Original Article2022-01-01 Diagnostic Immunology
Aera Han 
, M.D., Ph.D., Borum Suh , M.D., Gwang Yi , M.D., Yoo Jin Lee , M.D., and Sung Eun Kim , M.D.
Abstract : Background: Since 2017, automated assays have been used in most clinical laboratories for anti-Müllerian hormone (AMH) level measurement. We evaluated the analytical performance of the newly developed automated fluorescent immunoassay system (AFIAS) AMH assay (Boditech Med, Gangwon-do, Korea) in comparison with the Roche Elecsys and Beckman Coulter Access 2 AMH assays. Methods: Analytical performance of the AFIAS AMH assay was assessed in terms of linearity, repeatability, and within-laboratory precision (CV%) using human recombinant AMH samples according to the Clinical and Laboratory Standards Institute (CLSI) guidelines EP05 and EP06. Using 293 serum samples collected from an infertility clinic, the AMH levels were compared across AFIAS, Elecsys, and Access 2 AMH assays according to the CLSI EP09 guidelines. Results: The AFIAS AMH assay results were linear across the measurement range of 0.420–72.386 pmol/L AMH, with repeatability of 6.341%. CV% of the AFIAS AMH assay for three levels of control, 1.786, 7.143, and 56.857 pmol/L, were 5.801%, 5.714%, and 6.228%, respectively. The results of the three AMH assays showed strong correlation: AFIAS and Elecsys [slope, 1.055 (95% confidence interval (CI), 1.022–1.088) and Spearman’s rho, 0.978 (95% CI, 0.973–0.983)], Elecsys and Access 2 [slope, 0.813 (95% CI, 0.791–0.834) and Spearman’s rho, 0.986 (95% CI, 0.983–0.989)], and AFIAS and Access 2 [slope, 0.836 (95% CI, 0.821–0.853) and Spearman’s rho, 0.984 (95% CI, 0.980–0.988)]. Conclusions: The AFIAS AMH assay may be an alternative to the Roche Elecsys and Beckman Coulter Access 2 AMH assays.
Original Article2021-09-01 Clinical Microbiology
Yae Jee Baek , M.D., Young Ah Kim , M.D., Dokyun Kim , M.D., Jong Hee Shin , M.D., Young Uh , M.D., Kyeong Seob Shin , M.D., Jeong Hwan Shin , M.D., Seok Hoon Jeong , M.D., Geun Woo Lee , M.P.H., Eun Ji Lee , M.S, Dong-Sook Kim , Ph.D., Yoon Soo Park , M.D., Ph.D.
Abstract : Background: The prevalence of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) in the community has increased worldwide due to multifactorial reasons. ESBL-EC bloodstream infection (BSI) complicates the decision for proper antimicrobial administration. In this multicenter study, we investigated the prevalence, risk factors, and molecular background of community-onset (CO) ESBL-EC BSI. Methods: We included data for all episodes of ESBL-EC BSI of community origin from May 2016 to April 2017 obtained from the Korean national antimicrobial resistance surveillance system, which comprises six sentinel hospitals. Data, including previous history of admission and use of antimicrobials and medical devices before BSI, were collected, along with microbiological analysis results. Results: Among 1,189 patients with CO BSI caused by E. coli, 316 (27%) were identified as ESBL producers. History of admission, especially to a long-term care hospital (LTCH), and previous use of β-lactams/β-lactamase inhibitors, carbapenem, lincosamide, aminoglycoside, and extended-spectrum cephalosporin were independent risk factors for CO ESBL-EC BSI; admission to an LTCH showed the highest odds ratio (3.8, 95% confidence interval 2.3-6.1). The most common genotype was CTX-M-15 (N=131, 41%), followed by CTX-M-14 (N=86, 27%). ST131 was the most common sequence type among ESBL-EC groups (57%). Conclusions: In Korea, 27% of CO E. coli BSI were caused by ESBL producers. From perspectives of empirical treatment and infection control, history of admission to an LTCH and antimicrobial use should be noted.
Original Article2021-07-01 Diagnostic Genetics
Soo Yeon Kim , M.D., Chang Ho Shin , M.D., Young Ah Lee , M.D., Ph.D., Choong Ho Shin , M.D., Ph.D., Sei Won Yang , M.D., Ph.D., Tae-Joon Cho , M.D., Ph.D., and Jung Min Ko , M.D., Ph.D.
