No abstract available.
Diagnosis*

BACKGROUND: The aim of the study was to develop an accurate, convenient, and easy microplate system for the identification of enterococcal species from clinical specimens. METHODS: The microplate identification method was composed of twelve biochemical tests and identification programs. The tests comprised in microplate were initially screened by a two-tube method, NaCl-esculin hydrolysis and pyrrolidonyl-beta-naphthylamide test; arginine dihydrolase, acid production from mannitol, sorbitol, sucrose, arabinose, raffinose, methyl-alpha-D-glucopyranoside, and ribose in the microplate; and pigment production and hemolytic pattern in blood agar plate. The performance of the microplate for identifying enterococci to the species level was evaluated in comparison with conventional reference tests and commercial kits. RESULTS: Among the 111 clinical isolates of Enterococcus species, the microplate system correctly identified 100% to genus level, and 91.0% to species level. All of E. casseliflavus, E. durans, and E. hirae were correctly identified by the microplate. The diagnostic sensitivity and specificity for identification of Enterococcus species were as follows: 100% and 96.7% in E. faecium, 93.5% and 100% in E. faecalis, 100% and 97.2% in E. raffinosus, and 33.3% and 98.1% in both E. avium and E. gallinarum. CONCLUSIONS: It is concluded that the microplate method offers a simple, cost-effective, rapid, and accurate identification system for the identification of most clinical isolates of Enterococcus species.
Agar ; Arabinose ; Arginine ; Enterococcus* ; Hydrolysis ; Mannitol ; Raffinose ; Ribose ; Sensitivity and Specificity ; Sorbitol ; Sucrose

BACKGROUND: The selective media for culture of Helicobacter pylori(H. pylori) are Egg yolk emulsion medium, modified Thayer-Martin medium and Skirrow's medium. The non-selective media for culture of H. pylori are brucella agar, trypticase soy agar, and brain heart infusion agar. The selective media are more expensive and difficult to prepare than non-selective media, whereas non-selective media are difficult to isolate H. pylori due to contamination of upper respiratory tract bacteria. The objects of this study are to reduce upper respiratory contaminants by use of HCl-KCl buffer (H-K buffer) for primary isolation, and to compare with culture, CLO test, histologic examination and H. pylori IgG antibodies. METHODS: Seventy one patients underwent upper gastrointestinal endoscopy with biopsy. For 32 patients, two biopsies were taken from antrum: One for direct inoculation into blood agar plate, the other for pretreatment of H-K buffer. For fifty six patients, we performed culture, CLO test, histology, and H. pylori IgG. RESULTS: 1) Among the 32 patients, H. pylori were isolated in 25 patients (23 patients for direct inoculation and 25 patients for H-K pretreatment). Twelve cases among H-K buffer treatment group did not show contamination, whereas only two among direct inoculation group showed no contamination. The average number of contaminating colony forming unit (CFU) of direct inoculation and H-K buffer treatment were 77 and 9, respectively. 2) The positive rates of culture and CLO test, histology, and H. pylori IgG for H. pylori infection were 71.4%, 67.9%, 75.0%, and 57.1%, respective
Agar ; Antibodies ; Bacteria ; Biopsy ; Brain ; Brucella ; Egg Yolk ; Endoscopy, Gastrointestinal ; Heart ; Helicobacter pylori* ; Helicobacter* ; Humans ; Immunoglobulin G ; Respiratory System ; Stem Cells

Background: Malaria elimination strategies in the Republic of Korea (ROK) have decreased malaria incidence but face challenges due to delayed case detection and response. To improve this, machine learning models for predicting malaria, focusing on high-risk areas, have been developed. Methods: The study targeted the northern region of ROK, near the demilitarized zone, using a 1-km grid to identify areas for prediction. Grid cells without residential buildings were excluded, leaving 8,425 cells. The prediction was based on whether at least one malaria case was reported in each grid cell per month, using spatial data of patient locations. Four algorithms were used: gradient boosted (GBM), generalized linear (GLM), extreme gradient boosted (XGB), and ensemble models, incorporating environmental, sociodemographic, and meteorological data as predictors. The models were trained with data from May to October (2019–2021) and tested with data from May to October 2022. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). Results: The AUROC of the prediction models performed excellently (GBM = 0.9243, GLM = 0.9060, XGB = 0.9180, and ensemble model = 0.9301). Previous malaria risk, population size, and meteorological factors influenced the model most in GBM and XGB. Conclusion Machine-learning models with properly preprocessed malaria case data can provide reliable predictions. Additional predictors, such as mosquito density, should be included in future studies to improve the performance of models.

