Original Article2021-07-01
So Hyun Yu 
, B.S., Jeong Hyun Lee , B.S., Min-Chul Kim , M.D., Ph.D., Seong-Ho Choi , M.D., Ph.D., Jin-Won Chung , M.D., Ph.D., and Mi-Kyung Lee , M.D., Ph.D.
Abstract : Background: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains were first detected in hospitals in Korea between the late 2000s and early 2010s. However, there is limited information regarding the prevalence of CA-MRSA strains among hospital isolates and their phenotypic changes over the last decade. We investigated the prevalence trend of CA-MRSA strains isolated from different clinical specimens and their phenotypic changes between September 2009 and September 2019. Methods: CA-MRSA strains were phenotypically identified by confirming their resistance to penicillin (PCN) and oxacillin (OXA) and evaluating their susceptibility to trimethoprim-sulfamethoxazole, rifampin, fusidic acid, tetracycline, and at least one of the following four antimicrobials: clindamycin (CLI), erythromycin (ERY), ciprofloxacin (CIP), and gentamicin (GEN). A CA-MRSA strain that exhibited resistance to ERY, CLI, CIP, or GEN was classified as having resistance pattern I, II, III, or IV, respectively, regardless of its resistance to other antimicrobial agents. Results: Of the 8,278 MRSA isolates identified in specimens obtained two days after admission, 1,385 (16.73%) were CA-MRSA strains. The prevalence of CA-MRSA strains increased from 12.2% to 26.6% (3.21% per period, P=0.05). Resistance type analysis revealed an increasing trend in the prevalence of PCN/OXA-resistant (1.84%; P=0.049) and PCN/OXA/ERY/CLI/CIP-resistant (0.98%; P=0.04) CA-MRSA strains and in resistance pattern III strains (2.08%; P=0.004). Conclusions: The prevalence of CA-MRSA strains in Korea has increased significantly over the last decade, and CA-MRSA strains have gained phenotypic diversity beyond PCN/OXA-resistance, including antimicrobial resistance to non-β-lactams, especially CIP.
Brief Communication2021-09-01
Clinical Microbiology
Jun Ho Jeon , Ph.D., Chi-Hwan Choi , Ph.D., Jeong Hyun Kim , M.D., Junghee Hyun , M.S., Eun-Sun Choi , Ph.D., Sang-Yoon Choi , Ph.D., Yong-Woo Shin , Ph.D., Seong Wook Pyo , M.S., Dae-Won Kim , Ph.D., Byung Hak Kang , Ph.D., Young Joon Park , M.D., and Gi-eun Rhie , Ph.D.
Abstract : Botulism is a neuroparalytic disease caused by a neurotoxin produced by Clostridium botulinum. This study aimed to genetically characterize C. botulinum strain isolated from the first case of infant botulism in Korea reported on June 17, 2019. We isolated C. botulinum strain CB-27 from a stool sample of the patient and analyzed the toxin types and toxin gene cluster compositions of the strain using a mouse bioassay, real-time PCR, and genome sequencing. Toxin gene cluster analysis showed that strain CB-27 possesses a C. botulinum neurotoxin type A harboring an unexpressed B gene. Although the nucleotide and amino acid sequences of toxin genes as well as the toxin gene cluster arrangements in strain CB-27 were identical to those of the known strain CDC_69094, the total nucleotide sequences of the toxin gene clusters of CB-27 differed from those of CDC_69094 by 0.47%, indicating genetic diversity of toxin gene clusters of CB-27 among other previously reported C. botulinum strains. To our knowledge, this is the first description of a C. botulinum strain with two separate toxin gene clusters in Korea.
Editorial2021-11-01
Young Jin Kim , M.D., Ph.D., Heungsup Sung , M.D., Ph.D., Chang-Seok Ki , M.D., Ph.D., and Mina Hur , M.D., Ph.D.
Letter to the Editor2021-07-01
Clinical Microbiology
Dongke Chen , M.A., Han Wang , M.D., Xianlei Lu , M.A., Yao Cui , M.A., Xiaohan Ma , M.A., Jing Lou , M.M. and Haijian Zhou , M.M.
Brief Communication2021-07-01
Mi Suk Park , Ph.D., Young Eun Lee , M.S., Hye Ran Kim , Ph.D., Jong Hee Shin , M.D., Ph.D., Hyun Wook Cho , Ph.D., Jun Hyung Lee , M.D., Ph.D., and Myung Geun Shin , M.D., Ph.D.
Abstract : Phospholipase C beta 2 (PLC-β2) regulates various essential functions in cell signaling, differentiation, growth, and mobility. We investigated the clinical implications of PLC-β2 protein expression in newly diagnosed normal karyotype acute myeloid leukemia (NK-AML). The PLC-β2 expression status in bone marrow tissues obtained from 101 patients with NK-AML was determined using semiquantitative immunohistochemistry (IHC). IHC results were compared with those for known prognostic markers. Using a cutoff score for positivity of 7.0, the PLC-β2 overexpression group showed superior overall survival (OS) (72.6% vs. 26.5%; P=0.016) and low hazard ratio (HR) (0.453; P=0.019) compared with the PLC-β2 low-expression group. The PLC-β2 overexpression group showed no significant gain in event-free survival (50.6% vs. 43.0%, P=0.465) and HR (0.735; P=0.464). Among the known prognostic markers, only FLT3-ITD positivity was associated with a significantly low OS and high HR. In conclusion, PLC-β2 overexpression was associated with favorable OS in NK-AML patients. Our results suggest that PLC-β2 expression assessment using IHC allows prognosis prediction in NK-AML.
