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Methicillin-resistant Staphylococcus aureus in Nasal Surveillance Swabs at an Intensive Care Unit: An Evaluation of the LightCycler MRSA Advanced Test.

Hee Jin HUH ; Eu Suk KIM ; Seok Lae CHAE

Annals of Laboratory Medicine.2012;32(6):407-412. doi:10.3343/alm.2012.32.6.407

BACKGROUND: We compared the LightCycler MRSA advanced test (Roche Diagnostics, Germany) with enrichment culture methods to evaluate the relative diagnostic performance of the LightCycler MRSA advanced test for active surveillance in a high-prevalence setting. METHODS: A total of 342 nasal swab specimens were obtained from patients in the intensive care unit at admission and on the seventh day for follow-up. The results of LightCycler MRSA advanced test were compared to those of the enrichment culture. For discrepant results, mecA gene PCR was performed. RESULTS: For the detection of methicillin-resistant Staphylococcus aureus (MRSA), the LightCycler MRSA advanced test showed 98.5% sensitivity and 78.6% specificity and had positive and negative predictive values of 75.0% and 98.8%, respectively. A total of 46 samples had discrepant results between the LightCycler MRSA advanced test and enrichment culture. Of the 44 specimens that were positive in the LightCycler MRSA advanced test but negative by enrichment culture, mecA genes were detected in 37 specimens. In addition, of the original 44 cases, 21 patients had a history of MRSA colonization or infection within the last month; of those 21 specimens, 20 were positive for mecA gene as shown by PCR. Seven mecA-negative discrepant specimens comprised 3 methicillin-sensitive S. aureus-culture positive and only 2 patients had MRSA infections. CONCLUSIONS: Despite its low specificity and positive predictive value, the LightCycler MRSA advanced test could serve as a rapid test for patients colonized with MRSA.

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Evaluation of a Multiplex Real-time PCR Assay for the Detection of Respiratory Viruses in Clinical Specimens.

Insoo RHEEM ; Joowon PARK ; Tae Hyun KIM ; Jong Wan KIM

Annals of Laboratory Medicine.2012;32(6):399-406. doi:10.3343/alm.2012.32.6.399

BACKGROUND: In this study, we evaluated the analytical performance and clinical potential of a one-step multiplex real-time PCR assay for the simultaneous detection of 14 types of respiratory viruses using the AdvanSure RV real-time PCR Kit (LG Life Sciences, Korea). METHODS: Three hundred and twenty clinical specimens were tested with the AdvanSure RV real-time PCR Kit and conventional multiplex reverse transcription (RT)-PCR assay. The assay results were analyzed and the one-step AdvanSure RV real-time PCR Kit was compared with the conventional multiplex RT-PCR assay with respect to the sensitivity and specificity of the detection of respiratory viruses. RESULTS: The limit of detection (LOD) was 1.31 plaque-forming units (PFU)/mL for human rhinoviruses (hRVs), 4.93 PFU/mL for human coronavirus HCoV-229E/NL63, 2.67 PFU/mL for human coronavirus HCoV-OC43, 18.20 PFU/mL for parainfluenza virus 1 (PIV)-1, 24.57 PFU/mL for PIV-2, 1.73 PFU/mL for PIV-3, 1.79 PFU/mL for influenza virus group (Flu) A, 59.51 PFU/mL for FluB, 5.46 PFU/mL for human respiratory syncytial virus (hRSV)-A, 17.23 PFU/mL for hRSV-B, 9.99 PFU/mL for human adenovirus (ADVs). The cross-reactivity test for this assay against 23 types of non-respiratory viruses showed negative results for all viruses tested. The agreement between the one-step AdvanSure multiplex real-time PCR assay and the conventional multiplex RT-PCR assay was 98%. CONCLUSIONS: The one-step AdvanSure RV multiplex real-time PCR assay is a simple assay with high potential for specific, rapid and sensitive laboratory diagnosis of respiratory viruses compared to conventional multiplex RT-PCR.

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Correction of Pseudoreticulocytosis in Leukocytosis Samples Using the Sysmex XE-2100 Analyzer Depends on the Type and Number of White Blood Cells.

