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Single-target rapid antigen tests (RATs) are commonly used to detect highly transmissible respiratory viruses (RVs), such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses. The simultaneous detection of RVs presenting overlapping symptoms is vital in making appropriate decisions about treatment, isolation, and resource utilization; however, few studies have evaluated multiplex RATs for SARS-CoV-2 and other RVs. We assessed the diagnostic performance of multiplex RATs targeting both the SARS-CoV-2 and influenza A/B viruses with the GenBody Influenza/COVID-19 Ag Triple, InstaView COVID-19/Flu Ag Combo (InstaView), STANDARD TM Q COVID-19 Ag Test, and STANDARD TM Q Influenza A/B Test kits using 974 nasopharyngeal swab samples. The cycle threshold values obtained from the real-time reverse transcription polymerase chain reaction results showed higher sensitivity (72.7-100%) when the values were below, rather than above, the cut-off values. The InstaView kit exhibited significantly higher positivity rates (80.21% for SARS-CoV-2, 61.75% for influenza A, and 46.15% for influenza B) and cut-off values (25.57 for SARS-CoV-2, 21.19 for influenza A, and 22.35 for influenza B) than the other two kits, and was able to detect SARS-CoV-2 Omicron subvariants. Therefore, the InstaView kit is the best choice for routine screening for both SARS-CoV-2 and influenza A/B in local communities.

Background: The quality of laboratory test results is crucial for accurate clinical diagnosis and treatment. Pre-analytical errors account for approximately 60%-70% of all laboratory test errors. Laboratory test results may be largely impacted by pre-analytical phase management. However, primary care clinics currently do not have pre-analytical quality management audit systems. We aimed to understand the current status of pre-analytical quality management in laboratory medicine in Korean primary care clinics., Methods: Questionnaires were designed to focus on essential components of the pre-analytical process of primary care clinics. An online survey platform was used to administer the survey to internal medicine or family medicine physicians in primary care clinics., Results: A total of 141 physicians provided a complete response to the questionnaire. In 65.2% of the clinics, patient information was hand-labeled rather than barcoded on the specimen bottles; 14.2% of clinics displayed only one piece of patient information (name or identification number), and 19.9% of clinics displayed two pieces of information. Centrifuges were not available in 29.1% of the clinics. Institutions carrying out the National Health Screening Program (NHSP) used more barcode system and had more centrifuges than institutions that did not carrying out the NHSP., Conclusions: Pre-analytical quality management is inadequate in many primary clinics. We suggest implementation of a mandatory management system, allowing for a pre-analytical quality management to be carried out in primary care clinics.

Although coronavirus disease 2019 (COVID-19) is no longer a Public Health Emergency of International Concern (PHEIC), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has had a vast impact to date. Hence, continuous management is required, given the uncertainty caused by the potential evolution of SARS-CoV-2. Reverse transcription-quantitative PCR (RT-qPCR) diagnosis has been fundamental in overcoming this issue. In this study, the performances of two rapid RT-qPCR assays (Real-Q Direct SARS-CoV-2 Detection Kit and Allplex™ SARS-CoV-2 fast PCR Assay) with short PCR times were comparatively evaluated using a STANDARD M nCoV Real-Time Detection Kit (STANDARD M, conventional RT-qPCR assay). All kits showed a limit of detection values (10 2 -10 3 copies/reaction). The evaluation showed that the two rapid assay tests had ≥97.89% sensitivity and ≥99.51% specificity (κ = 0.98) for individual samples and ≥97.32% sensitivity and ≥97.67% specificity for pooled samples compared to STANDARD M. These results indicate that the two rapid RT-qPCR kits, which showed significant time reduction in performance, are as effective as a conventional RT-qPCR assay. They are likely to increase not only the number of tests that can be performed but also the efficiency of sustainable management of COVID-19 in the long term.

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., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2023 The Korean Academy of Medical Sciences.)

