 2008 to 62.5% in 2016. While the cefotaxime resistance of Escherichia coli increased from 9.0% in 1997 to 34.2% in 2016, E. coli became the most common species since 2013, accounting for 14.5% of all isolates in 2016. Pseudomonas aeruginosa and Acinetobacter baumannii rose to third and fifth places in 2008 and 2010, respectively, while imipenem resistance increased from 13.9% to 30.8% and 0.7% to 73.5% during the study period, respectively.Streptococcus agalactiae became the most common pathogenic streptococcal species in 2016, as the prevalence of Streptococcus pneumoniae decreased since 2010. During the same period, pneumococcal penicillin susceptibility decreased to 79.0%, and levofloxacin susceptibility of S. agalactiae decreased to 77.1% in 2016. @*Conclusion@#The epidemiology of pathogenic bacteria has changed significantly over the past 20 years according to trends in antimicrobial resistance in Korea. Efforts to confine antimicrobial resistance would change the epidemiology of pathogenic bacteria and, consequently, the diagnosis and treatment of infectious diseases.

Successful Treatment of Mycoplasma hominis Meningitis, Diagnosed Using Real-Time Polymerase Chain Reaction, with Ciprofloxacin in a Neonate

Mycoplasma hominis can cause life-threatening central nervous system infections in neonates following intrauterine infection or during delivery. In newborns, the dia gnosis and treatment of M. hominis meningitis are challenging, because cultures are often negative and the bacterium is not susceptible to empirical antibiotics. Herein, we describe a case of neonatal M. hominis meningitis diagnosed using real-time polymerase chain reaction (RT-PCR) and treated with ciprofloxacin. The patient was a 3-day-old female hospitalized for a fever and lethargy. Her blood laboratory findings were non-specific; cerebrospinal fluid (CSF) examination showed a white blood cell count of 580/µL and indicated meningitis. Her symptoms could not be controlled with empirical antibiotics. Urine culture on a special medium revealed ciprofloxacinsusceptible M. hominis. Furthermore, the RT-PCR performed with the CSF sample revealed M. hominis. Therefore, the patient was administered cipro­floxacin; after 2 days, the fever subsided. The patient was discharged on day 30 without complications.

Serotype Distribution and Antimicrobial Resistance of Invasive and Noninvasive Streptococcus pneumoniae Isolates in Korea between 2014 and 2016

BACKGROUND: Several factors contribute to differences in Streptococcus pneumoniae serotype distribution. We investigated the serotype distribution and antimicrobial resistance of S. pneumoniae isolated between 2014 and 2016 in Korea. METHODS: We collected a total of 1,855 S. pneumoniae isolates from 44 hospitals between May 2014 and May 2016, and analyzed the serotypes by sequential multiplex PCR. We investigated the distribution of each serotype by patient age, source of the clinical specimen, and antimicrobial resistance pattern. RESULTS: The most common serotypes were 11A (10.1%), followed by 19A (8.8%), 3 (8.5%), 34 (8.1%), 23A (7.3%), and 35B (6.2%). The major invasive serotypes were 3 (12.6%), 19A (7.8%), 34 (7.8%), 10A (6.8%), and 11A (6.8%). Serotypes 10A, 15B, 19A, and 12F were more common in patients ≤5 years old, while serotype 3 was more common in patients ≥65 years old compared with the other age groups. The coverage rates of pneumococcal conjugate vaccine (PCV)7, PCV10, PCV13, and pneumococcal polysaccharide vaccine 23 were 11.8%, 12.12%, 33.3%, and 53.6%, respectively. Of the 1,855 isolates, 857 (46.2%) were multi-drug resistant (MDR), with serotypes 11A and 19A predominant among the MDR strains. The resistance rates against penicillin, cefotaxime, and levofloxacin were 22.8%, 12.5%, and 9.4%, respectively. CONCLUSIONS: There were significant changes in the major S. pneumoniae serotypes in the community. Non-PCV13 serotypes increased in patients ≤5 years old following the introduction of national immunization programs with the 10- and 13-polyvalent vaccines.