Ahhyun KIM ; Joonhong PARK ; Myungshin KIM ; Jihyang LIM ; Eun Jee OH ; Yonggoo KIM ; Yeon Joon PARK ; Kyungja HAN

Annals of Laboratory Medicine.2012;32(6):392-398. doi:10.3343/alm.2012.32.6.392

BACKGROUND: The reticulocyte count is a good marker of erythropoietic activity of the bone marrow. In the mid-1990s, automated flow cytometric analysis replaced microscopy for the quantification of reticulocytes. Leukocytosis cases with an erroneously high reticulocyte count and a high immature reticulocyte fraction (IRF) have been reported. In this study, we analyzed reticulocyte counts in leukocytosis samples, in an effort to identify a correction method. METHODS: The study comprised of 21 samples from 16 leukocytosis patients. Results of reticulocyte analyses obtained using a XE-2100 hematology analyzer (Sysmex, Japan) were compared with those obtained using the supravital staining technique, which is a reference method. If the samples showed erroneously high reticulocyte counts and IRF, they were reanalyzed after serial dilution with isotonic solution. RESULTS: Five samples from 4 patients showed erroneously elevated reticulocyte counts and/or IRF on the XE-2100 analyzer. They displayed abnormal reticulocyte scattergrams, with 4 of 5 cases indicated by a flag. The white blood cell (WBC) fractions overlapped with the reticulocyte regions, especially with the IRF. Diagnoses and blast counts were variable when such errors occurred; WBC counts varied from 218.19x10(9)/L to 725.14x10(9)/L. The errors were corrected by simple dilution with isotonic solution. However, the corrective WBC counts differed according to individual cases. CONCLUSIONS: When leukocytosis samples exhibit an abnormal reticulocyte scattergram with a flag, or an abnormally high IRF, we recommend the dilution of the sample with isotonic solution to a WBC count of about 100.00x10(9)/L, followed by reanalysis of the reticulocyte count and reticulocyte scattergram.

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Correlations between Janus Kinase 2 V617F Allele Burdens and Clinicohematologic Parameters in Myeloproliferative Neoplasms.

Jung Sook HA ; Yu Kyung KIM ; Soon Il JUNG ; He Ra JUNG ; In Sung CHUNG

Annals of Laboratory Medicine.2012;32(6):385-391. doi:10.3343/alm.2012.32.6.385

BACKGROUND: This study evaluated potential correlations between the allele burden of the Janus kinase 2 (JAK2) V617F mutation and clinicohematologic characteristics in patients with myeloproliferative neoplasms (MPN). METHODS: Clinical and hematologic features were reviewed for 103 MPN patients, including patients with polycythemia vera (PV, 22 patients), essential thrombocythemia (ET, 64 patients), and primary myelofibrosis (PMF, 17 patients). JAK2 V617F allele status and allele burdens were measured by allele-specific PCR and pyrosequencing, respectively. RESULTS: The JAK2 V617F mutation was detected in 95.5%, 68.8%, and 52.9% of PV, ET, and PMF patients, respectively. JAK2 V617F-positive ET patients were significantly older and exhibited higher neutrophil fractions, a higher frequency of thrombotic events, and a higher myelofibrosis rate than JAK2 V617F-negative patients (P <0.05). PV patients carried the highest mean T allele burden (66.0%+/-24.9%) compared with ET (40.5%+/-25.2%) and PMF patients (31.5%+/-37.0%) (P =0.00). No significant correlations were detected between V617F allele burden and patient age, white blood cell count, Hb, Hct, or the platelet count for PV, ET, or PMF patients. ET patients with organomegaly had a higher JAK2 V617F allele burden (53.4%+/-23.7%) than patients without organomegaly (35.6%+/-24.3%) (P =0.03). CONCLUSIONS: The JAK2 V617F mutational status and its allele burden correlate with the clinicohematologic phenotypes of ET patients, including older age, higher neutrophil count, and greater rates of organomegaly, thrombotic events, and myelofibrosis. For PV and PMF patients, larger-scale studies involving more MPN patients are needed.

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HMOX1 Gene Promoter Polymorphism is Not Associated with Coronary Artery Disease in Koreans.

