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ABSTRACT: The analytical and clinical performance of a new rapid immunochromatography test, the SD Bioline Norovirus test, was evaluated for the detection of human norovirus in fecal specimens. The analytical performance studies were performed for detection limit, reproducibility, cross-reactivity, and interference. For comparison, 92 norovirus-positive stool samples and 126 norovirus-negative samples for which the results were confirmed by 2 different real-time PCR kits were used. The rapid immunochromatography test detected the equivalent of 4.48×10(6)copies/mL of the norovirus genome in stool samples. On performing the repeatability/reproducibility test, samples above this concentration all provided positive results (100%) and 97.8% of the samples slightly below this concentration (2.45×10(6)copies/mL) provided negative results. No cross-reactivity or interference was detected. Positive percent agreement (sensitivity), negative percent agreement (specificity), and overall percent agreement of the rapid immunochromatography test compared with testing by real-time PCR were 90.2%, 100%, and 95.9%, respectively. In addition, the rapid immunochromatography test was completed within 20min. The SD Bioline Norovirus test was, therefore, easier and more rapid to perform and showed excellent reproducibility, no cross-reactivity, no interference, and high agreement compared with real-time PCR. Thus, this test is useful for rapid screening to identity norovirus infection.
Journal of virological methods 08/2012; 186(1-2):94-98. · 2.13 Impact Factor
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ABSTRACT: We performed surveillance cultures of the surfaces of X-ray cassettes to assess contamination with methicillin-resistant Staphylococcus aureus (MRSA).
The surfaces of 37 X-ray cassettes stored in a radiology department were cultured using mannitol salt agar containing 6 µg/mL oxacillin. Suspected methicillin-resistant staphylococcal colonies were isolated and identified by biochemical testing. Pulsed-field gel electrophoresis (PFGE) analysis was performed to determine the clonal relationships of the contaminants.
Six X-ray cassettes (16.2%) were contaminated with MRSA. During the isolation procedure, we also detected 19 X-ray cassettes (51.4%) contaminated with methicillin-resistant Staphylococcus haemolyticus (MRSH), identified as yellow colonies resembling MRSA on mannitol salt agar. PFGE analysis of the MRSA and MRSH isolates revealed that most isolates of each organism were identical or closely related to each other, suggesting a common source of contamination.
X-ray cassettes, which are commonly in direct contact with patients, were contaminated with MRSA and MRSH. In hospital environments, contaminated X-ray cassettes may serve as fomites for methicillin-resistant staphylococci.
Annals of laboratory medicine. 05/2012; 32(3):206-9.
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ABSTRACT: We investigated the degree of lot-to-lot reagent variation for 5 common immunoassay items. We measured the commercial as well as in-house controls for α-fetoprotein (AFP), ferritin, CA19-9, quantitative hepatitis B surface antigen (HBsAg), and hepatitis B surface antibody (anti-HBs) 10 times each by using both the old and the new lot of reagents whenever a reagent lot was changed, over a period of 10 months. The differences in the mean control values, the percent difference (% difference), and the difference to between-run standard deviation ratio (D:SD ratio) between successive lots were calculated. The % difference in mean control values between 2 reagent lots ranged from 0.1 to 17.5% for AFP, 1.0 to 18.6% for ferritin, 0.6 to 14.3% for CA19-9, 0.6 to 16.2% for HBsAg, and 0.1 to 17.7% for anti-HBs except negative controls of HBsAg and anti-HBs. The maximum D:SD ratios between 2 lots were 4.37 for AFP, 4.39 for ferritin, 2.43 for CA19-9, 1.64 for HBsAg, and 4.16 for anti-HBs. Thus, we have experienced extensive variability in lot-to-lot reagent variation for 5 immunoassay items, indicating that reagent lot-to-lot comparability tests should be continuously performed and that laboratories should determine their own acceptance criteria for each item.
Annals of clinical and laboratory science 01/2012; 42(2):165-73. · 0.96 Impact Factor
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ABSTRACT: This study was performed to evaluate the clinical significance of procalcitonin in burn patients and to investigate whether procalcitonin levels at admission can be a prognostic indicator for sepsis and mortality.
