Comparative Evaluation of the STANDARD F Influenza A/B FIA Test with the Sofia Influenza A+B FIA and SD BIOLINE Influenza Ag A/B/A(H1N1) tests for Influenza A Virus Detection / 대한임상미생물학회지

Background@#This study aimed to evaluate the diagnostic performance of the STANDARD F Influenza A/B FIA test (SD Biosensor Inc., Korea) for the rapid detection of influenza A virus in comparison with the Sofia Influenza A+B FIA (Quidel Corp., USA) and SD BIOLINE Influenza Ag A/B/A(H1N1) (Standard Diagnostic, Inc., Korea) tests. @*Methods@#A total of 227 non-duplicated nasopharyngeal aspirates submitted for real-time RT-PCR analysis were included in the study. We used the three commercial tests in remnant samples from routine assays, according to the manufacturer’s instructions. We analyzed the diagnostic performance, including sensitivity and specificity, of the three tests. @*Results@#Real-time RT-PCR analysis showed that 67 (29.5%) samples were positive and 160 (70.5%) were negative for influenza A virus, and that all the specimens were negative for influenza B. The overall sensitivity and specificity for influenza A virus detection were 50.7% and 100% for the STANDARD F, 50.7% and 100% for the Sofia, and 29.9% and 100% for the SD BIOLINE tests, respectively. The STANDARD F and SD BIOLINE tests showed negative results for influenza B virus in all specimens, whereas the Sofia test showed two false-positive results. @*Conclusion@#The STANDARD F Influenza A/B test showed a good diagnostic performance and may be useful for the rapid diagnosis of influenza A.

Performance Evaluation of MEDITAPE UC-11A Strip Test in Estimating the Urine Albumin-to-Creatinine Ratio and Urine Protein-to-Creatinine Ratio

30 mg/g), the concordance rate, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of UACR, analyzed using MEDITAPE UC-11A, were 80.5, 97.5, 67.0, 70.3, and 97.1%, respectively. Using UPCR, analyzed via quantitative assay, as a reference to estimate proteinuria (UPCR >0.15 g/g), the concordance rate, sensitivity, specificity, PPV, and NPV of UPCR, analyzed using MEDITAPE UC-11A, were 86.7, 94.4, 81.5, 77.6, and 95.6%, respectively.CONCLUSIONS: UACR and UPCR, analyzed using MEDITAPE UC-11A, exhibited relatively high sensitivity and NPV, which is beneficial for laboratory screening for both albuminuria and proteinuria.

Development and Evaluation of Multiplex PCR for the Detection of Carbapenemase-Producing Enterobacteriaceae / 대한임상미생물학회지

BACKGROUND: The isolation of carbapenemase-producing Enterobacteriaceae (CPE) has become increasingly common. Continuous surveillance for these organisms is essential because their infections are closely related to outbreaks of illness and are associated with high mortality rates. The aim of this study was to develop and evaluate multiplex PCR as a means of detecting several important CPE genes simultaneously. METHODS: We aimed to develop a multiplex PCR that could detect seven CPE genes simultaneously. The multiplex PCR was composed of seven primer sets for the detection of KPC, IMP, VIM, NDM-1, GES, OXA-23, and OXA-48. We designed different PCR product sizes of at least 100 bp. We evaluated the performance of this new test using 69 CPE-positive clinical isolates. Also, we confirmed the specificity to rule out false-positive reactions by using 71 carbapenem-susceptible clinical strains. RESULTS: A total of 69 CPE clinical isolates showed positive results and were correctly identified as KPC (N=14), IMP (N=13), OXA-23 (N=12), OXA-48 (N=11), VIM (N=9), GES (N=5), and NDM (N=5) by the multiplex PCR. All 71 carbapenem-susceptible clinical isolates, including Enterococcus faecalis , Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, showed negative results. CONCLUSION: This multiplex PCR can detect seven CPE genes at a time and will be useful in clinical laboratories.

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.