Owing to the high transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, the capacity of testing systems based on the gold standard real-time reverse transcription-polymerase chain reaction (rRT-PCR) is limited. Rapid antigen tests (RATs) can substantially contribute to the prevention of community transmission, but their further assessment is required. Here, using 1503 nasopharyngeal swabs, we compared the diagnostic performance of four RAT kits (Abbott Panbio™ COVID-19 Ag Rapid Test, SD Biosensor Standard™ Q COVID-19 Ag Test, Humasis COVID-19 Ag Test, and SG Medical Acrosis COVID-19 Ag Test) to the cycle threshold (Ct) values obtained from rRT-PCR. The precision values, area under the curve values, SARS-CoV-2 variant detection ability, and non-SARS-CoV-2 specificity of all four kits were similar. An assay using the Acrosis kit had a significantly better positive detection rate with a higher recall value and cut-off value than that using the other three RAT kits. During the current COVID-19 pandemic, the Acrosis kit is an effective tool to prevent the spread of SARS-CoV-2 in communities.

We herein characterized rotavirus infection in hospitalized children under 5 years of age with gastroenteritis after introducing rotavirus vaccines in South Korea from 20 February 2012, to 31 March 2013. Enzyme-linked fluorescent immunoassay was performed to detect rotavirus antigens. G and P genotyping was performed using nested multiplex PCR. For the failed PCR samples, sequencing was conducted. We performed a test-negative case-control study to estimate vaccine effectiveness. Vaccine effectiveness was measured using a multivariate logistic regression model. Rotavirus was detected in 16 (13.2%) of the 121 patients, with a seasonal peak in April 2012. The dominant genotypes detected were G3P[8] (33.3%) and G4P[6] (26.7%), and vaccine effectiveness against rotavirus hospitalization was 84.9% [95% CI: 23.2−97.0] in the complete vaccinated group. A higher prevalence of rotavirus infection was observed among children with siblings than those without siblings (p < 0.001). Also, the presence of siblings was significantly associated with a history of nonvaccination (p < 0.001). In conclusion, the prevalence of rotavirus followed a decreasing trend, and there was no evidence of emergences of nonvaccine-type strains. Vaccine effectiveness against rotavirus hospitalization was 84.9%. Although children with siblings were more susceptible to rotavirus infection, they were less likely to receive vaccination against rotavirus.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the third highly pathogenic human coronavirus and is rapidly transmitted by infected individuals regardless of their symptoms. During the COVID-19 pandemic, owing to the dearth of skilled healthcare workers (HCWs) to collect samples for early diagnosis, self-collection emerged as a viable alternative. To evaluate the reliability of self-collection, we compared the virus detection rate using 3990 self-collected swabs and HCW-collected swabs, procured from the same individuals and collected immediately after the self-collection. The results of multiplex reverse-transcription quantitative polymerase chain reaction revealed that the viral load in the HCW-collected swabs was marginally (18.4-28.8 times) higher than that in self-collected swabs. Self-collection showed no significant difference in sensitivity and specificity from HCW-collection (κ = 0.87, McNemar's test; p = 0.19), indicating a comparable performance. These findings suggest that self-collected swabs are acceptable substitutes for HCW-collected swabs, and that their use improved the specimen screening efficiency and reduced the risk of SARS-CoV-2 infection among HCWs during and after the COVID-19 pandemic., Competing Interests: The authors declare no conflicts of interest.

Severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is still rapidly spreading as of March 2022. An accurate and rapid molecular diagnosis is essential to determine the exact number of confirmed cases. Currently, the viral transport medium (VTM) required for testing is in short supply due to a sharp increase in the laboratory tests performed, and alternative VTMs are needed to alleviate the shortage. Guanidine thiocyanate-based media reportedly inactivate SARS-CoV-2 and are compatible with quantitative reverse transcription polymerase chain reaction (RT-qPCR) assays, but the compatibility and the viral detection capacity have not been fully validated. To evaluate the guanidine thiocyanate-based Gene Transport Medium (GeneTM) as an alternative VTM, we prepared 39 SARS-CoV-2-positive and 7 SARS-CoV-2-negative samples in GeneTM, eNAT™, and phosphate-buffered saline (PBS). The cycle threshold (Ct) values of three SARS-CoV-2 targets (the S, RdRP, and N genes) were analyzed using RT-qPCR testing. The comparison of Ct values from the positive samples showed a high correlation ( R 2 = 0.95-0.96) between GeneTM and eNAT™, indicating a comparable viral detection capacity. The delta Ct values of the SARS-CoV-2 genes in each transport medium were maintained for 14 days at cold (4°C) or room (25°C) temperatures, suggesting viral samples were stably preserved in the transport media for 14 days. Together, GeneTM is a potential alternative VTM with comparable RT-qPCR performance and stability to those of standard media., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2022 Young Hyun Baek et al.)

Purpose: This study aimed to examine the changes in the characteristics of community-onset fluoroquinolone-resistant (FQ-R) Escherichia coli isolates causing community-acquired acute pyelonephritis (APN) in South Korea., Methods: Blood or urine samples were prospectively collected from patients aged ≥15 years with community-acquired APN who were admitted to one of the eight Korean hospitals included in this study between September 2017 and August 2018. Phylogenetic typing, multilocus sequence typing, and molecular characterization of β-lactamase resistance and plasmid-mediated quinolone resistance (PMQR) determinants were performed. The data were compared with those from a previous study with the same design conducted in 2010-2011., Results: A total of 300 and 346 isolates were identified in 2010-2011 and 2017-2018, respectively. Among them, 76 (22.0%) and 77 (25.7%) FQ-R isolates were identified in 2010-2011 and 2017-2018, respectively. A significantly higher antimicrobial resistance against third-to fourth-generation cephalosporins, including cefotaxime (23.9% vs. 77.9%, P < 0.001), were observed among FQ-R isolates in 2017-2018 than among those in 2010-2011. A higher proportion of ST131 isolates (27.6% vs. 66.2%, P < 0.001), as well as isolates that had extended-spectrum β-lactamase (ESBL)/plasmid-mediated AmpC β-lactamase (PABL) (23.7% vs. 79.2%, P < 0.001), was observed in 2017-2018 than in 2010-2011. Further, more PMQR determinants (11.8% vs. 40.8%, P < 0.001) were observed in 2017-2018 than in 2010-2011., Conclusions: Among uropathogenic FQ-R E. coli isolates in South Korea, the prevalence of ST131 and the proportion of isolates containing ESBL and/or PMQR determinants have increased., Competing Interests: Declaration of competing interest None declared., (Copyright © 2022. Published by Elsevier B.V.)