Between January 2009 and December 2010, procalcitonin levels in 175 patients were tested within the first 48 hours after burn injury. Serum procalcitonin was measured using an enzyme-linked fluorescence assay. Mortality rates and positive culture rates of blood, wound, and sputum were evaluated among the subgroups divided by burn size, procalcitonin levels, and clinical prognosis.
Positive blood culture and mortality rates correlated significantly with procalcitonin concentrations within the first 48 hours after burn injury. The area under the ROC curve for procalcitonin related to mortality was 0.844. Survival analysis revealed that the mortality rate was significantly higher in patients with procalcitonin concentrations ≥ 2 ng/mL than in patients with procalcitonin concentrations < 2 ng/mL (P < 0.001). Multivariate analysis demonstrated that procalcitonin was an independent prognostic factor for burn patients (Hazard ratio = 3.16, P = 0.001).
Procalcitonin concentrations determined within the first 48 hours after burn injury can be a useful prognostic indicator for sepsis and mortality in burn patients.
Annals of clinical and laboratory science 01/2012; 42(1):57-64. · 0.96 Impact Factor
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ABSTRACT: This study evaluated the activity of tigecycline combined with imipenem, amikacin, and ciprofloxacin against clinical isolates of multidrug-resistant Klebsiella pneumoniae and Escherichia coli co-producing extended-spectrum β-lactamases and acquired AmpC β-lactamases. Broth microdilution tests were performed for cefotaxime, ceftazidime, cefepime, imipenem, amikacin, ciprofloxacin, and tigecycline. Time-kill synergy studies were tested for tigecycline plus imipenem, tigecycline plus amikacin, and tigecycline plus ciprofloxacin. Imipenem (MIC(90) = 1 μg/ml for both K. pneumoniae and E. coli) and tigecycline (MIC(90) = 2 μg/ml for K. pneumoniae and 1 μg/ml for E. coli) were the most potent agents. Combination studies with tigecycline plus imipenem resulted in synergy against 18 K. pneumoniae and 3 E. coli isolates; tigecycline plus amikacin yielded synergy against 8 K. pneumoniae and 3 E. coli isolates; tigecycline plus ciprofloxacin yielded synergy against 7 K. pneumoniae and 2 E. coli isolates. No antagonism was observed with any combination. In the present study, imipenem, amikacin, and ciprofloxacin led to indifferent and some synergistic effects in combination with tigecycline, and none of them demonstrated antagonistic effects.
Annals of clinical and laboratory science 01/2011; 41(1):39-43. · 0.96 Impact Factor
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ABSTRACT: Norovirus is a common cause of non-bacterial acute gastroenteritis worldwide, and norovirus infection shows symptoms such as vomiting and diarrhea in patients of all age groups. Mass outbreaks of norovirus infection have been recently reported in Korea. Herein, we investigated the epidemiological characteristics of acute norovirus gastroenteritis.
We analyzed 11,219 fecal specimens of patients with acute gastroenteritis symptoms from the 5 participating hospitals for 3 yr (March 2007-February 2010) to determine positive rates of detection using RIDASCREEN Norovirus ELISA (R-Biopharm AG, Germany) kit by year, prevalence season, sex, age, and region.
Norovirus infection was prevalent during autumn and winter, and 13.0% specimens were positive for the infection. The positive rates of norovirus detection were 16.2%, 13.8%, and 9.9% in 2007, 2008, and 2009, respectively, and they tended to decrease every year. In 2007 and 2008, the epidemicity of norovirus started from October, reached its peak in November, and lasted until January. However, in 2009, it started from December, reached its peak in January, and lasted until February. Most patients were 0-3 yr old and this patient group had the highest positive rate. There was no significant inter-regional difference among the subjects.
We performed epidemiological analysis of norovirus infection using ELISA assay. Reverse transcription-PCR indicated higher prevalence of norovirus infection as compared with that reported before 2007. Further studies are warranted to examine the changes observed in the epidemic period of 2009.
The Korean Journal of Laboratory Medicine 12/2010; 30(6):647-53. · 0.63 Impact Factor
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ABSTRACT: T-SPOT.TB is a sensitive test that detects interferon-gamma producing T-cells in tuberculosis patients following stimulation with tuberculosis-specific antigens. Our study was aimed to investigate the possible causes of false negative results of the test by analyzing the patients with positive acid-fast bacilli (AFB) culture and negative T-SPOT.TB results.
