Serotyping and Antimicrobial Susceptibility of Salmonella Isolated in Korea in 2015 / 대한임상미생물학회지

BACKGROUND: Salmonella is an important pathogen that causes gastroenteritis and sepsis in humans. Recently, changes in serotype prevalence and an increase in antimicrobial resistance have been reported. This study investigated the distribution of Salmonella serotypes and determined the antimicrobial susceptibility of various strains. METHODS: We collected 113 Salmonella isolates other than Salmonella serotype Typhi from 18 university hospitals in 2015. The serotypes were identified by Salmonella antisera O and H according to the Kauffman White scheme. Antimicrobial susceptibility tests for 12 antibiotics were performed using the disk diffusion method or E-test. RESULTS: We identified 22 serotypes. Serotype group B (44.2%) was the most common, followed by groups C (34.5%) and D (21.2%). Salmonella I 4,[5],12:i:- (23.0%), S. Enteritidis (16.8%), and S. Typhimurium (12.4%) were the most common species. Resistance rates for ampicillin, chloramphenicol, ceftriaxone, and trimethoprim/sulfamethoxazole were 46.9%, 18.5%, 8.8%, and 5.3%, respectively. The intermediate resistance rate to ciprofloxacin was 29.2%. Six isolates were extended-spectrum β-lactamase (ESBL) producers, including 5 bla(CTX-M-15) and 1 bla(CTX-M-55). CONCLUSION: There have been changes in the serotype prevalence and antimicrobial resistance of Salmonella in Korea, with a high prevalence of CTX-M 15-positive strains. Continuous monitoring of Salmonella serotypes and antimicrobial resistance is warranted.

Changes in Antimicrobial Susceptibility Pattern of Blood Isolates at a University Hospital in the Kyungnam area during 2005–2014 / 고신대학교의과대학학술지

OBJECTIVES: Blood culture is a one of the most important procedure for diagnosis and treatment of infectious disease, but distribution of pathogenic species and the antimicrobial susceptibility can be vary from pathogen, individual trait, regional or environmental features. In this study, we investigated the changes in frequency of occurrence and antimicrobial susceptibility pattern of blood isolates from 2005 to 2014. METHODS: Data of blood isolates from Kosin Gospel Hospital during 2005 to 2014 were analyzed retrospectively. Blood isolates were cultured for 5 days using BACTEC Plus Aerobic/F and BACTEC lytic/10 Anaerobic/F. Identification and antimicrobial susceptibility test was performed using VITEK 1 system, VITEK 2 XL, PHOENIX 100 and conventional method. RESULTS: 9,847 isolates were identified during 10 years. Among the isolates aerobic or falcutative anaerobic bacteria were isolated in 99.5% specimens, anaerobic were 0.1%, and fugi were 0.4%. Most commonly isolated bacteria were coagulase-negative Staphylococcus (CoNS) followed by Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. Candida parapsilosis were most frequently isolated among fungi. The proportion of S. aureus, A. baumannii and E. faecium were increased, while Pseudomonas aeruginosa and Streptococcus pneumoniae decreased over decennium. Imipenem resistant K. pneumoniae were identified. Vancomycin resistant E. faecium and imipenem resistant A. baumannii were increased (7.1% in 2005 to 12.3% in 2014, 0% in 2005 to 55.6% in 2014, respectively). CONCLUSIONS: Over the last 10 year, CoNS were the most frequently isolated pathogen. Imipenem resistant K. pneumoniae was emerged. Vancomycin resistant E. faecium and imipenem resistant A. baumannii increased during this period.