Letter to the Editor2021-09-01
Diagnostic Genetics
Beatriz González Fernández , M.S., José Bartolomé Nieto Campuzano , M.D., Dolores García Rocamora , M.D., Jorge M Nieto , M.S., Fernando Ataúlfo González Fernández , M.D., Ana Villegas , M.D., Ph.D., Celina Benavente Cuesta , M.D., and Paloma Ropero , Ph.D.
Brief Communication2021-09-01
Clinical Chemistry
Isidor Minović , Pharm.D., Ph.D., Lambert D. Dikkeschei , Ph.D., Michel J. Vos , Ph.D., and Jenny E. Kootstra-Ros , Ph.D.
Abstract : Folate analysis in plasma is affected by hemolysis, which can lead to biased results. However, the degree of hemolysis that is considered acceptable is unclear. We explored the relationship between folate concentration and degree of hemolysis. Heparin plasma samples (N=77, hemolysis index ≤10 μmol/L) were spiked with increasing amounts of corresponding patient-specific hemolysate. Subsequently, the folate concentration and hemolysis index were measured using two Roche Cobas platforms, and their incremental relationship was investigated. The folate concentration ranged from 2.9 to 30.9 nmol/L with a median (interquartile range) of 11.4 (8.6-19.1) nmol/L. The linear relationship between the increments in folate concentration and hemolysis index was approximated by the function y=1.86x+1.56 (R2=0.996), where x represents the laboratory-specific critical difference in folate concentration, which can be calculated from the analytical variation of the employed folate assay(s), and y represents the hemolysis threshold. The hemolysis threshold did not significantly differ between the tertiles of plasma folate concentration (P=0.10). In conclusion, we have provided an evidence-based approach that can be used to reliably interpret folate concentrations in hemolytic samples, independent of the patient’s folate status.
Original Article2021-01-01
Transfusion Medicine
Hyun-Ji Lee , M.D., Ph.D., Seung-Hwan Oh , M.D., Ph.D., Su-Yeon Jo , M.D., and In-Suk Kim , M.D., Ph.D.
Abstract : Background: Patients with ongoing or expected bleeding require platelet (PLT) transfusions; however, owing to the testing required after a blood donation, manufacturing PLT products may take 1.5–2.0 days after a request is made. This supply-demand mismatch leads clinicians to retain spare PLTs for transfusions, leading to increased PLT discard rates. We developed a PLT inventory management program to supply PLTs more efficiently to patients requiring PLT transfusions within the expiration date, while reducing PLT discard rates. Methods: PLT concentrates (58,863 and 58,357 units) and apheresis products (7,905 and 8,441 units) were analyzed from May 2015 to November 2017 and from December 2017 to January 2020, respectively. We developed a program to manage total PLT inventories and prospective PLT transfusion patients based on blood type, blood product, and remaining period of efficacy; the program facilitates PLT preparation transfer to non-designated patients within the remaining period of efficacy. Results: The overall PLT concentrate discard rate was 3,254 (2.78%): 1,811 (3.07%) units before and 1,443 units (2.41%) after program application (P<0.001). The discard rate owing to expiration was reduced from 69 units (3.81%) before to two units (0.14%) after program application (P<0.001). Conclusions: This program can guide the allocation of PLT preparations based on the remaining period of efficacy, enabling PLT products to be used before their expiration date and reducing PLT product discard rate.
Letter to the Editor2021-03-01
Diagnostic Hematology
Han Joo Kim , M.D., Eunkyoung You , M.D., Seokchan Hong , M.D., Chan-Jeoung Park , M.D.
Original Article2022-05-01
Clinical Chemistry
Sunyoung Ahn , Ph.D., Hyun-Ki Kim , M.D., Woochang Lee , Ph.D., Sail Chun , Ph.D., and Won-Ki Min , Ph.D.
Abstract : Background: We established high-sensitivity cardiac troponin I (hsTnI) 99th percentile upper reference limits (URLs) for the Centaur XPT High-Sensitivity Troponin I assay (Centaur hsTnI; Siemens, Erlangen, Germany) and Atellica IM High-Sensitivity Troponin I assay (Atellica hsTnI; Siemens) and assessed the effect of outlier elimination. Methods: The reference population comprised 380 men and 387 women, satisfying the strict systematic reference population criteria. After reference population verification by the N-terminal pro-B-type natriuretic peptide (NT-proBNP) assay, 99th percentile URLs for Centaur hsTnI and Atellica hsTnI were calculated before and after outlier elimination. Results: The 99th percentile URL for Centaur hsTnI was 60.4 (men, 74.7; women, 57.5) ng/L and that for Atellica hsTnI was 59.6 (men, 75.2; women, 55.1) ng/L. After the elimination of 61 (8.0%) outlier samples in Centaur hsTnI and 58 (7.6%) in Atellica hsTnI, the 99th percentile URLs were 13.5 ng/L (men, 15.3 ng/L; women, 11.9 ng/L) and 13.4 ng/L (men, 15.5 ng/L; women, 12.9 ng/L), respectively, significantly lower than those before outlier elimination. The CVs at the 99th percentile URLs were 5.2% and 3.5%, respectively. The measurable fractions among the reference population were 91.5% and 93.4%, respectively. Performance evaluation of Atellica B-type natriuretic peptide (BNP), Atellica NT-proBNP, Centaur hsTnI, and Atellica hsTnI showed outstanding results. Conclusions: The Korean hsTnI 99th percentile URLs calculated in this study were significantly lower after outlier elimination than before. Centaur hsTnI and Atellica hsTnI meet the “Guideline acceptable” and “Level 3 (second generation, high sensitivity)” requirements, satisfying international standards.
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