We investigated 138 patients with positive AFB culture results reported between January 2009 and April 2010. Medical records of these patients were reviewed for the results of T-SPOT.TB test, AFB culture, PCR for Mycobacterium tuberculosis (TB-PCR), chest X-ray, drug treatment, etc. Diagnosis of tuberculosis was confirmed by positive TB-PCR or identification of Mycobacterium tuberculosis (MTB). Sensitivity of T-SPOT.TB test was calculated and the possible causes of AFB culture positive and T-SPOT.TB negative results were analyzed.
T-SPOT.TB test was performed in 63 of the 138 patients with AFB culture positive results. Fifty-six (88.9%) were positive and 7 patients (11.1%) were negative on T-SPOT.TB test. Of these 7 negative cases, 4 were confirmed as nontuberculous mycobacteria (NTM), 2 were suspected as NTM and diagnosis could not be confirmed in 1. Six of these 7 patients were over 70 yr old and 6 patients had lymphocytopenia. T-SPOT.TB negative results were not observed in any of the 44 patients confirmed to have active tuberculosis (sensitivity 100%).
Our results suggest that T-SPOT.TB test is very sensitive for diagnosing active tuberculosis. NTM may be the main cause of AFB culture positive and T-SPOT.TB negative results, but MTB infection in immunocompromised patients also has to be considered.
The Korean Journal of Laboratory Medicine 08/2010; 30(4):414-9. · 0.63 Impact Factor
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ABSTRACT: Tuberculosis-specific ELISPOT assay (T-SPOT.TB, Oxford Immunotec, UK) is a test that detects interferon-gamma producing T-cells after stimulating patient's lymphocytes with two kinds of tuberculosis-specific antigens (ESAT-6 and CFP-10). We evaluated clinical usefulness of T-SPOT.TB test in Korean adults with intermediate burden of tuberculosis and high rate of BCG vaccination at birth.
T-SPOT.TB test was performed in 79 patients and 64 healthy volunteers and these patients and volunteers were classified into four groups: group 1, patients with active tuberculosis (n=30); group 2, patients with not-active tuberculosis (n=27); group 3, patients without tuberculosis (n=24); group 4, healthy volunteers without tuberculosis history (n=62). Positive rates and average spot counts of T-SPOT.TB test were obtained among these groups.
Positive rates of group 1 (96.4%) and group 2 (92.3%) were higher than those of group 3 (31.6%) and group 4 (27.4%) (P<0.0001). The sensitivity deduced from group 1 and specificity deduced from group 4 of T-SPOT.TB test were 96.4% and 72.6%, respectively. The average spot counts of group 1 and 2 were higher than those of group 3 and 4 (P<0.001). There was a tendency of increasing positive rate with increasing age. Overall agreement between T-SPOT.TB test and tuberculin skin test was 63.8% (kappa=0.29).
T-SPOT.TB test would be a very useful screening and supplementary test for diagnosis of tuberculosis due to its high sensitivity. However, positive results of T-SPOT.TB should be cautiously interpreted because of high positivity in treated tuberculosis patients and healthy volunteers in Korea.
The Korean Journal of Laboratory Medicine 04/2010; 30(2):171-7. · 0.63 Impact Factor
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ABSTRACT: Procalcitonin (PCT) is a relatively new marker for bacterial infections, and its diagnostic utility has been variable across the studies. We investigated the diagnostic utility of PCT for the patients with blood culture-positive sepsis, and compared it with that of C-reactive protein (CRP).
In 1,270 consecutive blood samples, PCT and CRP were simultaneously measured and results were compared according to the five categories of PCT concentrations (<0.05 ng/mL; 0.05-0.49 ng/mL; 0.5-1.99 ng/mL; 2-9.99 ng/mL; > or = 10 ng/mL). In 506 samples, they were further analyzed according to the result of blood culture. PCT and CRP were measured using enzyme-linked fluorescent assay (bioMerieux Co., France) and rate nephelometry (Beckman Coulter Co., USA), respectively. Their diagnostic utilities were compared using ROC curves.
