Comparative Analysis of Clinical Samples Showing Weak Serum Reaction on AutoVue System Causing ABO Blood Typing Discrepancies

BACKGROUND: ABO blood typing in pre-transfusion testing is a major component of the high workload in blood banks that therefore requires automation. We often experienced discrepant results from an automated system, especially weak serum reactions. We evaluated the discrepant results by the reference manual method to confirm ABO blood typing. METHODS: In total, 13,113 blood samples were tested with the AutoVue system; all samples were run in parallel with the reference manual method according to the laboratory protocol. RESULTS: The AutoVue system confirmed ABO blood typing of 12,816 samples (97.7%), and these results were concordant with those of the manual method. The remaining 297 samples (2.3%) showed discrepant results in the AutoVue system and were confirmed by the manual method. The discrepant results involved weak serum reactions (<2+ reaction grade), extra serum reactions, samples from patients who had received stem cell transplants, ABO subgroups, and specific system error messages. Among the 98 samples showing ≤1+ reaction grade in the AutoVue system, 70 samples (71.4%) showed a normal serum reaction (≥2+ reaction grade) with the manual method, and 28 samples (28.6%) showed weak serum reaction in both methods. CONCLUSIONS: ABO blood tying of 97.7% samples could be confirmed by the AutoVue system and a small proportion (2.3%) needed to be re-evaluated by the manual method. Samples with a 2+ reaction grade in serum typing do not need to be evaluated manually, while those with ≤1+ reaction grade do.

Mutational Analysis of SH2B3 in Korean Patients With BCR-ABL1 Negative Myeloproliferative Neoplasm

No abstract available.

Distribution and Antimicrobial Resistance of Streptococcus pneumoniae at Four University Hospitals in Busan and Gyeongnam / 대한임상미생물학회지

BACKGROUND: Streptococcus pneumoniae is the most common human pathogen causing community-acquired pneumonia. There is little information on the recent antimicrobial susceptibility patterns of S. pneumoniae in Busan and Gyeongnam of Korea. The aim of this study was to investigate the distribution and antimicrobial resistance of S. pneumoniae at 4 university hospitals in Busan and Gyeongnam. METHODS: We collected and analyzed the antimicrobial susceptibility results of 850 S. pneumoniae strains isolated from regional 4 university hospitals during the last 2 years from July 2013 through June 2015. RESULTS: Among 850 S. pneumoniae strains, 635 strains were isolated from respiratory specimens, followed by blood (N=121), CSF (N=13), and others (N=81). Antimicrobial susceptibility rates to penicillin, cefotaxime and ceftriaxone were 79.4%, 76.6% and 83.6%, respectively. The resistant rates to erythromycin and clindamycin were 80.9% and 68.2%, respectively. The resistant rates to levofloxacin were 9.2%. There were some differences in resistant rates by age groups, years, and specimen types. CONCLUSION: We found the changes of antimicrobial resistance of S. pneumoniae during the last 2 years. It is necessary to monitor the antimicrobial susceptibility of S. pneumoniae regularly for empirical therapy and for early detection of the changes of resistance.

Clinical Relevance of High-Resolution Single Nucleotide Polymorphism Array in Patients with Relapsed Acute Lymphoblastic Leukemia with Normal Karyotype: A Report of Three Cases

We report three patients with normal karyotype (NK) ALL, who showed genetic aberrations as determined by high-resolution single nucleotide polymorphism array (SNP-A) analysis at both diagnosis and relapse. We evaluated the clinical relevance of the SNP-A assay for the detection of subtle changes in the size of affected genetic lesions at relapse as well as the prognostic value of the assay. In our patients, application of the SNP-A assay enabled sensitive detection of cryptic changes affecting clinically important genes in NK ALL. Therefore, this assay seems to be more advantageous compared to other conventional methods such as FISH assay, HemaVision (DNA Technology, Denmark), and conventional karyotyping for the detection of an "unstable genotype" at relapse, which may be associated with microscopic clonal evolution and poor prognosis. Further comprehensive studies are required to confirm the issues presented by our case patients in this report.