A Case of Thrombotic Thrombocytopenic Purpura with Exacerbation after Incomplete Remission of Therapeutic Plasma Exchange / 대한수혈학회지

Thrombotic thrombocytopenic purpura (TTP) is a rare blood disorder with a mortality rate of over 90% without prompt treatment. It is caused by congenital, idiopathic, or secondary diseases; idiopathic TTP is mainly associated with deficiency of ADAMTS13, a von Willebrand factor cleaving protease or ADAMTS13 inhibitors. The long-term survival rate of TTP has improved since the introduction of therapeutic plasma exchange (TPE), and the therapeutic aims have also been established. However, deciding on the end-point and appropriate treatment method requires careful assessment of clinical conditions of patients. The present study reports a case of a 33-year-old male patient with reduced ADAMTS13 activity and ADAMTS13 inhibitor, who developed symptoms after an early termination of TPE with improved symptoms, which finally improved with retreatment and additionally corticosteroid. We report our case with relevant literature review on TPE in TTP with this case.

Evaluation of three glucometers for whole blood glucose measurements at the point of care in preterm or low-birth-weight infants / 소아과

PURPOSE: We evaluated three blood glucose self-monitoring for measuring whole blood glucose levels in preterm and low-birth-weight infants. METHODS: Between December 1, 2012 and March 31, 2013, 230 blood samples were collected from 50 newborns, who weighed, 60 mg/dL, the correlation coefficients were 0.822, 0.819, and 0.839, respectively. All correlation coefficients were statistically significant. And the values from the blood glucose self-monitoring were not significantly different from the value of the laboratory equipment , after correcting for each device's average value (P>0.05). When using laboratory equipment (blood glucose < or =60 mg/dL), each device had a sensitivity of 0.458, 0.604, and 0.688 and a specificity of 0.995, 0.989, and 0.989, respectively. CONCLUSION: Significant difference is not found between three blood glucose self-monitoring and laboratory equipment. But correlation between the measured values from blood glucose self-monitoring and laboratory equipment is lower in preterm or low-birth-weight infants than adults.

Loss of Mismatched HLA Detected in the Peripheral Blood of an AML Patient who Relapsed After Haploidentical Hematopoietic Stem Cell Transplantation

No abstract available.

Performance Evaluation of the Syva EMIT Methotrexate Assay on the Toshiba 200FR NEO

BACKGROUND: Methotrexate (MTX) is an antifolate antagonist that is widely used for treating various malignancies and non-malignant diseases. MTX levels should be monitored when used in high concentration to determine when to start leucovorin rescue. In this study, we evaluated the analytical performance of the EMIT Methotrexate Assay on a 200FR NEO Chemistry Analyzer (Toshiba Medical System Co., Japan) and compared it with Viva-E Drug Testing System (Siemens Healthcare, Germany). METHODS: According to the Clinical Laboratory and Standards Institute (CLSI) Evaluation Protocol (EP) 5-A2, three concentrations of the Liquichek Therapeutic Drug Monitoring Control (Bio-Rad Laboratories, USA) were analyzed twice a day for 20 days to monitor assay precision. The 200FR NEO and Viva-E instruments were compared using 40 patients' sera, according to CLSI EP9-A2. The linearity and carry-over rate were also evaluated. RESULTS: Between-run CVs for low-, medium-, and high-level controls were 4.9%, 0.9%, and 2.0%, respectively, whereas between-day CVs for low-, medium-, and high-level controls were 8.1%, 1.3%, and 3.5%, respectively. In the linearity test, the coefficient of determination (R2) was 0.98 (0.06-1.92 micromol/L). In the comparison study, R2 was 0.955, showing good correlation between the 200FR NEO and Viva-E instruments. The carry-over rate was 0.9%. CONCLUSIONS: The EMIT assay showed good precision, linearity, and carry-over rate on the Toshiba 200FR. An excellent correlation was observed when comparing results obtained using the Toshiba and Viva-E instruments. In conclusion, the Syva EMIT MTX assay can be readily used for MTX monitoring on the Toshiba 200FR NEO.

