BACKGROUND: A rapid and sensitive surveillance culture has a pivotal role in infection control of methicillinresistant Staphylococcus aureus (MRSA). This study was aimed to compare the performance of MRSASelect (Bio-Rad, France) to that of mannitol salt agar containing 6 microgram/mL of oxacillin (MSA-OX) for detecting MRSA in surveillance cultures. METHOD: From May to June 2006, 86 nasal swabs and 21 sputum specimens were enrolled. All specimens were inoculated onto MRSASelect and MSA-OX, which were incubated for 2 days and 3 days, respectively, and colonies were read daily by a technologist. Pink colonies on MRSASelect and yellow colonies on MSA-OX were examined with Gram stain, Pastorex(R) Staph-plus (Bio-Rad) and mecA-PCR. After the final reading, both media were re-examined by a superviser. RESULTS: Of the 107 specimens cultured, 32 (29.9%) were positive for MRSA. Of these, 27 were detected by both media, one by MSA-OX only, and 4 by re-examination. The day-1 and day-2 sensitivities/specificities of MRSASelect were 78.1%/97.3% and 84.4%/97.3%, respectively, while those of MSA-OX were 53.1%/100% and 78.1%/92.1%, respectively. With MRSASelect, two more positives were detected at day 2, but their incubation was less than 18 hour at day 1. There were six false positive organisms detected: three Enterobacter spp., one Acinectobacter spp., and two coagulase-negative staphylococci (CNS). But, the two CNS grew on MSA-OX only. CONCLUSION: MRSASelect with 1-day incubation showed a sensitivity equivalent to and a specificity better than MSA-OX with 2-day incubation. MRSASelect should be a useful medium for MRSA surveillance when it is read after an incubation of 18-28 hours with the confirmatory Gram stain of screen-positives.
Agar ; Enterobacter ; Infection Control ; Mannitol ; Methicillin Resistance* ; Methicillin-Resistant Staphylococcus aureus* ; Oxacillin ; Sensitivity and Specificity ; Sputum ; Staphylococcus aureus

BACKGROUND: We have evaluated the analytical performance of SureStep Flexx (Johnson and Johnson, USA) which can report the plasma equivalent glucose test results and be connected to the hospital information networks, following ISO15197 analytic procedure for glucometer for the first time. METHODS: Adopting the guidelines of ISO15197, we measured the precision of ten glucometers from their repeatability and intermediate precision, and determined the accuracies of the glucometer, comparing to those of GEM Premier 4000 (Instrumentation Laboratory, USA). In addition, the guidelines of CLSI EP9-A2 and EP6-A were applied to correlate between data of glucometer and those of laboratory reference method by TBA-200FR (Toshiba Medical Systems, Japan) and to examine its linearity of glucose concentrations measured by SureStep Flexx. We used the clinical specimens and commercial control materials. RESULTS: Repeatabilities and intermediate precisions of those glucometers were 4.0-7.3%, and 4.3-6.2%, respectively. When glucose levels are under 75 mg/dL, the difference between results of those meters and the reference values were within +/-6 mg/dL. However when glucose levels are over 75 mg/dL, those differences were within +/-12.7%. These results were acceptable for the ISO15197 criteria in all glucose concentrations. The glucose concentrations showed the clinically relevant linearity in the range from 36 mg/dL to 491 mg/dL. Moreover, Error Grid Analysis showed that all glucose results were in "zone A", which means that these values were clinically accurate. CONCLUSIONS: This study showed that SureStep Flexx can provide reliable results for patients and clinicians to manage the diabetes mellitus, satisfying the ISO15197 criteria.
Blood Glucose/*analysis ; Blood Glucose Self-Monitoring/*instrumentation/methods/*standards ; Diabetes Mellitus/blood/diagnosis ; Humans ; Quality Control ; Reference Values ; Reproducibility of Results

A 42-yr-old man with hepatitis B virus associated liver cirrhosis was admitted to the emergency room because of multiple seizures, a history of chills and myalgia over the previous 2 weeks, and 3 days of melena. He was febrile with a temperature of 38.0degrees C. There were no symptoms and signs related to the genitourinary system, skin, or joints. Three sets of blood cultures were obtained and oxidase-positive, gram-negative diplococci were detected after 25.9-26.9 hr of incubation in all aerobic vials. The organism was positive for catalase and oxidase, and was identified as Neisseria gonorrhoeae, using a Vitek Neisseria-Haemophilus Identification card (bioMerieux Vitek, Inc., USA). Further, 16S rRNA sequencing of this isolate revealed a 99.9% homology with the published sequence of N. gonorrhoeae strain NCTC 83785 (GenBank Accession No. NR_026079.1). Acute bleeding by variceal rupture seems to be a likely route of introduction of N. gonorrhoeae from the mucosa into the blood. To the best of our knowledge, this is the first case of gonococcal bacteremia in Korea.
Adult ; Bacteremia/complications/*diagnosis/microbiology ; Catalase/metabolism ; Esophageal and Gastric Varices/complications/*diagnosis ; Gastrointestinal Hemorrhage/*etiology ; Gonorrhea/complications/*diagnosis/microbiology ; Humans ; Ligation ; Liver Cirrhosis/diagnosis ; Male ; Neisseria gonorrhoeae/genetics/*isolation & purification ; Oxidoreductases/metabolism ; RNA, Ribosomal, 16S/chemistry/genetics ; Sequence Analysis, DNA