Abstract : Background: Silver-Russell syndrome (SRS) is a pre- or post-natal growth retardation disorder caused by (epi)genetic alterations. We evaluated the molecular basis and clinical value of sequential epigenetic analysis in pediatric patients with SRS. Methods: Twenty-eight patients who met≥3 Netchine-Harbison clinical scoring system (NH-CSS) criteria for SRS were enrolled;26 (92.9%) were born small for gestational age, and 25 (89.3%) showed postnatal growth failure. Relative macrocephaly, body asymmetry, and feeding difficulty were noted in 18 (64.3%), 13 (46.4%), and 9 (32.1%) patients, respectively. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) on chromosome 11p15 was performed as the first diagnostic step. Subsequently, bisulfite pyrosequencing (BP) for imprinting center 1 and 2 (IC1 and IC2) at chromosome 11p15, MEST on chromosome 7q32.2, and MEG3 on chromosome 14q32.2 was performed. Results:. Seventeen (60.7%) patients exhibited methylation defects, including loss of IC1 methylation (N=14; 11 detected by MS-MLPA and three detected by BP) and maternal uniparental disomy 7 (N=3). The diagnostic yield was comparable between patients who met three or four of the NH-CSS criteria (53.8% vs 50.0%). Patients with methylation defects responded better to growth hormone treatment. Conclusions: NH-CSS is a powerful tool for SRS screening. However, in practice, genetic analysis should be considered even in patients with a low NH-CSS score. BP analysis detected additional methylation defects that were missed by MS-MLPA and might be considered as a first-line diagnostic tool for SRS.
Brief Communication2021-05-01 Clinical Microbiology
Ji Hun Jeong , M.D., Ph.D., Oh Joo Kweon , M.D., Hye Ryoun Kim , M.D., Ph.D., Tae-Hyoung Kim , M.D., Ph.D., Sung-min Ha , Ph.D., and Mi-Kyung Lee , M.D., Ph.D.
Abstract : Whole-genome sequencing (WGS) is an easily accessible and valuable tool in clinical microbiology, which can be used for identifying novel and rare species. We isolated gram-positive cocci from the blood of a pediatric patient, which could not be phenotypically identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) (BioMérieux, Marcy-l’Étoile, France). We could not identify the isolate to the species level using 16S ribosomal RNA (rRNA) sequencing. WGS was performed using the Illumina MiSeq platform (Illumina, San Diego, CA, USA); however, the subsequent genomic sequence database search using the TrueBac ID-Genome system (ChunLab, Inc., Seoul, Korea) did not yield any hits with an average nucleotide identity value >95.0%, which is the cut-off for species-level identification. Phylogenetic analysis suggested that the isolate belonged to a new Arsenicicoccus species, forming a subcluster with Arsenicicoccus bolidensis. Our data demonstrate that WGS allows a more accurate annotation of microbial genomes than other clinical microbiology tools, such as MALDI-TOF MS and 16S rRNA sequencing. This is the first report of the isolation of a novel Arsenicicoccus species from a clinical sample.
Letter to the Editor2022-01-01 Clinical Microbiology
Young-gon Kim , M.D., Hyunwoong Park , M.D., Ph.D., So Yeon Kim , M.D., Ph.D., Ki Ho Hong , M.D., Ph.D., Man Jin Kim , M.D., Jee-Soo Lee , M.D., Sung-Sup Park , M.D., Ph.D., and Moon-Woo Seong , M.D., Ph.D.
Original Article2022-01-01 Clinical Microbiology
Seri Jeong , M.D., Nuri Lee , M.D., Min-Jeong Park , M.D., Kibum Jeon , M.D., Han-Sung Kim , M.D., Hyun Soo Kim , M.D., Jae-Seok Kim , M.D., and Wonkeun Song , M.D., Ph.D.
Abstract : Background: The emergence of carbapenemase-producing Enterobacteriaceae (CPE) represents a major clinical problem. Recently, the occurrence of CPE has increased globally, but epidemiological patterns vary across region. We report the trends in the genotypic distribution and antimicrobial susceptibility of CPE isolated from rectal and clinical samples during a four-year period. Methods: Between January 2016 and December 2019, 1,254 nonduplicated CPE isolates were obtained from four university hospitals in Korea. Carbapenemase genotypes were determined by multiplex real-time PCR. Antimicrobial susceptibility was profiled using the Vitek 2 system (bioMérieux, Hazelwood, MO, USA) or MicroScan Walkaway-96 system (Siemens West Sacramento, CA, USA). The proportions of carbapenemase genotypes and nonsusceptibility were analyzed using Pearson’s chi-square test. Results: Among the 1,254 CPE isolates, 486 (38.8%), 371 (29.6%), 357 (28.5%), 8 (0.6%), 8 (0.6%), and 24 (1.9%) were Klebsiella pneumoniae carbapenemase (KPC), oxacillinase (OXA)-48-like, New Delhi metallo-β-lactamase (NDM), imipenemase (IMP), Verona integron-encoded metallo-β-lactamase (VIM), and multiple producers, respectively. The predominant species was K. pneumoniae (72.6%), followed by Escherichia coli (6.5%). More than 90% of the isolates harboring KPC, NDM, and OXA-48-like were nonsusceptible to cephalosporins, aztreonam, and carbapenems. Conclusions: The impact of CPE is primarily due to KPC-, NDM-, and OXA-48-like-producing K. pneumoniae isolates. Isolates carrying these carbapenemase are mostly multidrug-resistant. Control strategies based on these genotypic distributions and antimicrobial susceptibilities of CPE isolates are required.