Long-Term Stability of Selected Serum Biomarkers in Leftover Samples / 임상검사와정도관리

BACKGROUND: The purpose of this study was to assess the quality of long-term-stored leftover blood samples, and to evaluate the long-term stability of selected serum biomarkers such as proteins, enzymes, electrolytes, and tumour markers. METHODS: Stored blood samples were transferred to our biobank after being used to conduct tests for routine medical examinations in one health care institution, and were preserved at or below -70degrees C for 4 years. We analysed 24 biomarkers whose levels had been reported 4 years ago and tested them using the same analyser, reagents, and methods by utilizing an ADVIA Centaur Immunoassay System (Siemens Healthcare Diagnostics, USA) or an ADVIA 2400 Chemistry System (Siemens, USA). RESULTS: A total of 15 out of the 24 tested biomarkers showed significant differences in paired Student t-tests (P0.975). Two biomarkers, creatinine and rheumatoid arthritis factor, showed no significant differences but were poorly correlated with previously analysed data. Aspartate aminotransferase, alanine aminotransferase, hepatitis B virus (HBV) surface antigen, and insulin levels were discordant according to their reference ranges. A total of 3 biomarkers, C-reactive protein, cancer antigen 125, and HBV surface antibody, showed no significant differences and good correlations without discordant data. CONCLUSIONS: Our findings showed that long-term storage for more than 4 years can result in a considerable bias for variable biomarkers. Only 3 of the 24 biomarkers evaluated were found to be stable biomarkers. Long-term storage of leftover samples is not recommended for most chemical analyses.

Meta-Analysis for the Pooled Sensitivity and Specificity of anti-Human Immunodeficiency Virus Ab Rapid Tests / 대한진단검사의학회지

BACKGROUND: Many immunochromatography (ICA) kits for anti-human immunodeficiency virus type (HIV) antibody (Ab) have been introduced to improve the accessibility of HIV Ab tests. However, qualified evaluation reports for HIV rapid tests are not enough to validate their performances. Metaanalysis for the performances of the HIV Ab rapid tests was performed in this study. METHODS: PubMed database was searched with combination of search terms, 'human immunodeficiency virus', 'HIV Ab', 'rapid test', 'immunochromatography', 'performance', 'sensitivity', and 'specificity'. Criteria of inclusion were performance studies for HIV ICA kits with serum or EDTA whole blood. Methodological qualities were evaluated with standards for reporting of diagnostic accuracy studies (STARD) checklists by two investigators. Homogeneity among selected studies was evaluated and then pooled sensitivity and specificity were calculated. Positive and negative predictive values were simulated with presumed HIV prevalence in Korea. RESULTS: Twenty-three studies were selected from 12 high-qualified papers with STARD checklists. The performance of 23 studies were found to be heterogeneous (P<0.1) and random effect model was used. Pooled sensitivity was 99.71% (95% CI: 99.45-99.97%) and pooled specificity was 99.27% (95% CI: 98.83-99.70%). With HIV prevalence of 0.03%, positive and negative predictive values were presumed to be 3.936% and 99.999%, respectively. CONCLUSIONS: This meta-analysis for HIV ICA rapid tests showed good performance. In consideration of low positive predictive values of HIV rapid tests, confirmation by enzyme immunoassay or Western blot is still needed. This study would be helpful in evaluating and establishing proper performance guideline for those kits not fully evaluated.

Analysis of Clinical Characteristics and S Gene Mutation of Hepatitis B Virus (HBV) in Patients with Hepatitis B Surface Antigen RIA Negative and HBV DNA Positive / 대한진단검사의학회지