Serotyping and Antimicrobial Susceptibility of Salmonella Isolated in Korea in 2015 / 대한임상미생물학회지

BACKGROUND: Salmonella is an important pathogen that causes gastroenteritis and sepsis in humans. Recently, changes in serotype prevalence and an increase in antimicrobial resistance have been reported. This study investigated the distribution of Salmonella serotypes and determined the antimicrobial susceptibility of various strains. METHODS: We collected 113 Salmonella isolates other than Salmonella serotype Typhi from 18 university hospitals in 2015. The serotypes were identified by Salmonella antisera O and H according to the Kauffman White scheme. Antimicrobial susceptibility tests for 12 antibiotics were performed using the disk diffusion method or E-test. RESULTS: We identified 22 serotypes. Serotype group B (44.2%) was the most common, followed by groups C (34.5%) and D (21.2%). Salmonella I 4,[5],12:i:- (23.0%), S. Enteritidis (16.8%), and S. Typhimurium (12.4%) were the most common species. Resistance rates for ampicillin, chloramphenicol, ceftriaxone, and trimethoprim/sulfamethoxazole were 46.9%, 18.5%, 8.8%, and 5.3%, respectively. The intermediate resistance rate to ciprofloxacin was 29.2%. Six isolates were extended-spectrum β-lactamase (ESBL) producers, including 5 bla(CTX-M-15) and 1 bla(CTX-M-55). CONCLUSION: There have been changes in the serotype prevalence and antimicrobial resistance of Salmonella in Korea, with a high prevalence of CTX-M 15-positive strains. Continuous monitoring of Salmonella serotypes and antimicrobial resistance is warranted.

Molecular Genetic and Serologic Analysis of the O allele in the Korean Population / 대한수혈학회지

BACKGROUND: The recent expansion of knowledge about various ABO alleles has led to the need for a comprehensive measure to cover the numerous polymorphisms dispersed in the ABO gene. A few studies have examined the diversity of the O allele compared to A or B subgroup alleles, resulting in antigenic changes. This study investigated the relationship between the serologic and molecular genetic characteristics of the O alleles in the Korean population. METHODS: One hundred and five samples from healthy blood group O subjects were selected randomly. The isoagglutinin titer was measured using a tube agglutination and gel microcolumn assay. The ABO alleles were analyzed by sequencing exons 6 and 7 of the ABO gene. When the origin of a heterozygous nucleotide sequence was ambiguous, it was separated into a single allele using mono-allele amplification or cloning. RESULTS: The median IgM isoagglutinin titer was eight. In contrast, the median IgG anti-A and anti-B isoagglutinin titers were 64 and 32, respectively. The IgG isoagglutinin titer showed a significant increase with age (P<0.0001). Six O alleles were observed in 105 blood group O populations by sequencing. The O01 and O02 alleles were common (0.57, 0.36). Three rare O alleles (O04, O05, and O06) and one novel non-deletional O allele were found. CONCLUSION: The distribution of isoagglutinin titers of blood group O and the genetic frequency of O alleles in this study would form the basis of the development and interpretation of ABO genotyping and serologic workup in the Korean population.

Microbiological Characteristics of Corynebacterium striatum, an Emerging Pathogen / 한양의대학술지

C. striatum is part of the normal skin and mucous membrane flora in humans and is widely disseminated in the environment. Traditionally, these strains have been considered contaminants. However, C. striatum has been linked to respiratory infection, bacteremia, and endocarditis; and it is strongly related to nosocomial outbreaks. At present, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) is the most accurate routine identification method. Many C. striatum strains are multi-drug resistant, being susceptible only to vancomycin and linezolid. We should survey the antimicrobial susceptibility results regularly to monitor its resistance and consider it a possible pathogen.

A Case of Hemolytic Transfusion Reaction Attributable to Anti-Jk(b) Abolished in the Enzyme Phase Reaction / 대한수혈학회지

We report a case of an intravascular hemolytic reaction attributable to anti-Jk(b) antibodies that were not detected using an enzyme phase antibody identification test. A 61-year-old male who had received two units of red blood cells was admitted to the emergency room because his urine was dark. LISS/Coombs gel column agglutination tests suggested the presence of anti-Jk(b) and anti-E antibodies. However, his serum was negative for the Jk(b) antigen when an enzyme phase test was performed. A positive reaction was evident, however, when EDTA-treated plasma was tested; this excluded any possible complement-mediated reaction. The patient was diagnosed with an intravascular hemolytic transfusion reaction, caused by anti-Jk(b), and was later discharged without specific complications after receiving antigen-negative blood transfusions.

