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Background: Gastrointestinal (GI) infections, caused by various pathogens such as bacteria, viruses, protozoa, and parasites, are the second most common infectious diseases. Molecular diagnostics that can simultaneously detect these pathogens are commonly used in syndromic approaches. The authors aimed to identify the causative pathogens of GI infections to provide clinically useful information., Methods: This retrospective study used molecular diagnostic methods to determine the incidence and distribution of GI pathogens according to gender, age, and season and analyze their coinfection from August 2020 to December 2022., Results: The overall incidence of at least one GI pathogen was 40.1% (991/2, 471). The positivity rates for bacteria and viruses were 33.1% (817/2, 471) and 9.2% (227/2,471), respectively; the positivity rate for bacteria was significantly higher than that for viruses (p < 0.001). The incidence of GI pathogens according to age group was highest in group 3 (59.9%), followed by group 4 (57.0%). The most common bacterial pathogen associated with GI infections was C. difficile, followed by diarrheagenic E. coli, Campylobacter spp., and Salmonella spp. Enteropathogenic E. coli accounted for a large percentage of diarrheagenic E. coli (63.6%, 157/247). Among the viral pathogens, norovirus GI/GII was the most commonly detected virus, followed by adenovirus F40/41 and rotavirus A. For bacterial- or viral-positive cases, the distribution of GI pathogens according to age group showed the highest proportion of C. difficile in all groups, except for group 2. In group 2, rotavirus A accounted for the highest percentage (61.1%, 22/36). The incidence of GI pathogens was the highest in summer (36.1%), followed by autumn (32.7%), and winter (18.0%). The co-infection rate with two or more pathogens was 16.9% (167/991). The rates of co-infection with two or more bacteria, bacteria and viruses, and two viruses were 58.1%, 31.7%, and 10.2%, re-spectively., Conclusions: Information on the incidence and distribution of GI pathogens might be clinically useful; however, unlike the distribution of other infectious pathogens, it is necessary to consider that microorganisms identified through molecular diagnostics can be detected even in healthy people without clinical symptoms.

Background: Although the detection of respiratory viruses other than severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was significantly reduced because of quarantine due to the coronavirus disease (COVID-19) pandemic, an epidemic of several viruses was reported unexpectedly. We also detected a change in the pattern of human metapneumovirus (HMPV) outbreak compared to that before the COVID-19 pandemic. Therefore, the authors intended to identify the incidence and altered distribution pattern of the HMPV outbreak and provide useful information for clinical practice., Methods: This retrospective study investigated the incidence and distribution of HMPV from March 2020 to December 2022 during the COVID-19 pandemic. Detection of respiratory microorganisms was performed by multiplex polymerase chain reaction using a commercial kit and FilmArray assay., Results: The overall incidence of at least one respiratory microorganism was 50.3% (1,152/2,290). HMPV was not detected between March 2020 and June 2022. However, it was suddenly detected in July 2022 and continued for approximately five months until November 2022. In particular, the detection rate of HMPV was high in September and October 2022, accounting for approximately 76.1% (51/67) of the total HMPV-positive cases. Seasonally, 92.5% (62/67) of HMPV cases were detected in autumn, while the rest of the cases were detected in summer. The HMPV detection rate, according to the age group, was highest in group 4 (3 - 6 years) at 7.4% (27/367), followed by group 3 (4 months to 2 years) at 3.6% (31/861). In HMPV-positive cases, the rate of more than two respiratory pathogens was 46.3% (31/67). An analysis of co-infecting pathogens showed that HMPV with rhinovirus A/B/C/ enteroviruses accounted for the highest percentage (51.6%), followed by HMPV with respiratory syncytial virus (48.4%)., Conclusions: The COVID-19 pandemic has caused several changes in our lives. This study confirmed that the seasonal distribution of HMPV was different from that before the COVID-19 pandemic. Therefore, it can be assumed that the distribution of other respiratory microorganisms could have changed and it appears that changes could occur in previously known viral epidemiology. Clinicians should therefore be alert to this possibility.

