Performance of the Real-Q EBV Quantification Kit for Epstein-Barr Virus DNA Quantification in Whole Blood

허희재,박종은,김지연,윤선애,이명근,이남용,김종원,기창석 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.2

There has been increasing interest in standardized and quantitative Epstein-Barr virus (EBV) DNA testing for the management of EBV disease. We evaluated the performance of the Real-Q EBV Quantification Kit (BioSewoom, Korea) in whole blood (WB). Nucleic acid extraction and real-time PCR were performed by using the MagNA Pure 96 (Roche Diagnostics, Germany) and 7500 Fast real-time PCR system (Applied Biosystems, USA), respectively. Assay sensitivity, linearity, and conversion factor were determined by using the World Health Organization international standard diluted in EBV-negative WB. We used 81 WB clinical specimens to compare performance of the Real-Q EBV Quantification Kit and artus EBV RG PCR Kit (Qiagen, Germany). The limit of detection (LOD) and limit of quantification (LOQ) for the Real-Q kit were 453 and 750 IU/mL, respectively. The conversion factor from EBV genomic copies to IU was 0.62. The linear range of the assay was from 750 to 106 IU/mL. Viral load values measured with the Real-Q assay were on average 0.54 log10 copies/mL higher than those measured with the artus assay. The Real-Q assay offered good analytical performance for EBV DNA quantification in WB.

A Case of Misidentification of Aspergillus versicolor Complex as Scopulariopsis Species Isolated from a Homograft

허희재,이장호,박경선,전태국,강이석,김예진,기창석,이남용 대한임상미생물학회 2013 Annals of clinical microbiology Vol.16 No.2

We report a case of the isolation of the Aspergillus versicolor complex, initially misidentified by morphological characteristics as the Scopulariopsis species, from a homograft with a bicuspidalized pulmonary valve. An eighteen-month-old female, who had critical pulmonary stenosis, underwent pulmonary valve replacement. On postoperative day 8, she developed a fever, which did not respond to empiric broad-spectrum antibiotics. While no definitive source was identified, a filamentous fungus was isolated from the thawed homograft tissue culture prior to implantation on the operation day. The colonies were powdery green with white edges on Sabouraud dextrose agar. Microscopic examination showed septate hyphae with branched conidiophores and chains of spiny conidia, which suggested Scopulariopsis species. After direct sequencing of the internal transcribed spacer (ITS) regions, the fungus was identified as the A. versicolor complex. To our knowledge, the isolation of the A. versicolor complex from a homograft valve has not been previously described. This case shows that laboratory staff should be aware that microscopic morphology of the A. versicolor complex can resemble that of a number of other genera, including Scopulariopsis species.

신문사 콘텐츠의 현황과 과제

허희재 한국조사기자협회 2005 조사연구 Vol.17 No.-

Therapy-Related Myeloid Neoplasms in 39 Korean Patients: A Single Institution Experience

허희재,이수현,유건희,성기웅,구홍회,김기현,장준호,정철원,김선희,김희진,최윤라 대한진단검사의학회 2013 Annals of Laboratory Medicine Vol.33 No.2

Background: Therapy-related myeloid neoplasms (t-MN) occur as late complications of cytotoxic therapy. This study reviewed clinical and cytogenetic characteristics of patients with t-MN at a single institution in Korea. Methods: The study subjects included 39 consecutive patients diagnosed with t-MN. Each subject’s clinical history of previous diseases, treatments, and laboratory data was reviewed, including cytogenetics. The primary diagnosis was hematologic malignancy in 14 patients and solid tumor in 25 patients. Results: Therapy-related acute myeloid leukemia (t-AML, 66.7%) was found to be more common than therapy-related myelodysplastic syndrome (t-MDS). Primary hematologic malignancies that were commonly implicated included mature B-cell neoplasm and acute leukemia. Breast cancer was the most common primary solid tumor. The mean time interval from cytotoxic therapy initiation to t-MN detection was 49 months. Chromosomal aberrations were observed in 35 patients, and loss of chromosome 5, 7, or both accounted for 41% of all cases. Balanced rearrangements occurred in 13 patients; these patients showed shorter latency intervals (mean, 38 months) than patients with loss of chromosome 5 or 7(mean, 61 months). Conclusions: In this study, we determined the clinical and cytogenetic characteristics of Korean patients with t-MN. Although our results were generally consistent with those of previous reports, we found that t-MN resulting from de novo leukemia was common and that t-AML was more common than t-MDS at presentation. Multi-institutional studies involving a larger number of patients and additional parameters are required to investigate the epidemiology, genetic predisposition, and survival rate of t-MN in Korea.

