First Case of Septic Shock Caused by Cetobacterium Somerae.

BACKGROUND: Cetobacterium somerae rarely causes infection in humans. Most studies on C. somerae have analyzed its role in the intestinal system of freshwater fish. METHODS: Herein, we report a case of septic shock caused by C. somerae in an elderly patient. RESULTS: Blood culture revealed growth of a gram-negative, rod-shaped anaerobic bacterium, which was identified as C. somerae through MALDI-TOF analyses. Although C. somerae is a resident species in the gut, it can cause systemic infection, which can be fatal. CONCLUSIONS: When C. somerae is identified, consideration should be given to the possibility of the infection originating from the intestinal tract.

Successful Treatment of Thrombotic Thrombocytopenic Purpura in a Patient with Mixed Connective Tissue Disease.

BACKGROUND: Although the survival rate of thrombocytopenic purpura (TTP) has increased significantly due to the introduction of therapeutic plasma exchange (TPE). TTP in patients with mixed connective tissue disease (MCTD) has a very high mortality rate and a very small number of reported cases. In TTP, daily TPE is administered until a treatment response is achieved; however, in practice, TPE is often not performed for such long durations. METHODS: We report a case of TTP with MCTD in a female patient. She had developed thrombocytopenia and hemolytic anemia 9 months after delivery. She had status epilepticus and lapsed into a coma. RESULTS: The patient was successfully treated with extended sessions of TPE with corticosteroids and rituximab. CONCLUSIONS: Although the TTP regimen has not yet been established and remains controversial, this report demonstrates the importance of continuing daily TPE until achieving a treatment response.

Verification and Establishment of Reference Intervals for Prothrombin Time and Activated Partial Thromboplastin Time for Children in a Clinical Laboratory.

BACKGROUND: Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are routine coagulation tests. The absence of age-dependent reference interval (RI) may lead to abnormal results in children. In this study, we aimed to verify adult-based RIs in children and establish pediatric RIs for PT and aPTT. METHODS: We analyzed PT and aPTT results. Samples from inpatients and outpatients aged 1 - 18 years, considered healthy subjects, were divided into six groups by age. Verification and establishment of RIs were conducted. RESULTS: Applying adult-based RIs to pediatrics was statistically invalid for individuals aged 10 - 18 years for PT and invalid throughout childhood for aPTT. The new RI of PT for individuals aged 10 - 18 years was 11.1 - 14.1 seconds and that of aPTT for individuals aged 1 - 9 years was 28.2 - 46.0 seconds. CONCLUSIONS: Pediatric RIs were higher than adult-based RIs. Using pediatric RI can save time, labor, and costs to make clinical decision.

Anti-LW Confused with Anti-D: a Case Transfused RhD-positive RBCs and Literature Review.

BACKGROUND: Anti-LW is rarely identified, and it is known to have little clinical importance. However, it is often difficult to differentiate anti-LW from anti-D. METHODS: Here, we report a case where anti-LW was identified for pretransfusion testing in a patient suspected of having lymphoma. RESULTS: His blood group was O RhD-positive. Anti-D specificity, weak panreactivity and 2+ reactivity in auto control were shown as a result of antibody identification. The reactions became weaker with DTT-treated RBCs, which confirmed the specificity of an anti-LW. The patient received 8 units of O RhD-positive pRBC before discharge without any transfusion reaction. CONCLUSIONS: In conclusion, anti-LWs may show mimicking specificity of anti-D for antibody identification testing, but their clinical significance is completely different. Therefore, their prompt identification is important.

Septic shock caused by Slackia exigua in a patient with diabetes.

We report a case of septic shock caused by Slackia exigua, an obligatory anaerobic gram-positive rod, in an 82-year-old woman with diabetes. Dental assessment revealed a palatal lesion and untreated periodontitis. Although a resident species in the oral cavity and associated with localized disorders, S. exigua can cause extra-oral diseases, which can be fatal in individuals with risk factors, such as diabetes. Thus, control of oral lesions caused by S. exigua is important to prevent systemic infection.

Developing a Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of Seven Respiratory Viruses including SARS-CoV-2.