BACKGROUND: Hepatitis B virus (HBV) DNA quantification is necessary for starting and monitoring of antiviral therapy in patients with chronic hepatitis B. This study was intended to assess the clinical performance of Abbott RealTime HBV Quantification kit (Abbott Laboratories, USA). METHODS: The performance was evaluated in terms of precision, linearity, detection sensitivity, cross-reactivity, and carry-over. A correlation with the Real-Q HBV Quantification kit (BioSewoom Inc., Korea) was also examined using serum samples from 64 patients diagnosed with chronic hepatitis B and underwent lamivudine therapy in Asan Medical Center. We verified the trueness of the system by comparing the outputs with the assigned values of the BBI panel (BBI Diagnostics, USA). RESULTS: Within-run and between-run coefficients of variation (CV) were 3.56-4.71% and 3.03-4.98%, respectively. Linearity was manifested ranging from 53 to 10(9) copies/mL and the detection sensitivity was verified to be 51 copies/mL. None of hepatitis C virus showed cross-reactivity. No cross-contamination occurred when negative and positive samples were alternatively placed in a row. It showed a good correlation with the Real-Q HBV (r2=0.9609) and the test results for the BBI panel were also well agreed to the assigned values (r2=0.9933). CONCLUSIONS: The performance of Abbott RealTime HBV Quantification kit was excellent; thus, it should be widely used in starting and monitoring of antiviral therapy in Korean patients with chronic hepatitis B.
Computer Systems ; DNA, Viral/*blood ; Hepatitis B virus/genetics/*isolation & purification ; Hepatitis B, Chronic/*virology ; Humans ; Polymerase Chain Reaction/*methods ; Reagent Kits, Diagnostic ; Viral Load/*methods

BACKGROUND: Therapeutic drug monitoring (TDM) of tacrolimus is essential because of narrow therapeutic range and poor correlation of dose to blood concentration. Affinity Column Mediated Immunometric Assay (ACMIA) does not require a pretreatment steps in measurement of tacrolimus. In this study, we evaluated the performance of tacrolimus assay using ACMIA (Dimension RxL Max, Dade Behring). METHODS: The imprecision, the linearity and the detection limits and the interferences by bilirubin and chyle, and correlation with hematocrit for tacrolimus by ACMIA were evaluated according to Clinical and Laboratory Standards Institute guidelines EP5-A2, EP6-A, EP17-A, EP9-A2, and EP7-A2. Method comparison studies with microparticle enzyme immunoassay (MEIA) (IMx Tacrolimus II, Abbott Laboratories) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) (Waters 2795 Quattromicro API, Micromass) were also performed. RESULTS: The total imprecision for low, middle and high level was 12.8%, 9.0% and 6.7%, respectively. The range of tacrolimus from 3.1 ng/mL to 35.4 ng/mL showed a clinically relevant linearity. The limit of detection and the functional sensitivity were 0.24 ng/mL and 0.72 ng/mL, respectively. Tacrolimus concentration measurement (Tac-CM) with ACMIA did not show significant interferences with bile and chyle and also did not show significant correlation with hematocrit. In comparison study for Tac-CM with MEIA and LC-MS/MS, Tac-CM with ACMIA showed a good correlation with MEIA (r=0.950) and LC-MS/MS (r=0.946). CONCLUSIONS: The imprecision, linearity, detection limits, interference and correlation of Tac-CM with ACMIA were suitable for clinical use. Tac-CM with ACMIA could reduce turn around time and help clinicians to manage transplant patients on immunosuppressant therapy.
Bilirubin/chemistry ; Chromatography, Affinity ; Chyle/chemistry ; Drug Monitoring ; Humans ; Immunoassay/*methods ; Immunosuppressive Agents/*blood ; Limit of Detection ; Reagent Kits, Diagnostic ; Reproducibility of Results ; Tacrolimus/*blood