Seong Woo HAN ; Wonkeun SONG ; Han Sung KIM ; Kyu Sung SHIN ; Heejung KANG ; Hyoun Chan CHO ; Chang Seok KI ; Min Jeong PARK

Annals of Laboratory Medicine.2014;34(5):337-344. doi:10.3343/alm.2014.34.5.337

BACKGROUND: The heme oxygenase-1 gene (HMOX1) promoter polymorphisms modulate its transcription in response to oxidative stress. This study screened for HMOX1 polymorphisms and investigated the association between HMOX1 polymorphisms and coronary artery disease (CAD) in the Korean population. METHODS: The study population consisted of patients with CAD with obstructive lesions (n=110), CAD with minimal or no lesions (n=40), and controls (n=107). Thirty-nine patients with CAD with obstructive lesions underwent follow-up coronary angiography after six months for the presence of restenosis. The 5'-flanking region containing (GT)n repeats of the HMOX1 gene was analyzed by PCR. RESULTS: The numbers of (GT)n repeats in the HMOX1 promoter showed a bimodal distribution. The alleles were divided into two subclasses, S25 and L25, depending on whether there were less than or equal to and more than 25 (GT)n repeats, respectively. The allele and genotype frequencies among groups were statistically not different. More subjects in the S25-carrier group had the low risk levels of high sensitivity C-reactive protein (hsCRP) for the CAD than those in the non-S25 carrier group (P=0.034). Multivariate logistic regression analysis revealed that the genotypes of (GT)n repeats were not related to CAD status. The restenosis group in the coronary angiography follow-up did not show any significant difference in HMOX1 genotype frequency. CONCLUSIONS: The HMOX1 genotypes were not found to be associated with CAD, but the short allele carrier group contained more individuals with hsCRP values reflecting low risk of cardiovascular disease in the Korean population.
5' Untranslated Regions ; Adult ; Alleles ; Asian Continental Ancestry Group/*genetics ; C-Reactive Protein/analysis ; Coronary Angiography ; Coronary Artery Disease/*genetics/pathology ; Coronary Restenosis/complications/therapy ; Dinucleotide Repeats/genetics ; Female ; Genetic Predisposition to Disease ; Genotype ; Heme Oxygenase-1/*genetics ; Humans ; Male ; Middle Aged ; Polymorphism, Genetic ; Promoter Regions, Genetic ; Republic of Korea ; Risk Factors

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Inflammatory Cytokines and Their Prognostic Ability in Cases of Major Burn Injury.

Jun HUR ; Hyeong Tae YANG ; Wook CHUN ; Jong Hyun KIM ; Seon Hee SHIN ; Hee Jung KANG ; Hyun Soo KIM

Annals of Laboratory Medicine.2015;35(1):105-110. doi:10.3343/alm.2015.35.1.105

BACKGROUND: Major burn injuries induce inflammatory responses and changes in the levels of various cytokines. This study was conducted to assess early changes in the serum levels of inflammatory cytokines after burn injury, identify cytokines associated with mortality, and characterize correlations among cytokines. METHODS: Blood samples of 67 burn patients were collected on days 1 and 3 after burn injury, and the concentrations of 27 cytokines were measured using the Bio-Plex Suspension Array System (Bio-Rad Laboratories, USA). Blood samples of 25 healthy subjects were used as controls. We analyzed statistical differences in the concentrations of each cytokine between the control and patient groups, between day 1 and day 3, and between survival and nonsurvival groups. Correlations among 27 cytokines were analyzed. RESULTS: Median concentrations of granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin 1 receptor antagonist (IL-1RA), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 10 (IL-10), interleukin 15 (IL-15), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein 1beta (MIP-1beta), and vascular endothelial growth factor (VEGF) were significantly higher in burn patients than in controls. IL-1RA, IL-6, and MCP-1 levels were significantly higher in the nonsurvival group than in the survival group on day 1 after burn injury. Correlation analysis of 27 cytokines showed different relationships with one another. Stronger correlations among interferon gamma (IFN-gamma), IL-2, IL-4, IL-7, IL-12p70, and IL-17 were found. CONCLUSIONS: IL-1RA, IL-6, and MCP-1 may be used as prognostic indicators of mortality in burn patients and the increase in cytokine concentrations is induced by interactions within a complex network of cytokine-related pathways.
Adult ; Aged ; Burns/*blood/mortality/*pathology ; Case-Control Studies ; Cytokines/*blood ; Female ; Humans ; Male ; Middle Aged ; Prognosis ; Prospective Studies ; Survival Rate ; Young Adult

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Comparison of Quantitation of Cytomegalovirus DNA by Real-Time PCR in Whole Blood with the Cytomegalovirus Antigenemia Assay.

