Background/Aims: There is a recent increase in the use of stool multiplex PCR assay-based diagnostic tests in patients with acute diarrhea. We used multiplex PCR assays to analyze the distribution of diarrhea-causing bacteria and viruses, as well as the clinical features of patients with acute diarrhea. Methods: We retrospectively reviewed stool specimens of inpatients complaining of acute diarrhea from October 2018 to July 2020.The stool specimens had been tested for bacteria and viruses using multiplex PCR assays. Results: A total of 414 stool specimens from 346 patients were tested, and 152 pathogens were detected in 131 stool samples (131/414, 31.6%). Co-infection was detected in 20 patients (20/346, 5.8%). The common pathogens detected as causes of acute diarrhea, including co-infection, were Clostridium perfringens (34.9%), Clostridioides difficile (19.7%), and Campylobacter spp. (18.4%). The average age of patients with multiplex PCR-positive tests was lower than those with multiplex PCR-negative tests (p=0.001). In patients with suspected C. difficile infection (CDI), the RT-PCR for toxin gene assay was performed in 370 stool samples, 35 of which were positive (9.5%). Furthermore, 16 of the 35 samples were positive on the multiplex PCR assay (45.7%). Conclusions The multiplex PCR assay revealed that C. perfringens was the most common diarrhea-causing pathogen. In addition, in patients with suspected CDI, the multiplex PCR assay alone was insufficiently sensitive to detect pathogens and a conventional CDI test was additionally required.

Background: We evaluated the analytical performance and cost-effectiveness of lateral flow immunoassays (LFIAs) in detecting Clostridioides difficile glutamate dehydrogenase (GDH) antigen and toxin A/B, followed by a rapid nucleic acid amplification test (NAAT). Methods: A total of 341 unformed stools were tested using a two-step algorithmic approach with C. DIFF QUIK CHEK COMPLETE (QCC) LFIA (TechLab, USA), followed by Xpert C. difficile NAAT (Xpert). The performance of the QCC assay was compared with that of the VIDASC. difficile GDH and toxin A/B assay (bioMérieux, France), an enzyme-linked fluorescence im munoassay. The clinical performance and cost-effectiveness of the diagnostic algorithms using the QCC or VIDAS assays were compared to the results obtained using the Xpert assay alone. Results: For GDH and toxin detection, the QCC and VIDAS assays dem onstrated an almost perfect agreement, with no significant difference in sensitivity (QCC-GDH, 90.5%; VIDAS-GDH, 91.9%; QCC-toxin, 51.4%; VIDAStoxin, 55.4%) and specificity (QCC-GDH, 92.9%; VIDAS-GDH, 89.1%; QCC-toxin, 100%; VIDAS-toxin, 99.6%), compared to the Xpert. The algorithmic approach (GDH and toxin plus Xpert) increased the sensitivity (QCC, 93.2%; VIDAS, 94.6%) and specificity (QCC, 100%; VIDAS, 99.6%). The algorithmic approach reduced the cost compared to the Xpert alone, and the turnaround time of the QCC was shorter than that of the VIDAS assay. Conclusions Simultaneous detection of GDH and toxin A/B, using QCC or VIDAS assays showed comparable sensitivity and specificity when followed by the Xpert assay. The QCC assay is preferable in turnaround time and cost, which are important considerations for laboratories handling smaller number of samples.

Background and Objectives: Following the transsphenoidal approach (TSA), appropriate sphenoid sinus fat packing has been preferred to prevent postoperative cerebrospinal fluid leakage; however, studies on the behavior of fat tissue transplanted in the sphenoid sinus are lacking. This study aimed to determine the long-term fate of these fat grafts using magnetic resonance imaging (MRI).Subjects and Method: A total of 139 postoperative MRI scans of 41 patients who underwent sphenoid sinus fat packing using the standard TSA were evaluated. Additionally, MRI time series indicating the vital fat volumes were assessed postoperatively. Results: In 82.9% of cases, the fat volumes measured in the final MRI scans declined to <20% of the initial volumes; only 4.9% of cases exhibited declines to >60% of the initial volume. The fat tissue volume decreased significantly with time, with a median half-life of 18 months. Typically, the sphenoid sinus was eventually almost filled with air rather than transplanted fat. In the subgroup analysis, the fat clearance rate was significantly lower in patients with residual tumors than in those without such remnants (p=0.013). Conclusion Long-term MRI surveillance of fat grafts in the sphenoid sinus revealed that the transplanted fat graft had degraded and was gradually eliminated.

