Hwan Tae Lee

Performance evaluation of Mindray CAL 8000(BC‐6800 and SC‐120) hematology analyzer and slidemaker/stainer

The Mindray CAL 8000 is a cellular analysis line that consists of the BC‐6800, an automated hematology analyzer, and the SC‐120, an automated slidemaker/stainer. We evaluated the performances of the BC‐6800 and the SC‐120.

The Prognostic Value of Serum Levels of Heart-Type Fatty Acid Binding Protein and High Sensitivity C-Reactive Protein in Patients With Increased Levels of Amino-Terminal Pro-B Type Natriuretic Peptide

Background Amino-terminal pro-B type natriuretic peptide (NT-proBNP) is a well-established prognostic factor in heart failure (HF). However, numerous causes may lead to elevations in NT-proBNP, and thus, an increased NT-proBNP level alone is not sufficient to predict outcome. The aim of this study was to evaluate the utility of two acute response markers, high sensitivity C-reactive protein (hsCRP) and heart-type fatty acid binding protein (H-FABP), in patients with an increased NT-proBNP level. Methods The 278 patients were classified into three groups by etiology: 1) acute coronary syndrome (ACS) (n=62), 2) non-ACS cardiac disease (n=156), and 3) infectious disease (n=60). Survival was determined on day 1, 7, 14, 21, 28, 60, 90, 120, and 150 after enrollment. Results H-FABP (P<0.001), NT-proBNP (P=0.006), hsCRP (P<0.001) levels, and survival (P<0.001) were significantly different in the three disease groups. Patients were divided into three classes by using receiver operating characteristic curves for NT-proBNP, H-FABP, and hsCRP. Patients with elevated NT-proBNP (≥3,856 pg/mL) and H-FABP (≥8.8 ng/mL) levels were associated with higher hazard ratio for mortality (5.15 in NT-proBNP and 3.25 in H-FABP). Area under the receiver operating characteristic curve analysis showed H-FABP was a better predictor of 60-day mortality than NT-proBNP. Conclusions The combined measurement of H-FABP with NT-proBNP provides a highly reliable means of short-term mortality prediction for patients hospitalized for ACS, non-ACS cardiac disease, or infectious disease.

Multiple Brain Abscesses Caused by Nocardia asiatica in a Patient With Systemic Lupus Erythematosus: The First Case Report and Literature Review

Dear Editor, Nocardia species are uncommon pathogens that affect immunosuppressed patients; although cerebral nocardiosis is a rare condition, it is associated with significant morbidity and mortality [1]. Because Nocardia species exhibit different antibiotic susceptibilities, accurate species identification is important for prognoses. To the best of our knowledge, this is the first case of Nocardia asiatica brain abscesses reported in a systemic lupus erythematosus (SLE) patient. A 51-yr old man visited our emergency department on May 2016 complaining of left leg weakness, dysarthria, dizziness, nausea, vomiting, and uncontrolled fever lasting three days. His past medical history consisted of SLE (diagnosed in August 2002) treated intermittently with steroid and platelet transfusion because of severe thrombocytopenia. In addition, in April 2015, he was diagnosed as having diabetes; however, no medical treatment had been undertaken. His last admission to hospital, due to severe thrombocytopenia (6×10/L), was two months prior to this presentation. He was subsequently treated with danazol (400 mg twice daily), hydroxychloroquine (200 mg twice daily), methotrexate (15 mg/week), and prednisolone (15 mg/day). At presentation, the patient’s temperature was 39.1°C, and blood tests indicated a white blood cell count of 11.03×10/L with a differential count of 76.2% neutrophils. Serum C-reactive protein (71.9 mg/L) and erythrocyte sedimentation rate (28 mm/ hr) were elevated. Brain magnetic resonance imaging (MRI) revealed multiple contrast-enhanced lesions in both cerebral and cerebellar hemispheres (Fig. 1A). A subsequent brain abscess aspiration removed 5 mL of a yellowish aspirate; Gram staining of the aspirate revealed gram-positive filamentous branched bacilli, and specimen culturing on blood agar plates for 48 hr at 37°C under aerobic conditions yielded white, rough, and dry colonies, which also presented gram-positive filamentous branched bacilli and were modified acid fast bacilli stain-positive (Fig. 1BE). 16S rRNA gene sequencing was performed for isolate identification according to the CLSI guidelines with primer pair forward 4F and reverse 801R [2]. The isolate 16S rRNA sequence (671 bp; GenBank accession number KY417120) showed 100% homology with N. asiatica (KC333452.1) and N. abscessus (GU471235.1). Alternative gene targets, such as the secA1 gene, are necessary for accurate species discrimination in the Nocardia asteroides group, because several N. asiatica, N. abscessus, N. asteroides, and N. arthritidis strains share ≥99.6% identity [2]. Thus, gene amplification and additional sequencing of secA1 were performed with primer pair forward F47 and reverse ConR. The results (497; KY417121) showed 99.4% (494/497) and