We used a Vitek 2 AST-YS08 (YS08) system and the broth microdilution method (BMD) adopted by the Clinical and Laboratory Standards Institute (CLSI) to compare the susceptibility of 184 isolates of 11 Candida species to fluconazole, voriconazole, micafungin, caspofungin, amphotericin B, and flucytosine. In Candida albicans, the categorical agreement (CA) was 79.2%, 91.7%, 95.8%, and 95.8% for fluconazole, voriconazole, micafungin, and caspofungin, respectively. About 12.5% and 4.2% of very major errors were detected for fluconazole and voriconazole, respectively. C. glabrata showed excellent essential agreements (EAs) (>90%) for azoles but different MIC distributions for fluconazole and caspofungin. The CA between BMD fluconazole MICs and YS08 voriconazole MICs by the method-specific clinical breakpoint (CBP) was 90% in C. glabrata. Over 80% of C. glabrata and C. krusei isolates identified as micafungin-susceptible were labeled intermediate or resistant to caspofungin in YS08. In C. parapsilosis, 5.3% of very major errors and 10.5% of minor errors were found, whereas 33.3% of minor errors were observed in C. tropicalis for fluconazole. For C. tropicalis, 13 (61.9%) non-wild type (WT) isolates of fluconazole and 7 (33.3%) non-WTs of voriconazole were classified in YS08 as WT. For C. auris, the EAs were 93.3%, 100%, 82.2%, 97.8%, and 97.8% for fluconazole, voriconazole, micafungin, caspofungin, and amphotericin B, respectively. YS08 showed comparable results to the BMD. However, considering the lower YS08 fluconazole MIC results compared with BMD in Candida species and YS08 caspofungin results in C. glabrata and C. krusei, improvements are needed. IMPORTANCE The new Vitek 2 AST-YS08 (YS08) card has been updated to reflect the recently revised Clinical and Laboratory Standards Institute (CLSI) guideline. In this study, antifungal drug susceptibility tests were performed using the YS08 card and compared with the CLSI broth microdilution (BMD) method. In conclusion, YS08 showed similar results to BMD, including with C. auris. However, about 12.5% and 4.2% of major errors were detected for fluconazole and voriconazole, respectively, in C. albicans. More than 80% of C. glabrata and C. krusei isolates identified as susceptible to micafungin were labeled moderate or resistant to caspofungin in YS08. The categorical agreement between BMD fluconazole MICs and YS08 voriconazole MICs was 90% by the method-specific CBP of voriconazole, 80% by the current epidemiological cutoff value (ECV) (0.25 μg/mL) of voriconazole, and 85% by the previous ECV (0.5 μg/mL) of voriconazole. Further improvements in YS08 for the detection of fluconazole and echinocandin resistance are thus needed.

Background: Rotavirus (RV) is a common cause of viral gastroenteritis in children worldwide. We aimed to investigate the incidence, symptoms, and genotype of RV infection in a neonatal intensive care unit (NICU) in South Korea 5 years after the introduction of RV vaccination to evaluate its effect on newborn infants., Methods: A total of 431 fecal specimens were collected from patients admitted to NICU between April 20, 2012 and September 10, 2013. Enzyme-linked immunoassays were used to detect RV antigen. Nested multiplex polymerase chain reaction was used for genotyping., Results: The overall incidence of RV infection was 43.9% and was significantly higher in preterm infants, infants born in the study hospital, low birth weight infants, and cesarean births ( P < 0.05). Symptoms of diarrhea, poor feeding, abdominal distension, and apnea were significantly higher in infants with RV infection than those without infection. RV infection gradually increased depending on infant care at home, postpartum clinic, or hospital (26.0, 45.1, and 60.2%, respectively; P = 0.000). The dominant RV genotype in the NICU was G4P[6] at 95.4%., Conclusion: Current RV vaccines did not affect the incidence of RV infection in newborn and preterm infants in the NICU. Most RV-positive patients in the NICU had symptoms, and the incidence of RV infection was relatively higher in hospitals and postpartum clinics with group life than home. The dominant RV genotype was G4P[6] across study groups., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yoon, Lim, Sohn and Kim.)

Background: Inappropriate use of antibiotics not only increases antibiotic resistance as collateral damage but also increases clinical failure rates and medical costs. The purpose of this study was to determine the relationship between the appropriateness of antibiotic prescription and outcomes of community-acquired acute pyelonephritis (CA-APN)., Methods: A multicenter prospective cohort study was conducted at eight hospitals in Korea between September 2017 and August 2018. All hospitalized patients aged ≥ 19 years who were diagnosed with CA-APN on admission were recruited. The appropriateness of empirical and definitive antibiotics, as well as the appropriateness of antibiotic treatment duration and route of administration, was evaluated in accordance with the guideline and expert opinions. Clinical outcomes and medical costs were compared between patients who were administered antibiotics 'appropriately' and 'inappropriately.', Results: A total of 397 and 318 patients were eligible for the analysis of the appropriateness of empirical and definitive antibiotics, respectively. Of them, 10 (2.5%) and 18 (5.7%) were administered 'inappropriately' empirical and definitive antibiotics, respectively. Of the 119 patients whose use of both empirical and definitive antibiotics was classified as 'optimal,' 57 (47.9%) received antibiotics over a longer duration than that recommended; 67 (56.3%) did not change to oral antibiotics on day 7 of hospitalization, even after stabilization of the clinical symptoms. Patients who were administered empirical antibiotics 'appropriately' had shorter hospitalization days (8 vs. 10 days, P = 0.001) and lower medical costs (2381.9 vs. 3235.9 USD, P = 0.002) than those who were administered them 'inappropriately.' Similar findings were observed for patients administered both empirical and definitive antibiotics 'appropriately' and those administered either empirical or definitive antibiotics 'inappropriately'., Conclusions: Appropriate use of antibiotics leads to better outcomes, including reduced hospitalization duration and medical costs., (© 2022. The Author(s).)

