Hwan Tae Lee, M.D., Jeong-Yeal Ahn, M.D., Ja Young Seo, M.D., Yiel-Hea Seo, M.D., Pil-Whan Park, M.D., Kyung-Hee Kim, M.D., Jaehyung You, Wookwan Park, Woo Jin Kim, M.D., Young Ho Yoon, M.D., Gwiyoung Oh, M.D., Daewon Kim, M.D.. Lab Med Online 2024;14:118-26. https://doi.org/10.47429/lmo.2024.14.2.118

Background: The distribution of bacteria isolated from bloodstream infections and cumulative antimicrobial susceptibility data are the basis for empirical decisions regarding antibiotics as an initial treatment. Therefore, it is important to consistently collect blood culture results of individual patients and analyze them correctly. Methods: The blood culture results of patients at Gachon University Gil Medical Center from 2016 to 2020 were analyzed retrospectively to determine the bacterial distributions and antibiotic resistance patterns. Duplicates were eliminated by including only the first isolate of each species per patient. Results: Escherichia coli (27.1%) was the most commonly isolated bacterium from blood cultures, followed by Klebsiella pneumoniae (10.1%) and Staphylococcus aureus (8.6%). The methicillin resistance rate of S. aureus was 49.2%, and the vancomycin resistance rate of Enterococcus faecium was 39.5%; with no significant changes over the study period. The cefotaxime, ciprofloxacin, and ertapenem resistance rates of E. coli were 35.0%, 46.8%, and 0.7%, respectively. Seventeen carbapenem-resistant E. coli strains were isolated, of which 11 produced carbapenemase. The cefotaxime, ciprofloxacin, and ertapenem resistance rates of K. pneumoniae were 29.5%, 31.7%, and 5.4%, respectively. Forty-eight carbapenem-resistant K. pneumoniae strains were isolated, of which 37 produced carbapenemase. The imipenem resistance rates of Acinetobacter baumannii and Pseudomonas aeruginosa were 72.3% and 23.4%, respectively. Conclusion: In the blood culture results from 2016 to 2020, the isolation frequency of E. coli, K. pneumoniae, and E. faecium showed an increasing trend, whereas that of S. aureus was stable. Over the 5 year study period, the ciprofloxacin resistance rate of E. coli and P. aeruginosa and ampicillin/sulbactam resistance rate of A. baumannii significantly increased.

What is known and objective Age and gender have been reported to play a crucial role in modulating the disposition of pharmacological agents, and to influence the activities of cytochrome P450 (CYP) 2D6, a drug-metabolizing enzyme involved in the disposition of clinically used drugs. In the present study, the effects of age and gender on the CYP2D6 activity were evaluated using dextromethorphan as a probe drug in humans. Methods Healthy young (20 < age < 30 years, n = 60) and old age (age >60 years, n = 60) subjects were enrolled and were given 15 mg dextromethorphan orally. Blood samples were collected before and 3 h after medication. Dextromethorphan and its metabolite dextrorphan were measured using HPLC-fluorescence, and dextromethorphan metabolic ratio (MR, log [dextromethorphan/dextrorphan]) was used to evaluate the CYP2D6 activity. Results and discussion Mean (+/- SD) dextromethorphan MR was -2.42 +/- 0.46 for the young male group, -2.28 +/- 0.56 for the young female group, -2.46 +/- 0.55 for the older male group and -2.34 +/- 0.65 for the old female group. Based on our findings, the effects of age and gender on CYP2D6 activity were not statistically significant. What is new and conclusion The results of the present study indicate that age and gender play a minor role in the modulation of CYP2D6 activity in the Korean population.