Background: The incidence of respiratory viral diseases including parainfluenza virus (PIV) infection has decreased noticeably due to strict quarantine measures during the COVID-19 pandemic. However, the recent outbreak of PIV in children occurred unexpectedly and the distribution pattern showed prominent differences from before the COVID-19 pandemic. PIV is one of the major viral pathogens related to acute lower respiratory infection in young children and the elderly. Accordingly, the authors intended to identify the incidence and distribution pattern of PIV outbreaks and to contribute to public health by providing information on it., Methods: This study was conducted retrospectively to investigate the incidence and distribution of PIV according to age group, gender, month, and season, and to analyze the co-infections from March 2020 to February 2022. The detection for respiratory microorganisms was performed through FilmArray assay., Results: The overall incidence for at least one respiratory pathogen was 45.9% (665/1,450). PIV was not detected at all from March 2020 to August 2021. However, it was first detected in September 2021 and the rate in the month that followed, October, accounted for 60% (114/190) of the total PIV infections during the entire study period. It also accounted for 44.9% (190/423) of patients with respiratory pathogens from September 2021 to February 2022. It reached the highest proportion at 90.5% (114/126) in October 2021. As for the distribution according to the age groups, group 3 (58.4%) accounted for the highest percentage, followed by group 4 (21.1%). In the PIV positive cases, the overall rate of more than two respiratory pathogens was 32.6% (62/190). The most common pattern of co-infection was PIV3 with rhinovirus/enterovirus (67.7%), followed by PIV3 with adenovirus (8.1%) and PIV3 with rhinovirus/enterovirus and adenovirus (8.1%)., Conclusions: The COVID-19 pandemic has brought about many changes in our daily lives. It has been confirmed that the seasonal distribution of PIV was distinctly different from before the COVID-19 pandemic. It is anticipated that this phenomenon will affect the incidence or distribution of other respiratory pathogens and viral epidemiology. Therefore, clinicians should pay attention to these changes in terms of public health.

Background: Laboratory parameter abnormalities are commonly observed in COVID-19 patients; however, their clinical significance remains controversial. We assessed the prevalence, characteristics, and clinical impact of laboratory parameters in COVID-19 patients hospitalized in Daegu, Korea., Methods: We investigated the clinical and laboratory parameters of 1,952 COVID-19 patients on admission in nine hospitals in Daegu, Korea. The average patient age was 58.1 years, and 700 (35.9%) patients were men. The patients were classified into mild (N=1,612), moderate (N=294), and severe (N=46) disease groups based on clinical severity scores. We used chi-square test, multiple comparison analysis, and multinomial logistic regression to evaluate the correlation between laboratory parameters and disease severity., Results: Laboratory parameters on admission in the three disease groups were significantly different in terms of hematologic (Hb, Hct, white blood cell count, lymphocyte%, and platelet count), coagulation (prothrombin time and activated partial thromboplastin time), biochemical (albumin, aspartate aminotransferase, alanine aminotransferase, lactate, blood urea nitrogen, creatinine, and electrolytes), inflammatory (C-reactive protein and procalcitonin), cardiac (creatinine kinase MB isoenzyme and troponin I), and molecular virologic (Ct value of SARS-CoV-2 RdRP gene) parameters. Relative lymphopenia, prothrombin time prolongation, and hypoalbuminemia were significant indicators of COVID-19 severity. Patients with both hypoalbuminemia and lymphopenia had a higher risk of severe COVID-19., Conclusions: Laboratory parameter abnormalities on admission are common, are significantly associated with clinical severity, and can serve as independent predictors of COVID-19 severity. Monitoring the laboratory parameters, including albumin and lymphocyte count, is crucial for timely treatment of COVID-19.