Background: Community-acquired acute pyelonephritis (CA-APN) is relatively rare in men. This study aimed to compare the clinical characteristics of CA-APN between male and female patients., Methods: We prospectively collected the clinical and microbiological data of hospitalized CA-APN patients aged ≥19 years in South Korea from March 2010 to February 2011 in 11 hospitals and from September 2017 to August 2018 in 8 hospitals. Only the first episodes of APN of each patient during the study period were included., Results: From 2010 to 2011, 573 patients from 11 hospitals were recruited, and from 2017 to 2018, 340 patients were recruited from 8 hospitals. Among them, 5.9% (54/913) were male. Male patients were older (66.0 ± 15.2 vs. 55.3 ± 19.0 years, P < 0.001), had a higher Charlson comorbidity index (1.3 ± 1.5 vs. 0.7 ± 1.2, P = 0.027), and had a higher proportion of structural problems in the urinary tract (40.7% vs. 6.1%, P < 0.001) than female patients. Moreover, the total duration of antibiotic treatment was longer (21.8 ± 17.8 d vs. 17.3 ± 9.4 d, P = 0.001) and the proportion of carbapenem usage was higher (24.1% vs. 9.5%, P = 0.001) in men than in women. Male patients were hospitalized for longer durations than female patients (median, 10 d vs. 7 d, P < 0.001)., Conclusions: Male CA-APN patients were older and had more comorbidities than female CA-APN patients. In addition, male patients received antibiotic treatment for a longer duration than female patients., (Copyright © 2021 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

With the increasing number of fungal infections and immunocompromised patients, rapid and accurate fungal identification is required in clinical microbiology laboratories. We evaluated the applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system, MicroIDSys Elite (ASTA Corp., South Korea) for the identification of medically important filamentous fungi. A total of 505 strains comprising 37 genera and 90 species collected from 11 Korean hospitals were sent to the microbiology laboratory of International St. Mary's Hospital. All isolates were tested using MicroIDSys Elite, and data were analyzed using the MoldDB v.1.22 database (ASTA). Correct identification rates were compared with the multigene sequencing results. MicroIDSys Elite correctly identified 86.5% (437/505) and 88.9% (449/505) of all tested isolates at the species and genus level, respectively. About 98.2% of Aspergillus isolates were identified at the species level, including cryptic and rare species of A. calidoustus, A. tamarii, A. lentulus, A. versicolor and A. aculeatus. MicroIDSys Elite identified 75.0% of basidiomycetes, including Schizophyllum commune, and 84.3% of the dermatophytes. It also distinguished Sprothrix globosa at the species level. The mean scores of total isolates corresponding to correct species identification were significantly higher than those obtained for genus-level identification (253.5 ± 50.7 vs. 168.6 ± 30.3, P < 0.001). MicroIDSys Elite showed high accuracy for the identification of filamentous fungi, including cryptic and rare Aspergillus species. It is suitable for use in clinical laboratories as a rapid and efficient tool for clinical mold identification. Further evaluations are recommended for MicroIDSys Elite as a rapid and efficient tool for the identification of medically important filamentous fungi.