The mean concentrations of CRP in five categories of PCT were 15.4 mg/L, 42.1 mg/L, 101.2 mg/L, 125.0 mg/L, 167.1 mg/L, respectively (P<0.0001). Both PCT and CRP showed significant differences between the two positive and negative groups of blood culture (PCT, 8.47 vs 2.44 ng/mL, P=0.0133; CRP, 110.48 vs 59.78 mg/L, P<0.0001). The areas under the ROC curves (95% confidence interval) for PCT and CRP were 0.720 (0.644-0.788) and 0.558 (0.478-0.636), respectively, and showed a significant difference (P=0.005).
The diagnostic utility of PCT is superior to that of CRP for the patients with blood culture-positive sepsis. PCT seems to be reliable for sepsis diagnosis, and may provide useful information for the critically ill patients.
The Korean Journal of Laboratory Medicine 12/2009; 29(6):529-35. · 0.63 Impact Factor
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ABSTRACT: Variant Klinefelter syndrome with 48,XXXY/46,XY mosaicism has been rarely reported, and its phenotypic features, compared with those of the classic type, have not been well delineated. We describe a newborn baby with phenotypic abnormalities, including cleft palate and low-set ears. The cytogenetic analysis of peripheral blood lymphocytes showed a karyotype of 48,XXXY[36]/46,XY[4]. To the best of our knowledge, this is the first case in which 48,XXXY/46,XY mosaicism was related to the congenital anomaly of cleft palate. This case underscores that cytogenetic analysis should be a mandatory workup for the patient with cleft palate and that cleft palate may be a rare clinical presentation of the variant Klinefelter syndrome.
The Cleft Palate-Craniofacial Journal 09/2009; 46(5):555-7. · 0.82 Impact Factor
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ABSTRACT: This study was designed to evaluate the performance of the broth microdilution (BMD) method to detect production of extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases in Enterobacteriaceae by using clavulanic acid (CA) and boronic acid (BA) as ESBL and AmpC beta-lactamase inhibitors, respectively. A total of 100 clinical isolates of Enterobacteriaceae were analyzed. Mueller-Hinton broth containing serial twofold dilutions of cefotaxime (CTX), ceftazidime (CAZ), aztreonam (ATM), or cefepime (FEP) with or without either or both CA and BA was prepared. An eightfold or greater decrease in the MIC of CTX, CAZ, ATM, or FEP in the presence of CA and BA was considered a positive result for ESBL and plasmid-mediated AmpC beta-lactamase (PABL), respectively. In tests with CA, expanded-spectrum beta-lactams containing BA (CTX-BA, CAZ-BA, ATM-BA, and FEP-BA) showed higher positive rates in detecting ESBL producers than those without BA. The combination of CTX- and CAZ-based BMD tests with CA and BA showed sensitivity and specificity of 100% for the detection of ESBLs and PABLs. The BMD testing could be applicable for routine use in commercially available semiautomated systems for the detection of ESBLs and PABLs in Enterobacteriaceae.
Journal of clinical microbiology 09/2009; 47(11):3409-12. · 4.16 Impact Factor
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ABSTRACT: Coagulase is produced by all strains of Staphylococcus aureus. The 3' coding region of the coagulase (coa) gene contains varying numbers of 81 bp tandem repeats. S. aureus produces a variety of extracellular protein toxins. Here, we typed S. aureus strains isolated from blood by coa gene restriction fragment length polymorphism (RFLP) patterns and toxin gene profiles.
A total of 120 strains of S. aureus were isolated from blood cultures during 2003-2006 at Kangdong Sacred Heart Hospital. The isolates were typed by PCR RFLP analysis of the coa gene and by multiplex PCR for detection of genes encoding enterotoxins (sea, seb, sec, sed, and see), toxic shock syndrome toxin-1 (tst), exfoliative toxins (eta and etb), mecA and femA.
All the S. aureus strains were classified into 16 types on the basis of coa gene RFLP and could be further differentiated into 34 types according to the combined patterns of coa gene RFLP and toxin gene profiles. Of 85 methicillin-resistant S. aureus (MRSA) strains, 43 (50.6%) and 36 (42.4%) belonged to the RFLP pattern L5 and pattern L1, respectively. MRSA strains belonging to pattern L5 frequently carried tst (93.0%) or sec gene (81.4%), and strains belonging to pattern L1 frequently carried sea (88.9%) or see gene (44.4%). The rate of the pattern L5 in MRSA strains increased over the past few years and was higher in intensive care unit than in other wards.
