Syndromic Testing for Sexually Transmitted Infection: Current and Future Demand / 대한임상미생물학회지

Sexually transmitted infections (STIs) are a major global public health problem, with significant social burden worldwide. Accurate and appropriate diagnosis and treatment of STIs are important for preventing the transmission of STIs as well as major health consequences of untreated STIs, such as infertility and certain cancer. For diagnosis of STIs, the application of conventional culture and immunoassays is limited by their low sensitivity and long turnaround time. Nucleic acid amplification tests for STIs allow for syndromic tests for multiple pathogens simultaneously and show high sensitivity with a short turnaround time. In this review, we discuss the characteristics of commercially available multiplex molecular platforms and the features needed in next-generation syndromic tests for STIs.

Diagnostic Performance of the GENEDIA MTB/NTM Detection Kit for Detecting Mycobacterium tuberculosis and Nontuberculous Mycobacteria With Sputum Specimens

The GENEDIA MTB/NTM Detection Kit (GENEDIA MTB/NTM; Green Cross Medical Science Corp., Chungbuk, Korea) is a multiplex real-time PCR assay used for differential identification of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM). While the importance of differential identification of MTB/NTM is recognized, there is limited data on the performance of GENEDIA MTB/NTM assay to date. A total of 687 consecutive sputum specimens were cultured and analyzed with the GENEDIA MTB/NTM and GENEDIA MTB assays. Nineteen specimens (2.8%) were MTBC-positive, and 69 (10.0%) were NTM-positive based on mycobacterial culture. All specimens showed concordant results for MTBC using both assays, with a kappa value of 1.00, overall sensitivity of 63.2% (12/19), and specificity of 100% (668/668). The overall NTM sensitivity and specificity were 23.2% (16/69) and 99.7% (616/618) for GENEDIA MTB/NTM. The association between NTM-positivity using GENEDIA MTB/NTM and the diagnosis of NTM pulmonary disease was not statistically significant. In conclusion, the two real-time PCR assays showed similar diagnostic performance for MTBC detection. However, the sensitivity for NTM detection was lower than that for MTBC detection.

Linezolid Resistance in Methicillin-Resistant Staphylococcus aureus in Korea: High Rate of False Resistance to Linezolid by the VITEK 2 System

As various linezolid resistance mechanisms have been identified in methicillin-resistant Staphylococcus aureus (MRSA), we investigated the molecular characteristics of MRSA with elevated linezolid minimum inhibitory concentrations (MICs), using the VITEK 2 system (bioMérieux, Marcy-l'Étoile, France). Twenty-seven MRSA isolates from 14 patients exhibiting linezolid MICs ≥8 µg/mL were examined by broth microdilution (BMD) test as well as by sequencing for mutations in the 23S rRNA gene or ribosomal proteins (L3, L4, and L22) and the presence of the optrA, cfr, and cfr(B) genes. Of the 27 isolates, four (14.8%) from one patient were confirmed as linezolid resistant by BMD and harbored a 23S rRNA T2500A mutation. The remaining 23 were confirmed as linezolid susceptible, indicating that the linezolid-resistant results were major errors generated by VITEK 2. The most commonly detected mutation (19/27, 70.4%), L3 Gly152Asp, was detected in only linezolid-susceptible isolates. No isolates contained optrA, cfr, or cfr(B) or any L4 or L22 protein alterations. Our results show that the 23S rRNA T2500A mutation was mainly associated with linezolid resistance, while the L3 Gly152Asp mutation was not related to linezolid resistance. A confirmatory test is recommended for VITEK 2 linezolid-resistant results owing to the high probability of false resistant results.

Comparison of 16S Ribosomal RNA Targeted Sequencing and Culture for Bacterial Identification in Normally Sterile Body Fluid Samples: Report of a 10-Year Clinical Laboratory Review

As 16S ribosomal RNA (rRNA)-targeted sequencing can detect DNA from non-viable bacteria, it can be used to identify pathogens from clinical samples even in patients pretreated with antibiotics. We compared the results of 16S rRNA-targeted sequencing and culture for identifying bacterial species in normally sterile body fluid (NSBF): cerebrospinal, pericardial, peritoneal and pleural fluids. Over a 10-year period, a total of 312 NSBF samples were evaluated simultaneously using 16S rRNA-targeted sequencing and culture. Results were concordant in 287/312 (92.0%) samples, including 277 (88.8%) negative and 10 (3.2%) positive samples. Of the 16 sequencing-positive, culture-negative samples, eight showed clinically relevant isolates that included Fusobacterium nucleatum subsp. nucleatum, Streptococcus pneumoniae, and Staphylococcus spp. All these samples were obtained from the patients pretreated with antibiotics. The diagnostic yield of 16S rRNA-targeted sequencing combined with culture was 11.2%, while that of culture alone was 6.1%. 16S rRNA-targeted sequencing in conjunction with culture could be useful for identifying bacteria in NSBF samples, especially when patients have been pretreated with antibiotics and when anaerobic infection is suspected.