Cryptococcus is an opportunistic pathogen that mainly affects immunocompromised hosts and, less frequently, immunocompetent hosts. It causes serious morbidity and mortality due to systemic infections such as meningoencephalitis and pulmonary infection. Urinary involvement of Cryptococcus is sometimes reported among cases of disseminated cryptococcosis in AIDS patients, but no such reports have been published in Korea. We report two cases of cryptococcuria that developed in a 71-year old female with diabetes and liver cirrhosis and in a 50-year old male who received a liver transplant due to HBV-associated hepatic failure. The female patient had received prednisolone for 12 days before we detected C. neoformans in urine culture. Even though no antifungal therapy was indicated for cryptococcuria, following urine culture became negative, but still positive for cryptococcal antigen on hospital day 25. Her blood, CSF culture, and antigen tests were negative, and therefore she was diagnosed with isolated cryptococcuria. The male patient had received prednisolone and tacrolimus for 10 days before sputum and urine cultures became positive for C. neoformans. He had ill defined nodules and pleural effusion in both lungs on chest CT. His cryptococcuria was sustained for over 2 months, despite receiving amphotericin B treatment. His cryptococcuria seemed to be a symptom of disseminated cryptococcosis.
Amphotericin B ; Cryptococcosis ; Cryptococcus ; Cryptococcus neoformans ; Female ; Humans ; Immunocompromised Host ; Korea ; Liver ; Liver Cirrhosis ; Liver Failure ; Lung ; Male ; Meningoencephalitis ; Pleural Effusion ; Prednisolone ; Sputum ; Tacrolimus ; Thorax ; Transplants

BACKGROUND: GenoType(R) MTBDRplus assay (Hain Lifescience, Germany) enables detection of the mutations prevalent in rpoB, katG, and inhA genes and identification of Mycobacterium tuberculosis complex (MTB). We evaluated the performance of the MTBDRplus assay in detecting multidrug resistant M. tuberculosis in sputum specimens by directly comparing it to the performance of conventional drug susceptibility testing (DST) with M. tuberculosis culture isolates. METHODS: From December 2007 to July 2008, 40 patients with acid-fast bacilli (AFB) smear-positive and AFB culture-positive sputa, including 19 patients with rifampin (RIF)- or isoniazid (INH)-resistant MTB isolates, were enrolled. The MTBDRplus assay was performed using DNA extracted from respiratory specimens. DST of the culture isolates was performed using an absolute concentration method. RESULTS: The result of the AFB smear test was +/-1 for 7 specimens, +1 for 8 specimens, +2 for 9 specimens, +3 for 9 specimens, and +4 for 7 specimens. The MTBDRplus assay revealed that 37 of the 40 specimens were positive for an MTB-specific band, 12 specimens were RIF-resistant, and 16 specimens were INH-resistant. The rpoB S531L mutation was detected in 58.3% of the RIF-resistant specimens, and the katG S315T1 and inhA C15T mutations were detected in 56.3% and 31.3% of the INH-resistant specimens, respectively. Compared to the sensitivity and specificity of DST, both sensitivity and specificity of MTBDRplus assay for RIF resistance were 100%, and the corresponding values for INH resistance were 82.4% and 90.0%. Discrepant MTBDRplus assay and DST results were obtained in 3 INH-resistant isolates without mutation and 2 INH-susceptible isolates with katG S315T1 and inhA C15T mutations. CONCLUSIONS: The MTBDRplus assay can be applied for AFB smear-positive specimens with positivity +/- to 4+. The assay was reliable for predicting the RIF resistance of culture isolates, but DST was required for confirming INH resistance.
DNA ; Humans ; Isoniazid ; Mycobacterium ; Mycobacterium tuberculosis ; Rifampin ; Sensitivity and Specificity ; Sputum ; Tuberculosis