Background and Objectives: The coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to be a pandemic even in 2022. As the initial symptoms of COVID-19 overlap with those of infections from other respiratory viruses, an accurate and rapid diagnosis of COVID-19 is essential for administering appropriate treatment to patients. Currently, the most widely used method for detecting respiratory viruses is based on real-time polymerase chain reaction (PCR) and includes reverse-transcription real-time quantitative PCR (RT-qPCR). However, RT-qPCR assays require sophisticated facilities and are time-consuming. This study aimed to develop a real-time quantitative loop-mediated isothermal amplification (RT-qLAMP) assay and compare its analytical performance with RT-qPCR. Materials and Methods: A total of 315 nasopharyngeal swabs from patients with symptoms of respiratory infections were included in this study. A primary screening of the specimens was performed using RT-qPCR. RNA/DNA from standard strains for respiratory viruses and heat-inactivated preparations of standard strains for SARS-CoV-2 were used to evaluate the accuracy and target specificity of the RT-qLAMP assay. Results: We successfully developed an RT-qLAMP assay for seven respiratory viruses: respiratory syncytial virus (RSV) A, RSV B, adenovirus, influenza (Flu) A (H1N1 and H3N2), Flu B, and SARS-CoV-2. RT-qLAMP was performed in a final reaction volume of 9.6 µL. No cross-reactivity was observed. Compared with the RT-PCR results, the sensitivity and specificity of the RT-qLAMP assay were 95.1% and 100%, respectively. The agreement between the two methods was 97.1%. The median amplification time to RT-qLAMP positivity was 22:34 min (range: 6:80-47:98 min). Conclusions: The RT-qLAMP assay requires a small number of reagents and samples and is performed with an isothermal reaction. This study established a fast, simple, and sensitive test that can be applied to point-of-care testing devices to facilitate the detection of respiratory viruses, including SARS-CoV-2.

Bacteremia Caused by Moraxella Osloensis: a Fatal Case of an Immunocompromised Patient and Literature Review.

BACKGROUND: Moraxella osloensis rarely causes infection in humans, and most of the reported cases are not fatal. It is often difficult to identify M. osloensis using conventional biochemical methods. METHODS: Here, we report a bacteremia case caused by M. osloensis in a patient with advanced lung cancer who initially presented symptoms of fever. RESULTS: Blood culture revealed growth of a gram-negative bacterium, which was identified as M. osloensis through 16S rRNA gene sequencing and MALDI-TOF analyses. The patient could not recover from sepsis with empirical treatment. CONCLUSIONS: As M. osloensis can cause serious infections in immunocompromised patients, its prompt identification is important.

Introduction of a Borderline Range for the Interpretation of QuantiFERON-TB Gold In-Tube Results in Korean Healthcare Workers.

BACKGROUND: South Korea is the only Organisation for Economic Co-operation and Development (OECD) country with a high incidence of tuberculosis (TB). Healthcare workers (HCWs) have an increased risk of TB infection. QuantiFERON-TB Gold In-Tube (QFT-GIT) testing is performed for occupational health screening to detect latent TB infection (LTBI). METHODS: We evaluated the introduction of new criteria for borderline ranges for interferon-gamma release assay (IGRA) results in HCWs. The results of QFT-GIT tests in HCWs in 2017 and 2018 were collected, with high-risk HCWs having two serial test results. Existing dichotomous criteria and new criteria with borderline ranges (bor-derline negative [BN], 0.20 - 0.34 IU/mL; borderline positive [BP], 0.35 - 0.99 IU/mL) were applied to each test re-sult. RESULTS: After applying the borderline range, 26.4% of the positive results were classified as BP (4% of total results), while 4.2% of the negative results were classified as BN (3.6% of total results). Among seven HCWs with initial results in the borderline range, two had repeated borderline results while 71.4% had low negative results. CONCLUSIONS: We recommend the introduction of borderline ranges in the interpretation of QFT-GIT results to reduce unnecessary TB therapy in HCWs.

Etest Methods for Screening Heterogeneous Vancomycin-Intermediate Staphylococcus aureus (hVISA) strains.