Objectives: Severe fever with thrombocytopenia syndrome (SFTS) has no vaccine or treatment and an extremely high fatality rate. We aimed to analyze and evaluate the risk factors for death associated with SFTS. Methods: Among reports from 2018 to 2022, we compared and analyzed 1,034 inpatients aged 18 years or older with laboratory-confirmed SFTS who underwent complete epidemiological investigations. Results: Most of the inpatients with SFTS were aged 50 years or older (average age, 67.6 years). The median time from symptom onset to death was 9 days, and the average case fatality rate was 18.5%. Risk factors for death included age of 70 years or older (odds ratio [OR], 4.82); agriculture-related occupation (OR, 2.01); underlying disease (OR, 7.20); delayed diagnosis (OR, 1.28 per day); decreased level of consciousness (OR, 5.53); fever/chills (OR, 20.52); prolonged activated partial thromboplastin time (OR, 4.19); and elevated levels of aspartate aminotransferase (OR, 2.91), blood urea nitrogen (OR, 2.62), and creatine (OR, 3.21). Conclusion The risk factors for death in patients with SFTS were old age; agriculture-related occupation; underlying disease; delayed clinical suspicion; fever/chills; decreased level of consciousness; and elevated activated partial thromboplastin time, aspartate aminotransferase, blood urea nitrogen, and creatine levels.

Clostridium difficile is a significant nosocomial and community-acquired pathogen, and is the leading cause of antibiotic-induced diarrhea associated with high morbidity and mortality. Given that the treatment outcome depends on the severity of C. difficile infection (CDI), we aimed to establish an efficient method of assessing severity, and focused on the stool biomarker fecal calprotectin (FC). FC directly reflects the intestinal inflammation status of a patient, and can aid in interpreting the current guidelines, which requires the integration of indirect laboratory parameters. The distinction of 80 patients with CDI versus 71 healthy controls and 30 severe infection cases versus 50 mild cases was possible using FC as a marker. The area under the receiver operating characteristic curves were 0.821 and 0.746 with a sensitivity of 75% and 70% and specificity of 79% and 80%, for severe versus mild cases, respectively. We suggest FC as a predictive marker for assessing CDI severity, which is expected to improve the clinical management of CDI.
Aged ; Area Under Curve ; Biomarkers/analysis ; Clostridium difficile/*isolation & purification ; Enterocolitis, Pseudomembranous/diagnosis/microbiology/*pathology ; Enzyme-Linked Immunosorbent Assay ; Feces/*chemistry ; Female ; Humans ; Leukocyte L1 Antigen Complex/*analysis ; Male ; Middle Aged ; ROC Curve ; Severity of Illness Index

Clostridium difficile (C. difficile) is a common causative agent of pseudomembranous colitis (PMC). C. difficile-associated diarrhea (CDAD) ranges from mild diarrhea to life threatening PMC. Recently, a highly virulent strain of C. difficile polymerase chain reaction ribotype 027 was found in North America, Europe, and Japan. A 52-yr-old woman with anti-tuberculosis medication and neurogenic bladder due to traffic accident experienced five episodes of C. difficile PMC after taking antibiotics for pneumonia along with septic shock and acute renal failure. She was readmitted to the intensive care unit and treated with oral vancomycin with refractory of oral metronidazole, inotropics and probiotics for over 60 days. C. difficile isolated both at the first and the last admission was identified as C. difficile ribotype 027 by ribotyping, toxinotyping, and tcdC gene sequencing, which turned out the same pathogen as the epidemic hypervirulent B1/NAP1 strain. This is the first case of C. difficile PCR ribotype 027 in Korea. After discharge, she was maintained on probiotics and rifaximin for 3 weeks. She had no relapse for 6 months.
Accidents, Traffic ; Antitubercular Agents/therapeutic use ; Base Sequence ; Clostridium difficile/*classification/genetics/isolation & purification ; Enterocolitis, Pseudomembranous/*diagnosis/drug therapy/*microbiology ; Female ; Humans ; Kidney Failure, Acute/diagnosis ; Korea ; Middle Aged ; Molecular Sequence Data ; Polymerase Chain Reaction ; Ribotyping ; Shock, Septic/diagnosis