Incidence, Clinical Features, and Prognostic Impact of CALR Exon 9 Mutations in Essential Thrombocythemia and Primary Myelofibrosis: An Experience of a Single Tertiary Hospital in Korea

We evaluated the incidence, clinical characteristics, and prognostic impact of calreticulin (CALR) mutations in essential thrombocythemia (ET) and primary myelofibrosis (PMF) patients. In all, 48 ET and 14 PMF patients were enrolled, and the presence of CALR mutations was analyzed by direct sequencing. Patients were classified into three subgroups according to Janus kinase 2 (JAK2) V617F and CALR mutation status, and their clinical features and prognosis were compared. CALR mutations were detected in 15 (24.2%) patients, and the incidence increased to 50.0% in 30 JAK2 V617F mutation-negative cases. These included 11 patients with three known mutations (c.1092_1143del [seven cases], c.1154_1155insTTGTC [three cases], and c.1102_1135del [one case]) and 4 patients with novel mutations. ET patients carrying CALR mutation were younger, had lower white blood cell counts, and experienced less thrombosis during follow-up than those carrying JAK2 V617F mutation, while both patient groups showed similar clinical features and prognosis. In ET patients without JAK2 V617F mutation, CALR mutation did not significantly affect clinical manifestation and prognosis. In conclusion, CALR mutation analysis could be a useful diagnostic tool for ET and PMF in 50% of the cases without JAK2 V617F mutations. The prognostic impact of CALR mutations needs further investigation.

Evaluation of Propidium Monoazide Real-Time PCR for Early Detection of Viable Mycobacterium tuberculosis in Clinical Respiratory Specimens

BACKGROUND: Conventional acid-fast bacilli (AFB) staining cannot differentiate viable from dead cells. Propidium monoazide (PMA) is a photoreactive DNA-binding dye that inhibits PCR amplification by DNA modification. We evaluated whether PMA real-time PCR is suitable for the early detection of viable Mycobacterium tuberculosis (MTB) in clinical respiratory specimens. METHODS: A total of 15 diluted suspensions from 5 clinical MTB isolates were quadruplicated and subjected to PMA treatment and/or heat inactivation. Eighty-three AFB-positive sputum samples were also tested to compare the DeltaC(T) values (C(T) value in PMA-treated sputum samples-C(T) value in non-PMA-treated sputum samples) between culture-positive and culture-negative specimens. Real-time PCR was performed using Anyplex MTB/NTM Real-Time Detection (Seegene, Korea), and the C(T) value changes after PMA treatment were compared between culture-positive and culture-negative groups. RESULTS: In MTB suspensions, the increase in the C(T) value after PMA treatment was significant in dead cells (P=0.0001) but not in live cells (P=0.1070). In 14 culture-negative sputum samples, the median DeltaC(T) value was 5.3 (95% confidence interval [CI], 4.1-8.2; P<0.0001), whereas that in 69 culture-positive sputum samples was 1.1 (95% CI, 0.7-2.0). In the ROC curve analysis, the cutoff DeltaC(T) value for maximum sensitivity (89.9%) and specificity (85.7%) for differentiating dead from live cells was 3.4. CONCLUSIONS: PMA real-time PCR is a useful approach for differentiating dead from live bacilli in AFB smear-positive sputum samples.