The importance of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) as a preceding stage for the development of vancomycin-resistant S. aureus is growing. We analyzed the prevalence of hVISA among bacteremia with methicillin-resistant S. aureus (MRSA) using two Etests and evaluated the clinical characteristics and outcomes. Ninety-eight MRSA isolates from blood were collected at two University hospitals in Korea. Macrodilution Etest and glycopeptide resistance detection Etests were used for detection of hVISA. Staphylococcal cassette chromosome mec (SCCmec) typing was performed by multiplex PCR. Clinical data were collected retrospectively from patient medical records. About 30% of MRSA strains were identified as hVISA. Diabetes mellitus was associated (P = 0.047) with hVISA infections. The hVISA isolates were associated with high teicoplanin MIC and multidrug resistance (P = 0.001). SCCmec type II accounted for the majority (79.3%) of hVISA strains. The prevalence of hVISA strains was increased and can lead to the development of multidrug-resistant strains. Patients with diabetes were found to have a greater risk for infection with hVISA strains. As the impact of hVISA on clinical outcome is not yet clear, large-scale studies about clinical outcomes and optimal detection methods of hVISA are needed. In conclusion, hVISA strains have a high prevalence in bloodstream MRSA infections. Awareness of the increase in hVISA strains should motivate laboratories to establish a system to detect and monitor hVISA.

Clinical use of anti-DFS70 autoantibodies.

The dense fine speckled (DFS) nuclear pattern is one of the most common indirect immunofluorescence (IIF) patterns detected during routine anti-nuclear antibody (ANA) screening. There is a negative association between anti-DFS70 status and systemic autoimmune rheumatic disease (SARD), especially in the absence of concomitant SARD-specific autoantibodies. The purpose of this study was to determine the need for confirming anti-DFS70 status when a DFS pattern is observed in IIF-ANA. The frequency of anti-DFS70 detection on Western blot and the positive rate of connective tissue disease (CTD)-related autoantibody screening with a fluorescence-based enzyme immunoassay was evaluated in DFS (n = 182) and non-DFS (n = 359) groups. Specific autoantibodies against 15 autoantigens were identified by line immunoassay. We evaluated the frequency of cases of DFS mistaken for non-DFS and non-DFS cases mistaken for DFS, as well as the clinical impacts of these misinterpretations. Among cases of IIF-ANA with an observable DFS pattern, 68.1% had only anti-DFS70 without CTD-related autoantibodies, 20.3% were false positive for IIF-ANA, and the remaining 11.5% had CTD-related autoantibodies independent of anti-DFS70 status. These results indicated that CTD-related autoantibodies may be present with or without anti-DFS70 even if a DFS pattern is observed in IIF-ANA. Among patients who are ANA negative or have a low probability of SARD, an anti-DFS70 confirmation test has no clinical benefit and cannot replace specific tests for detecting CTD-related autoantibodies. Specific tests to detect CTD-related autoantibodies should be performed instead of anti-DFS70 confirmation tests when a DFS pattern is observed in IIF-ANA.

Performance evaluation of cobas HBV real-time PCR assay on Roche cobas 4800 System in comparison with COBAS AmpliPrep/COBAS TaqMan HBV Test.

BACKGROUND: Hepatitis B virus (HBV) nucleic acid amplification testing (NAAT) is important for the diagnosis and management of HBV infection. We evaluated the analytical performance of the cobas HBV NAAT (Roche Diagnostics GmbH, Mannheim, Germany) on the cobas 4800 System in comparison with COBAS AmpliPrep/COBAS TaqMan HBV Test (CAP/CTM HBV). METHODS: Precision was evaluated using three levels of cobas HBV/HCV/HIV-1 Control Kit, and linearity was evaluated across the anticipated measuring range (10.0-1.0×109 IU/mL) at seven levels using clinical samples. Detection capability, including limit of blank (LOB), limit of detection (LOD) and limit of quantitation (LOQ), was verified using the 4th WHO International Standard for HBV DNA for NAT (NIBSC code: 10/266). Correlation between the two systems was compared using 205 clinical samples (102 sera and 103 EDTA plasma). RESULTS: Repeatability and total imprecision (coefficient of variation) ranged from 0.5% to 3.8% and from 0.5% to 3.5%, respectively. Linearity (coefficient of determination, R2) was 0.999. LOB, LOD and LOQ were all acceptable within the observed proportion rate (85%). Correlation was very high between the two systems in both serum and plasma samples (correlation coefficient [r]=0.995). CONCLUSIONS: The new cobas HBV real-time PCR assay on the cobas 4800 System showed reliable analytical performances.