Prevalence and Immunophenotypic Characteristics of Monoclonal B-Cell Lymphocytosis in Healthy Korean Individuals With Lymphocytosis

Epidemiological studies of monoclonal B-cell lymphocytosis (MBL) have been conducted in limited geographical regions. Little is known about the prevalence of MBL in Asia. We investigated the prevalence and immunophenotypic characteristics of MBL in Koreans who had idiopathic lymphocytosis (lymphocyte count >4.0×109/L) and were ≥40 years of age. A total of 105 leftover peripheral blood samples met these criteria among those from 73,727 healthy individuals who visited the Health Promotion Center, Samsung Medical Center, Korea, from June 2018 to August 2019. The samples were analyzed using eight-color flow cytometry with the following monoclonal antibodies: CD45, CD5, CD10, CD19, CD20, CD23, and kappa and lambda light chains. The overall prevalence of MBL in the study population was 2.9% (3/105); there was one case of chronic lymphocytic leukemia (CLL)-like MBL (CD5+CD23+), one case of atypical CLL-like MBL (CD5+CD23−), and one case of CD5−MBL with a lambda restriction pattern. This is the first study on the MBL prevalence in an East Asian population, and it reveals a relatively low prevalence of MBL in healthy Korean individuals with lymphocytosis.

Comparison Between the SFTS-QS Kit and the PowerChek SFTSV Real-time PCR Kit for the Detection of Severe Fever With Thrombocytopenia Syndrome Virus

The recent increase in severe fever with thrombocytopenia syndrome (SFTS) cases has led to the development of the SFTS-QS kit (MiCoBioMed, Seongnam, Korea) for detecting the SFTS virus (SFTSV, now renamed Huaiyangshan banyangvirus). SFTS-QS is a qualitative real-time reverse transcription PCR assay based on lab-on-a-chip technology. We evaluated the performance of the SFTS-QS kit and compared it with that of the PowerChek SFTSV Real-time PCR kit (PowerChek; Kogene Biotech, Seoul, Korea). A total of 117 serum samples were simultaneously assayed using the SFTS-QS and PowerChek kits. Sanger sequencing targeting the S and M segments of SFTSV was performed as the reference method. The total turnaround time of the two kits was compared. The SFTS-QS results agreed with those of PowerChek with a kappa value of 0.92. The diagnostic sensitivity and specificity of the SFTS-QS kit were both 100% (14/14 and 103/103, respectively), whereas those of the PowerChek kit were 100% (14/14) and 98.1% (101/103), respectively. The results of SFTS-QS and PowerChek were comparable; however, the SFTS-QS kit required a shorter total turnaround time. The SFTS-QS kit produced accurate and fast results and thus could serve as a useful tool for detecting SFTSV.

Simultaneous Detection of Clostridioides difficile Glutamate Dehydrogenase and Toxin A/B: Comparison of the C. DIFF QUIK CHEK COMPLETE and RIDASCREEN Assays

Various commercial assays have recently been developed for detecting glutamate dehydrogenase (GDH) and/or toxin A/B to diagnose Clostridioides difficile infection (CDI). We compared the performance of two assays for the simultaneous detection of C. difficile GDH and toxin A/B, using 150 stool samples: C. DIFF QUIK CHEK COMPLETE (QCC; TechLab, Blacksburg, VA, USA) and RIDASCREEN Clostridium difficile GDH (RC-GDH) and Toxin A/B (RC-Toxin A/B; R-Biopharm, Darmstadt, Germany). For GDH detection, QCC and RC-GDH showed satisfactory sensitivity (95.7% and 94.3%, respectively) and specificity (92.5% and 93.8%, respectively) compared with C. difficile culture. For toxin A/B detection, QCC showed higher sensitivity than RC-Toxin A/B (60.0% vs 33.3%, P < 0.001) compared with toxigenic C. difficile culture. When the results of QCC or RC-GDH+RC-Toxin A/B were used as the first step of a two-step algorithm for diagnosing CDI, QCC permitted more accurate discrimination than RC of positive or negative results for CDI (77.3% and 65.3%, respectively). QCC is useful for the simultaneous detection of C. difficile GDH and toxin A/B as a part of the two-step algorithm for diagnosing CDI.