Falsely Elevated Tacrolimus Concentrations Using Chemiluminescence Microparticle Immunoassay in Kidney Transplant Patient / 대한이식학회지

Tacrolimus is one of the effective immunosuppressive drugs used after an organ transplant procedure. However, due to its narrow therapeutic range, its usefulness in preventing transplant rejection and minimizing nephrotoxicity is dependent on the monitoring of whole blood trough levels of tacrolimus. A 49-year-old kidney transplant recipient presenting with cough and general weakness was admitted to the hospital. Due to the patient's deeply compromised clinical condition, an immunosuppressive therapy was discontinued. Tacrolimus concentrations in the patient's whole blood samples were measured, using an automated chemiluminescent microparticle immunoassay (CMIA) instrument. Interference was suspected because tacrolimus concentrations after the discontinuation of tacrolimus dose were 20.9 and 18.2 ng/mL at day 2 and 3, respectively. Tacrolimus concentrations were 11.1 and 12.6 ng/mL, respectively, when re-tested using an antibody-conjugated magnetic immunoassay (ACMIA). We evaluated the relationship between the CMIA and ACMIA results, and calculated the expected values from the regression equation. Residuals were –8.4 and –4 ng/mL, respectively. There have been several cases with false detection of elevated tacrolimus concentrations using ACMIA; however, such falsely detected elevations using CMIA have rarely been reported. When unexpectedly high concentrations of tacrolimus are detected by CMIA in transplant patients, an immediate re-test using another technique might be necessary to rule out falsely elevated results.

Distribution and Antimicrobial Resistance of Streptococcus pneumoniae at Four University Hospitals in Busan and Gyeongnam / 대한임상미생물학회지

BACKGROUND: Streptococcus pneumoniae is the most common human pathogen causing community-acquired pneumonia. There is little information on the recent antimicrobial susceptibility patterns of S. pneumoniae in Busan and Gyeongnam of Korea. The aim of this study was to investigate the distribution and antimicrobial resistance of S. pneumoniae at 4 university hospitals in Busan and Gyeongnam. METHODS: We collected and analyzed the antimicrobial susceptibility results of 850 S. pneumoniae strains isolated from regional 4 university hospitals during the last 2 years from July 2013 through June 2015. RESULTS: Among 850 S. pneumoniae strains, 635 strains were isolated from respiratory specimens, followed by blood (N=121), CSF (N=13), and others (N=81). Antimicrobial susceptibility rates to penicillin, cefotaxime and ceftriaxone were 79.4%, 76.6% and 83.6%, respectively. The resistant rates to erythromycin and clindamycin were 80.9% and 68.2%, respectively. The resistant rates to levofloxacin were 9.2%. There were some differences in resistant rates by age groups, years, and specimen types. CONCLUSION: We found the changes of antimicrobial resistance of S. pneumoniae during the last 2 years. It is necessary to monitor the antimicrobial susceptibility of S. pneumoniae regularly for empirical therapy and for early detection of the changes of resistance.

Acute Myeloid Leukemia With MLL Rearrangement and CD4+/CD56+ Expression can be Misdiagnosed as Blastic Plasmacytoid Dendritic Cell Neoplasm: Two Case Reports

No abstract available.

Comparison of the Clinical Performance of Binax NOW RSV Versus Multiplex RT-PCR for Detection of Respiratory Syncytial Virus

BACKGROUND: Respiratory syncytial virus (RSV) is one of the most important causes of lower respiratory tract infection. The rapid antigen test is a simple, cheap, and quick method for RSV detection, however, it has an acknowledged low sensitivity. The aim of this study is to evaluate the diagnostic performance of the rapid antigen test by comparing it with a multiplex reverse transcription-PCR (RT-PCR). METHODS: A total of 557 nasopharyngeal aspirates or swabs that were submitted for both a rapid antigen test, Binax NOW RSV (Binax; Alere Scarborough, Inc., USA) and multiplex RT-PCR, Seeplex RV7 (Seegene Inc., Korea) were included in this study. We performed both tests according to the manufacturer's recommendations and analyzed the diagnostic performances of a rapid antigen tests based on the results of multiplex RT-PCR. RESULTS: Among the 557 specimens, the positive rates determined from the rapid antigen test and multiplex RT-PCR were 12.2% (N=68) and 25.1% (N=140), respectively. The relative sensitivity and specificity of the rapid antigen test were 46.4% and 99.3% based on the multiplex RT-PCR, respectively. Positive and negative predictive values were 95.6% and 84.7%, respectively. The diagnostic sensitivity was lower (28.6%) in children >36 months compared with children < or =36 months of age. Test sensitivity declined when RSV infection was accompanied by infection with other respiratory viruses. CONCLUSIONS: Binax NOW RSV exhibited good diagnostic performance, easy handling, and rapidity. However, it does have the possibility of false-negative results, and additional tests are needed when there is clinical suspicion of RSV infection.