We typed S. aureus strains isolated from blood on the basis of coa gene RFLP and toxin genes. The strains belonging to coa gene RFLP pattern L5 and L1 appeared to be the major types of MRSA isolasted from bacteremia and revealed specific toxin gene profiles according to the coa gene RFLP patterns.
The Korean Journal of Laboratory Medicine 09/2008; 28(4):286-92. · 0.63 Impact Factor
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ABSTRACT: Major thrombophilic mutations have been identified as risk factors for nontraumatic osteonecrosis of the femoral head (ONFH) in Caucasians. We asked whether the genetic background of patients with ONFH in the Korean population was similar. We analyzed factor V G1691A mutation (factor V Leiden), prothrombin G20210A mutation, and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms in 71 patients (53 men, 18 women) with ONFH. We classified these patients as 51 alcohol-induced, 18 idiopathic, one steroid-induced, and one dysbaric. We recruited 200 normal control subjects (128 men, 72 women). We used multiplex PCR/restriction fragment length polymorphism for each genotyping. We observed neither factor V Leiden nor prothrombin G20210A mutation. Although methylenetetrahydrofolate reductase A1298C genotypes were not associated with osteonecrosis, methylenetetrahydrofolate reductase C677T variant genotypes increased the risk of ONFH compared with 677CC. Odds ratios of 677CT and 677CT+TT were 2.00 (95% confidence interval, 1.05-3.81) and 1.96 (95% confidence interval, 1.07-3.59), respectively, compared with 677CC. Our data suggest methylenetetrahydrofolate reductase C677T polymorphism plays a role in the pathogenesis of osteonecrosis in the Korean population. It also implies the genetic risk profile of ONFH may differ among ethnic populations.
Clinical Orthopaedics and Related Research 06/2008; 466(5):1041-6. · 2.53 Impact Factor
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ABSTRACT: A study using boronic acid (BA) was designed to detect the extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae producing chromosomal AmpC beta-lactamases. A total of 197 clinical isolates of Enterobacter spp. (n=100), Serratia marcescens (n=62) and Citrobacter freundii (n=35) were analysed. Genes encoding ESBLs were detected by polymerase chain reaction (PCR) amplification followed by direct sequencing of PCR products. The Clinical and Laboratory Standards Institute confirmatory test detected only 72.1% of the ESBL-producing isolates. When a > or =5mm increase in the zone diameter of either the cefotaxime/clavulanic acid and/or the ceftazidime/clavulanic acid disks tested in combination with BA versus cefotaxime and/or ceftazidime containing BA was considered to be a positive for ESBL, the method detected 60 (98.4%) of the 61 isolates that harboured ESBLs and showed no false-positive results for ESBL-non-producing isolates. In conclusion, the BA disk test is a highly sensitive and specific method for the detection of ESBLs in Enterobacteriaceae producing chromosomal AmpC beta-lactamases.
International Journal of Antimicrobial Agents 05/2008; 31(5):467-71. · 4.13 Impact Factor
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Van Phan Le,
Ji-Yeon Kim,
Sung-Lim Cho,
Sun-Woo Nam,
Inseok Lim,
Hee-Joong Lee,
Kijeong Kim,
Sang-In Chung,
Wonkeun Song, Kyu Man Lee,
Moon-Soo Rhee,
Jung-Sook Lee,
Wonyong Kim
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ABSTRACT: Five hundred four fecal specimens, collected between 2004 and 2006 from young children with acute diarrhea, were screened for rotavirus by ELISA with VP6-specific antibody. Of these samples, 394 (78.2%) were confirmed as group A rotavirus and they underwent G- and P typing using a combination of ELISA, RT-PCR, and sequence analysis methods. The dominant circulating G serotype was G1 (35.6%) followed by G3 (26.4%), G4 (14.7%), and G2 (11.9%). There was a low prevalence of G9 (1.0%) and of unusual G type rotavirus, in particular, G12 (0.5%) and G8 (0.3%). Of the P genotype rotavirus in circulation, P[8] (53.0%) was most common followed by P[6] (15.5%), P[4] (15.2%), and P[9] (2.3%). Determination of G- and P type combinations revealed that G1P[8] strains were most prevalent (25.4%), amid G3P[8] (16.8%), G2P[4] (6.3%), and G4P[6] (6.1%) strains. Unusual or rare combinations such as G2P[6], G2P[8], G3P[4], G2P[9], G1P[9], G3P[9], G12P[6], G1P[4], G3P[6], and G8P[8] were also found. Owing to the recent emergence of G8 and G12 rotavirus, the findings from this study are important since they provide new information concerning the local and global spread of rotavirus genotypes.