Mycobacterium shimoidei Pulmonary Disease: The First Case in Korea

Mycobacterium shimoidei is a nontuberculous mycobacterium (NTM), and is rarely reported as a pathogen causing the NTM pulmonary disease. We describe here the case of a 52-year-old male with symptoms such as chronic cough and a history of pulmonary tuberculosis. Radiologic studies revealed a cavitary lesion in the left upper lobe of his lung. Sputum culture was positive for NTM, which was later identified as M. shimoidei using 16S rRNA and hsp65 sequencing. The patient's symptoms, radiologic evidence, and positive culture results together substantiate that this is the first case of M. shimoidei pulmonary disease from Korea.

A Case of Mature B-cell Neoplasm with Light Chain Clonality Confirmed by Cytoplasmic Light Chain Expression Using Flow Cytometry

Surface immunoglobulin light-chain restriction is evidence of clonality in mature B-cell neoplasms. An aberrant pattern of surface light-chain expression can also be considered evidence of clonality. However, because this result could occur due to nonspecific staining or failure to stain, careful interpretation is required for accurate diagnosis. According to a previous study, flow cytometric analysis of the cytoplasmic pattern of light-chain expression in mature B-cell neoplasms is a viable approach to confirming clonality. Herein, we report a case, in which clonality could not be proven by surface light-chain analysis, but was demonstrated by cytoplasmic light-chain analysis. The case was in a patient with B-cell lymphoma showing non-specific surface expression of light-chains. This case support consideration of flow cytometric analysis of cytoplasmic light-chain expression patterns when aberrant surface light chain expression is observed, to confirm clonality of mature B-cell neoplasms.

First Isolation of Mycobacterium virginiense From a Human Pulmonary Specimen

No abstract available.

Diagnostic Utility of Polymerase Chain Reaction for Acanthamoeba in Contact Lens-related Keratitis with Epithelial Defects

PURPOSE@#To report contact lens related Acanthamoeba keratitis with corneal epithelial defect cases which were diagnosed using polymerase chain reaction (PCR).CASE SUMMARY: A 51-year-old male visited our hospital for loss of visual acuity and ocular pain in both eyes. He had been wearing therapeutic contact lenses in both eyes for 4 days prior to his visit, and showed a corneal epithelial defect with corneal edema in both eyes. The corneal edema did not improve after treatment for bacterial and herpes keratitis, so we conducted PCR for Acanthamoeba using the aqueous fluid in the anterior chamber, which showed positive results. A 32-year-old male complained of low visual acuity and ocular pain in both eyes. He had a history of corneal erosion. He had been wearing therapeutic contact lenses in both eyes for 3 days prior to his visit for a corneal epithelial defect. We suspected recurrent corneal erosion syndrome, but PCR for Acanthamoeba of the corneal scraping showed positive results. A 26-year-old female visited our hospital for ocular pain, and discomfort in her left eye. Because of severe dry eye, she had been wearing therapeutic contact lenses for 6 weeks prior to her visit. Her left eye showed corneal infiltration and epithelial defects. The left cornea scraping was positive for bacteria, and PCR for Acanthamoeba also showed positive results.@*CONCLUSIONS@#Clinicians should consider the use of PCR for the early diagnosis of Acanthamoeba keratitis in contact lens-related keratitis with corneal epithelial defects.

Evaluation of BacT/Alert FAN Plus Bottles for the Culture of Peritoneal Dialysate / 대한임상미생물학회지

BACKGROUND: A major complication of peritoneal dialysis (PD) is peritonitis, and bacterial culture of PD effluent in a blood culture bottle is the preferred technique for diagnosis of peritonitis. In this study, we compared dialysate inoculation and culture using the BacT/AlerT® Fastidious Antimicrobial Neutralization Plus blood culture bottles (FAN Plus; bioMérieux, France) to the conventional centrifugation culture method.METHODS: A total of 170 PD effluents were simultaneously processed by the conventional centrifugation culture method and by culture using FAN Plus media with two different inoculation procedures: inoculation after centrifugation and direct bedside inoculation.RESULTS: Of the 52 cultures that were positive on at least one of the culture methods, 27 samples were positive on conventional centrifugation. However, 46 samples showed growth following inoculation into the FAN Plus media after centrifugation, and 47 samples were positive on the direct FAN Plus inoculation method. Using the case definition for PD peritonitis to classify samples, sensitivity of the conventional method was 50.0% (95% CI, 33.7–66.3%), whereas the sensitivity of the FAN Plus media was 78.9% (95% CI, 62.2–89.9%) by inoculation after centrifugation and 86.8% (95% CI, 71.1–95.1%) by direct inoculation. Use of both inoculation methods with FAN Plus media resulted in 92.1% sensitivity (95% CI, 89.2–99.9%).CONCLUSION: Culture using FAN Plus media demonstrated a superior bacterial recovery rate to the conventional centrifugation culture method. A combination of the two inoculation methods with FAN Plus media is recommended for the best diagnostic yield, while direct inoculation alone can be useful due to its simplicity and cost-effectiveness.