BACKGROUND: Clostridium difficile is the main etiologic agent of antibiotic-associated diarrhea and the most common cause of hospital-acquired diarrhea. Recently, the incidence of C. difficile infections (CDI) has increased and new highly virulent C. difficile strains have emerged. Therefore, accurate and rapid diagnosis is needed. We compared the results of using chromID C. difficile (chromID CD, bioMerieux, France) with the conventional C. difficile Selective Agar (CDSA; BD, USA) for the isolation of C. difficile. METHODS: A total of 738 stool specimens of suspected CDI patients at the Severance Hospital from July to August 2011 were inoculated onto CDSA. Among them, 104 stool specimens revealed colonies on CDSA that were then re-inoculated onto chromID CD. The stool samples were stored at -20degrees C until the time of the re-inoculation. Cultured agars were interpreted after 24 hrs and 48 hrs, respectively. Species identification was performed on the basis of colony characteristics on agar plates as well as the ATB 32A system (API System SA, France). RESULTS: The recovery rates of CDSA and chromID CD were 30.1% and 77.5% after 24 hrs, and 77.5% and 98.6% after 48 hrs, respectively. All of the C. difficile isolates were recovered as typical gray/black colonies on chromID CD. CONCLUSION: The performance of chromID CD for the isolation of C. difficile was better than that of conventional CDSA. The chromID CD could provide easy and sensitive detection of C. difficile even after 24hrs of incubation.
Agar ; Clostridium ; Clostridium difficile ; Diarrhea ; Humans ; Incidence

BACKGROUND: Increased isolation of extended-spectrum beta-lactamase (ESBL)-producing Entero bacteriaceae resistant to third generation cephalosporins and aztreonam has been noted recently. This study was to determine the prevalence of resistance to these drugs and ESBL in Enterobacteriaceae and to evaluate the methods for de tection. METHODS: During the period of October, 1997 and March, 1998, a total of 731 clinical isolates of Enterobacteriaceae were collected from patients of the Kosin Medical Center, Pusan, Korea. Antimicrobial susceptibility test by disk diffusion method and double disk synergy test were performed. MICs of beta-lactams were determined by agar dilution method. And ESBL genotypes were determined by polymerase chain reaction. RESULTS: About 10% of Escherichia coli isolates and 20% of Klebsiella pneumoniae isolates were intermediate or resistant to the third generation cephalosporins or aztreonam. Sensitivities of cefotaxime, ceftazidime, ceftriaxone and cefpodoxime disks for the detection of ESBL- producing strains of E. coli and K. pneumoniae by NCCLS standards were 100%, respectively, but that of aztreonam disk was 97%. Positive predictive value of the ceftazidime disk was higher than those of other disks. Twenty strains of E. coli, 20 K pneumoniae, 19 Enterobacter spp., six Citrobacter freundii, and eight Serratia marcescens showed positive results in double disk synergy test. The transconjugant strain of K. pneumoniae K20482 had blaSHV, and remains of transconjugants of ESBL-producing K. pneumoniae, Enterobacter spp. and S. marcescens had blaTEM. CONCLUSIONS: In this study, many strains of Enterobacteriaceae isolated in Korea were resistant to third generation cephalosporins and aztreonam. Some of the strains of Enterobacter spp. and S. marcescens as well as E. coli and K. pneumoniae produced ESBL, and majority of these strains had blaTEM. In the detection of ESBL-producing strains of E. coli and K. pneumoniae by NCCLS standards, all of the antimicrobial agent disks tested were useful, but ceftazidime disk was most effective because of its highest positive predictive value.
Agar ; Aztreonam ; beta-Lactamases ; beta-Lactams ; Busan ; Cefotaxime ; Ceftazidime ; Ceftriaxone ; Cephalosporins ; Citrobacter freundii ; Diffusion ; Enterobacter ; Enterobacteriaceae* ; Escherichia coli ; Genotype ; Humans ; Klebsiella pneumoniae ; Korea ; Pneumonia ; Polymerase Chain Reaction ; Prevalence* ; Serratia marcescens

A yeast-like strain was isolated from the brain abscess of a patient diagnosed with astrocytoma. Morphological and molecular analysis on D1/D2 domain in the 26S rRNA gene and internal transcript spacer region of the strain revealed that the strain belonged to the genus Pseudozyma. To the best of our knowledge, this is the first report on the isolation of a Pseudozyma strain from brain abscess.
Aged ; Astrocytoma/*complications ; Brain Abscess/complications/diagnosis/*microbiology ; Brain Diseases/*complications ; DNA, Fungal/genetics ; Humans ; Male ; Mycological Typing Techniques ; Phylogeny ; RNA, Ribosomal/genetics ; Ustilaginales/classification/genetics/*isolation &purification