This study examined changes in the clinical characteristics of community-acquired acute pyelonephritis (CA-APN) in South Korea between the period 2010-2011 and 2017-2018. We recruited all CA-APN patients aged ≥19 years who visited eight hospitals in South Korea from September 2017 to August 2018, prospectively. Data collected were compared with those from the previous study in 2010-2012, with the same design and participation from 11 hospitals. A total of 617 patients were enrolled and compared to 818 patients' data collected in 2010-2011. Escherichia coli was the most common causative pathogen of CA-APN in both periods (87.3% vs. 86.5%, p = 0.680). E. coli isolates showed significantly higher antimicrobial resistance against fluoroquinolone (32.0% vs. 21.6%, p < 0.001), cefotaxime (33.6% vs. 8.3%, p < 0.001), and trimethoprim/sulfamethoxazole (37.5% vs. 29.2%, p = 0.013) in 2017-2018 than in 2010-2011. Total duration of antibiotic treatment increased from 16.55 ± 9.68 days in 2010-2011 to 19.12 ± 9.90 days in 2017-2018 ( p < 0.001); the duration of carbapenem usage increased from 0.59 ± 2.87 days in 2010-2011 to 1.79 ± 4.89 days in 2010-2011 ( p < 0.001). The median hospitalization was higher for patients in 2017-2018 than in 2010-2011 (9 vs. 7 days, p < 0.001). In conclusion, antimicrobial resistance of E. coli to almost all antibiotic classes, especially third generation cephalosporin, increased significantly in CA-APN in South Korea. Consequently, total duration of antibiotic treatment, including carbapenem usage, increased.

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., Competing Interests: No potential conflicts of interest relevant to this article were reported., (© The Korean Society for Laboratory Medicine.)

Objective: To investigate the predominant Lactobacillus species types (LSTs) of vaginal microbiota in pregnant Korean women by quantifying five Lactobacillus species and two anaerobes., Methods: In all, 168 pregnant Korean women under antenatal care at Eulji University Hospital and local clinics were enrolled in the prospective cohort study during pregnancy (10-14 weeks). Vaginal samples were collected with Eswab for Quantitative polymerase chain reaction (qPCR) and stored in a -80 °C freezer. qPCR was performed for five Lactobacillus species and two anaerobes. To identify the predominant LSTs, quantifications were analyzed by the Cluster and Tree View programs of Eisen Lab. Also the quantifications were compared among classified groups., Results: L. crispatus and L. iners were most commonly found in pregnant Korean women, followed by L. gasseri and L. jensenii; L. vaginalis was nearly absent. Five types (four predominant LSTs and one predominant anaerobe type without predominant Lactobacillus species) were classified., Conclusions: Five predominant LSTs were identified in vaginal microbiota of pregnant Korean women. L. crispatus and L. iners predominant types comprised a large proportion.

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, ≤2,300 g or were ≤36 weeks old, in the the neonatal intensive care unit of Eulji University Hospital. Three blood glucose self-monitoring (A: Precision Pcx, Abbott; B: One-Touch Verio, Johnson & Johnson; C: LifeScan SureStep Flexx, Johnson & Johnson) were used for the blood glucose measurements. The results were compared to those obtained using laboratory equipment (D: Advia chemical analyzer, Siemens Healthcare Diagnostics Inc.)., Results: The correlation coefficients between laboratory equipment and the three blood glucose self-monitoring (A, B, and C) were found to be 0.888, 0.884, and 0.900, respectively. For glucose levels≤60 mg/dL, the correlation coefficients were 0.674, 0.687, and 0.679, respectively. For glucose levels>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 ≤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.