Prevalence of Plasmid-mediated Quinolone Resistance and Its Association with Extended-spectrum Beta-lactamase and AmpC Beta-lactamase in Enterobacteriaceae / 대한진단검사의학회지

BACKGROUND: We investigated the prevalence of plasmid-mediated quinolone resistance and its association with extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase in Enterobacteriaceae. METHODS: A total of 347 non-duplicated isolates of Enterobacteriaceae were collected between August and October 2006 from 2 hospitals. Qnr determinant screening was conducted using PCR amplification, and all positive results were confirmed by direct sequencing. Qnr-positive strains were determined on the basis of the presence of ESBL and AmpC beta-lactamase genes. RESULTS: The qnr gene was detected in 47 of 347 clinical Enterobacteriaceae isolates. Among the 47 qnr-positive strains, Klebsiella pneumoniae (N=29) was the most common, followed by Escherichia coli (N=6), Enterobacter cloacae (N=6), Citrobacter freundii (N=5), and Enterobacter aerogenes (N=1). These isolates were identified as qnrA1 (N=6), 8 qnrB subtypes (N=40), and qnrS1 (N=1). At least 1 ESBL was detected in 38 of the 47 qnr-positive strains. Qnr-positive strains also showed high positive rates of ESBL or AmpC beta-lactamase, such as TEM, SHV, CTX-M, and DHA. DHA-1 was detected in 23 of 47 qnr-positive strains, and this was co-produced with 1 qnrA1 and 22 qnrB4. Strains harboring MIR-1T and CMY were also detected among the qnr-positive strains. Antimicrobial-resistance rates of qnr-positive strains to ciprofloxacin, levofloxacin, norfloxacin, nalidixic acid, and moxifloxacin were 51.1%, 46.8%, 46.8%, 74.5%, and 53.2%, respectively. CONCLUSIONS: The qnr genes were highly prevalent in Enterobacteriaceae, primarily the qnrB subtypes. They were closely associated with EBSL and AmpC beta-lactamase.

Evaluation of a Colorimetric Antifungal Susceptibility Test by 2,3-Diphenyl-5-Thienyl-(2)-Tetrazolium Chloride for Fluconazole in Candida Species Isolated from Clinical Specimens / 대한임상미생물학회지

BACKGROUND: The aims of this study were to evaluate the colorimetric antifungal susceptibility test to fluconazole using 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC) for various Candida species isolated from clinical specimens and to compare the results with those of the CLSI M27-A2 standard method. METHODS: The fluconazole MICs for 204 clinical Candida isolates consisting of 100 C. albicans, 45 C. glabrata, 28 C. tropicalis, 22 C. parapsilosis, and 9 other Candida species were determined by the CLSI and STC colorimetric methods. RESULTS: All 204 Candida strains were grown on the growth control wells of CLSI standard plates, but 26 Candida strains (6 C. albicans and 20 C. tropicalis) were not grown on those containing STC. Therefore, those 26 Candida strains were excluded from the comparison of MICs in this report. Overall, the STC visual and spectrophotometric readings of fluconazole MICs showed 96.1% (N=171) and 89.9% (N=160) accordance with those obtained by the CLSI standard method within 2 dilutions, respectively. The STC visual reading of C. albicans showed 76.6, 92.6, and 95.8% accordance with the CLSI standard method within 1, 2, and 3 dilutions, respectively. The agreement between the two endpoint determinations of the STC colorimetric method (visual and spectrophotometric readings) was excellent, with 170 of the 178 MICs within 2 dilutions. CONCLUSION: The STC colorimetric method to determine the MIC for Candida species except C. tropicalis showed high levels of agreement with CLSI method. And also, it is useful with objective and easy interpretation.

Serum Hepatitis B Virus DNA Quantitative Analysis Using Polymerase Chain Reaction in Patients with Chronic Hepatits B Virus Infection / 대한진단검사의학회지