Analysis of Blood Culture Data at a Tertiary University Hospital, 2006-2015

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 carbapenemaseproducing 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. (Ann Clin Microbiol 2017;20:35-41)

Screening PCR Versus Sanger Sequencing: Detection of CALR Mutations in Patients With Thrombocytosis.

Background Mutations in calreticulin (CALR) have been reported to be key markers in the molecular diagnosis of myeloid proliferative neoplasms. In most previous reports, CALR mutations were analyzed by using Sanger sequencing. Here, we report a new, rapid, and convenient system for screening CALR mutations without sequencing. Methods Eighty-three bone marrow samples were obtained from 81 patients with thrombocytosis. PCR primers were designed to detect wild-type CALR (product: 357 bp) and CALR with type 1 (product: 302 bp) and type 2 mutations (product: 272 bp) in one reaction. The results were confirmed by Sanger sequencing and compared with results from fragment analysis. Results The minimum detection limit of the screening PCR was 10 ng for type 1, 1 ng for type 2, and 0.1 ng for cases with both mutations. CALR type 1 and type 2 mutants were detected with screening PCR with a maximal analytical sensitivity of 3.2% and <0.8%, respectively. The screening PCR detected 94.1% (16/17) of mutation cases and showed concordant results with sequencing in the cases of type 1 and type 2 mutations. Sanger sequencing identified one novel mutation (c.1123_1132delinsTGC). Compared with sequencing, the screening PCR showed 94.1% sensitivity, 100.0% specificity, 100.0% positive predictive value, and 98.5% negative predictive value. Compared with fragment analysis, the screening PCR presented 88.9% sensitivity and 100.0% specificity. Conclusions This screening PCR is a rapid, sensitive, and cost-effective method for the detection of major CALR mutations.

Weak D Testing is not Required for D− Patients With C−E− Phenotype

Background Although testing to detect weak D antigens using the antihuman globulin reagent is not required for D− patients in many countries, it is routinely performed in Korea. However, weak D testing can be omitted in D− patients with a C−E− phenotype as this indicates complete deletion of the RHD gene, except in rare cases. We designed a new algorithm for weak D testing, which consisted of RhCE phenotyping followed by weak D testing in C+ or E+ samples, and compared it with the current algorithm with respect to time and cost-effectiveness. Methods In this retrospective study, 74,889 test results from January to July 2017 in a tertiary hospital in Korea were analyzed. Agreement between the current and proposed algorithms was evaluated, and total number of tests, time required for testing, and test costs were compared. With both algorithms, RHD genotyping was conducted for samples that were C+ or E+ and negative for weak D testing. Results The algorithms showed perfect agreement (agreement=100%; κ=1.00). By applying the proposed algorithm, 29.56% (115/389 tests/yr) of tests could be omitted, time required for testing could be reduced by 36% (8,672/24,084 min/yr), and the test cost could be reduced by 16.53% (536.11/3,241.08 USD/yr). Conclusions Our algorithm omitting weak D testing in D− patients with C−E− phenotype may be a cost-effective testing strategy in Korea.

Detection and genomic analysis of genital group B streptococcus in pregnant Korean women: Detection and genomic analysis of genital GBS

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.