Background: In Korea, the first community outbreak of coronavirus disease 2019 (COVID-19) occurred in Daegu on February 18, 2020. This study was performed to investigate the prevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibodies in healthcare workers (HCWs) at 6 major hospitals in Daegu., Methods: Blood specimens of 2,935 HCWs at 6 major hospitals in Daegu from January 2021 to February 2021 were collected. Every specimen was tested for antibody against SARS-CoV-2 using both Elecsys Anti-SARS-CoV-2 electrochemiluminescence immunoassay (Roche Diagnostics, Rotkreuz, Switzerland) and R-FIND COVID-19 IgG/M/A enzyme-linked immunosorbent assay kit (SG medical Inc., Seoul, Korea) as screening tests. If 1 or more of these screening test results was positive, 2 additional antibody tests were performed using Abbott Anti-SARS-CoV-2 IgG assay (Abbott, Abbott Park, IL, USA) and cPass SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript USA Inc., Piscataway, NJ, USA). If 2 or more of the total 4 test results were positive, it was determined as positive for the antibody against SARS-CoV-2., Results: According to the criteria of SARS-CoV-2 antibody positivity determination, 12 subjects were determined as positive. The overall positive rate of the SARS-CoV-2 antibody was 0.41% (12/2,935). Of the 12 subjects determined as positive, 7 were diagnosed with COVID-19, and the remaining 5 were nondiagnosed cases of COVID-19., Conclusion: In early 2021, the overall seroprevalence of SARS-CoV-2 antibody among HCW located in Daegu was 0.41%, and 0.17% excluding COVID-19 confirmed subjects. These results were not particularly high compared with the general public and were much lower than HCWs in other countries., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2021 The Korean Academy of Medical Sciences.)

Background: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) started to spread in Daegu beginning at the end of February 2020. IgG and IgM antibodies against SARS-CoV-2 were measured in hospitalized patients with COVID-19 with moderate to severe symptoms to improve the understanding of antibody responses., Methods: We enrolled 312 patients with COVID-19 admitted to seven hospitals located in Daegu. Using serum (or plasma) samples from patients with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infections, both IgG and IgM antibodies were measured using commercial enzyme-linked immunosorbent assay (R-FIND CO¬VID-19 ELISA, SG medical, Seoul, Korea)., Results: The median value from the initial diagnosis, confirmed by SARS-CoV-2 PCR, to the sampling date was 24 days (day 1 to 88). The total positive rate of IgG was 93.9% and the positive IgM rate was 39.4%, without considering the elapsed period after diagnosis. Positive IgG and IgM rates were highest at 100.0% and 59.0%, respectively, at 3 weeks (15 - 21 days). IgG showed a high positive rate of 79.3% even within 7 days after the initial diag-nosis of the disease and maintained a positive rate of 97.8% until after 8 weeks., Conclusions: Among hospitalized patients with COVID-19, IgG was detected from the beginning of the diagnosis and persisted for an extended time period.

Background: The pathogens involved in central nervous system (CNS) infections are various, such as viruses, bacteria, and fungi, so a syndromic approach can be required. In addition, since their rapid and accurate detection is very crucial, molecular diagnostics using cerebrospinal fluid is becoming the emerging standard method., Methods: The study was conducted retrospectively to identify the incidence and distribution patterns of the pathogens according to gender, age, season, and month and to analyze their codetection from August 2017 to July 2020. It was also conducted to investigate turn-around times (TATs) according to the detection method. The detection methods were FilmArray® Meningitis/Encephalitis (M/E) method (FilmArray), Cepheid® Xpert EV assay (Xpert), and Multiplex PCR method for five species of bacteria., Results: The overall incidence for at least one pathogen was 13.9% (346/2,496). The highest incidence was shown in age group 4 (3 - 6 years), with 27.4%. The detection rates by FilmArray, Xpert, and Multiplex PCR method were 39.8%, 41.7%, and 0.4%, respectively. Enterovirus (EV) showed the highest incidence rate, which accounted for 37.0%. The distribution of the pathogens according to the age groups were the highest in age group 4, with 47.5% (168/354), followed by 27.4% (97/354) in age group 5. Of the ten cases in which bacteria were detected, S. agalactiae accounted for 60.0% (6/10), most of which occurred in age group 1. E. coli K1, L. monocytogenes, and N. meningitidis were not detected. In the viral distribution, EV accounted for the highest proportion in all age groups. The overall proportion of EV accounted for 87.6% (310/354), followed by human parechovirus with 2.8% (10/354). The most commonly detected season was summer, comprising 75.1%. A total of eight cases of co-detection with two pathogens accounted for 1.6% (8/507) in FilmArray. In FilmArray, all TATs were found to be shorter than Xpert., Conclusions: The information on the incidence and distribution patterns of the pathogens causing CNS infections and their rapid detection are critically important to clinicians in the management of immunocompromised patients, elderly, and children. The expeditious molecular diagnostics for these pathogens would be valuable in medical decisions by clinicians.