The aim of this study was to determine whether peptidyl arginine deiminase (PADI) genes could affect susceptibility to tuberculosis (TB), which can be a presumptive base to explain the increased incidence of TB in patients with rheumatoid arthritis (RA) in Korean. The study population consisted of 47 patients with active TB, 35 patients with nontuberculous mycobacterial disease, 50 RA patients, and 83 healthy controls who had received comprehensive medical testing. Genomic DNA was isolated from peripheral blood mononuclear cells using a standard protocol. All of the patients and healthy controls were genotyped for two nonsynonymous SNPs in PADI4, namely PADI4&#95;89, PADI4&#95;90, and one synonymous SNP in PADI4&#95;104. There was the complete linkage between PADI4&#95;89 and PADI4&#95;90 SNPs. In the allele and haplotype analyses of PADI4&#95;89 and PADI4&#95;104, no significant associations are observed between disease groups and control groups. The frequencies of heterozygote (A/G) for PADI4&#95;89 were significantly lower in patients with active TB than in controls [adjusted odd ratios (OR) = 0.35, p values = 0.020]. When the analysis was conducted by overdominant model, more significant associations are observed (adjusted OR = 0.34, p values = 0.005). We found that heterozygote genotypes for PADI4&#95;89 were protectively associated with susceptibility to TB.

Culture is the gold standard for diagnosis of tuberculosis, but it takes 6 to 8 weeks to confirm the result. This issue is complemented by the detection method using polymerase chain reaction, which is now widely used in a routine microbiology laboratory. In this study, we evaluated the performance of the Seegene Anyplex TB PCR to assess its diagnostic sensitivity and specificity, and compared its results with the Roche Cobas TaqMan MTB PCR, one of the most widely used assays in the world. Five university hospitals located in the Chungcheong area in South Korea participated in the study. A total of 1,167 respiratory specimens ordered for acid-fast bacilli staining and culture were collected for four months, analyzed via the Seegene Anyplex TB PCR, and its results were compared with the Roche Cobas TaqMan MTB PCR. For detection of Mycobacterium tuberculosis, the diagnostic sensitivity and specificity of the Anyplex TB PCR were 87.5% and 98.2% respectively, whereas those of the Cobas TaqMan were 92.0% and 98.0% respectively (p value > 0.05). For smear-positive specimens, the sensitivity of the Anyplex TB PCR was 95.2%, which was exactly the same as that of the Cobas TaqMan. For smear-negative specimens, the sensitivity of the Anyplex TB PCR was 69.2%, whereas that of the Cobas TaqMan TB PCR was 84.6%. For detection of MTB, the Seegene Anyplex TB PCR showed excellent diagnostic performance, and high sensitivity and specificity, which were comparable to the Roche Cobas TaqMan MTB PCR. In conclusion, the Anyplex TB PCR can be a useful diagnostic tool for the early detection of tuberculosis in clinical laboratories.

The performance of a recently developed real-time PCR system, the ExiStation HBV diagnostic system, for quantitation of hepatitis B virus (HBV) in human blood was evaluated. The detection limit, reproducibility, cross-reactivity, and interference were evaluated as measures of analytical performance. For the comparison study, 100 HBV-positive blood samples and 100 HBV-negative samples from Korean Blood Bank Serum were used, and the results of the ExiStation HBV system showed good correlation with those obtained using the Cobas TaqMan (r2=0.9931) and Abbott real-time PCR systems (r2=0.9894). The lower limit of detection was measured as 9.55 IU/mL using WHO standards and the dynamic range was linear from 6.68 to 6.68×10(9) IU/mL using cloned plasmids. The within-run coefficient of variation (CV) was 9.4%, 2.1%, and 1.1%, and the total CV was 11.8%, 3.6%, and 1.7% at a concentration of 1.92 log10 IU/mL, 3.88 log10 IU/mL, and 6.84 log10 IU/mL, respectively. No cross-reactivity or interference was detected. The ExiStation HBV diagnostic system showed satisfactory analytical sensitivity, excellent reproducibility, no cross-reactivity, no interference, and high agreement with the Cobas TaqMan and Abbott real-time PCR systems, and is therefore a useful tool for the detection and monitoring of HBV infection., (Copyright © 2013 Elsevier B.V. All rights reserved.)