In some cases, hematopoietic stem cell transplants (HSCT) show differences in the D antigen.In previous studies, there have been few cases of de novo anti-D alloimmunization, and even rarer cases of serious side effects or the outcomes.De novo anti-D alloimmunization has been reported to occur more frequently in minor D mismatch than in major D mismatch.For the RhD type of blood components, RhD-negative type is recommended in transfusion in RhD mismatch HSCT without anti-D in donors and recipients.But in situations of insufficient RhD-negative blood supply, this study suggests that the RhD type of blood components depends on the patients' RhD type before transplantation, and it depends on the donors' RhD type after transplantation, and an RhD-positive platelet transfusion may be available.(

Background: Rapid and accurate diagnosis of acute myocardial infarction (AMI) is critical for initiating effective treatment and achieving better prognosis. We investigated the performance of copeptin for early diagnosis of AMI, in comparison with creatine kinase myocardial band (CK-MB) and troponin I (TnI). Methods: We prospectively enrolled 271 patients presenting with chest pain (within six hours of onset), suggestive of acute coronary syndrome, at an emergency department (ED). Serum CK-MB, TnI, and copeptin levels were measured. The diagnostic performance of CK-MB, TnI, and copeptin, alone and in combination, for AMI was assessed by ROC curve analysis by comparing the area under the curve (AUC). Sensitivity, specificity, negative predictive value, and positive predictive value of each marker were obtained, and the characteristics of each marker were analyzed. Results: The patients were diagnosed as having ST elevation myocardial infarction (STEMI; N=43), non-ST elevation myocardial infarction (NSTEMI; N=25), unstable angina (N=78), or other diseases (N=125). AUC comparisons showed copeptin had significantly better diagnostic performance than TnI in patients with chest pain within two hours of onset (AMI: P=0.022, <= 1 hour; STEMI: P=0.017, <= 1 hour and P=0.010, <= 2 hours). In addition, TnI and copeptin in combination exhibited significantly better diagnostic performance than CK-MB plus TnI in AMI and STEMI patients. Conclusions: The combination of TnI and copeptin improves AMI diagnostic performance in patients with early-onset chest pain in an ED setting.

The aim of this study was to determine the relationship between phenotypic antimicrobial susceptibility patterns and extended-spectrum, carbapenem-resistance genes. A total of 109 clinical Staphilococcus aureus strains were subjected to 19 antimicrobial susceptibility tests. Resistance to methicillin (mecA), penicillin (blaTEM), and tetracycline (tetM) was detected. We compared the presence of the blaTEM genes with extended-spectrum, carbapenem-related genes and identified the types of SCCmec genes. Of 109 clinical S. aureus strains, 62 (56.88%) had methicillin resistance and 60 strains carried mecA. The prevalence of blaTEM and tetM genes was 81.65% and 37.61%, respectively. The most predominant SCCmec type was SCCmec type II 28/60 (46.67%), in 60 mecA-positive methicillin-resistant S. aureus (MRSA) isolates. The SCCmec prevalence rates were type IVA 30.00% (18/60), type IVb 8.33% (5/60), type IVd 6.67% (4/60), and non-typable 8.33% (5/60). Sixty of the 109 (55.05%) MRSA isolates were positive for extended-spectrum carbapenems (31/60) (51.67%), cephalosporins 40/60 ( 66.67%) and carbapenems 31/60 (51.67%). The predominant SCCmec type II demonstrated more carbapenem-resistance than the IVA, IVb and IVd types.