Original Article2022-03-01 Clinical Chemistry
Fernando Marques-Garcia , Ph.D., David Hansoe Heredero Jung , M.D., and Sandra Elena Pérez, B.D.
Abstract : Background: Hemolysis is the most common type of preanalytical interference. Cut-offs based on the hemolysis index level can be established using different approaches. The Working Group for Preanalytical Phase of the European Federation of Laboratory Medicine has developed a protocol for hemolysis management based on cut-offs estimated from biological variation (BV) and the use of interpretative comments. We developed and assessed the implementation of the protocol in our laboratory. Methods: Hemolysates from whole blood were prepared following the Meites method, and pooled serum samples with known Hb concentrations were prepared. For each analyte (42 ), interferograms were generated and used to establish cut-offs: desirable analytical quality specification and reference change value. This protocol was assessed, both pre- and post-implementation, according to expert rules in the Laboratory Information System. Results: Among the analytes evaluated, we selected those that showed the highest degree of hemolysis interference: lactate dehydrogenase (LDH), aspartate aminotransferase, direct bilirubin, potassium, and folic acid. The cut-offs for LDH and direct bilirubin were the lowest. Only 28.16% of all LDH values were adequately reported in the pre-implantation retrospective study, but this percentage improved in the post-implementation stage. Conclusions: The development and implementation of a harmonized protocol for hemolysis management based on BV cut-offs and result reporting significantly improve hemolysis detection and lead to a decrease in the number of hemolyzed samples over time.
Brief Communication2021-09-01 Transfusion Medicine
Sooin Choi , M.D., Jungwon Hyun , M.D., HongBi Yu , B.S., and Duck Cho , M.D.
Abstract : Fatal ABO-incompatible (ABOi) transfusion is one of the most common causes of transfusion-related death, but its reporting has been limited in Korea. We comprehensively reviewed ABOi transfusion events in Korea by analyzing cases reported in literature, Korean hemovigilance system (KOHEVIS) annual reports, and written judgments. Written judgments were assessed using a written judgment management system or a comprehensive legal information system. We found nine cases of ABOi transfusion events in written judgments (from 1953 to 2019), 16 in the KOHEVIS (from 2008 to 2018), and nine in published reports (from 1978 to 2019). One case was found in all three sources. Overall, we found 32 cases of ABOi transfusion events. Four cases died and 23 survived, while the outcomes for five were unavailable. ABOi transfusion errors occurred at the administration (50%, 16/32), sample (13%, 4/32), and testing (9%, 3/32) stages. The causes of errors were unavailable for nine cases (28%, 9/32). We report the status of ABOi transfusions in Korea and expect our results to contribute to the prevention of adverse reactions due to ABOi transfusion.
Letter to the Editor2021-09-01 Diagnostic Hematology
Kuenyoul Park , M.D., Hyeri Kim , M.D., Ph.D., Kyung-Nam Koh , M.D., Ph.D., Ho Joon Im , M.D., Ph.D., Young-Uk Cho , M.D., Ph.D., Seongsoo Jang , M.D., Ph.D., Eul-Ju Seo , M.D., Ph.D., Chan-Jeoung Park , M.D., Ph.D.
Original Article2021-07-01 Clinical Microbiology
Seong Jin Choi , M.D., Jieun Kang , M.D., and Young Uh , M.D.
Abstract : Background: Although group B Streptococcus (GBS) colonization rate among pregnant Korean women is lower than that among women from many Western countries, recent data show an upward trend. We investigated recent epidemiological changes in GBS among pregnant Korean women in terms of colonization rate, antimicrobial susceptibility, serotype, and resistance genotype. Methods: Vaginal and anorectal swab specimens from 379 pregnant Korean women were cultured on Strep B Carrot Broth with GBS Detect (Hardy Diagnostics, USA), selective Todd-Hewitt broth (Becton Dickinson, USA), and Granada agar plate medium (Becton Dickinson). The antimicrobial susceptibility, serotypes, and macrolide-lincosamide-streptogramin B (MLSB) resistance genes of the GBS isolates were tested. Results: The GBS colonization rate among pregnant Korean women was 19.8% (75/379). Colonization rates using Strep B Carrot Broth with GBS Detect, selective Todd-Hewitt broth, and Granada agar plate medium cultures were 19.5%, 19.3%, and 15.0%, respectively. Six pregnant women were colonized by non-beta-hemolytic GBS and were detected only in Strep B Carrot Broth with GBS Detect. Resistance rates of GBS to clindamycin, erythromycin, and tetracycline were 16.0%, 28.0%, and 42.7%, respectively. The most common GBS serotypes were V (22.7%), VIII (20.0%), and III (20.0%). The frequency of MLSB resistance genes erm(B) and erm(TR) were 63.6% and 36.4%, respectively. Conclusions: The GBS colonization rate among pregnant Korean women has risen to levels observed in Western countries. To accurately evaluate GBS epidemiology among pregnant Korean women, periodic studies in multiple centers, including primary clinics, are necessary.
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