Identification of Erysipelothrix rhusiopathiae by DNA Sequencing in a Culture-Negative Intra-Abdominal Abscess

허희재,김현영,하영은,기창석,이남용 대한임상미생물학회 2014 Annals of clinical microbiology Vol.17 No.4

Erysipelothrix rhusiopathiae is a Gram-positive bacillus that causes infections primarily in animals. In humans, the bacteria usually cause localized or generalized cutaneous infections. A 75-year-old man with chronic alcoholism presented with abdominal pain. Abdominal computed tomography and laboratory findings suggested an intra-abdominal abscess in the periaortic soft tissue. While no definitive infectious source was identified, E. rhusiopathiae was identified by 16S rRNA-based gene sequencing from culture-negative, periaortic necrotic tissue, subsequent to empiric antibiotic treatment. It is suggested that E. rhusiopathiae has the potential to cause intra-abdominal abscesses. This case report highlights the usefulness of DNA sequencing to identify pathogens in patients pretreated with antibiotics. (Ann Clin Microbiol 2014;17:-135)

Comparative Evaluation Between the RealStar Pneumocystis jirovecii PCR Kit and the AmpliSens Pneumocystis jirovecii (carinii)-FRT PCR Kit for Detecting P. jirovecii in Non-HIV Immunocompromised Patients

허희재,임경리,기창석,허경민,심향진,송동준,김예진,정두련,이남용 대한진단검사의학회 2019 Annals of Laboratory Medicine Vol.39 No.2

Background: Real-time PCR is more sensitive than microscopic examination for detecting Pneumocystis jirovecii. We compared the performance of two assays for detecting P. jirovecii DNA: the RealStar Pneumocystis jirovecii PCR Kit 1.0 CE (Altona Diagnostics, Hamburg, Germany) and the AmpliSens Pneumocystis jirovecii (carinii)-FRT PCR kit (InterLabService Ltd., Moscow, Russia). Methods: We used 159 samples from the lower respiratory tract (112 bronchoalveolar lavage [BAL] fluid, 37 sputum, and 10 endotracheal aspirate [ETA] samples) of non-HIV immunocompromised patients. Nested PCR and sequencing were used to resolve discordant results. The performance of the two assays was evaluated according to clinical categories (clinical Pneumocystis pneumonia [PCP], possible PCP, or unlikely PCP) based on clinical and radiological observations. Results: The positive and negative percent agreement values were 100% (95% confidence interval [CI], 85.4–100%) and 96.6% (95% CI, 90.9–98.9%), respectively, and kappa was 0.92 (95% CI, 0.84–0.99). P. jirovecii DNA load was significantly higher in the clinical PCP group than in the other groups (P<0.05). When stratified by sample type, the positive rate for BAL fluids from the clinical PCP group was 100% using either assay, whereas the positive rate for sputum/ETA samples was only 20%. Conclusions: The two assays showed similar diagnostic performance and detected low P. jirovecii burden in BAL fluids. Both assays may be useful as routine methods for detecting P. jirovecii DNA in a clinical laboratory setting, though their results should be interpreted considering sample type.

Importance of Specimen Type and Quality in Diagnosing Middle East Respiratory Syndrome

허희재,고재훈,김영은,박창훈,홍지혜,최리화,유신애,조선영,강지만,이명근,기창석,강은숙,이남용,김종원,김예진,하영은,강철인,정두련,백경란,송재훈 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.1

Dear Editor, From May to July 2015, there was a hospital-associated outbreak in South Korea reporting 186 laboratory-confirmed cases. Highly sensitive and specific laboratory diagnostic tests are important for the control of Middle East respiratory syndrome coronavirus (MERS-CoV) outbreaks. Clinical guidelines for the molecular diagnosis of MERS-CoV are based on the interim recommendations from the WHO, the United States Centers for Disease Control and Prevention (US CDC), and other available resources [1-4]. To date, only a few studies have reported the molecular detection of this disease during an outbreak [5-8]. To validate the current guidelines for MERS-CoV laboratory testing, we retrospectively reviewed the results of MERS-CoV real-time reverse transcription (rRT)-PCR assays in the Korean tertiary care hospital with the largest number of MERS cases (Samsung Medical Center). The Institutional Review Board of the Samsung Medical Center (IRB #2015-06-201) approved this study.