BackgroundApixaban and rivaroxaban are approved for the prevention and treatment of deep vein thrombosis (DVT), pulmonary embolism (PE), and embolic stroke in atrial fibrillation (AF) patients. The aim of this study was to find appropriate methods of monitoring the anticoagulant effects of are direct oral anticoagulants (DOACs) and establish on‐therapy ranges using conventional tests.MethodsA total of 184 samples were collected from 91 patients receiving DOACs. Concentrations of apixaban and rivaroxaban in plasma were accessed by an anti‐factor Xa chromogenic assay. PT, APTT, antithrombin, D‐dimer, dRVVT screen/confirm, FDP, and fibrinogen levels were measured. On‐therapy ranges were calculated by substituting previously reported trough plasma concentrations of DOACs.ResultsAnti‐factor Xa chromogenic assay‐based DOACs levels were 26.0‐279.5 (115.9 ± 56.5) ng/mL for apixaban at 2.5 mg BID, 19.9‐565.1 (205.3 ± 162.4) ng/mL for apixaban at 5 mg BID, 2.3‐395.3 (205.3 ± 162.4) ng/mL for rivaroxaban at 15 mg OD, 3.6‐494.8 (119.6 ± 95.1) ng/mL for rivaroxaban at 20 mg OD, and 9.6‐431.4 (140.8 ± 113.6) ng/mL for rivaroxaban at 15 mg BID. PT (%), antithrombin, and dRVVT confirm tests showed good correlation with plasma apixaban levels. Plasma rivaroxaban concentrations were correlated well with PT (sec), PT (%),and dRVVT confirm results. On‐therapy ranges established for dRVVT confirm test by linear regression were as follows: 1.32‐1.52 for apixaban 2.5 mg BID, 1.12‐1.75 for apixaban 5 mg BID, 1.11‐1.78 for rivaroxaban 15 mg OD, 1.09‐1.64 for rivaroxaban 20 mg OD, and 1.22‐1.81 for rivaroxaban 20 mg BID.ConclusionsApixaban concentrations were well correlated with PT (%), antithrombin, and dRVVT confirm test. Rivaroxaban concentrations showed good correlation with PT (sec), PT (%), and dRVVT confirm test.

This study was to determine the relationship between pbp3 and pbp4 gene compared with mecA and TEM resistance genes expression patterns. Total 134 clinical S. aureus strains were subjected to 19 antimicrobial susceptibility tests. We detected resistance to methicillin (mecA), penicillin (blaTEM) and expression of pbp (Penicillin-binding proteins) genes. We were compared blaTEM, extended spectrum, carbapenem related genes and types of SCCmec identified. Total of 134 clinical S. aureus strains, 79 (58.96%) in methicillin resistance, and 77 strains carried mecA. Prevalence rates of blaTEM and pbp genes were 107/134 (79.85%) and 128/134 (95.52%). Multiplex PCR results revealed that the predominant SCCmec type among 77 mecA-positive MRSA strains were similer too SCCmec type II 41.56% (32/77) and type IVA 40.26% (31/77). Prevalence rates of type IVb, IVd and non-typable were 18.18% (14/77), respectively. From a total of 77/134 (57.46%) MRSA isolate strains, 35/77 (45.46%) were positive for extended spectrum, 40/77 (51.95%) for cephalosporins, and 35/77 (45.46%) for carbapenems. The predominant SCCmec type II had more carbapenem resistances than IVA, IVb and IVd. TEM and mecA gene expression were not correlated with pbp gene, and the properties of drug resistance were appeared not associated with pbp3, 4 genes.

BackgroundBone marrow (BM) study plays an important role as initial investigation specimen of lymphoma as well as staging lymphoma. This study aimed to investigate the utility of BM studies for classification of lymphoma and evaluate features of BM involvement by lymphoma over a period of 11 years.MethodsA total of 1162 cases of BM studies for lymphoma evaluation were reviewed for the incidence of lymphoma subtypes, the percentage of marrow involvement, the pattern of involvement and discordance with histopathologic diagnoses of lymph nodes and other tissues.ResultsA total of 255 of 1162 cases underwent BM study without pathologic information, and 108 cases show lymphoma involvement. Lymph node biopsy underwent in 66 cases, and 10 cases show discordant result between BM and lymph node biopsy. Seven discordant cases were due to insufficient further studies. Lymphoma was diagnosed only by BM study in 38 cases. Abnormal lymphocytes were found in BM aspiration in 34 cases. Also, abnormal clonal lymphocytes were detected by flow cytometry in 26 cases. Four cases showed disease‐related chromosomal abnormalities. FISH analysis detected abnormal findings in two cases, however, discordant with other additional studies.ConclusionsDiscrepancies between the BM study and lymph node biopsy were due to insufficient further study and discordance of immunohistochemical stain result. BM study can be utilized as initial diagnosis of lymphoma by the combination of morphological feature, involvement pattern, and additional tests such as flow cytometry, chromosomal analysis, and FISH analysis. Thus, BM study with further analysis is an essential choice when lymph node biopsies are unavailable.