Limitations of Preoperative PFA-200 as a Predictor of Postoperative Blood Loss in Total Knee Arthroplasty: According to Use of Tranexamic Acid.

BACKGROUND: Recently, anti-fibrinolytic agents (tranexamic acid) have been used to reduce blood loss or and the need for transfusion. We evaluated the clinical utility of PFA-200 as a predictor of postoperative blood loss in a clinical setting, where hemostasis can be affected by variables such as existing comorbidities and medication use. METHODS: We analyzed retrospectively 243 TKA patients having PFA-200 results between March 2014 and May 2016. We collected the medication history of anti-thrombotic agents, closure time measured by PFA-200, postoperative drainage volume, and perioperative change of hemoglobin values. Parameters associated with postoperative blood loss were compared to the prolongation of closure time and medication use. The influence of variables on postoperative blood loss was analyzed. RESULTS: The closure times of PFA-200 were prolonged in 68 patients (295.8 ± 10.7) and were not prolonged in 175 patients (125.4 ± 35.8). The prolonged closure time did not affect any parameters associated with postoperative blood loss. A history of preoperative anti-platelet agents used was a factor that statistically significantly increased the amount of postoperative drainage and reduction of perioperative hemoglobin values. In addition, postoperative tranexamic acid treatment was the factor that decreased the postoperative hemoglobin levels (OR = 0.297 with p = 0.010) most. CONCLUSIONS: The effectiveness of preoperative PFA-200 in assessments of postoperative bleeding risk is reduced with postoperative use of tranexamic acid.

Modified Complete Blood Count Indices as Predicting Markers of Preeclampsia from Gestational Hypertension: Neutrophil to Lymphocyte Ratio, Platelet to Lymphocyte Ratio, and Platelet to Neutrophil Ratio.

BACKGROUND: To evaluate modified complete blood count (CBC) indices as a predicting marker of preeclampsia (PE) from gestational hypertension (GH), we analyzed the neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and platelet to neutrophil ratio (PNR). PNR was a newly designed index in this study based on results of PE patients having a tendency toward higher neutrophil count and lower platelet count compared to normal pregnant women in previous studies. METHODS: We recruited 86 normal pregnant women, 33 patients with GH and 68 patients with PE. Subjects with any history of membrane rupture, infection, or multiple pregnancies were excluded. PNR, NLR, and PLR values including other CBC indices were statistically analyzed. RESULTS: NLR value of PE patients was significantly higher than GH patients (p = 0.011). PNR value was the most statistically significant index separating patients with PE and GH (p < 0.001). PLR value was lower in patients with PE compared to GH; however, statistical significance was low. CONCLUSIONS: NLR as well as PNR is a useful index to help predicting progression from GH to PE. Further studies are required to evaluate the full extent of utility of PNR as a predictive index in PE patients.

Pure Red Cell Aplasia Associated with Monoclonal Gammopathy of Undetermined Significance and Literature Review.