Association between Metformin Use and Risk of Lactic Acidosis or Elevated Lactate Concentration in Type 2 Diabetes

PURPOSE: Metformin can reduce diabetes-related complications and mortality. However, its use is limited because of potential lactic acidosis-associated adverse effects, particularly in renal impairment patients. We aimed to investigate the association of metformin use with lactic acidosis and hyperlactatemia in patients with type 2 diabetes. MATERIALS AND METHODS: This was a cross-sectional study from a tertiary university-affiliated medical center. A total of 1954 type 2 diabetes patients were recruited in 2007–2011, and stratified according to the estimated glomerular filtration rate of 60 mL/min/1.73 m2. Lactic acidosis was defined as plasma lactate levels >5 mmol/L and arterial pH <7.35. RESULTS: Metformin was used in 61.4% of the patients with type 2 diabetes mellitus. Plasma lactate levels were not different in the patients with and without metformin use. There was no difference in prevalence of hyperlactatemia and lactic acidosis between the patients with and without metformin use (18.9% vs. 18.7%, p=0.905 for hyperlactatemia and 2.8% vs. 3.3%, p=0.544 for lactic acidosis). Similar results were observed in the patients with estimated glomerular filtration rate <60 mL/min/1.73 m². Most patients with lactic acidosis had at least one condition related to hypoxia or poor tissue perfusion. Multiple regression analysis indicated no association between metformin use and lactic acidosis, whereas tissue hypoxia was an independent risk factor for lactic acidosis [odds ratio 4.603 (95% confidence interval, 1.327–15.965)]. CONCLUSION: Metformin use was not associated with hyperlactatemia or lactic acidosis in patients with type 2 diabetes.

A Case of Therapy-Related Acute Leukemia With Mixed Phenotype With BCR-ABL1 After Treatment of Diffuse Large B-Cell Lymphoma

No abstract available.

Falsely Elevated Tacrolimus Concentrations Using Chemiluminescence Microparticle Immunoassay in Kidney Transplant Patient / 대한이식학회지

Tacrolimus is one of the effective immunosuppressive drugs used after an organ transplant procedure. However, due to its narrow therapeutic range, its usefulness in preventing transplant rejection and minimizing nephrotoxicity is dependent on the monitoring of whole blood trough levels of tacrolimus. A 49-year-old kidney transplant recipient presenting with cough and general weakness was admitted to the hospital. Due to the patient's deeply compromised clinical condition, an immunosuppressive therapy was discontinued. Tacrolimus concentrations in the patient's whole blood samples were measured, using an automated chemiluminescent microparticle immunoassay (CMIA) instrument. Interference was suspected because tacrolimus concentrations after the discontinuation of tacrolimus dose were 20.9 and 18.2 ng/mL at day 2 and 3, respectively. Tacrolimus concentrations were 11.1 and 12.6 ng/mL, respectively, when re-tested using an antibody-conjugated magnetic immunoassay (ACMIA). We evaluated the relationship between the CMIA and ACMIA results, and calculated the expected values from the regression equation. Residuals were –8.4 and –4 ng/mL, respectively. There have been several cases with false detection of elevated tacrolimus concentrations using ACMIA; however, such falsely detected elevations using CMIA have rarely been reported. When unexpectedly high concentrations of tacrolimus are detected by CMIA in transplant patients, an immediate re-test using another technique might be necessary to rule out falsely elevated results.

Identification of Acinetobacter Species Using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

BACKGROUND: Acinetobacter baumannii has a greater clinical impact and exhibits higher antimicrobial resistance rates than the non-baumannii Acinetobacter species. Therefore, the correct identification of Acinetobacter species is clinically important. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has recently become the method of choice for identifying bacterial species. The purpose of this study was to evaluate the ability of MALDI-TOF MS (Bruker Daltonics GmbH, Germany) in combination with an improved database to identify various Acinetobacter species. METHODS: A total of 729 Acinetobacter clinical isolates were investigated, including 447 A. baumannii, 146 A. nosocomialis, 78 A. pittii, 18 A. ursingii, 9 A. bereziniae, 9 A. soli, 4 A. johnsonii, 4 A. radioresistens, 3 A. gyllenbergii, 3 A. haemolyticus, 2 A. lwoffii, 2 A. junii, 2 A. venetianus, and 2 A. genomospecies 14TU. After 212 isolates were tested with the default Bruker database, the profiles of 63 additional Acinetobacter strains were added to the default database, and 517 isolates from 32 hospitals were assayed for validation. All strains in this study were confirmed by rpoB sequencing. RESULTS: The addition of the 63 Acinetobacter strains' profiles to the default Bruker database increased the overall concordance rate between MALDI-TOF MS and rpoB sequencing from 69.8% (148/212) to 100.0% (517/517). Moreover, after library modification, all previously mismatched 64 Acinetobacter strains were correctly identified. CONCLUSIONS: MALDI-TOF MS enables the prompt and accurate identification of clinically significant Acinetobacter species when used with the improved database.

