This study aimed to survey the status of quality control (QC) assurance for stool examinations at clinical laboratories in Korea. We sent a questionnaire related to QC practices in stool examination by electronic mail to Korean clinical laboratories that performed stool examination. Overall, 20 of the 39 laboratories (51.3%) reported performing stool concentration methods, and 28 (71.8%) examined the slides using only saline. A large proportion (74.4%) of respondents did not check the internal QC because of the restriction of appropriate control materials. Only four laboratories (10.3%) checked the reactivity of the dye solution routinely. For appropriate external QC systems, QC slides (43.6%) were preferred, followed by QC materials (30.8%), virtual slides (17.9%), and a combination of the above options (7.7%). The most commonly observed parasites in stool samples at the clinical laboratories were Clonorchis sinensis (75%), followed by Endolimax nana, Enterobius vermicularis, and Entamoeba coli. The present study describes the difficulties in internal QC assessment due to the absence of standardized QC materials and systems. We hope the findings of this report will provide a foundation for a QC assessment program for stool examinations in the near future.
Clonorchis sinensis ; Electronic Mail ; Endolimax ; Entamoeba ; Enterobius ; Hope ; Korea ; Parasites ; Quality Control ; Surveys and Questionnaires

Annual proficiency surveys were conducted in March, May, and August of 2017 as the Korean Association of External Quality Assessment Service. Overall, four image samples (MPI-17-01, MPI-17-02, MPI-17-03, MPI-17-04) in the first trial, three image samples (MPI-17-05, MPI-17-06 , MPI-17-07) in the second trial, and a slide specimen (MPS-17-01) using parasite samples in the third trial were distributed to participating institutions. The first and second trial specimens were prepared by photographing slides made of formalin-ether concentrate of positive samples stored for educational purposes. The slide distributed in the third trial was prepared using cellophane tape, which was stored after diagnosis of the patients infected with Enterobius vermicularis . There were 191 participating institutions in the first, 204 in the second, and 212 in the third trial. The correct identification rates were 27.2% for MPI-17-01 Diphyllobothrium species (sp.), 96.6% for MPI-17-02 no parasite, 67.5% for MPI-17-03 Metagonimus yokogawai , 71.2% for MPI-17-04 Balantidium coli , 99.0% for MPI-17-05 Taenia sp., 99.0% for MPI-17-06 Trichuris trichiura , 92.7% for MPI-17-07 Cryptosporidium sp., and 96.7% for MPS-17-01 E. vermicularis . The current external quality assessment for clinical parasitology was performed using image samples and standard slides. Surveys of parasitic infections should be accompanied by continuous education on various parasitic infections, for which there was lack of experience of inspection in clinical laboratories. In the future, it will be necessary to establish a standard material using parasitic samples, and ultimately to conduct a survey on whole series of tests for the diagnosis of parasitic diseases.
Balantidium ; Cellophane ; Cryptosporidium ; Diagnosis ; Diphyllobothrium ; Education ; Enterobius ; Heterophyidae ; Humans ; Korea* ; Parasites ; Parasitic Diseases ; Parasitology* ; Quality Control ; Taenia ; Trichuris

BACKGROUND: Because of a lack of quality control (QC) materials, stool examination has not been standardised. This study examined intestinal parasites in diarrhea specimens to manufacture and evaluate the performance stability of QC materials for stool examination. METHODS: This study examined diarrhea specimens submitted for stool culture. Microscopic examination was performed using the direct smear and formalin-ether concentration method (Military General Laboratory, MGL). Enzyme-linked immunosorbent assay (ELISA) kits (R-Biopharm AG, Germany) and xTAG Gastrointestinal Pathogen Panel (Luminex Corp., USA) were used for the three major protozoa: Cryptosporidium parvum, Giardia lamblia, and Entamoeba histolytica. Polymerase chain reaction (PCR) was performed for Dientamoeba fragilis and Blastocystis hominis. The QC materials for stool examination were generated using Diphyllobothrium nihonkaiense ova. The manufactured QC materials were evaluated under different storage conditions, with varying preservatives, temperatures, and storage times. RESULTS: From November 2015 to April 2016, 82 diarrhea specimens were collected and tested. All results from microscopy and ELISA were negative; C. parvum (n=2) and G. lamblia (n=1) were detected by xTAG, while D. fragilis (n=10) and B. hominis (n=2) were detected by PCR. High- and low-concentration QC materials were manufactured. Using the high-concentration QC material, ova were observed in all storage conditions using MGL. Using the low-concentration QC material, the ova were observed until 14 days, but not after 3 weeks. CONCLUSIONS: It should be considered for making QC materials for stool examinations that focus on D. fragilis and B. hominis frequently found in Korea and with the caution to the low-concentration of QC materials could be unstable.
Blastocystis hominis ; Cryptosporidium parvum ; Diarrhea* ; Dientamoeba ; Diphyllobothrium ; Entamoeba histolytica ; Enzyme-Linked Immunosorbent Assay ; Giardia ; Giardia lamblia ; Korea ; Methods* ; Microscopy ; Ovum ; Parasites* ; Polymerase Chain Reaction ; Quality Control*

BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid and accurate identification of clinical yeast isolates. In-tube formic acid/acetonitrile (FA/ACN) extraction is recommended prior to the analysis with MALDI Biotyper, but the direct on-plate FA extraction is simpler. We compared the Biotyper with the VITEK MS for the identification of various clinically relevant yeast species, focusing on the use of the FA extraction method. METHODS: We analyzed 309 clinical isolates of 42 yeast species (four common Candida species, Cryptococcus neoformans, and 37 uncommon yeast species) using the Biotyper and VITEK MS systems. FA extraction was used initially for all isolates. If ‘no identification' result was obtained following the initial FA extraction, these samples were then retested by using FA (both systems, additive FA) or FA/ACN (Biotyper only, additive FA/ACN) extraction. These results were compared with those obtained by sequence-based identification. RESULTS: Both systems correctly identified all 158 isolates of the four common Candida species after the initial FA extraction. The Biotyper correctly identified 8.7%, 30.4%, and 100% of 23 C. neoformans isolates after performing initial FA, additive FA, and FA/ACN extractions, respectively, while VITEK MS identified all C. neoformans isolates after the initial FA extraction. Both systems had comparable identification rates of 37 uncommon yeast species (128 isolates), following the initial FA (Biotyper, 74.2%; VITEK MS, 73.4%) or additive FA (Biotyper, 82.0%; VITEK MS, 73.4%). CONCLUSIONS: The identification rate of most common and uncommon yeast isolates is comparable between simple FA extraction/Biotyper method and VITEK MS methods, but FA/ACN extraction is necessary for C. neoformans identification by Biotyper.
Candida ; Cryptococcus neoformans ; Mass Spectrometry* ; Methods* ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Yeasts*

No abstract available.
Aged ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Cefotaxime/analogs & derivatives/therapeutic use ; Cholangiopancreatography, Endoscopic Retrograde ; Gallstones/surgery ; Gram-Negative Anaerobic Bacteria/drug effects/genetics/*isolation & purification ; Gram-Negative Bacterial Infections/*diagnosis/drug therapy/microbiology ; Humans ; Male ; Metronidazole/therapeutic use ; Microbial Sensitivity Tests ; RNA, Ribosomal, 16S/chemistry/genetics/metabolism ; Sequence Analysis, DNA ; Tomography, X-Ray Computed

No abstract available.
Korea* ; Nontuberculous Mycobacteria*

BACKGROUND: Little is known of the mutation and tumor spectrum of Korean patients with Li-Fraumeni syndrome (LFS). Owing to the rarity of LFS, few cases have been reported in Korea thus far. This study aimed to retrospectively review the mutations and clinical characteristics of Korean patients with LFS. METHODS: TP53 mutation was screened in 89 unrelated individuals at the Samsung Medical Center in Korea, from 2004 to 2015. Six additional mutation carriers were obtained from the literature. RESULTS: We identified nine different mutations in 14 Korean patients (male to female ratio=0.3:1). Two such frameshift mutations (p.Pro98Leufs*25, p.Pro27Leufs*17) were novel. The recurrent mutations were located at codons 31 (n=2; p.Val31Ile), 175 (n=3; p.Arg175His), and 273 (n=4; p.Arg273His and p.Arg273Cys). The median age at the first tumor onset was 25 yr. Ten patients (71%) developed multiple primary tumors. A diverse spectrum of tumors was observed, including breast (n=6), osteosarcoma (n=4), brain (n=4), leukemia (n=2), stomach (n=2), thyroid (n=2), lung (n=2), skin (n=2), bladder (n=1), nasal cavity cancer (n=1), and adrenocortical carcinoma (n=1). CONCLUSIONS: There was considerable heterogeneity in the TP53 mutations and tumor spectrum in Korean patients with LFS. Our results suggest shared and different LFS characteristics between Caucasian and Korean patients. This is the first report on the mutation spectrum and clinical characteristics from the largest series of Korean LFS patients.
Adolescent ; Adult ; Asian Continental Ancestry Group/genetics ; Base Sequence ; Child ; Child, Preschool ; Codon ; Female ; Frameshift Mutation ; Germ-Line Mutation ; Humans ; Infant ; Li-Fraumeni Syndrome/*genetics/pathology ; Male ; Middle Aged ; Neoplasms, Multiple Primary ; Polymorphism, Genetic ; Republic of Korea ; Retrospective Studies ; Tumor Suppressor Protein p53/*genetics ; Young Adult