BACKGROUND: We investigated hepatitis B virus (HBV) infection cases, who were HBsAg negative by radioimmunoassay (RIA) and HBV DNA positive for their clinical characteristics, the S gene mutation of hepatitis B virus (HBV), and usefulness of other HBsAg immunoassay. METHODS: Among the patients requested for HBV DNA quantification, 16 patients positive in HBV DNA but negative in HBsAg RIA (BNIBT HBsAg Kit, China) were enrolled. The "a" determinant of HBV S gene was sequenced and clinical characteristics were reviewed. Additional HBsAg assay was performed using Architect HBsAg kit (Abbott laboratories, USA) employing chemiluminescent immunoassay method. RESULTS: Eleven of the 16 patients showed multiple mutations in the "a" determinant. These patients received liver transplantation several years ago and have been treated with hepatitis B immune globulin (HBIG) and antiviral drugs. G145R mutation was found in 8 patients and G145K, D144G, and D144A were also frequently found. Among 9 of the 11 patients tested for HBsAg by Architect HBsAg kit, 8 showed positive results. Among 4 of the remaining 5 patients, only 2 showed weak positive results (< or =1 IU/mL) in Architect HBsAg kit. CONCLUSIONS: HBV DNA-positive/HBsAg RIA-negative results were mostly observed in the patients treated with HBIG after liver transplantation, in whom HBIG escape mutations were found. Majority of these cases were positive in Architect HBsAg assay, and it is recommended to use other HBsAg immunoassay methods that are more sensitive than RIA in the detection limit as well as in the detection of escape mutant in hospitals performing liver transplantation.

Subgenotype and Serotype Analysis of Hepatitis B virus in Korean Chronic Hepatitis B Patients Under Treatment / 대한진단검사의학회지

BACKGROUND: Hepatitis B virus (HBV) detected in Korean patients almost belongs to genotype C, which is subdivided into subgenotype C1 (or Cs) and C2 (or Ce). It was recently reported that the risk of hepatocellular carcinoma is different between subgenotype C1 and C2. Thus, we studied the distribution of subgenotypes of HBV in Korean chronic hepatitis B (CHB) patients. METHODS: Specimens of 421 patients, who were diagnosed as CHB and underwent antiviral treatment, were used. After sequence analysis for HBV S gene, subgenotype was identified through phylogenetic analysis. Utilizing the same sequence data, the distribution of serotypes was also investigated. RESULTS: Among 421 patient specimens, genotype C was found in 419 (99.5%) and genotype B in 2 (0.5%). Among the genotype C strains, 417 strains were C2 subgenotype and 2 strains were mixed subgenotypes. However, C2 was evidently found even in the mixed sequences. Serotypes of 419 HBV with genotype C were classified as follows: adr, 385 (91.9%), adw, 22 (5.3%), ayr, 2 (0.4%) and mixed serotype, 10 (2.3%). Serotype of both HBV with genotype B was adw. CONCLUSIONS: It was found that HBV detected in Korean CHB patients under treatment almost all belong to the C2 (Ce) genotype.

Experience on Identification of Cross-Reactive Group Specificity Performed by Anti-human Globulin Panel Reactive Antibody Tests / 대한진단검사의학회지

BACKGROUND: Panel reactive antibody (PRA) is to screen and identify HLA antibody. Majority of antibody specificities in high-PRA are directed against cross reactive group (CREG). Thus, this study was to know the advantage of identifying CREG specificity and whether antibody specificities are changed according to CREG classification. METHODS: HLA class I antibodies were identified from 159 sera from 108 patients in Asan Medical Center, who had shown more than 5% PRA by anti-human globulin (AHG)-complement-dependent cytotoxicity (CDC). Tail analysis-based computer program was developed to identify specificities, applying both Rodey (R-ABC) and Takemoto (T-ABC) classification. The results were also compared with those obtained when without CREG application (ABC). RESULTS: Among 151 cases in which HLA specificities was identified, the frequency of CREG specificity was 22.5% in R-ABC and 27.2% in T-ABC. Eleven cases showed CREG specificities only in one classification. However, the individual antigen specificities in one hand were all included in the CREG identified in the other hand. CREG specificities in samples with PRA >50% (60%) were more frequently identified than those in samples with PRA < or =50% (9%) (in R-ABC, P<0.0001). Without applying CREG to interpretation, specificity was not identified in 9 cases. CONCLUSIONS: Application of CREG enhanced the rate of antibody identification. Antibody specificities of those cases where CREG specificities were different between Rodey and Takemoto classifications were almost the same when compared at the individual antigen level. Therefore, it was thought that it makes no difference to use any one of these two classifications in interpreting PRA.