Detection of Carbapenemases in Clinical Enterobacteriaceae Isolates Using the VITEK AST-N202 Card

BACKGROUND: The rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) in clinical microbiology laboratories is essential for the treatment and control of infections caused by these microorganisms. This study was performed to evaluate the ability of the VITEK AST-N202 card to detect CPE isolates. MATERIALS AND METHODS: A total of 43 (Klebsiella pneumoniae, n = 37; Escherichia coli, n = 3; and Enterobacter cloacae, n = 3) CPE isolates and 79 carbapenemase-non-producing Enterobacteriaceae (CNE) isolates were included in this study. The CPE isolates harbored KPC-2 (n = 11), KPC-3 (n = 20), GES-5 (n = 5), VIM-2 (n = 2), IMP-1 (n = 1), NDM-1 (n = 2), or OXA-232 (n = 2). Of the 79 CNE isolates, eight K. pneumoniae isolates were resistant to ertapenem, imipenem, and meropenem, while the remaining 71 isolates were susceptible to the carbapenems. Antimicrobial susceptibilities were tested using the VITEK AST-N202 card, and the results were interpreted as positive when the isolates showed resistant or intermediate results. Modified-Hodge tests (MHTs) were performed using ertapenem or meropenem disks for the screening of carbapenemase production. Polymerase chain reaction (PCR) and direct sequencing were used to identify beta-lactamase genes. RESULTS: Sensitivity of MHT with ertapenem and meropenem disks for the detection of carbapenemase was 81.4% (35/43) and 81.4% (35/43), respectively, and a combination with both antibiotic disks increased the sensitivity to 88.4% (38/43). Specificity of the MHT was 100% (79/79) for the CNE isolates. Sensitivity of ertapenem, imipenem, and meropenem as assessed by the VITEK AST-N202 card was 100% (43/43), 93% (40/43), and 95.3% (41/43), respectively. Specificity (89.8%, 71/79) of the test with each carbapenem was improved to 100% (71/71) when eight carbapenem-resistant CNE isolates were excluded from the testing. CONCLUSION: The VITEK AST-N202 card showed high sensitivity for the detection of carbapenemases in Enterobacteriaceae strains. PCR and sequencing experiments for the detection of carbapenemases are recommended when clinical Enterobacteriaceae isolates show non-susceptibility to carbapenems.

Peformance Evaluation of Bioporto Diagnostics' Neutrophil Gelatinase-associated Lipocalin Assay on Automated Clinical Chemistry Analyzer Hitachi 7600 / 임상검사와정도관리

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) is known to be one of the ideal biomarkers for acute kidney injury providing early information on damage to the kidney. METHODS: We evaluated the performance for precision and the reportable range of the automated NGAL Test (Bioporto Diagnostics, Denmark) assay and compared the values of these tests with widely used point of care test. The reference interval of NGAL was established in Korean adults. RESULTS: Within run percent coefficient of variation (%CV) and total precision %CV for 2 levels were all within 5%. The reportable range was found to be acceptable for the range of 57.0 - 3182.0 ng/mL (r=0.999). The method comparison was made between Biosite's assay and Bioporto Diagnostics' (Passing and Bablok fit, y=1.94x - 5.29; x, Biosite; y, Bioporto; n=31; y range, 250 to 1,308 ng/mL; r2=0.959). The correlation was linear within the limit of 1,500 ng/mL, but not beyond this limit. The 2.5 and 97.5 percentile of the reference range for the samples were 43.2 ng/mL and 124.8 ng/mL, respectively. CONCLUSIONS: Since NGAL Test can be used in automated chemical analyzer, it can not only reduce the man power and time consumed in but also displayed excellent precision and linearity.