Bone Marrow Oxalosis in a Patient With Pancytopenia Following Bilateral Nephrectomy

Dear Editor, Bone marrow (BM) oxalosis is a type of systemic oxalosis wherein oxalate is deposited in BM. It is characterized by cytopenias, leukoerythroblastosis, and hepatosplenomegaly [1] as well as BM findings of calcium oxalate crystals that are birefringent under polarized microscopy and granulomatous structures [2]. Hyperoxaluria (excessive urinary excretion of oxalate) can develop into systemic oxalosis when oxalate is deposited in organs [3]. Hyperoxaluria is classified as primary or secondary. Primary hyperoxaluria is an autosomal recessive disease with defective oxalate metabolism [3] in which the overproduction of oxalate results from an enzyme deficiency in the liver; its clinical presentation involves nephrocalcinosis and renal impairment. Systemic deposition of excess oxalate occurs in the bone and all organs and tissues, except the liver. The retina, arteries, peripheral nervous system, myocardium, thyroid, skin, and BM are the major areas of oxalate deposition. Bone is the most common site, although the bone lesions can mimic clinical renal osteo-dystrophy [4,5]. Primary hyperoxaluria includes three types of enzyme deficiency. The most common form is primary hyperoxaluria type I, with an incidence rate of approximately 1/120,000 live births per year in Europe. It is caused by a mutation in the AGXT gene resulting in a functional defect of the liver enzyme alanine-glyoxylate aminotransferase and represents 80% of primary hyperoxaluria. Primary hyperoxaluria type II is caused by a deficiency of glyoxylate reductase/hydroxypyruvate reductase (GRHPR), and type III is caused by a deficiency of the mitochondrial enzyme HOGA1 [2,3]. Secondary hyperoxaluria occurs when dietary and intestinal absorption of oxalate or intake of oxalate precursors is increased and the intestinal microflora is changed [3]. The clinical presentation of secondary hyperoxaluria is similar to that of primary hyperoxaluria, although systemic oxalosis is less common [3]. We present a case of BM oxalosis with pancytopenia in a patient who had been on hemodialysis after bilateral nephrectomy due to recurrent nephrocalcinosis. A 51-yr-old male patient underwent a BM biopsy due to pancytopenia. He had been on hemodialysis via an arterio-venous graft since 2009 when he underwent a bilateral nephrectomy owing to recurrent renal stones and renal failure. One of his siblings had died owing to end-stage renal disease in his or her 30s (the sex is unknown). The patient had no history of a high-oxalate diet or gastrointestinal symptoms. His complete blood count revealed a Hb level of 5.7 g/dL, white blood cell count of 1.2×109/L (absolute neutrophil count 0.81), and platelet count of 98×109/L. Anemia persisted for five years despite treatment with erythropoietin, and leukopenia and thrombocytopenia also developed. Radiography revealed diffuse sclerotic changes and osteolytic lesions in multiple sites that resulted in a spontaneous fracture in his elbow. Endocrinologically, subclinical hypothyroidism was present with an increased thyroid-stimulating hormone level of 5.344 mIU/L (reference range 0.55-4.78 mIU/L), and a near-normal free thyroxine level of 8.1 ng/L (reference range 8.9-17.8 ng/L). Laboratory data showed the following: blood urea nitrogen, 0.36 g/L, creatinine, 43 mg/L, and erythropoietin 33.2 IU/L (reference rage 4.3-29 IU/L). Tear drop cells and left-shifted neutrophils were observed on a peripheral blood smear. BM aspirates were hemodiluted and showed a few multinucleated giant cells. Extensive oxalate crystals depositions surrounded by macrophages and granulomatous formations were revealed on BM biopsy. The crystals were birefringent under polarized microscopy (Fig. 1). The patient demonstrated systemic oxalosis involving the bone, possibly thyroid, and BM, with no evidence of involvement in the retina, arteries, peripheral nervous system, myocardium, or skin. Fig. 1 (A) Pancytopenia showing tear drop cells indicated by the arrow (peripheral blood smear, Wright stain, ×1,000). (B) Bone marrow biopsy shows oxalate crystals surrounded by granuloma (Hematoxylin & Eosin stain, ×200)