BACKGROUND: Pure red cell aplasia (PRCA) is an uncommon disease which involves an almost complete absence of the erythroid lineage in bone marrow (BM) and causes severe anemia. Cases due to monoclonal gammopathy occurring in plasma cell disorder have been infrequently reported. Here we report a case of PRCA associated plasma cell disorder, especially monoclonal gammopathy of undetermined significance (MGUS). METHODS: A 55-year-old male visited the ER due to general weakness. At his initial visit he exhibited severe anemia. Mild intravascular hemolysis was suspected. For anemia evaluation, BM examination was performed. In BM aspiration, almost no erythroid precursor cells were observed. Also, plasma cells were relatively elevated, at 7.2%. Serum electrophoresis and immunofixation revealed paraproteinemia of 5.1 g/L (IgG and lambda). No hypercalcemia, renal insufficiency or lytic bone lesions were found. This unusual case showed MGUS accompanied by PCRA. We were also able to assume the erythroid cell-specific restriction due to paraprotein, because we ruled out possible causes of PRCA. RESULTS: We discovered several reported cases associated with plasma cell dyscrasia. However, most of these cases involved plasma cell myeloma, characterized by high immunoglobulin burden. Our case demonstrates that PRCA is also observed in cases with MGUS, where immunoglobulin burden is low. CONCLUSIONS: It is not yet accurately known, what parts of erythroid precursors are targeted by M-protein nor what the mechanism is. Therefore, additional research into this matter is necessary.

The Incidence of Non-tuberculous Mycobacterium Lung Disease in Patients with Suspected Pulmonary Tuberculosis.

Non-tuberculous mycobacterium (NTM) lung disease is increasing in prevalence. We analyzed the frequency of NTM lung disease among patients who are suspected of tuberculosis. NTM was isolated from about one-fourth of the mycobacterium culture-positive patients and about half of these had NTM lung disease. Therefore, NTM isolates should be routinely identified at the species level for adequate treatment.

Occult hepatitis B virus infection in Korean patients with isolated anti-HBc.

Serological detection of isolated anti-hepatitis B core antibody (anti-HBc) can occur in various scenarios, but the most clinically relevant situation is occult hepatitis B virus (HBV) infection (OBI). The purpose of this study was to evaluate the prevalence and clinical relevance of isolated anti-HBc and of OBI with isolated anti-HBc from an unselected hospital population. A total of 14,253 patients referred for hepatitis B surface antigen (HBsAg)/anti-HBs testing were classified into either the Health Promotion Center (HPC) group or the patient group. For patients who were negative for both HBsAg and anti-HBs, an anti-HBc test was additionally performed. An HBV DNA real-time PCR test was performed on isolated anti-HBc patients, and their demographic and clinical data were reviewed. The measured prevalence of isolated anti-HBc and OBI in isolated anti-HBc patients was 5.9 % and 4.7 %, respectively. Prevalence was higher in males, elderly people, and the patient group than in females, the younger, and the HPC group, respectively. In most cases, the levels of HBV DNA load were very low (less than 200 IU/mL), and most cases of OBI presented without liver disease or history of HBV infection. The prevalence of isolated anti-HBc and OBI are affected by the methods of detection, subject population, and constituent factors such as sex and age. Although detection of HBV DNA does not always indicate infectivity, highly sensitive standardized HBV DNA tests are needed in clinical settings to exclude the possibility of OBI, especially in the advanced age group.

Mean platelet volume and mean platelet volume/platelet count ratio in infective endocarditis.

Infective endocarditis (IE), an infection of the endocardial surface, frequently leads to life-threatening complications, such as thromboembolism due to platelet activation. We investigated the mean platelet volume (MPV) in Korean patients with IE and the serial changes thereof, in comparison with other laboratory parameters. We analyzed 248 MPV results from 22 patients diagnosed with IE in our hospital between January 2011 and April 2012. MPV was measured with an Advia 2120 (Siemens Healthcare Diagnostics, Tarrytown, NY) using EDTA-containing tubes. The mean MPV differed significantly between the patient and control groups, 8.74 vs. 7.96 fl, respectively. In addition, the platelet count and MPV/platelet count ratio were significantly decreased in the patient group. The total platelet mass and platelet size in IE might be increased. Further studies should examine more patients to verify the changes in the MPV and MPV/platelet count ratio in IE and assess in greater detail the relationship between MPV and thrombotic complications caused by platelet activation.

Relevance of indirect immunofluorescence patterns and autoantibodies identified via line immunoassay in patients with rheumatoid arthritis.