Group B streptococcus (GBS) is a leading cause of life‐threatening bacterial infections among newborns, and neonates born to heavily colonized women may be subject to vertical transmission. We sought to determine an appropriate detection method for genital GBS in pregnant women by comparing culture‐based methods and real‐time polymerase chain reaction (PCR). In addition, we performed molecular serotyping and multilocus sequence typing (MLST) on isolates.

Nanomaterials that exhibit enzyme-like characteristics, which are called nanozymes, have recently attracted significant attention due to their potential to overcome the intrinsic limitations of natural enzymes, such as low stability and relatively high cost for preparation and purification. In this study, we report a highly efficient colorimetric allergy detection system based on an immunoassay utilizing the peroxidase-mimicking activity of hierarchically structured platinum nanoparticles (H-Pt NPs). The H-Pt NPs had a diameter of 30 nm, and were synthesized by a seed-mediated growth method, which led to a significant amount of peroxidase-like activity. This activity mainly occurs because of the high catalytic power of the Pt element, and the fact that the H-Pt NPs have a large surface area available for catalytic events. The H-Pt NPs were conjugated to an antibody for the detection of immunoglobulin E (IgE) in the analytes; IgE is a representative marker for the diagnosis of allergies. They were then successfully integrated into a conventionally used allergy diagnostic test, the ImmunoCAP diagnostic test, as a replacement for natural signaling enzymes. Using this strategy, total and specific IgE levels were detected within 5 min at room temperature, with high specificity and sensitivity. The practical utility of the immunoassay was also successfully verified by correctly determining the levels of both total and specific IgE in real human serum samples with high precision and reproducibility. The present H-Pt NP-based immunoassay system would serve as a platform for rapid, robust, and convenient analysis of IgE, and can be extended to the construction of diagnostic systems for a variety of clinically important target molecules.

We have developed a colorimetric biosensing system for the detection of antibody against MPT64, a protein secreted by Mycobacterium tuberculosis, using aptamer DNA adsorbed Fe₃O₄ magnetic nanoparticles (MNPs) for diagnosis of tuberculosis (TB). In this system, MNPs were first incubated with single stranded (ss) DNA-type aptamer having a high affinity toward target antibody against MPT64 (anti-MPT64), resulting in quick inhibition of the peroxidase-like activity of MNPs via the adsorption of aptamer on the surface of MNPs. By the addition of sample solutions containing anti-MPT64, aptamer bound on the surface of MNPs would strongly interact with free anti-MPT64 and be detached from the MNPs, thereby increasing the available surface area of the MNPs and consequently yielding enhanced peroxidase activity. Using this strategy, target anti-MPT64 was successfully detected by displaying increased colorimetric intensities from the higher oxidation of employed peroxidase substrate, 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS). Based on these results, we anticipate that aptamer adsorbed MNPs can serve as a potent probe system for the detection of clinically important target molecules.