BACKGROUND/AIMS: The incidence and severity of Clostridium difficile infection (CDI) have increased worldwide, resulting in a need for rapid and accurate diagnostic methods. METHODS: A retrospective study was conducted to compare CDI diagnosis methods between January 2014 and December 2014. The stool samples, which were obtained in presumptive CDI patients, were compared for their diagnostic accuracy and rapidity, including real-time polymerase chain reaction (PCR) of toxin genes, C. difficile toxin assay, and culture for C. difficile. RESULTS: A total of 207 cases from 116 patients were enrolled in this study and 117 cases (56.5%) were diagnosed as having CDI. Among the 117 cases, the sensitivities of real-time PCR, C. difficile toxin assay, and culture for C. difficile were 87.2% (102 cases; 95% CI, 80.7%–92.8%), 48.7% (57 cases; 95% CI, 41.0%–59.8%), and 65.0% (76 cases; 95% CI, 60.2%–78.5%), respectively (P < 0.005). Notably, 34 cases (29.0%) were diagnosed with CDI by real-time PCR only. The time required to obtain results was 2.27 hours (136.62±82.51 minutes) for real-time PCR, 83.67 hours (5,020.66±3,816.38 minutes) for toxin assay, and 105.79 hours (6,347.68±3,331.46 minutes) for culture (P < 0.005), respectively. CONCLUSIONS: We confirmed that real-time PCR of toxin genes is the most effective diagnostic method for accurate and early diagnosis of CDI. It also helps to diagnose hypervirulent CDI, such as ribotype 027 infection.
Clostridium difficile ; Clostridium ; Diagnosis ; Early Diagnosis ; Humans ; Incidence ; Methods ; Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction ; Retrospective Studies ; Ribotyping

OBJECTIVES: The neutrophil gelatinase-associated lipocalin (NGAL) level following non cardiac surgery is useful for predicting acute kidney damage. However, there is insufficient conclusive evidence as to whether NGAL can be used to predict subclinical AKI following non-cardiac surgery. METHODS: We measured serum NGAL and creatinine levels in 41 patients following non-cardiac surgery, and the increase of these variables was used to predict acute decreases in kidney function. RESULTS: The study included a total of 41 patients. The mean age was 64.65 ± 17.09 years. The serum creatinine concentration was increased 12 hours after surgery. The mean SD serum NGAL decreased after 4hours after surgery and continued to decrease after 12 hours after surgery. The incidence of subclinical AKI determined by the 4 hour serum NGAL level was 10(24.4%), and the incidence of serum creatinine elevation was 0(0.0%). The incidence of subclinical AKI determined by the 12 hour serum NGAL level was 4(9.8%), and the incidence of subclinical AKI determined by serum creatinine was 4(9.8%). The elevation of NGAL was more rapid than the serum creatinine 4 hours after surgery. CONCLUSIONS: We verified the usefulness of the serum NGAL level as a predictive factor for subclinical AKI after non-cardiac surgery.
Acute Kidney Injury* ; Creatinine ; Humans ; Incidence ; Kidney ; Lipocalins ; Neutrophils* ; Prognosis* ; Thoracic Surgery