We performed a large case-control study (3,932 cases, 15,562 controls) to investigate the association of hepatitis B virus (HBV) and hepatitis C virus (HCV) with hematopoietic malignancies in Korea, where HBV is endemic. HBV was present in 636 control patients (4.1%), 333 lymphoma patients (12.4%), and 75 leukemia patients (6.0%). HCV infection was present in 173 control patients (1.1%), 76 lymphoma patients (2.8%), and 18 leukemia patients (1.4%). Co-infection of HBV and HCV was present in one (0.007%) control patient, seven lymphoma patients (0.3%), and one leukemia patient (0.08%). HBV infection was associated with increased risks for most subtypes of B and T/NK-cell lymphomas, Hodgkin's lymphoma, and acute myeloid leukemia. HCV infection was associated with increased risks for diffuse large B cell lymphoma, extranodal marginal zone B cell lymphoma, peripheral T cell lymphoma, and acute lymphoid leukemia B cell early pre-B type. HBV seems to have a more important role than HCV in the pathogenesis of specific hematologic malignancies in Korea.

Background: The Abbott RealTime hepatitis C virus (HCV) Genotype II (Abbott Molecular Inc.) for HCV genotyping, which uses real-time PCR technology, has recently been developed., Methods: Accuracy and sensitivity of detection were assessed using the HCV RNA PHW202 performance panel (SeraCare Life Sciences). Consistency with restriction fragment mass polymorphism (RFMP) data, cross-reactivity with other viruses, and the ability to detect minor strains in mixtures of genotypes 1 and 2 were evaluated using clinical samples., Results: All performance panel viruses were correctly genotyped at levels of >500 IU/mL. Results were 100% concordant with RFMP genotypic data (66/66). However, 5% (3/66) of the samples examined displayed probable genotypic cross reactivity. No cross reactivity with other viruses was evident. Minor strains in the mixtures were not effectively distinguished, even at quantities higher than the detection limit., Conclusions: The Abbott RealTime HCV Genotype II assay was very accurate and yielded results consistent with RFMP data. Although the assay has the advantages of automation and short turnaround time, we suggest that further improvements are necessary before it is used routinely in clinical practice. Efforts are needed to decrease cross reactivity among genotypes and to improve the ability to detect minor genotypes in mixed infections.

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. Meta-analysis 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.

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.

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.

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.

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.

Context: Chronic hepatitis B infection is the leading cause of cirrhosis and hepatocellular carcinoma. Human leukocyte antigen may be involved in the chronicity of hepatitis B virus (HBV) infection., Objective: To analyze the association between HBV chronicity and human leukocyte antigen alleles and haplotypes of 636 organ donors and recipients., Design: Subjects were categorized into 2 groups according to their clinical and serologic profiles, specifically, an HBV natural convalescent group and an HBV chronic carrier (CC) group., Results: Hepatitis B chronicity was positively associated with A33 (P = .004, odds ratio [OR] = 1.59) and DR7 (P < .001, OR = 2.58), and negatively associated with HLA-DR13 (P < .001, OR = 0.40). Coexpression of A33 and DR7 was significantly higher in the CC group (OR = 3.63), compared with that of either allele alone (OR = 1.76 in A33; OR = 2.53 in DR7). The statistically significant haplotypes were B44-DR7 (P < .001, OR = 5.44), A33-DR7 (P < .001, OR = 4.47), and A33-B44-DR7 (P < .001, OR = 7.31) in the CC group., Conclusions: Our results indicate that alleles of A33, DR7, and haplotypes containing DR7 are associated with HBV chronicity among Koreans. Moreover, the 2 antigens had an additive effect on chronicity. These findings support the theory that human leukocyte antigen class I-restricted cytotoxic T cells and human leukocyte antigen class II-restricted helper T cells play an important role in HBV chronicity.