A Nationwide Multicenter Survey for Mycobacterial Testing in Korea / 대한임상미생물학회지

BACKGROUND: There have been steady changes and improvements in diagnostic tests for Mycobacterium tuberculosis, so it is necessary to carry out periodic surveys to understand the current situation. The aims of this study were to investigate the changes in principal practices and quality control for M. tuberculosis using a nationwide survey in the Republic of Korea. METHODS: We constructed a questionnaire composed of four subseries with 42 items. We e-mailed this survey to members of the Korean Society of Clinical Microbiology from April to September 2014 and analyzed the replies. RESULTS: Employees at a total of 65 hospital laboratories and 5 commercial laboratories participated in the survey. AFB staining was reportedly performed in all 70 institutions, and fluorescent staining was used as the primary detection method in 59 (84.3%) laboratories. Solid and liquid culture methods for Mycobacterium were performed at 62 (88.6%) and 59 (84.3%) laboratories, respectively. There were 57 laboratories (90.5%) that identified strains growing on primary culture media using a rapid antigen kit or molecular method. The mean values of positive and contamination rates for solid culture media were 8.2% (range 3.7-19.9%) and 4.0% (0.4-8.4%), respectively. In liquid culture, the mean values of positive and contamination rates were 11.5% (4.8-22.3%) and 6.8% (0.3-18.7%), respectively. CONCLUSION: There have been significant changes and improvements in overall mycobacterial testing, especially in the numbers of laboratories using fluorescent staining, liquid culture, and identification of M. tuberculosis cultured media compared with previous surveys in Korea.

Evaluation of the Automated Hematology Analyzer Sysmex XN-2000 and the Accuracy of Differential Leukocyte Counts Using the Low WBC Mode

BACKGROUND: The XN-series (Sysmex, Japan) is the new hematology analyzer from Sysmex, with new channels to improve the accuracy of differential leukocyte count and platelet count in the low cell count range. We evaluated the analytical performance and low white blood cell (WBC) mode of the XN-2000. METHODS: Precision, linearity, and carryover were evaluated for the analyzer. We analyzed the accordance of complete blood count (CBC), reticulocyte count, and differential leukocyte count between the XN-2000 and XE-2100 (Sysmex), using 200 samples from normal controls and patients. For 80 samples with a WBC count 0.9800 for all CBC parameters except mean corpuscular hemoglobin concentration, mean platelet volume, and platelet distribution width, and >0.9900 for differential leukocyte count except monocytes and basophils. The low WBC mode provided accurate counts for neutrophils and lymphocytes, with r>0.9300 for samples with a WBC count of 0.1-1.5x10(9) cells/L. CONCLUSIONS: The XN-2000 showed good analytical performance and correlation with the existing model, the XE-2100. The XN-2000 provided accurate results for differential leukocyte count in samples with a WBC count of 0.1-1.5x10(9) cells/L, and reduced manual slide reviews.

Clinical Usefulness of Routine Use of Anaerobic Blood Culture Bottle / 대한임상미생물학회지

BACKGROUND: Blood culture for diagnosis of bacteremia and fungemia comprises aerobic and anaerobic cultures. The clinical utility of routine anaerobic blood culture has been questioned for a long time and was evaluated in this study. METHODS: A total of 9,028 positive blood cultures were collected from adults at four university-affiliated hospitals. We recorded the species distribution according to growth in aerobic or anaerobic culture. RESULTS: Among the 9,028 positive results, 3,239 cases (35.9%) occurred in aerobic culture, 1,543 cases (17.1%) in anaerobic culture and 4,246 cases (47.0%) in both cultures. The species grown only in the anaerobic cultures consisted of 81.4% facultative anaerobes, 2.0% strict anaerobes, 8.5% strict aerobes, and 8.1% yeasts. CONCLUSION: Routine use of paired aerobic/anaerobic blood culture is essential because a considerable number of facultative anaerobes and yeasts grow only in anaerobic blood culture. Strict aerobes and fungi were more commonly isolated in the anaerobic bottles than were strict anaerobes.

Clinical Significance of Clonal Rearrangement of the Immunoglobulin Gene in the Bone Marrow of Patients with B-cell Non-Hodgkin Lymphoma

BACKGROUND: In the early stages of non-Hodgkin lymphoma (NHL), it can be difficult to recognize minimal morphological changes in the bone marrow (BM). In particular, when the quality of the BM biopsy is poor, determining BM involvement is limited to microscopic findings on BM aspiration. In this study, we compared the results of clonal immunoglobulin (IG) gene rearrangements with BM morphology results in B-cell NHL patients who underwent BM analysis as a staging workup and evaluated the usefulness of the clonal IG gene rearrangements for staging. METHODS: Forty two B-cell NHL patients were analyzed. Clonal rearrangements of the IG heavy chain (IGH), kappa light chain (IGK) and lambda light chain (IGL) genes were detected using the IdentiClone(TM) Clonality assay (InVivoScribe Technologies, USA). Clinical characteristics and outcomes were evaluated based on the detection of monoclonal IG gene rearrangements. RESULTS: Monoclonal IG gene rearrangements were found in 9 of 42 patients (21.4%). Microscopic BM involvement was found in only 2 of 42 patients (4.8%). The monoclonality rate of IG genes in BM was correlated with clinical stage and the international prognostic index (P<0.01). Patients with monoclonal IG gene rearrangements in BM had a significantly higher relapse rate (P=0.014) and poorer overall survival at 2 yr (P<0.01). CONCLUSIONS: Clonality analysis of BM in B-cell NHL can contribute to identification of patients with occult BM involvement with a significantly poorer overall survival despite normal BM histology.