Objectives: We report our experience with an emergency room (ER) shutdown related to an accidental exposure to a patient with coronavirus disease 2019 (COVID-19) who had not been isolated., Setting: A 635-bed, tertiary-care hospital in Daegu, South Korea., Methods: To prevent nosocomial transmission of the disease, we subsequently isolated patients with suspected symptoms, relevant radiographic findings, or epidemiology. Severe acute respiratory coronavirus 2 (SARS-CoV-2) reverse-transcriptase polymerase chain reaction assays (RT-PCR) were performed for most patients requiring hospitalization. A universal mask policy and comprehensive use of personal protective equipment (PPE) were implemented. We analyzed effects of these interventions., Results: From the pre-shutdown period (February 10-25, 2020) to the post-shutdown period (February 28 to March 16, 2020), the mean hourly turnaround time decreased from 23:31 ±6:43 hours to 9:27 ±3:41 hours (P < .001). As a result, the proportion of the patients tested increased from 5.8% (N=1,037) to 64.6% (N=690) (P < .001) and the average number of tests per day increased from 3.8±4.3 to 24.7±5.0 (P < .001). All 23 patients with COVID-19 in the post-shutdown period were isolated in the ER without any problematic accidental exposure or nosocomial transmission. After the shutdown, several metrics increased. The median duration of stay in the ER among hospitalized patients increased from 4:30 hours (interquartile range [IQR], 2:17-9:48) to 14:33 hours (IQR, 6:55-24:50) (P < .001). Rates of intensive care unit admissions increased from 1.4% to 2.9% (P = .023), and mortality increased from 0.9% to 3.0% (P = .001)., Conclusions: Problematic accidental exposure and nosocomial transmission of COVID-19 can be successfully prevented through active isolation and surveillance policies and comprehensive PPE use despite longer ER stays and the presence of more severely ill patients during a severe COVID-19 outbreak.

Background: Acute respiratory infection caused by respiratory microorganisms including various kinds of viruses and bacteria is the most common infectious disease. When managing patients, it is crucial to detect these microorganisms rapidly and monitor their occurrence and tendency. Recently, the methods of detecting them have been implemented by molecular diagnostics. The authors intended to investigate their incidence and distribution and identify the significance of the molecular diagnosis for their detection., Methods: The retrospective study was conducted to investigate the incidence and distribution of respiratory microorganisms according to the age, gender, month, season, and the detection method and to analyze their co-infections from July 2016 to December 2019. In addition, the four types of turn-around time (TAT) for each detec-tion method were also analyzed., Results: The overall incidence for at least one respiratory microorganism was 23.1% (3,645/15,808). The highest incidence was identified in age group 2 (1 - 3 months), 38.5%. The incidence rates by multiplex PCR using Anyplex and Allplex, FilmArray method, and influenza virus (flu) antigen detection test were 44.2% (718/1,625), 63.1% (1,198/1,899), and 14.1% (1,729/12,284), respectively. The overall incidence between male and female patients showed no statistically significant difference (p = 0.980), except for the flu antigen detection test (p = 0.000). Influenza A viruses (flu A) accounted for the highest percentage (34.9%), followed by rhinovirus/enterovirus (20.5%), RSV (12.8%), flu B (8.3%), and adenovirus (7.6%). These microorganisms showed characteristic distribution patterns according to season and month. Flu A and flu B predominated in winter and accounted for an increasing proportion as age increased according to the age groups. The overall co-infection rate was 22.5% (432/1,916). The average TATs of the FilmArray method were significantly much faster than multiplex PCR using Anyplex and Allplex (p = 0.000)., Conclusions: The information on the incidence and distribution of respiratory microorganisms and their expeditious detection are considered critical to the management of the elderly, immunocompromised patients, and children. The rapid molecular-based diagnosis of respiratory infections would be beneficial in medical decision and prevention of their propagation.