Evaluation of Urine NMP22 Point-of-Care Test for the Screening of Bladder Cancer / 대한진단검사의학회지

BACKGROUND: Screening of high-risk patients using bladder tumor markers can offer an advantage of early detection and saving medical costs. For these purpose many tumor markers have been developed to supplement invasive cystoscopy. Our study evaluated the NMP22 point-of-care test (NMP22 POCT), which is one of the tumor makers, comparing with the standard urine cytology for the diagnosis of bladder cancer. METHODS: From January to September 2005, 232 patients who had undergone a cystoscopy due to bladder cancer associated symptoms including hematuria and dysuria were enrolled in this study. Urine specimens were collected for NMP22 POCT and cytology. NMP22 POCT and urine cytology were compared for sensitivity and specificity. In addition, we evaluated urine stick test and microscopy to explain some false-positive results in NMP22 POCT. RESULTS: Superficial transitional cell carcinoma was diagnosed in 10 patients. The sensitivity of NMP22 test was 60% (95% confidence interval [CI], 26.2-87.8%), whereas that of cytology was 33.3% (95% CI, 7.5-70.1%); however, the difference was not significant. The specificity of NMP22 test was 69.8% (95% CI, 63.3-75.8%), compared with 99.0% (95% CI, 96.5-99.9%) for cytology (P<0.001). The presence of microscopic RBCs in urine specimen was significantly associated with the lower specificity of NMP22 POCT (P=0.02). CONCLUSIONS: NMP22 POCT was significantly less specific than urine cytology. To be useful as a bladder cancer screening test, the NMP22 test should have a higher specificity.

A Case of Hereditary Sideroblastic Anemia

We experienced a case of pyridoxine refractory hereditary sideroblastic anemia (HSA) in a 4 year-old girl and; therefore, conducted a study of her family. She was admitted to hospital for anemia, which was uncorrected by iron treatment. The peripheral blood smears showed hypochromic microcytic anemia. The results of the biochemical study indicated serum iron of 80 microgram/dL, TIBC of 275 microgram/dL and serum ferritin of 67ng/dL. The bone marrow smears showed 80% cellularity, with mild dyserythropoiesis. Many ringed sideroblasts, 45% of normoblasts and an increased amount of hemosiderin particles were observed with iron staining. Despite high-dose pyridoxine therapy, the anemia was not corrected. In the peripheral blood and iron studies conducted on her family members, the mother, maternal aunt and aunt's son showed microcytic hypochromic anemia and normal iron metabolism. Her mother's brother had died of acute myeloid leukemia that had transformed from myelodysplastic syndrome. From a search of the Korean literature, this is the first reported case of HSA with pedigree.

Clinical Resistance to the Tyrosine Kinase Inhibitor Imatinib (STI571) and Detection of BCR-ABL Gene Mutations in Korean Patients with Chronic Myeloid Leukemia

BACKGROUND: Imatinib mesylate, the tyrosine kinase activity of the BCR-ABL fusion gene, induces a remarkable remission in chronic myeloid leukemia (CML) patients. However, resistance to imatinib has been observed in a significant proportion of subjects, with the point mutations of the BCR-ABL kinase domain clinically identified as a possible mechanism. The aim of this study was to investigate clinical resistance to imatinib in Korean CML patients, and search for the point mutation of the BCR-ABL gene. METHODS: The clinical data and cytogenetic results of thirty two CML patients, who were treated with imatinib, between Jan. 2002 and Aug. 2003, were evaluated. Mutational analyses for the point mutations of the BCR-ABL kinase domain in clinically resistant patients were tested using RT-PCR and direct sequencing methods. RESULTS: Complete hematological remission was obtained in all CML patients with a chronic phase and in 4 of 6 CML with accelerated or blast crisis. However, 4 patients (2 in the chronic phase and 2 with blast crisis) relapsed to blast crisis following continued treatment. A major cytogenetic response was observed in 67% of the chronic phase patients, but in 2, the Philadelphia chromosomes reemerged in a follow-up chromosome study. Mutational analyses showed point mutations in the 351st amino acid of the BCR-ABL kinase domain in 2 patients: M351T, which has previously been reported in many studies, and a novel substitution, M351L. CONCLUSION: The frequency of imatinib resistance in Koreans was similar to that found in well-controlled western studies. Point mutations of the BCR-ABL kinase domain were detected in two patients. Further studies, with more sensitive methods and a greater number of patients will help reveal other mechanisms of imatinib resistance and establish more effective treatment plans.