PURPOSE: The lack of identified mammalian target of rapamycin (mTOR) pathway downstream genes that overcome cross-talk in nonmuscle invasive low grade (LG)-urothelial carcinoma (UC) of the bladder is a clinical limitation in the use of mTOR inhibitor for the treatment of UC. MATERIALS AND METHODS: Presently, gene expression patterns, gene ontology, and gene clustering by dual (p70S6K and S6K) siRNAs or rapamycin in 253J and TR4 cell lines were investigated by microarray analysis. mTOR/S6K pathway downstream genes suppressed to siRNAs, and rapamycin up-regulated or rapamycin down-regulated genes were identified. The mTOR downstream genes examined using a tissue microarray of 90 nonmuscle invasive LG-UC patients to assess whether any of these genes predicted clinical outcomes. A knockout study evaluated the synergistic effect with rapamycin. RESULTS: In the microarray analysis, mTOR pathway downstream genes selected consisted of 4 rapamycin down-regulated (FOXM1, KIF14, MYBL2, and UHRF1), and 4 rapamycin up-regulated (GPR87, NBR1, VASH1, and PRIMA1). In the tissue microarray, FOXM1, KIF14, and NBR1 were more expressed at T1, and MYBL2, and PRIMA1 were more expressed in tumors exceeding 3 cm. In a multivariate Cox regression model, KIF14 and NBR1 were significant predictors of recurrence in nonmuscle invasive LG-UC of the bladder. In a NBR1 knock out model, rapamycin treatment synergistically inhibited cell viability and colony forming ability compared to rapamycin only. CONCLUSIONS: The results implicate KIF14 and NBR1 as mTOR/S6K pathway downstream genes that predict recurrence in nonmuscle invasive LG-UC of the bladder and demonstrate that NBR1 knockout overcomes rapamycin cross-talk.
Biomarkers ; Cell Line ; Cell Survival ; Gene Expression ; Gene Ontology ; Humans ; Microarray Analysis ; Recurrence* ; RNA, Small Interfering ; Sirolimus* ; Urinary Bladder Neoplasms ; Urinary Bladder*

BACKGROUND: Anti-hepatitis C virus antibody (anti-HCV) assays are recommended for screening HCV-infected persons. The VIDAS Anti-HCV Assay (bioMérieux, France), based on the enzyme-linked fluorescence test principle, was recently introduced in Korea. We evaluated the clinical performance of the VIDAS assay. METHODS: One hundred HCV-positive and 1,002 HCV-negative blood samples confirmed by Architect anti-HCV (Abbott Laboratories, USA) and COBAS TaqMan HCV real-time PCR (Roche Diagnostics, USA) or the Procleix Ultrio Plus Assay (Gen-Probe Incorporated, USA) were obtained from the Human Serum Bank (HSB) and tested by VIDAS. In case of discrepant results, we conducted a recombinant immunoblot assay (RIBA). RESULTS: The agreement rates for known HCV-positive and HCV-negative samples between the VIDAS assay and the HSB testing were 100% (95% confidence interval [CI]: 96.4-100%) and 99.5% (95% CI: 98.8-99.8%), respectively. One of the five discrepant samples was positive for Core 2+ and NS3-2 2+ reactivity, two samples were negative, and the other two were indeterminate regarding NS4 2+ reactivity in RIBA. We observed a significant but weak positive correlation between the titers of VIDAS and Architect assays (r=0.315, P<0.001). CONCLUSIONS: The VIDAS anti-HCV assay, developed on the VIDAS automated immunoassay platform based on the ready-to-use, single-sample test concept may be useful in small-to-medium-sized laboratories. It showed good agreement with Architect anti-HCV and COBAS PCR assays and is therefore useful for detection of HCV infection. Weakly test-positive (ambiguous) samples require additional testing by another anti-HCV, RIBA, or HCV RNA assay.
Automation ; Hepatitis C/*diagnosis ; Hepatitis C Antibodies/*blood ; Humans ; *Immunoassay ; Immunoblotting ; Reagent Kits, Diagnostic ; Sensitivity and Specificity

BACKGROUND: We evaluated the efficacy of two chemiluminescence immunoassays that detect treponemal antibodies, Centaur Syphilis and Immulite Syphilis, in comparison with Mediace Treponema pallidum latex agglutination (TPLA). METHODS: The study was conducted in two phases. In the first phase, we tested 1,147 serum samples that were sequentially submitted for routine syphilis serology. In the second phase, we tested a panel of 119 frozen serum samples that had previously tested positive by Mediace RPR. The kappa value, total agreement percentage, and sensitivity and specificity were analyzed. RESULTS: Of the 1,147 random samples, 24 (2.09%) tested positive with Centaur Syphilis, 16 (1.39%) with Immulite Syphilis, and 19 (1.66%) with Mediace TPLA. Of the 119 Mediace RPR-positive samples, 103 (86.6%) tested positive with Centaur Syphilis, 101 (84.9%%) with Immulite Syphilis, and 105 (88.2%) with Mediace TPLA. The percent agreements (kappa values) were 98.8% (0.934) between Centaur Syphilis and Mediace TPLA, 99.0% (0.94) between Immulite Syphilis and Mediace TPLA, and 99.2% (0.955) between Centaur Syphilis and Immulite Syphilis. To measure the sensitivity and specificity of each treponemal test, samples showing agreement in three or four of the tests (three treponemal tests and Mediace-RPR) were regarded as true positive (n=117) or true negative (n=1,142). The respective values for sensitivity and specificity were 100% and 99.6% for Centaur Syphilis, 98.3% and 100% for Immulite Syphilis, and 99.2% and 99.7% for Mediace TPLA. CONCLUSIONS: Results from the three treponemal assays were in good agreement. Greater sensitivity of Centaur Syphilis and greater specificity of Immulite Syphilis were suggested.
Agglutination ; Antibodies* ; Immunoassay ; Latex ; Luminescence ; Sensitivity and Specificity ; Syphilis* ; Treponema pallidum