A Case of Cruoricaptor ignavus Isolated From the Blood of a Patient With Ewing Sarcoma

No abstract available.

Evaluation of Stability of Thiopurine Metabolites Using a Validated LC-MS/MS Method

Measurement of thiopurine metabolites is helpful to monitor adverse effects and assess compliance in patients on thiopurine treatment. The purpose of this study was to develop and validate an analytical method for measurement of thiopurine metabolites, thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine nucleotide (6-MMPN), in RBCs. We developed and validated a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for the quantification of 6-TGN and 6-MMPN and evaluated the stability of the thiopurine metabolites in RBC and whole blood states without any preprocessing at various storage conditions. The linear range was 0.1–10 µmol/L and 0.5–100 µmol/L for 6-TGN and 6-MMPN, respectively. The mean extraction recovery at the two concentrations was 71.0% and 75.0% for 6-TGN, and 102.2% and 96.4% for 6-MMPN. Thiopurine metabolites in preprocessed RBC samples were stable at 25℃ and 4℃ after storage for 4 hours and at −70℃ for up to 6 months. However, 6-TGN decreased by 30% compared with the initial concentration when stored at −20℃ for 180 days. In whole blood states, 6-TGN decreased by about 20% at four days after storage at 4℃. We validated a reliable LC-MS/MS method and recommend that the patient's whole blood sample be preprocessed as soon as possible.

Penicillium Species Other Than Talaromyces marneffei Producing Red Pigment from Clinical Specimens: Isolation of Talaromyces albobiverticillius

No abstract available.

Novel 4-bp Intronic Deletion (c.1560+3_1560+6del) in LEMD3 in a Korean Patient With Osteopoikilosis

Osteopoikilosis is an autosomal dominant bone disorder characterized by symmetric multiple osteosclerotic lesions throughout the axial and appendicular skeleton. Pathogenic variants in the LEMD3 have been identified as the cause of osteopoikilosis. LEMD3 encodes an inner nuclear membrane protein that interacts with bone morphogenetic protein (BMP) and transforming growth factor (TGF)-β pathways. We report the case of a 19-year-old man presenting with lower back pain and sciatica. His radiograph revealed bilateral and symmetrical multiple osteosclerotic bone lesions in both scapular areas. Sanger sequencing of LEMD3 revealed a four-base-pair deletion in intron 2 (c.1560+3_1560+6del), which was inherited from his father. We found that this four-base-pair deletion in intron 2 causes aberrant splicing and consequent deletion of exon 2. To the best of our knowledge, this is the first report of genetically confirmed osteopoikilosis in Korea.

Performance of an Automated Fluorescence Antinuclear Antibody Image Analyzer

BACKGROUND: The gold standard for antinuclear antibody (ANA) screening is the indirect immunofluorescence (IIF) assay with human epithelial cells (HEp-2). However, a number of substantial disadvantages of manual IIF assays have highlighted the need for the automation and standardization of fluorescent ANA (FANA) testing. We evaluated the performance of EUROPattern Suite (Euroimmun AG, Germany), an automated FANA image analyzer, with regard to ANA detection and pattern recognition compared with conventional manual interpretation using the fluorescence microscopic IIF assay. METHODS: A total of 104 samples including 70 ANA-positive sera and 34 ANA-negative sera collected from September to October 2015 were included. The sensitivity, specificity, and pattern recognition function were evaluated to determine the performance of EUROPattern Suite compared with the manual IIF assay results. RESULTS: The sensitivity and specificity of EUROPattern Suite for ANA detection were 94.3% and 94.1%, respectively. The concordance rate between the two methods was 94.2%. For pattern recognition, 45.7% of the samples were assigned identical ANA patterns including simple and mixed. When major pattern matching was considered, 83.7% (41/49) and 95.2% (20/21) of the samples with simple and mixed patterns, respectively, showed concordant results between the two methods. CONCLUSIONS: EUROPattern Suite, an automated FANA image analyzer, provides a viable option for distinguishing between positive and negative results, although the ability to assign specific patterns is insufficient to replace manual microscopic interpretation. This automated system may increase efficiency in laboratories, in which a large number of samples need to be processed.