Effect of the Least Incompatible Blood Transfusion in Patients with Panagglutination (Least Incompatible Blood Transfusion) / 대한수혈학회지

BACKGROUND: In patients who had serum autoantibody that reacted with all screening red blood cells (panagglutination), waiting for compatible blood is likely to delay a needed transfusion. In some cases of severely diminished hemoglobin counts, the least incompatible blood may be transfused. However, the least incompatible transfusion therapy is challenged by the presence of unexpected antibody in patient's serum, which may cause a transfusion reaction. The aim of this study was to evaluate the effect of the least incompatible transfusion on clinical outcomes in patients with panagglutination. METHODS: We conducted a retrospective study of 49 patients with panagglutination on an unexpected antibody screening test between January 2006 and July 2010. In 36 patients having the least incompatible blood transfusion, changes in hemoglobin and lactate dehydrogenase (LD) values before and after transfusion were analyzed. One year mortality after initial need for transfusion was documented. RESULTS: In all 36 patients who underwent transfusion, hemoglobin values showed an increase of 1.2 (0.0~3.0) g/dL per unit without occurrence of acute transfusion reactions indicated by an increase in the LD level. The least incompatible transfusion did not show an association with increased all-cause mortality. CONCLUSION: As an alternative to the time consuming process of alloantibody detection, patients with severe anemia can be effectively transfused with "least incompatible units" in an emergency clinical setting without experiencing acute transfusion reactions.

Evaluation of ACCU-CHEK(R) Inform II Blood Glucose Meter and ACCU-CHEK(R) Performa Strip / 임상검사와정도관리

BACKGROUND: Self-monitoring of blood glucose levels is recommended for all diabetic patients who receive insulin treatment, because such monitoring of glucose levels may aid in achieving better control in type II diabetes. Further, the use of point-of-care (POC) blood glucose testing in hospitals has increased substantially. In the present study, we validated the performance of ACCU-CHEK(R) Inform II Blood Glucose Meter and ACCU-CHEK(R) Performa Strip (Roche Diagnostics, Germany). METHODS: We evaluated the precision, accuracy, and maltose interference of the ACCU-CHEK(R) Inform II Blood Glucose Meter and ACCU-CHEK(R) Performa Strip. Further, precision was evaluated using dedicated quality control (QC) and Bio-Rad Whole Blood (WB) QC materials (Meter Trax(TM) Control; Bio-Rad, USA). Forty samples were used to compare the results obtained using the ACCU-CHEK(R) Inform II Blood Glucose Meter and ACCU-CHEK(R) Performa Strip with those obtained using the clinical chemistry analyzer Hitachi 7600 (Hitachi, Japan). Maltose interference was assessed at 2 glucose concentration levels at 3 maltose concentration levels. RESULTS: For each concentration level of control materials, within-run coefficient of variation (CV) and total CV obtained were less than 5%. Good correlation was obtained using the Hitachi 7600 (y = 1.02x - 0.18; r 2 = 0.996; N = 40). Effects of maltose interference were less than 10%. CONCLUSIONS: Thus, the ACCU-CHEK(R) systems show good precision and correlation with the routine clinical chemistry analyzer and allow only minimal effects of maltose interference.