Journal of Medical Virology 02/2008; 80(1):175-82. · 2.82 Impact Factor
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ABSTRACT: Some differences exist among various Hepatitis B virus (HBV) DNA quantification assays due to lack of standardization and besides clinical usefulness has not been firmly elucidated in Korean HBV patients.
We compared Bayer VERSANT HBV DNA 3.0 Assay (VERSANT 3.0) with Digene Hybrid Capture II HBV DNA Test (HC-II) according to HBeAg status and ALT levels in 232 HBV-infected Korean patients. One hundred and seventeen sera with undetectable DNA levels by HC-II were further analyzed by Real-Q HBV quantification assay (BioSewoom).
Although VERSANT 3.0 and HC-II showed an excellent correlation (r=0.9739), the results (copies/mL) by VERSANT 3.0 were 0.45 log(10) higher than those by HC-II. HBV DNA levels were higher in HBeAg-positive group than in HBeAg-negative group (P=0.002), and in abnormal ALT group than in normal ALT group (P<0.0001). The detection rate of HBV DNA by VERSANT 3.0 was lower in HBeAg-negative and normal ALT group (n=68) than in HBeAg-positive or abnormal ALT group (n=164) (35.3% vs 89.6%, P<0.0001). Fifty two sera out of 61 sera with undetectable DNA by VERSANT 3.0 were measurable by Real-Q with mean value of 3.26 log(10) copies/mL.
VERSANT 3.0 and HC-II showed an excellent correlation, but a little difference (0.45 log10) existed. VERSANT 3.0 effectively measured clinically relevant HBV DNA levels in most HBV-infected patients in Korea. However, more sensitive assays are needed for patients with negative HBeAg and normal ALT to see the low copies of HBV DNA levels.
The Korean Journal of Laboratory Medicine 12/2007; 27(6):451-7. · 0.63 Impact Factor
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ABSTRACT: TT virus (TTV) infection is highly prevalent in general population and patients with hepatitis B virus (HBV) infection. The aim of the present study was to determine the distribution of the genotypes and genogroups of TTV in healthy and HBV-infected individuals in Korea.
Distribution of TTV genotypes and genogroups was investigated in the serum samples of 69 healthy and 59 HBV-infected individuals. PCR products of N22 region were genotyped by sequence analysis. TTV genogroups were determined by 5 different genogroup-specific PCR assays.
Among the 20 sequenced isolates, 9 (45%) were genotype 2, 8 (40%) were genotype 1, 2 (10%) were genotype 3, and 1 (5%) was genotype 4. TTV genogroup 4 was found most frequently (52/128), followed by genogroup 3 (42/128), genogroup 1 (35/128), genogroup 5 (32/128), and genogroup 2 (1/128). Mixed infections with different genogroups were frequent.
TTV genotype 2 and 1 are predominant genotypes. TTV genotype 3 was detected for the first time in Korea. TTV genogroups 4 and 3 were predominant genogroups. No significant difference was observed in the distribution of TTV genogroups between healthy and HBV-infected individuals.
The Korean Journal of Laboratory Medicine 09/2007; 27(4):257-64. · 0.63 Impact Factor
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ABSTRACT: Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by some Staphylococcus aureus strains and associated with skin and soft tissue infections; these strains are epidemiologically associated with current outbreaks of community-acquired methicillin-resistant S. aureus (MRSA) and with necrotizing pneumonia in healthy adults in USA and Europe. This study was performed to investigate the presence of PVL-positive S. aureus and the significant infections known to be caused by this organism.