The Comparison of Restriction Fragment Mass Polymorphism Method with Sequecing Method for the Detection of HBV YMDD Mutants / 대한진단검사의학회지

BACKGROUND: YMDD motif mutants of the hepatitis B virus (HBV) emerged in some chronic hepatitis B patients after prolonged lamivudine treatment. Recently a novel genotyping assay, the restriction fragment mass polymorphism (RFMP) method, was introduced for the detection of YMDD mutations. We compared the performance of the RFMP method with that of sequencing method in chronic hepatitis B patients who had suffered the HBV DNA breakthrough after lamivudine treatment. METHODS: Enrolled in this study were 18 chronic hepatitis B patients who experienced the DNA breakthrough after a period during which HBV DNA was undetectable by Hybrid capture II HBV DNA test (Digene Inc., Gaithersburg, MD, USA). Both sequencing and RFMP methods were used to detect YMDD variants in three phases such as before treatment, before breakthrough and after breakthrough. RESULTS: YMDD mutants were detected in 13 samples (72.2%) by both methods after DNA breakthrough. Among them were two samples with a mixed HBV population detected by RFMP. Before breakthrough, the mutants were detected in three samples (16.7%) by sequencing and four (22.2%) by RFMP, showing discrepant results for two samples. The concordance rate between both methods was 92.6%. CONCLUSIONS: Both sequencing and RFMP methods were highly concordant except in a few cases, so it is suggested that both methods are appropriate in detecting YMDD mutants.

The Evaluation of Clinical Utility of ATB FUNGUS 2 for Antifungal Susceptibility Testing in Candida Species / 대한임상미생물학회지

BACKGROUND: Although the National Committee for Clinical Laboratory Standards (NCCLS) defined a standard reference broth microdilution method for testing the susceptibility of Candida species to antifungal drugs, many clinical laboratories require easier but reliable alternatives for routine antifungal susceptibility testing. We evaluated ATB FUNGUS 2 (bioMerieux, France.; ATB) compared to the method recommended by the NCCLS (NCCLS). METHODS: A total of 28 strains of Candida species consecutively isolated from blood and CSF cultures at Asan Medical Center from April to June 2004 were tested. In addition, 12 strains comprising C. krusei (3), C. glabrata (7) and C. guilliermondii (2) from the collection of Chonnam National University Hospital were included in the study. These strains were tested for minimum inhibitory concentrations (MICs) against flucytosine (FC), fluconazole (FZ), itraconazole (IZ) and amphotericin B (AB) by both of ATB and NCCLS. In NCCLS, MICs were read using a spectrophotometer after 24 and 48 hour-incubation. RESULTS: The concordance rates of MICs between ATB and NCCLS after 24 hour-incubation were 100%, 75%, 89% and 96% within two-fold dilution and 100%, 97%, 97%, 100% within four-fold dilution for FC, FZ, IZ and AB, respectively. For C. krusei, all three FC and FZ-resistant strains were either intermediate or SDD and one IZ-resistant strain was SDD in ATB, respectively. One C. tropicalis strain resulted in AB MICs of 0.5 microgram/mL in NCCLS, but 2 microgram/mL in ATB. CONCLUSIONS: ATB showed good concordance rates with NCCLS after 24 hour-incubation. ATB appears to be a useful alternatives to NCCLS for routine antifungal susceptibility tests. However, ATB needs further evaluation with more clinical strains, especially those resistant to antifungal agents.