Analysis of Multi-variate Recurrent Fall Risk Factors in Elderly People Using Residential Assessment Instrument-Home Care: Comparisons between Single and Recurrent Fallers

PURPOSE: This study was done to determine the risk factors for recurrent fallers (2+falls) compared to single fallers. METHODS: Participants were 104 community-dwelling people 65 yr of age or older. The data were collected from June 1, 2008 to June 30, 2009 using the Residential Assessment Instrument-Home Care. RESULTS: Over the past 90 days, 55.7% of the 104 participants fell once, and 44.2% experienced recurrent falls (2+falls). In comparison of recurrent fallers with single fallers, there were significant differences in scores on the following factors: gender (chi2=4.22, p=.040), age (chi2=5.74, p=.017), educational level (chi2=5.22, p=.022), living arrangements (chi2=35.02, p<.001), cardiovascular diseases (chi2=17.10, p<.001), hypertension (chi2=4.43, p=.035), diabetes mellitus (chi2=4.44, p=.035), glaucoma (chi2=13.95, p<.001), Minimal Data Set (MDS)-Pain (t=-2.56, p=.012), fear of falling (chi2=4.08, p=.034), reduced vision (t=-3.06, p=.003), MDS-activity of daily living (t=3.46, p=.001), MDS-Instrumental Activities of daily living (t=3.24, p=.002), cognition (MDS-Cognition Performance Scale) (t=3.40, p=.001), and 'difficulties entering and leaving the house' (chi2=4.53, p=.033). CONCLUSION: It is important to assess the risk factors for recurrent falls and develop differentiated strategies that will help prevent recurrent falls. Additionally, utilizing a standardized tool, such as RAI-HC, would help health professionals assess multi-variate fall risk factors to facilitate comparisons of different community care settings.

The Comparison of Functional Status and the Level of Health Care Needs in Elderly Koreans in Health Care Institutions

PURPOSE: The purpose of this study was to compare functional status and the level of health care needs in elderly Koreans in health care institutions. METHODS: Data were collected from 2,521 elderly patients admitted in 50 health care institutions (hospitals, oriental hospitals, geriatric hospitals, and health care facilities) selected through proportional stratified sampling in 2008. We used a long-term care (LTC) assessment tool developed by the government, which consists of 52 items with 5 subscales. RESULTS: Statistically significant differences were detected in functional status and the level of health care needs among the subjects in different health care institutions. Of the sample population in geriatric hospitals, 48.9% were eligible for LTC Category 1, 20.9% for Category 2, and 17.2% for Category 3, and 13.1% of the subjects were not eligible for any of the categories. Of the sample population in health care facilities, 29.9% were eligible for LTC Category 1, 20.5% for Category 2, and 21.8% for Category 3, and 27.0% of the subjects were not eligible for any of the categories. CONCLUSION: The findings of this study indicate the necessity of the development of an evaluation system that helps determine whether a subject is eligible for LTC.

A Study of Psychosocial distress, Intention to Quit and Nursing Performance in General Ward Nurses / 산업간호학회지

PURPOSE: The purpose of this study was to examine the relationship of psychosocial distress, intention to quit and nursing performance. METHODS: The data were collected through structured questionnaires from 210 registered nurses in a general hospital. They were analyzed by descriptive statistics, t-test, ANOVA, scheffe test, Pearson's correlation coefficient and multiple regression with the SPSS WIN program. RESULTS: The results of the analysis showed that the mean of the psychosocial distress was 25.38+/-7.26, intention to quit was 3.51+/-0.78, and nursing performance was 3.67+/-0.46. In the correlation analysis, the nursing performance had negative correlation with psychosocial distress(r=-.371, p=.000) and intention to quit(r=-.211, p=.002). There were statistically significant differences in nursing performance depending on age, marital status, position and work experience. The psychosocial distress and age explained 15.1% of nursing performance. CONCLUSION: This study showed psychosocial distress and intention to quit affects the nursing performance. Therefore, nursing executives and unit managers need to concern on the significance of the stress management programs so that these can be organizational support.