Postsurgical Wound Infection Caused by Mycobacterium conceptionense Identified by Sequencing of 16S rRNA, hsp65, and rpoB Genes in an Immunocompetent Patient / 대한임상미생물학회지

Rapidly growing mycobacteria are ubiquitous in the environment and are increasingly being recognized as opportunistic pathogens. Recently, a new species, Mycobacteium conceptionense, has been validated from the Mycobacterium fortuitum third biovariant complex by molecular analysis. However, there are few reports, and postsurgical wound infection by this species is rare. We report a case of postsurgical wound infection caused by M. conceptionense in an immunocompetent patient that was identified by a sequencing analysis of 16S rRNA, hps65, and rpoB genes.

Evaluation of DNA Extraction Methods and Their Clinical Application for Direct Detection of Causative Bacteria in Continuous Ambulatory Peritoneal Dialysis Culture Fluids from Patients with Peritonitis by Using Broad-Range PCR

BACKGROUND: The aims of this study were to compare several DNA extraction methods and 16S rDNA primers and to evaluate the clinical utility of broad-range PCR in continuous ambulatory peritoneal dialysis (CAPD) culture fluids. METHODS: Six type strains were used as model organisms in dilutions from 10(8) to 100 colony-forming units (CFU)/mL for the evaluation of 5 DNA extraction methods and 5 PCR primer pairs. Broad-range PCR was applied to 100 CAPD culture fluids, and the results were compared with conventional culture results. RESULTS: There were some differences between the various DNA extraction methods and primer sets with regard to the detection limits. The InstaGene Matrix (Bio-Rad Laboratories, USA) and Exgene Clinic SV kits (GeneAll Biotechnology Co. Ltd, Korea) seem to have higher sensitivities than the others. The results of broad-range PCR were concordant with the results from culture in 97% of all cases (97/100). Two culture-positive cases that were broad-range PCR-negative were identified as Candida albicans, and 1 PCR-positive but culture-negative sample was identified as Bacillus circulans by sequencing. Two samples among 54 broad-range PCR-positive products could not be sequenced. CONCLUSIONS: There were differences in the analytical sensitivity of various DNA extraction methods and primers for broad-range PCR. The broad-range PCR assay can be used to detect bacterial pathogens in CAPD culture fluid as a supplement to culture methods.

Autoimmune Hemolytic Anemia after Aplastic Crisis due to Parvovirus B19 Infection in a Patient with Hereditary Spherocytosis

Hereditary spherocytosis (HS) is a genetic disorder characterized by the production and destruction of spherocytes due to a deficiency of red cell membrane cytoskeletal proteins, resulting in the clinical presentation of chronic hemolytic anemia. This disease can be accompanied by an aplastic crisis due to parvovirus B19 infection. Parvovirus B19 infection causes diseases such as erythema infectiosum and arthritis, and can also trigger various autoimmune diseases, including autoimmune hemolytic anemia (AIHA). Here, we report a rare case of AIHA developing 3 months after an aplastic crisis due to parvovirus B19 infection in an 11-year-old boy with HS and provide the relevant literature review.

Autoimmune Hemolytic Anemia after Aplastic Crisis due to Parvovirus B19 Infection in a Patient with Hereditary Spherocytosis

Hereditary spherocytosis (HS) is a genetic disorder characterized by the production and destruction of spherocytes due to a deficiency of red cell membrane cytoskeletal proteins, resulting in the clinical presentation of chronic hemolytic anemia. This disease can be accompanied by an aplastic crisis due to parvovirus B19 infection. Parvovirus B19 infection causes diseases such as erythema infectiosum and arthritis, and can also trigger various autoimmune diseases, including autoimmune hemolytic anemia (AIHA). Here, we report a rare case of AIHA developing 3 months after an aplastic crisis due to parvovirus B19 infection in an 11-year-old boy with HS and provide the relevant literature review.