Evaluation of an Automated Instrument, PREVI Isola(R) for Inoculation of Body Fluids and Urine Samples onto Agar Plates

BACKGROUND: In most clinical microbiology laboratories, inoculation of specimens on plates is performed manually and is a time-consuming process. The efficiency of this process can be improved by using an automated instrument. Currently, several automated instruments have been introduced for inoculation of samples. In this study, we have evaluated an automated instrument, PREVI Isola(R) (Biomerieux, France), used for inoculation of body fluids and urine specimens. METHODS: Both manual and automated instrument methods were used to inoculate 74 body fluid and 204 urine samples. Precision was evaluated by testing 3 types of urine samples (A, 6x10(3) colony-forming units (CFU)/mL; B, 3x10(4) CFU/mL; and C, >10(6) CFU/mL) in replicates of 20. Results of the 2 methods were compared by counting the isolated colonies on agar plates after incubation. The time required for both methods was also compared. RESULTS: The coefficient of variation (CV) of samples A, B, and C examined using the automated instrument method was 176.1%, 18.1%, and 12.6%, respectively. The sensitivity and specificity of testing body fluid samples were 77% and 100%, respectively, and those of urine samples were 87% each. The time required for testing 15 body fluid specimens and that for inoculation of each specimen was 9.7 min shorter using PREVI Isola(R) than using the manual method. CONCLUSIONS: The results of body fluid and urine culture by inoculation using the automated instrument, PREVI Isola(R), showed relative good agreement with those obtained using the manual method. The use of PREVI Isola(R) would be expected to reduce the time and labor involved in inoculating various kinds of specimens.

Evaluation of the i-Smart 30 Point-of-Care Analyzer for Use in Clinical Laboratory Settings / 임상검사와정도관리

BACKGROUND: The i-Smart 30 point-of-care (POC) analyzer (i-SENS, Korea) is a compact and portable system used for the analysis of electrolytes (sodium, potassium, chloride) and hematocrit in whole blood samples. In this study, we evaluated the analytical performance of the i-Smart 30 analyzer. METHODS: Precision and sample-related percent carry-over were determined using the quality control materials. Comparison study was performed with the Stat Profile Critical Care Xpress (STP CCX; Nova Biomedical, USA) analyzer using venous whole blood samples. RESULTS: In the precision study, imprecision studies demonstrated within-run and total-run coefficients of variation within 0.5-3.9% and 0.7-4.4%, respectively, for all analytes. A good correlation was found between the i-Smart 30 analyzer and the STP CCX analyzer, except for chloride that showed high intercept. In the study of carry-over, sample-related carry-over for Na+, K+, Cl- and Hct were demonstrated as 0.84%, 0%, 0.86% and 1.56%, respectively. CONCLUSIONS: We conclude that the i-Smart 30 analyzer is suitable for routine use in clinical laboratories, especially where rapid test results are required such as emergency departments, intensive care units, and dialysis units. However, for Cl-, it is necessary that a significant correlation between this analyzer and a reference method should be demonstrated.

Evaluation of HbA1c on COBAS INTEGRA 800 Closed Tube System Compared with Variant II Turbo / 임상검사와정도관리

BACKGROUND: We evaluated the HbA1c assay on COBAS INTEGRA 800 Closed Tube System (Roche Diagnostics, USA). METHODS: Precision was determined following Clinical and Laboratory Standards Institute (CLSI) EP5-A2 using the Lyphochek Diabetes Control (Bio-Rad Laboratories, Canada). Two levels of QC materials were assayed in duplicates at two separate times per day for 20 days. The within-run, between-run and between-day precisions were evaluated. We compared the HbA1c of COBAS INTEGRA 800 Closed tube system using Tina quant Hemoglobin A1c Gen.2 (Roche Diagnostics, Germany) reagent with Variant II Turbo (Bio-Rad Laboratories, USA). Bias was determined following CLSI EP9-A2. RESULT: The HbA1c assay on COBAS INTEGRA 800 Closed Tube System showed excellent precision performance: at a level of 5.9%, total, between run, and between day CVs were 1.8%, 0.5%, and 1.6%, respectively. At a level of 9.6%, total, between run, and between day CVs were 1.4%, 0.3%, and 1.1%, respectively. The assay correlated well with the Variant II Turbo (y=0.9x+0.53, r2=0.9857). Mean bias against Variant II Turbo was -0.2%. Compared with Variant II Turbo, the estimate of the predicted bias at a given medical decision level (HbA1c at 6% and 9%) was -0.1% and -0.31%, respectively. CONCLUSIONS: The COBAS INTEGRA 800 Closed Tube System HbA1C assay was precise and equivalent to Variant II Turbo.