BACKGROUND: The conventional indocyanine green retention rate at 15 minutes (ICG R15) test is inefficient and inconvenient because it requires the use of a manual spectrophotometer and several samples per patient. This study aimed to establish the automation of the ICG R15 test using an automated clinical chemistry analyzer, and to evaluate the calculation of R15 with a small number of samples. METHODS: The performance of the AU5832 (Beckman Coulter, USA) for determining ICG concentration was evaluated in accordance with the Clinical Laboratory Standards Institute (CLSI) guidelines. The R15 results for 77 patients determined by spectrophotometry and AU5832 were compared. We evaluated the calculation of R15 with three samples, except for one sample in which the results had been obtained previously, at 5, 10, and 15 minutes after injection of ICG into the patients, and compared the results with those obtained with four samples. RESULTS: The automated ICG test using the AU5832 system showed proper performances according to CLSI. Although the difference in the R15 results between the two methods was within the 95% confidence interval, the R15 was adjusted by the regression equation because it was slightly lower according to the automated method compared with the manual method. The R15 with three samples (0, 5, and 15 minutes) showed the best correlation with conventional R15 with four samples (r2=0.996). Compared with the manual method, the R15 result using the AU5832 showed excellent agreement with four samples (kappa value 0.904) and with three samples (kappa value 0.880). CONCLUSIONS: The ICG R15 test using the AU5832 system is comparable with the conventional method in clinical use.
Automation ; Chemistry, Clinical* ; Humans ; Indocyanine Green* ; Methods ; Spectrophotometry

BACKGROUND: Acinetobacter species are the leading cause of bloodstream infection (BSI), but their correct identification is challenging. We evaluated the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based VITEK MS (bioMerieux, France), and two automated systems, VITEK 2 (bioMerieux) and MicroScan (Siemens, USA) for identification of Acinetobacter BSI isolates. METHODS: A total of 187 BSI isolates recovered at a university hospital in Korea between 2010 and 2012 were analyzed. The identification results obtained using VITEK MS and two automated systems were compared with those of rpoB sequencing. RESULTS: Of 187 isolates analyzed, 176 were identified to the species level by rpoB sequencing: the Acinetobacter baumannii group (ABG; 101 A. baumannii, 43 A. nosocomialis, 10 A. pittii isolates) was most commonly identified (82.4%), followed by Acinetobacter genomic species 13BJ/14TU (5.3%), A. ursingii (2.1%), A. soli (2.1%), A. bereziniae (1.1%), and A. junii (1.1%). Correct identification rates to the species group (ABG) level or the species level was comparable among the three systems (VITEK MS, 90.3%; VITEK 2, 89.2%; MicroScan, 86.9%). However, VITEK MS generated fewer misidentifications (0.6%) than VITEK 2 (10.8%) and MicroScan (13.1%) (P<0.001). In addition, VITEK MS demonstrated higher specificity (100%) for discrimination between ABG and non-ABG isolates than the other systems (both, 31.8%) (P<0.001). CONCLUSIONS: The VITEK MS system is superior to the VITEK 2 and MicroScan systems for identification of Acinetobacter BSI isolates, with fewer misidentifications and better discrimination between the ABG and non-ABG isolates.
Acinetobacter/*genetics/isolation & purification ; Acinetobacter Infections/diagnosis/microbiology ; Bacterial Proteins/genetics ; Bacterial Typing Techniques/*instrumentation/*methods ; Blood/*microbiology ; DNA, Bacterial/*analysis/metabolism ; Databases, Genetic ; Humans ; *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

The AdvanSure tuberculosis/non-tuberculous mycobacterium (TB/NTM) PCR (LG Life Science, Korea) and COBAS TaqMan Mycobacterium tuberculosis (MTB) PCR (Roche Diagnostics, USA) are commonly used in clinical microbiology laboratories. We aimed to evaluate these two commercial real-time PCR assays for detection of MTB in a large set of clinical samples over a two-year period. AdvanSure TB/NTM PCR and COBAS TaqMan MTB PCR were performed on 9,119 (75.2%) and 3,010 (24.8%) of 12,129 (9,728 respiratory and 2,401 non-respiratory) MTB specimens, with 361 (4.0%) and 102 (3.4%) acid-fast bacilli (AFB)-positive results, respectively. In MTB culture, 788 (6.5%) MTB and 514 (4.2%) NTM were identified. The total sensitivity and specificity of the AdvanSure assay were 67.8% (95% confidence interval [CI], 63.9-71.6) and 98.3% (95% CI, 98.0-98.6), while those of the COBAS TaqMan assay were 67.2% (95% CI, 60.0-73.8) and 98.4% (95% CI, 97.9-98.9), respectively. The sensitivities and specificities of the AdvanSure and COBAS TaqMan assays for AFB-positive and AFB-negative samples were comparable. Furthermore, the AdvanSure assay showed fewer invalid results compared with the COBAS TaqMan assay (5.0 vs. 20.4 invalid results/1,000 tests, P<0.001). AdvanSure assay represents a comparable yet more reliable method than COBAS TaqMan for the identification of mycobacteria in routine clinical microbiology.
DNA, Bacterial/genetics/metabolism ; Humans ; Mycobacterium tuberculosis/*genetics/isolation & purification ; Reagent Kits, Diagnostic ; Real-Time Polymerase Chain Reaction ; Republic of Korea ; Sensitivity and Specificity ; Tuberculosis, Pulmonary/diagnosis