BACKGROUND: We evaluated the efficacy of two chemiluminescence immunoassays that detect treponemal antibodies, Centaur Syphilis and Immulite Syphilis, in comparison with Mediace Treponema pallidum latex agglutination (TPLA). METHODS: The study was conducted in two phases. In the first phase, we tested 1,147 serum samples that were sequentially submitted for routine syphilis serology. In the second phase, we tested a panel of 119 frozen serum samples that had previously tested positive by Mediace RPR. The kappa value, total agreement percentage, and sensitivity and specificity were analyzed. RESULTS: Of the 1,147 random samples, 24 (2.09%) tested positive with Centaur Syphilis, 16 (1.39%) with Immulite Syphilis, and 19 (1.66%) with Mediace TPLA. Of the 119 Mediace RPR-positive samples, 103 (86.6%) tested positive with Centaur Syphilis, 101 (84.9%%) with Immulite Syphilis, and 105 (88.2%) with Mediace TPLA. The percent agreements (kappa values) were 98.8% (0.934) between Centaur Syphilis and Mediace TPLA, 99.0% (0.94) between Immulite Syphilis and Mediace TPLA, and 99.2% (0.955) between Centaur Syphilis and Immulite Syphilis. To measure the sensitivity and specificity of each treponemal test, samples showing agreement in three or four of the tests (three treponemal tests and Mediace-RPR) were regarded as true positive (n=117) or true negative (n=1,142). The respective values for sensitivity and specificity were 100% and 99.6% for Centaur Syphilis, 98.3% and 100% for Immulite Syphilis, and 99.2% and 99.7% for Mediace TPLA. CONCLUSIONS: Results from the three treponemal assays were in good agreement. Greater sensitivity of Centaur Syphilis and greater specificity of Immulite Syphilis were suggested.
Agglutination ; Antibodies* ; Immunoassay ; Latex ; Luminescence ; Sensitivity and Specificity ; Syphilis* ; Treponema pallidum

The aim of this study was to determine antimicrobial susceptibility of recent clinical Stenotrophomonas maltophilia isolates from Korea, and to compare the activity levels of several combinations of antimicrobials. A total of 206 non-duplicate clinical isolates of S. maltophilia was collected in 2010 from 11 university hospitals. Antimicrobial susceptibility testing was performed using the Clinical Laboratory Standards Institute agar dilution method. In vitro activity of antimicrobial combinations was tested using the checkerboard method. The susceptibility rates to trimethoprim-sulfamethoxazole and minocycline were 96% and 99%, respectively. The susceptibility rate to levofloxacin was 64%. All of four antimicrobial combinations showed synergy against many S. maltophilia isolates. A combination of trimethoprim-sulfamethoxazole plus ticarcillin-clavulanate was most synergistic among the combinations. None of the combinations showed antagonistic activity. Therefore, some of the combinations may be more useful than individual drugs in the treatment of S. maltophilia infection. Further clinical studies are warranted to validate our in vitro test results.
Anti-Infective Agents/*pharmacology ; Gram-Negative Bacterial Infections/microbiology ; Hospitals, University ; Humans ; Microbial Sensitivity Tests ; Minocycline/pharmacology ; Ofloxacin/pharmacology ; Republic of Korea ; Stenotrophomonas maltophilia/*drug effects/isolation & purification ; Trimethoprim-Sulfamethoxazole Combination/pharmacology