HLA-B*51:315 differs from B*51:01:01:01 by a single nucleotide polymorphism in codon 87 (CAG → CGG)., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Clostridium difficile is one of the main etiological agents causing antibiotic-associated diarrhea. This study investigated the genetic diversity of 70 toxigenic C. difficile isolates from two Korean hospitals by employing toxinotyping, ribotyping, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Toxin gene amplification resulted in 68 A⁺B⁺ and two A-B+ isolates. Most isolates (95.7-100%) were susceptible to daptomycin, metronidazole, and vancomycin. Seventy C. difficile isolates were classified into five toxinotypes, 19 ribotypes, 16 sequence types (STs), and 33 arbitrary pulsotypes. All C. difficile isolates of ribotype 018 (n = 38) were classified into ST17, which was the most prevalent ST in both hospitals. However, C. difficile isolates of ST17 (ribotype 018) exhibited pulsotypes that differed by hospital. ST2 (ribotype 014/020), 8 (ribotypes 002), 17 (ribotype 018), and 35 (ribotypes 015) were detected in both hospitals, whereas other STs were unique to each hospital. Statistical comparison of the different typing methods revealed that ribotyping and PFGE were highly predictive of STs. In conclusion, our epidemiological study indicates that C. difficile infections in both hospitals are associated with the persistence of endemic clones coupled with the emergence of many unique clones. A combination of MLST with PFGE or ribotyping could be useful for monitoring epidemic C. difficile strains and the emergence of new clones in hospitals.

Context: -The traceability of clinical results to internationally recognized and accepted reference materials and reference measurement procedures has become increasingly important. Therefore, the establishment of traceability has become a mandatory requirement for all in vitro diagnostics devices., Objectives: -To evaluate the traceability of the Abbott Architect c8000 system (Abbott Laboratories, Abbott Park, Illinois), consisting of calibrators and reagents, across 4 different chemistry analyzers, and to evaluate its general performance on the Toshiba 2000FR NEO (Toshiba Medical Systems Corporation, Otawara-shi, Tochigi-ken, Japan)., Design: -For assessment of traceability, secondary reference materials were evaluated 5 times, and then bias was calculated. Precision, linearity, and carryover were determined according to the guidelines of the Clinical and Laboratory Standards Institute (Wayne, Pennsylvania)., Results: -The biases from 4 different analyzers ranged from -2.33% to 2.70% on the Toshiba 2000FR NEO, -2.33% to 5.12% on the Roche Hitachi 7600 (Roche Diagnostics International, Basel, Switzerland), -0.93% to 2.87% on the Roche Modular, and -2.16% to 2.86% on the Abbott Architect c16000. The total coefficients of variance of all analytes were less than 5%. The coefficients of determination (R(2)) were more than 0.9900. The carryover rate ranged from -0.54% to 0.17%., Conclusions: -Abbott clinical chemistry assays met the performance criteria based on desirable biological variation for precision, bias, and total error. They also showed excellent linearity and carryover. Therefore, these clinical chemistry assays were found to be accurate and reliable and are readily applicable on the various platforms used in this study.