A total of 573 strains of S. aureus blood isolates at university-affiliated hospital during 2002 to 2005 were selected. The presence of PVL was investigated using PCR. Additional 12 staphylococcal toxin genes were also examined in PVL-positive S. aureus strains, and MRSA isolates were typed for the staphylococcal cassette chromosome mec (SCCmec).
PVL genes were detected in 5 (0.9%) of 573 S. aureus strains, including 1 MRSA and 4 MSSA. The PVL-positive MRSA isolate was SCCmec type IV, and no other staphylococcal toxins were detected. The median age of the patients infected with PVL-positive S. aureus was 36 yr. Three cases of bacteremia were preceded by skin and soft-tissue infections.
Bacteremia caused by PVL-positive S. aureus strain were detected in 5 patients in Korea, and some of the patients were associated with severe skin and soft-tissue infections. In addition, the PVL-positive MRSA strain of SCCmec type IV, a characteristic of community-acquired MRSA isolates in USA and Europe, also exists in Korea, and can cause the severe infections known to be associated with this organism.
The Korean Journal of Laboratory Medicine 09/2007; 27(4):286-91. · 0.63 Impact Factor
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ABSTRACT: Many methicillin-resistant Staphylococcus aureus (MRSA) isolates in Korea possess a specific profile of staphylococcal enterotoxins in that the toxic shock syndrome toxin gene (tst) coexists with the staphylococcal enterotoxin C gene (sec). Because the analysis of staphylococcal cassette chromosome mec (SCCmec), a mobile genetic element mecA gene encoding methicillin resistance, showed that majority of these are SCCmec type II, these MRSA isolates with tst and sec may be genetically related with each other. This study was performed to investigate the genetic relatedness of tstand sec-harboring MRSA strains isolated in Korea by using pulsed-field gel electrophoresis (PFGE).
A total of 59 strains of MRSA isolates of SCCmec type II possessing tst and sec were selected for PFGE and phylogenetic analyses. These isolates were collected from 13 health care facilities during nationwide surveillance of antimicrobial resistance in 2002.
The 59 MRSA isolates were clustered into 11 PFGE types, including one major group of 26 strains (44.1%) isolated from 7 healthcare facilities. Seven PFGE types contained 2 or more isolates each, comprising 55 isolates in total.
Most of SCCmec type II MRSA isolates containing tst and sec showed closely related PFGE patterns. Moreover, MRSA isolates collected from different healthcare facilities showed identical PFGE patterns. These findings suggested a clonal spread of MRSA strains possessing tst and sec in Korean hospitals.
The Korean Journal of Laboratory Medicine 05/2007; 27(2):118-23. · 0.63 Impact Factor
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ABSTRACT: A study using boronic acid (BA), an AmpC enzyme inhibitor, was designed to detect the combined expression of plasmid-mediated AmpC beta-lactamases (pAmpCs) and extended-spectrum beta-lactamases (ESBLs) in bacterial isolates naturally lacking chromosomal ampC genes. A total of 122 Klebsiella spp., Salmonella spp., and Proteus mirabilis isolates producing or nonproducing pAmpCs and/or ESBLs were analyzed. Detection of genes encoding ESBLs and AmpCs was confirmed by polymerase chain reaction (PCR) followed by sequencing of PCR products. A > or = 5-mm increase in zone diameter for i) cefoxitin (FOX) and/or cefotetan (CTT) containing BA versus FOX and/or CTT alone was considered positive for AmpC; ii) ceftazidime (CAZ)-clavulanate (CA) and/or cefotaxime (CTX)-CA tested in combination with BA versus CAZ and/or CTX containing BA was considered positive for ESBL. The disk tests of FOX and/or CTT alone and with BA detected 98.4% of organisms producing pAmpCs. All of the 21 pAmpC and ESBL coproducers were accurately detected ESBL by the disk tests of CTX-CA and/or CAZ-CA containing BA and CTX and/or CAZ containing BA. In conclusion, The BA disk test using Clinical and Laboratory Standards Institute methodology is simple and very efficient method to detect pAmpC and ESBL in organisms naturally lacking chromosomal AmpC enzymes. In particular, the method accurately detects the isolates that harbor both AmpCs and ESBLs.
Diagnostic Microbiology and Infectious Disease 03/2007; 57(3):315-8. · 2.53 Impact Factor