Dear Editor, Hemolysis, icterus, and lipemia are important preanalytic sources of errors in coagulation testing of blood samples, besides sample-to-anticoagulant ratio, transport stability, and storage temperature. Lipemia (13%), hyperbilirubinemia (11%), and hemolysis (4%) in whole blood cause errors in coagulation testing [1, 2]. Hemoglobin, bilirubin, and triglyceride are major interfering substances that affect test results by spectral overlap [3, 4]. Hemolytic, icteric, and lipemic (HIL) sample check functions have been implemented in the preanalytic module of the ACL TOP family 50 series spectrophotometric hemostasis equipment (Instrumentation Laboratory Company, Bedford, MA, USA) to support preanalytic sample evaluation. We evaluated the performance of the ACL TOP 750 preanalytic module, using patient samples. In total, 353 blood samples assigned HIL flags by the ACL TOP 750 preanalytic module were collected from samples subjected to the routine hemostasis test. HIL sample flags were given based on absorbance at a specific wavelength. Samples were collected between June and September 2016 and in August 2017 at Gachon University Gil Medical Center, Korea. There were 80 samples with hemolysis flag, 185 samples with icteric flag, 33 samples with lipemic flag, and 55 samples from patients with triglyceride levels over 5,000 mg/L, including samples without lipemic flag. Preanalytic values measured by the ACL TOP 750 preanalytic module were compared with reference values obtained from ADVIA chemistry XPT (Siemens Healthineers, Erlangen, Germany) using an enzymatic method and from ADVIA 2120i (Siemens Healthineers, Erlangen, Germany) using a spectrophotometric method. Medians of preanalytic readings were used for analysis. Passing–Bablok regression and Bland–Altman tests were conducted for hemolytic and icteric sample evaluation. Linear regression analysis was conducted for lipemic samples. In each HIL sample group, subgroups of samples with HIL flag and with a value interval around the modal value of the reference method, which included 68% of all samples with 95% confidence level, were defined as low-level HIL samples (Table 1). Passing–Bablok regression for hemolytic samples revealed constant, non-proportional differences between reference and preanalytic values (Fig. 1A). In a Bland–Altman plot, 77/80 (96.3%) hemolytic and 55/58 (94.8%) low-level hemolytic samples were within the limit of agreement (Fig. 1B, 1C). For icteric samples, Passing–Bablok regression indicated constant, proportional differences between reference and preanalytic values (Fig. 1D). In a Bland–Altman plot, 174/185 (94.1%) icteric and 127/137 (92.7%) low-level icteric samples were within the limit of agreement (Fig. 1E, 1F). The CUSUM test for linearity, indi-

목적: 침습 B군 사슬알균(group B streptococcus [GBS]) 감염증에서 분리된 균의 혈청형과 임상적 특징의 관계를 분석하고자 하였다. 방법: 가천대 길병원과 삼성서울병원에 입원한 GBS 감염 환자 데이터를 후향적으로 수집하고 슬라이드 응집법으로 혈청형을 정하였다. 결과: 총 37명 중 만삭아 22명, 미숙아 15명이었고, 조발형 15명(40.5%), 지발형 19명(51.4%), 늦은 지발형 3명(8.1%)이었다. 조발형이 미숙아에서 더 많이 발생하였다(P =0.17). 임상 양상은 균혈증(70.3%)이 가장 흔했고, 수막염, 화농관절염 순이었다. 혈청형 분석이 가능했던 24 균주 중 III형이 가장 흔했고 (41.7%), V (16.7%), Ia, Ib, II (각각 12.5%), non-typeable (4.2%)였다. III형은 만삭아에서 더 많았던 반면, V형은 미숙아에서 더 흔했다. 페니실린 내성균은 없었고 에리트로마이신과 클린다마이신 내성은 각각 64.9%였다. 결론: GBS는 미숙아와 만삭아에게 모두 중요한 병원체이며 혈청형 분포에서도 미숙아와 만삭아 간에 차이가 있을 수 있다. 조발형 질환의 발생을 과소평가하지 않고 적절한 예방 대책을 마련하기 위해 미숙아를 포함한 GBS 질환의 전국적인 역학을 감시하는 것이 필요하다.

eISSN 2093-6338 derived from bovine tissues are routinely used for dural closure in cranial and spinal surgery because they provide a watertight dural closure and should have low antigenicity [2-4]. Pediatric cases of eosinophilic meningitis following duraplasty with a bovine graft have been previously published [3, 5-10]. Here, we describe an adult patient with eosinophilic meningitis following Chiari decompression surgery via bovine graft duraplasty.