Identification of ATM Mutations in Korean Siblings with Ataxia-Telangiectasia

허희재,이필휴,권민정,기창석,조규호,이지은 대한진단검사의학회 2013 Annals of Laboratory Medicine Vol.33 No.3

Ataxia-telangiectasia (A-T) is a rare autosomal recessive neurodegenerative disorder. It is characterized by early-onset, progressive cerebellar ataxia, oculomotor apraxia, choreoathetosis,conjunctival telangiectasias, immunodeficiency, and an increased risk of malignancy. Although A-T is known to be the most common cause of progressive cerebellar ataxia in childhood, there have been no confirmed cases in Korea. We report the clinical and genetic findings of Korean siblings who presented with limb and truncal ataxia, oculomotor apraxia, choreoathetosis, and telangiectasias of the eyes. Sequence analysis of the ataxiatelangiectasia mutated (ATM) gene revealed a known missense mutation (c.8546G>C;p.Arg2849Pro) and a novel intronic variant of intron 17 (c.2639-19_2639-7del13). Reversetranscription PCR and sequencing analysis revealed that the c.2639-19_2639-7del13 variant causes a splicing aberration that potentiates skipping exon 18. Because A-T is quite rare in Korea, the diagnosis of A-T in Korean patients can be delayed. We recommend that a diagnosis of A-T should be suspected in Korean patients exhibiting the clinical features of A-T.

Streptococcus suis Meningitis with Bilateral Sensorineural Hearing Loss

허희재,박경진,장자현,이미나,이장호,안윤희,강철인,기창석,이남용 대한진단검사의학회 2011 Annals of Laboratory Medicine Vol.31 No.3

Streptococcus suis infection is an emerging zoonosis in Asia. The most common disease manifestation is meningitis, which is often associated with hearing loss and cochleovestibular signs. S. suis infection in humans mainly occurs among risk groups that have frequent exposure to pigs or raw pork. Here, we report a case of S. suis meningitis in a 67-yr-old pig carcass handler, who presented with dizziness and sensorineural hearing loss followed by headaches. Gram-positive diplococci were isolated from cerebrospinal fluid (CSF) and blood cultures and showed gray-white colonies with α-hemolysis. S. suis was identified from CSF and blood cultures by using a Vitek 2 system (bioMérieux, France), API 20 STREP (bioMérieux), and performing 16S rRNA and tuf gene sequencing. Even after receiving antibiotic treatment, patients with S. suis infection frequently show complications such as hearing impairment and vestibular dysfunction. To the best of our knowledge, this is the first case of S. suis meningitis in Korea. Prevention through public health surveillance is recommended, especially for individuals who have occupational exposures to swine and raw pork.

Evaluation of the iNtRON VRE vanA/vanB Real-Time PCR Assay for Detection of Vancomycin-Resistant Enterococci

허희재,장미애,서자영,김지윤,기창석,김종원,이남용 대한진단검사의학회 2015 Annals of Laboratory Medicine Vol.35 No.1

Background: Recently, the iNtRON VRE vanA/vanB real-time PCR (iNtRON; iNtRON Biotechnology, Korea) assay, a multiplex real-time PCR method, was introduced. In this prospective study, we compared the iNtRON assay with the Seeplex VRE ACE detection kit (Seeplex; Seegene, Korea), a conventional multiplex PCR assay. Methods: A chromogenic agar-based culture, in which pre-selected vancomycin-resistant enterococci (VRE) was grown and subsequently plated on blood agar with vancomycin disks, was regarded as the reference method. A total of 304 consecutive rectal swab specimens were tested for VRE by culture and by iNtRON and Seeplex PCR assays. For the PCR assays, specimens were enriched for 16-24 hr before PCR. Results: VRE were isolated from 44 (14.5%) specimens by chromogenic agar-based culture. The clinical sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the iNtRON assay were 100% (95% confidence interval: 89.8%-100%), 99.2% (96.9%-99.9%), 95.6% (83.6%-99.2%), and 100% (98.2%-100%), respectively, while those of the Seeplex assay were 97.7% (86.2%-99.9%), 99.6% (97.5%-99.9%), 97.7% (86.2%-99.9%), and 99.6% (97.5%-99.9%), respectively. The iNtRON assay had a detection limit of 3,159 copies/μL and 13,702 copies/μL for the vanA and vanB genes, respectively. No cross-reactivity was observed in 11 non-VRE bacterial culture isolates. Conclusions: The overall performance of the iNtRON assay was comparable to that of a chromogenic agar-based culture method for prompt identification of VRE-colonized patients in hospitals. This assay could be an alternative or supportive method for the effective control of nosocomial VRE infection.