Genotype Analysis of Hepatitis B Virus Isolated from Korean Hepatitis Patients / 대한진단검사의학회지

BACKGROUND: Hepatitis B virus (HBV) is classified into 7 genotypes (A-G) that have distinct geographic distribution. Several studies have suggested that the HBV genotypic differences influence the severity of liver disease and clinical outcomes such that genotype C is associated with more advanced liver diseases and genotype B is associated with the earlier development of hepatocellular carcinoma. With the different genotypes of HBV reported in Shanghai, Taiwan and Japan, wetried to investigate the distribution of the HBV genotype and the utility of HBV genotyping tests in the Korea population. METHODS: A total of 51 HBV DNA positive serum from Korean hepatitis B patients were used for the genotyping. After PCR and sequencing, HBV genotypes were determined by phylogenetic analysis using the NCBI database (www.ncbi.nlm.nih.gov). RESULTS: By phylogenetic analysis in the Pre-S region, all the genotypes of HBV (100%) proved to be C. CONCLUSIONS: All patients in this study had genotype C. This result is consistent with previous studies reporting 96-100% distribution of genotype C in Korea. HBV genotyping in Korea is not informative in predicting individual variation of clinical outcome, so that it is meaningless to genotype HBV in routine laboratory genotyping.

Genotype Analysis of Hepatitis B Virus Isolated from Korean Hepatitis Patients / 대한진단검사의학회지

BACKGROUND: Hepatitis B virus (HBV) is classified into 7 genotypes (A-G) that have distinct geographic distribution. Several studies have suggested that the HBV genotypic differences influence the severity of liver disease and clinical outcomes such that genotype C is associated with more advanced liver diseases and genotype B is associated with the earlier development of hepatocellular carcinoma. With the different genotypes of HBV reported in Shanghai, Taiwan and Japan, wetried to investigate the distribution of the HBV genotype and the utility of HBV genotyping tests in the Korea population. METHODS: A total of 51 HBV DNA positive serum from Korean hepatitis B patients were used for the genotyping. After PCR and sequencing, HBV genotypes were determined by phylogenetic analysis using the NCBI database (www.ncbi.nlm.nih.gov). RESULTS: By phylogenetic analysis in the Pre-S region, all the genotypes of HBV (100%) proved to be C. CONCLUSIONS: All patients in this study had genotype C. This result is consistent with previous studies reporting 96-100% distribution of genotype C in Korea. HBV genotyping in Korea is not informative in predicting individual variation of clinical outcome, so that it is meaningless to genotype HBV in routine laboratory genotyping.

Comparison of FAB and WHO Classifications and Validation of WHO Classifications in 218 Korean Patients with Myelodysplastic Syndrome / 대한진단검사의학회지

BACKGROUND: World Health Organization (WHO) proposed a new classification of myelodysplastic syndrome (MDS) in 1999, based on significant modifications of the original FAB proposals. The aim of the present study was to validate the new classification with respect to prognostic importance. METHODS: Two hundred and eighteen patients were diagnosed with MDS according to the FAB criteria between August 1989 and June 2001 in the Asan Medical Center. They were studied retrospectively to evaluate morphological, clinical and cytogenetic data for diagnosis and clinical outcomes with long-term follow up, and reclassified with a new WHO classification. RESULTS: According to the original FAB classification, 218 patients were classified as RA 78, RARS 17, RAEB 76, RAEB-t 38 and CMML 9. They were reclassified to the WHO classification to RA 24, RARS 6, RCMD 51, RCMD-RS 11, RAEB-1 42, RAEB-2 51, del(5q) syndrome 1 and unclassifiable 2. Twenty-one cases of RAEB-t and 9 cases of CMML were reclassified to acute myeloid leukemia and myelodysplastic syndrome/myeloproliferative disease (MDS/MPD). Among the reclassified groups in the WHO classification, there is a significant difference in prognosis between RA and RCMD (median survival, not reached vs. 28.4 months, P=0.020), and in leukemic transformation between RAEB-1 and RAEB-2 (5% vs. 37%, P=0.001). CONCLUSIONS: These data provide the proper evidence, especially of prognosis and leukemic transformation for the WHO classifications. We recommended using the WHO classification rather than the FAB classification of the diagnosis of MDS.