Annual Report on External Quality Assessment in Therapeutic Drug Monitoring and Drug of Abuse in Korea (2009) / 임상검사와정도관리

We performed two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Laboratory (KAQACL) in 2009. The number of participating laboratories were 110, which is similar with that of previous 3 years. Average response rates were 97.8% in both trials, similar to those of previous years. Two kinds of control materials were requested to be tested in each trial so that each institution could find the possible systematic errors. The average drug item responded was 6.2 per institution, which was decreased slightly from 6.5 in recent 5 years. The most common test items were valproic acid, digoxin, carbamazepine, phenytoin, and theophylline which were peformed in more than 63.8% of participating laboratories, followed by phenobarbital, cyclosporine, tacrolimus, vancomycin, lithium, methotrexate, amikacin, gentamicin, acetaminophen, tobramycin, salicylate, free phenytoin, amitryptyline, ethosuximide, and primidone. The widely used TDM analyzers were Abbott AxSym (26.9%), followed by Abbott TDx/TDxFLx (24.8%), Roche Cobas Integra (15.1%), Siemens Diagnostics Viva-E (5.5%), Roche cobas c501 (5.1%), Siemens Diagnostics Dimension (3.4%), and many other analyzers. The inter-laboratory coefficients of variations showed similar tendency comparing with those of the previous years. The number of participating laboratories for drug of abuse (DOA) tests were 19, which was slightly increased compared to that of the previous year. Average DOA items were 3.8~4.2. We found the good performance of participating laboratories for DOA. In conclusion, the TDM and DOA external quality assessment of 2009 showed similar performance comparing with that of the recent 3 years.

Annual Report on 2008 External Quality Assessment in Therapeutic Drug Monitoring and Drug of Abuse in Korea (2008) / 임상검사와정도관리

Two trials of external quality assessment for Therapeutic Drug Monitoring (TDM) subcommittee of Korean Association of Quality Assurance for Clinical Laboratory (KAQACL) were performed in 2008. The number of participating laboratories were 114, which is similar with that of the previous year. Average response rates were 97.8% in both trials slightly lower than that of the previous year. Two kinds of control materials were requested to be tested in each trial so that each laboratory could know the possible systematic error. The average drug item was 6.3 per laboratory, which was decreased slightly from 6.8 in recent 5 years, and the maximum was 18 items. The most common test items were valproic acid, digoxin, carbamazepine, theophylline, phenytoin, and phenobarbital which were peformed in more than 52.1% of participating laboratories, followed by cyclosporine, vancomycin, tacrolimus, lithium, methotrexate, amikacin, tobramycin, gentamycin, acetaminophen, salicylate, free phenytoin, primidone, and amitryptyline. The widely used TDM analyzers were Abbott TDx/TDxFLx (35.3%), followed by Abbott AxSym (26.5%) and Roche Cobas Integra (17.3%), Abbott IMx (3.3%), and Siemens Viva E (3.0%). The inter-laboratory coefficients of variations showed similar tendency comparing with those of the previous years. The number of participating laboratories for drug of abuse tests were 17, which is similar to that of the previous year. Average drug item were 3.7 for the 1st trial. We found the relatively good performance as we got the correct answers for all laboratories except 2 laboratories. In conclusion, the TDM external quality assessment of 2008 showed grossly similar pattern comparing with that of previous year.