BACKGROUND: In 2010, the Clinical and Laboratory Standards Institute (CLSI) revised the minimum inhibitory concentration (MIC) breakpoints of cephalosporins and aztreonam to exempt extended-spectrum beta-lactamase (ESBL) confirmatory tests for Enterobacteriaceae. However, the CLSI did not change the MIC breakpoint of cefepime. Here, a proficiency survey of a strain of ESBL-producing Klebsiella pneumoniae was analyzed for MIC distribution and interpretation of cephalosporins and aztreonam. METHODS: The survey strain, K. pneumoniae, which produced SHV-18, was distributed to 170 clinical laboratories as 1 of 5 presumptive clinical specimens through the proficiency survey of the clinical microbiology division of the Korean Association of Quality Assurance for Clinical Laboratories (KAQACL). MIC, zone diameter of inhibition (ZDI), and interpretation of tested antimicrobials, methods of antimicrobial susceptibility testing (AST), and ESBL confirmatory results were collected. RESULTS: According to the revised breakpoints of the 2010 CLSI guidelines, MIC results indicated resistance to aztreonam in 100%, cefepime in 5.5%, cefotaxime in 20%, ceftazidime in 100%, and ceftriaxone in 100% of samples by broth microdilution methods. ZDI results also indicated resistance to aztreonam in 75%, cefepime in 0%, cefotaxime in 66.7%, ceftazidime in 100%, and ceftriaxone in 80% of samples by disk diffusion method. Ninety (75.6%) participants performed an ESBL confirmatory test, and 89 (98.9%) reported ESBL-positive tests. Of the 55 laboratories that tested the susceptibility of cefepime, 50 (90.9%) self-reported to be "resistant" because of ESBL-positive results. CONCLUSIONS: In conclusion, susceptibility testing of ESBL producers against certain cephalosporins is not reliable enough to apply the revised breakpoints presented in the 2010 CLSI guidelines. It is therefore necessary to reach a consensus for interpretation of ASTs of ESBL producers in Korea. Ideally, clinicians should be provided two interpretations based on both the revised breakpoints and ESBL confirmatory testing.
Aztreonam ; beta-Lactamases ; Cefotaxime ; Ceftazidime ; Ceftriaxone ; Cephalosporins ; Consensus ; Diffusion ; Enterobacteriaceae ; Klebsiella ; Klebsiella pneumoniae ; Korea ; Microbial Sensitivity Tests ; Pneumonia ; Sprains and Strains

Haemophilus influenzae has rarely been implicated as the causative agent of urinary tract infections (UTIs). However, cases of UTIs caused by H. influenza in patients with anatomical or functional urinary tract abnormalities have been steadily reported. We report a case of asymptomatic bacteriuria caused by H. influenzae in a kidney transplant recipient. The patient was a 61-yr-old woman who visited the hospital for a routine follow-up after receiving a kidney transplant from a living-related donor; the patient showed no symptoms. Urine microscopy revealed white blood cell (WBC) count of >30/high power field (HPF). Urine culture on blood agar showed non-hemolytic, tiny, translucent, grayish colonies with satellitism around beta-hemolytic colonies of Staphylococcus epidermidis. The organism in the satellite colonies was identified as H. influenzae by using VITEK Neisseria/Haemophilus Identification Card (bioMerieux, Marcy L'Etoile, France) and found to require both X and V factors for growth. The organism did not produce beta-lactamase. Urine culture performed 1 week later revealed H. influenza again. The patient was not treated with antimicrobials. Urine culture performed using chocolate agar 7 weeks later did not reveal H. influenzae. Since H. influenzae does not grow in the media commonly used for urine culture such as blood agar, the use of these media could lead to underestimation of the true frequency of H. influenzae. If UTI is suspected in a patient with anatomical or functional urinary tract abnormality, chocolate agar should be considered for urine culture.
Agar ; Bacteriuria ; beta-Lactamases ; Cacao ; Female ; Follow-Up Studies ; Haemophilus ; Haemophilus influenzae ; Humans ; Influenza, Human ; Kidney ; Kidney Transplantation ; Leukocytes ; Microscopy ; Staphylococcus epidermidis ; Transplants ; Urinary Tract ; Urinary Tract Infections

Haemophilus influenzae has rarely been implicated as the causative agent of urinary tract infections (UTIs). However, cases of UTIs caused by H. influenza in patients with anatomical or functional urinary tract abnormalities have been steadily reported. We report a case of asymptomatic bacteriuria caused by H. influenzae in a kidney transplant recipient. The patient was a 61-yr-old woman who visited the hospital for a routine follow-up after receiving a kidney transplant from a living-related donor; the patient showed no symptoms. Urine microscopy revealed white blood cell (WBC) count of >30/high power field (HPF). Urine culture on blood agar showed non-hemolytic, tiny, translucent, grayish colonies with satellitism around beta-hemolytic colonies of Staphylococcus epidermidis. The organism in the satellite colonies was identified as H. influenzae by using VITEK Neisseria/Haemophilus Identification Card (bioMerieux, Marcy L'Etoile, France) and found to require both X and V factors for growth. The organism did not produce beta-lactamase. Urine culture performed 1 week later revealed H. influenza again. The patient was not treated with antimicrobials. Urine culture performed using chocolate agar 7 weeks later did not reveal H. influenzae. Since H. influenzae does not grow in the media commonly used for urine culture such as blood agar, the use of these media could lead to underestimation of the true frequency of H. influenzae. If UTI is suspected in a patient with anatomical or functional urinary tract abnormality, chocolate agar should be considered for urine culture.
Agar ; Bacteriuria ; beta-Lactamases ; Cacao ; Female ; Follow-Up Studies ; Haemophilus ; Haemophilus influenzae ; Humans ; Influenza, Human ; Kidney ; Kidney Transplantation ; Leukocytes ; Microscopy ; Staphylococcus epidermidis ; Transplants ; Urinary Tract ; Urinary Tract Infections