Seonhee KWON ; Bo Kyeung JUNG ; Sun Young KO ; Chang Kyu LEE ; Yunjung CHO

Annals of Laboratory Medicine.2015;35(1):99-104. doi:10.3343/alm.2015.35.1.99

BACKGROUND: Quantitation of cytomegalovirus (CMV) DNA using real-time PCR has been utilized for monitoring CMV infection. However, the CMV antigenemia assay is still the 'gold standard' assay. There are only a few studies in Korea that compared the efficacy of use of real-time PCR for quantitation of CMV DNA in whole blood with the antigenemia assay, and most of these studies have been limited to transplant recipients. METHOD: 479 whole blood samples from 79 patients, falling under different disease groups, were tested by real-time CMV DNA PCR using the Q-CMV real-time complete kit (Nanogen Advanced Diagnostic S.r.L., Italy) and CMV antigenemia assay (CINA Kit, ArgeneBiosoft, France), and the results were compared. Repeatedly tested patients were selected and their charts were reviewed for ganciclovir therapy. RESULTS: The concordance rate of the two assays was 86.4% (Cohen's kappa coefficient value=0.659). Quantitative correlation between the two assays was a moderate (r=0.5504, P<0.0001). Among 20 patients tested repeatedly with the two assays, 13 patients were transplant recipients and treated with ganciclovir. Before treatment, CMV was detected earlier by real-time CMV DNA PCR than the antigenemia assay, with a median difference of 8 days. After treatment, the antigenemia assay achieved negative results earlier than real-time CMV DNA PCR with a median difference of 10.5 days. CONCLUSIONS: Q-CMV real-time complete kit is a useful tool for early detection of CMV infection in whole blood samples in transplant recipients.
Antiviral Agents/therapeutic use ; Cytomegalovirus/*genetics ; Cytomegalovirus Infections/drug therapy/pathology/virology ; DNA, Viral/*blood/metabolism ; Ganciclovir/therapeutic use ; Humans ; *Immunoassay ; Organ Transplantation ; Phosphoproteins/genetics/immunology/*metabolism ; *Real-Time Polymerase Chain Reaction ; Viral Matrix Proteins/genetics/immunology/*metabolism ; Virology/*methods

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Antimicrobial Susceptibility of Clinical Isolates of Bacteroides fragilis Group Organisms Recovered from 2009 to 2012 in a Korean Hospital.

Jisook YIM ; Yangsoon LEE ; Myungsook KIM ; Young Hee SEO ; Wan Hee KIM ; Dongeun YONG ; Seok Hoon JEONG ; Kyungwon LEE ; Yunsop CHONG

Annals of Laboratory Medicine.2015;35(1):94-98. doi:10.3343/alm.2015.35.1.94

BACKGROUND: Periodic monitoring of antimicrobial resistance trends of clinically important anaerobic bacteria such as Bacteroides fragilis group organisms is required. We determined the antimicrobial susceptibilities of clinical isolates of B. fragilis group organisms recovered from 2009 to 2012 in a tertiary-care hospital in Korea. METHODS: A total of 180 nonduplicate clinical isolates of B. fragilis group organisms were collected in a tertiary care hospital. The species were identified by conventional methods: the ATB 32A rapid identification system (bioMerieux, France) and the Vitek MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (bioMerieux). Antimicrobial susceptibility was determined by the CLSI agar dilution method. RESULTS: Imipenem and meropenem resistance rates were 0-6% for B. fragilis group isolates. The rate of resistance to piperacillin-tazobactam was 2% for B. fragilis and 0% for other Bacteroides species, but 17% for B. thetaiotaomicron isolates. High resistance rates to piperacillin (72% and 69%), cefotetan (89% and 58%), and clindamycin (83% and 69%) were observed for B. thetaiotaomicron and other Bacteroides spp. The moxifloxacin resistance rate was 27% for other Bacteroides spp. The MIC50 and MIC90 of tigecycline were 2-4 microg/mL and 8-16 microg/mL, respectively. No isolates were resistant to chloramphenicol or metronidazole. CONCLUSIONS: Imipenem, meropenem, chloramphenicol, and metronidazole remain active against B. fragilis group isolates. Moxifloxacin and tigecycline resistance rates are 2-27% and 8-15% for B. fragilis group isolates, respectively.
Anti-Infective Agents/*pharmacology ; Bacteroides Infections/*microbiology/pathology ; Bacteroides fragilis/*drug effects/isolation & purification ; Drug Resistance, Multiple, Bacterial ; Humans ; Imipenem/pharmacology ; Inhibitory Concentration 50 ; Microbial Sensitivity Tests ; Penicillanic Acid/analogs & derivatives/pharmacology ; Piperacillin/pharmacology ; Republic of Korea ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Tertiary Care Centers ; Thienamycins/pharmacology

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Prevalence of Antibody to Toxic Shock Syndrome Toxin-1 in Burn Patients.