OBJECTIVE: To analyze indirect immunofluorescence (IIF) patterns and autoantibodies identified by line immunoassay (LIA) in rheumatoid arthritis (RA) patients, and to compare the autoantibody profiles with serological markers to determine their relevance. METHODS: A total of 153 specimens were obtained from RA patients for diagnostic or monitoring purposes. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), and anti-cyclic citrullinated peptide (anti-CCP) were measured, and autoantibody testing using IIF and LIA was performed. Frequencies of IIF patterns and autoantibodies identified by LIA were analyzed and compared with each other and with serologic markers of RF, including anti-CCP, ESR, and CRP. RESULTS: The overall positivity of IIF and LIA results was 49.7% and 34.0%, respectively. The most frequent IIF pattern in RA was homogenous (20.9%), followed by dense fine speckled (DFS) pattern (17%). Anti-SS-A and/or anti-Ro-52 were most frequently detected in RA irrespective of the observed IIF pattern. Positive rates and intensities of autoantibodies detected did not differ by therapeutic regimen or disease activity, as reflected by CRP levels or ESR. Only anti-CCP showed a tendency to increase depending on IIF intensity. CONCLUSIONS: RA patients did not display a specific or dominant IIF pattern or autoantibody presence, as identified by LIA. RA patients had lower frequencies of anti-SS-A and anti-Ro-52 compared with other systemic autoimmune diseases (serologically characteristic of RA). IIF and LIA appear insufficient for diagnosing RA and monitoring disease activity yet can be useful for screening and differentiating major systemic autoimmune diseases.

Comparison of indirect immunofluorescence and line immunoassay for autoantibody detection.

OBJECTIVES: The aim of the present paper is to evaluate the diagnostic performance of indirect immunofluorescence (IIF) and line immunoassay (LIA) for autoantibody (autoAb) detection and provide sufficient information to interpret the results of autoAb tests. METHODS: The study included 1,052 patients for whom IIF and LIA tests had been performed simultaneously for a systemic autoimmune disease work-up. All patients were divided into either the systemic autoimmune group or non-autoimmune group, and the systemic autoimmune group was further divided into systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren's syndrome, systemic sclerosis (SSc), and dermatomyositis/polymyositis (DM/PM). The diagnostic performance of IIF and LIA was analysed according to the distribution of IIF patterns and autoAbs identified by LIA. RESULTS: The overall sensitivity/specificity of IIF and LIA for systemic autoimmune disease was 63.5%/80.3% and 66.1%/83.2%, respectively. IIF showed higher sensitivity for SLE than LIA, but the sensitivity of LIA was higher for Sjögren's syndrome and DM/PM. The speckled pattern was the most commonly observed pattern in systemic autoimmune diseases with the exception of SSc. In the majority of systemic autoimmune diseases and their various IIF patterns, both anti-Ro-52 and anti-SS-A were the most prevalent autoAbs. In addition, a majority of the systemic autoimmune diseases showed specific dominant positive patterns or a combination of IIF and LIA results that were disease specific. CONCLUSIONS: Utilising both methods together not only increased the sensitivity in most cases but also provided more information from the combination of results, augmenting their interpretation with the advantage of simultaneous identification of autoAbs.

Mean platelet volume/platelet count ratio in hepatocellular carcinoma.

Mean platelet volume (MPV) has been actively investigated in liver disease such as steatosis, cirrhosis and hepatitis. Recently, MPV/platelet count (PC) ratio has been proposed as a predictor of long-term mortality after myocardial infarction. As PC is known to be decreased in various liver diseases such as cirrhosis, hepatosplenomegaly and malignancy, we planned to evaluate MPV/PC ratio in patients with hepatocellular carcinoma (HCC) in this study. Mean of MPV levels showed significant difference, which were 8.69 fl (range 6.7-12.2 fl) in patients group and 8.02 fl in control group (range 6.7-11.0 fl). In receiver operating characteristic (ROC) curve analysis, the MPV/PC ratio (fl/(10(9)/l)) presented 74.5% of sensitivity and 96.5% of specificity at the criterion > 0.0491 (area under the curve (AUC) = 0.884), while MPV alone showed 57.4% of sensitivity and 81.4% of specificity at the criterion > 8.4 fl. Further studies should evaluate underlying pathogenic mechanisms of MPV/PC ratio difference and various possibilities of this ratio as an indicator of presence of a tumor in HCC.