BACKGROUND: The treatment using more potent antiviral agents for the hepatitis B virus (HBV) infection has been performed widely and a highly sensitive quantification method using the polymerase chain reaction (PCR) that measures the HBV viral genome in sera is available. In this study, the HBV DNA level in each disease status including the inactive HBsAg carrier is evaluated. METHODS: Samples were obtained from 227 patients with chronic HBV infection that were grouped into chronic hepatitis (111), liver cirrhosis (71), and inactive HBsAg carrier (45). Quantification of HBV DNA was performed using the automated Cobas Amplicor HBV monitor test(TM). RESULTS: Among the chronic hepatitis B group (9.76 x 10(7) copies/mL), the liver cirrhosis group (4.88x10(5) copies/mL), and the inactive carrier group (3.18 x10(3)copies/mL), the medians of serum HBV DNA levels were significantly different from one group to another (P=0.000). Also, the median of HBV DNA levels in the patients with positive HBeAg (1.77 x10(8) copies/mL) was significantly higher than that of negative HBeAg (2.71 x 10(4) copies/mL) (P=0.000). In the patients with negative HBeAg, HBV DNA level in the inactive carrier group (Median 3.18 x 10(3) copies/mL) was significantly lower than that of the chronic hepatitis group (Median 2.2 x 10(5) copies/mL (P=0.000). CONCLUSIONS: The serum HBV DNA level varied among different disease groups, particularly according to HBeAg positivity. 40% of the chronic hepatitis group with negative HBeAg had HBV DNA levels below 10(5) copies/mL. Therefore, the quantitative analysis of HBV DNA using this sensitive and automated PCR method would be useful in detecting viral proliferation.

Evaluation of Diagnostic Utility of Intradermal Test for the Diagnosis of Clonorchis sinensis Infestation / 대한임상미생물학회지

BACKGROUND: The intradermal test for the screening of Clonorchis sinensis is difficult to interpret because the sensitivity and persistence rates of reactions after treatment are not well known. METHODS: Stool egg examinations and intradermal tests for C. sinensis and Paragonimus westermani were performed for 1,207 persons who lived in endemic areas of C. sinensis infestation, and epidemiologic data were also surveyed. RESULTS: The infestation rate of C. sinensis was 12% (male 14%, female 9%). It was higher in Southeastern area of Gyungsang Namdo Province and Ulsan (22%) than in Busan (10%), whereas much higher in Gangseo/Buk/Sasang (28%) than in other areas of Busan. The performance of C. sinensis intradermal test was as belows; sensitivity 45%, specificity 80.8%, positive predictive value 24%, negative predictive value 92%, and diagnostic efficiency 77%. Positive C. sinensis intradermal reaction persisted for longer than 40 years after treatment of C. sinensis infestation in at least 30% of patients. C. sinensis intradermal reaction turned to be positive within 4 months after intake of raw fish in more than half the patients. CONCLUSION: The infestation rate of C. sinensis was still very high in inhabitants around Nakdong River, an endemic area. We think that C. sinensis intradermal test is inadequate to diagnose current clonorchiasis.

Early Screening of Oxacillin-Resistant Staphylococcus aureus and Staphylococcus epidermidis from Blood Culture

The timely detection of blood-borne pathogens is one of the most important functions of the microbiology laboratory. Recently, methicillin-resistant staphylococci have become the most important pathogens seen by the laboratory. The purpose of this study was to evaluate Staphy agar, a novel screening medium, for the detection methicillin-resistant Staphylococcus aureus, S. epidermidis, or other coagulase-negative staphylococci (CNS) from positive blood cultures showing Gram-positive cocci in clusters. Eighty-six blood cultures that yielded Gram-positive cocci in clusters were included in this study. The organisms were finally identified by the Vitek system, and oxacillin resistance was confirmed by polymerase chain reaction (PCR)-based mecA gene detection. The identification and oxacillin resistance of all S. aureus strains showed complete agreement with the Vitek and PCR results. The presumptive detection of S. epidermidis and other CNS were consistent with the Vitek system in 94.7%, and the screening of oxacillin resistance was consistent with the result of PCR in 92.1% of 38 strains. The Staphy agar method is reliable and rapid for differentiating Gram-positive cocci in clusters in blood and for determining their methicillin resistance.