Ji Young PARK ; Jae Seok KIM ; Heungjeong WOO

Annals of Laboratory Medicine.2015;35(1):89-93. doi:10.3343/alm.2015.35.1.89

BACKGROUND: Burn wounds lack normal barriers that protect against pathogenic bacteria, and burn patients are easily colonized and infected by Staphylococcus aureus. Toxic shock syndrome (TSS) is a rare but fatal disease caused by S. aureus. A lack of detectable antibodies to TSS toxin-1 (TSST-1) in serum indicates susceptibility to TSS. METHODS: A total of 207 patients (169 men and 38 women; median age, 42.5 yr) admitted to a burn center in Korea were enrolled in this study. The serum antibody titer to TSST-1 was measured by sandwich ELISA. S. aureus isolates from the patients' nasal swab culture were tested for TSST-1 toxin production by PCR-based detection of the TSST-1 toxin gene. RESULTS: One hundred seventy-four (84.1%) patients showed positive results for antibody against TSST-1. All patients aged > or =61 yr (n=28) and <26 months (n=7) were positive for the anti-TSST-1 antibody. S. aureus was isolated from 70 patients (33.8%), and 58.6% of the isolates were methicillin resistant. Seventeen patients were colonized with TSST-1-producing S. aureus. The antibody positivity in these 17 carriers was 88.2%, and the positivity in the non-carriers was 83.7%. CONCLUSIONS: Most burn patients had antibody to TSST-1, and nasal colonization with TSST-1-producing S. aureus was associated with positive titers of anti-TSST-1 antibody. Additionally, patients with negative titers of anti-TSST-1 antibody might be susceptible to TSS.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antibodies, Bacterial/*blood ; Bacterial Toxins/genetics/immunology/*metabolism ; Burns/blood/*immunology/*microbiology/pathology ; Child ; Child, Preschool ; Enterotoxins/genetics/immunology/*metabolism ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Infant ; Male ; Middle Aged ; Nasal Cavity/microbiology ; Polymerase Chain Reaction ; Prevalence ; Staphylococcal Infections/epidemiology ; Staphylococcus aureus/isolation & purification/*metabolism ; Superantigens/genetics/immunology/*metabolism ; Young Adult

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Evaluation of the Impact of Automated Specimen Inoculation, Using Previ Isola, on the Quality of and Technical Time for Stool Cultures.

Alexander MISCHNIK ; Marlies TRAMPE ; Stefan ZIMMERMANN

Annals of Laboratory Medicine.2015;35(1):82-88. doi:10.3343/alm.2015.35.1.82

BACKGROUND: This study was designed as a quasi-experiment to evaluate automatic inoculation of fecal specimens, using the automated specimen inoculator Previ Isola (bioMerieux, France). METHODS: We evaluated the quality of cultures, recovery rates of enteropathogenic bacteria (Salmonella, Shigella, Campylobacter, and Yersinia species), and cost-effectiveness in terms of technical time. The Previ Isola recovery rates for the two-year period from August 2009 to July 2011 were compared with historical manual inoculation data of the previous two years (August 2007 to July 2009). The regional (Baden-Wurttemberg) and nationwide (Germany) trends of recovery rates for this four-year period were referred. RESULTS: A total of 5,884 fecal specimens were collected over the study period. Most positive cultures were for Salmonella, followed by Campylobacter. Compared with the historical data, the numbers of Campylobacter-positive specimens for a year between August and July were increased significantly, from 19 in 2007-2008 and 10 in 2008-2009 to 32 in 2009-2010 (P=0.002) and 32 in 2010-2011 (P=0.003), respectively. During the study period, the official data for our region and nationwide did not show this increase in the recovery rate of Campylobacter. For Salmonella, Shigella, and Yersinia, no significant changes were observed. Compared with manual inoculation, the mean hands-on time with Previ Isola inoculation was significantly shortened, from 37:30 min to 8:42 min per 15 fecal specimens. CONCLUSIONS: Inoculation by Previ Isola improves the quality of routine culture of fecal specimens, with better sensitivity for Campylobacter and less hands-on time.
Automation ; Bacteria/*isolation & purification ; Bacteriological Techniques/*methods/standards ; Campylobacter/isolation & purification ; Feces/*microbiology ; Humans ; Quality Control ; Salmonella/isolation & purification ; Shigella/isolation & purification ; Yersinia/isolation & purification

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