BackgroundClostridium difficile is a major pathogen responsible for nosocomial infectious diarrhea. We explored optimal laboratory strategies for diagnosis of C. difficile infection (CDI) in our clinical settings, a 1400‐bed tertiary care hospital.MethodsUsing 191 fresh stool samples from adult patients, we evaluated the performance of Xpert C. difficile (Xpert CD), C. diff Quik Chek Complete (which simultaneously detects glutamate dehydrogenase [GDH] and C. difficile toxins [CDT]), toxigenic culture, and a two‐step algorithm composed of GDH/CDT as a screening test and Xpert CD as a confirmatory test.ResultsClostridium difficile was detected in 35 samples (18.3%), and all isolates were toxigenic strains. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value of each assay for detecting CDI were as follows: Quik Chek Complete CDT (45.7%, 100%, 100%, 89.1%), Quik Chek Complete GDH (97.1%, 99.4%, 97.1%, 99.4%), Xpert CD (94.3%, 100%, 100%, 98.7%), and toxigenic culture (91.4%, 100%, 100%, 98.1%). A two‐step algorithm performed identically with Xpert CD assay.ConclusionOur data showed that most C. difficile isolates from adult patients were toxigenic. We demonstrated that a two‐step algorithm based on GDH/CDT assay followed by Xpert CD assay as a confirmatory test was rapid, reliable, and cost effective for diagnosis of CDI in an adult patient setting with high prevalence of toxigenic C. difficile.

Ji Hun Jeong, M.D., Song Mi Moon, M.D. , Pil Whan Park, M.D., Jeong Yeal Ahn, M.D., Kyung Hee Kim, M.D., Ja Young Seo, M.D., Hwan Tae Lee, M.D., Kwoun Woo Jae, M.D. , and Yiel Hea Seo, M.D.. Ann Lab Med 2017;37:459-61. https://doi.org/10.3343/alm.2017.37.5.459

Background Cumulative blood culture data provide clinicians with important information in the selection of empiric therapy for blood stream infections. Methods We retrospectively analyzed blood culture data from a university hospital during the period from 2006 to 2015. Only the initial isolates of a given species for each patient were included. Results The number of blood cultures per 1,000 inpatient-days increased from 64 in 2006 to 117 in 2015. The ratio of significant pathogens to total isolates was 0.56-0.63. The most common organisms were Escherichia coli in 2006-2010 but changed to coagulase-negative staphylococci (CoNS) in 2011. The proportion of Staphylococci aureus was decreased during the study period, but Klebsiella pneumoniae was increased. Enterococci were increased, especially E. faecium, which was more frequently isolated than E. faecalis in 2015. Pseudomonas aeruginosa was decreased during the study, but Acinetobacter baumannii was increased. The prevalence of methicillin-resistant S. aureus (MRSA) changed from 62.2% to 53.9%, while vancomycin-resistant E. faecium increased to 35.8%. Extended-spectrum beta-lactamase (ESBL)-producing E. coli and K. pneumoniae increased to 25% and 34%, respectively, in 2015. Starting in 2008, three E. coli and 11 K. pneumoniae isolates were carbapenem-resistant Enterobacteriaceae (CRE), and three were carbapenemase-producing Enterobacteriaceae (CPE). The prevalence of imipenem-resistant A. baumannii rapidly increased during the study period. Conclusion About 60% of all blood isolates were significant pathogens. The most common isolates changed from E. coli to CoNS in 2011. ESBL-producing E. coli and K. pneumoniae, vancomycin-resistant E. faecium, and imipenem-resistant A. baumannii were increased during the study, while the proportion of MRSA tended to decrease slightly. Of the total isolates, 14 were CRE, and 3 were CPE.