[Show abstract][Hide abstract] ABSTRACT: Background:
We investigated the species distribution and amphotericin B (AMB) susceptibility of Korean clinical Aspergillus isolates by using two Etests and the CLSI broth microdilution method.
A total of 136 Aspergillus isolates obtained from 11 university hospitals were identified by sequencing the internal transcribed spacer (ITS) and β-tubulin genomic regions. Minimal inhibitory concentrations (MICs) of AMB were determined in Etests using Mueller-Hinton agar (Etest-MH) and RPMI agar (Etest-RPG), and categorical agreement with the CLSI method was assessed by using epidemiological cutoff values.
ITS sequencing identified the following six Aspergillus species complexes: Aspergillus fumigatus (42.6% of the isolates), A. niger (23.5%), A. flavus (17.6%), A. terreus (11.0%), A. versicolor (4.4%), and A. ustus (0.7%). Cryptic species identifiable by β-tubulin sequencing accounted for 25.7% (35/136) of the isolates. Of all 136 isolates, 36 (26.5%) had AMB MICs of ≥2 μg/mL by the CLSI method. The categorical agreement of Etest-RPG with the CLSI method was 98% for the A. fumigatus, A. niger, and A. versicolor complexes, 87% for the A. terreus complex, and 37.5% for the A. flavus complex. That of Etest-MH was ≤75% for the A. niger, A. flavus, A. terreus, and A. versicolor complexes but was higher for the A. fumigatus complex (98.3%).
Aspergillus species other than A. fumigatus constitute about 60% of clinical Aspergillus isolates, and reduced AMB susceptibility is common among clinical isolates of Aspergillus in Korea. Molecular identification and AMB susceptibility testing by Etest-RPG may be useful for characterizing Aspergillus isolates of clinical relevance.
Annals of Laboratory Medicine 09/2015; 35(6):602-10. DOI:10.3343/alm.2015.35.6.602 · 1.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Recently, genotypic identification of anaerobes is emerging as an alternative to the phenotypic method. In this study, we evaluated the performance of Vitek 2, API 20A and 16s rRNA gene sequencing for the identification of anaerobic bacteria.
[Show abstract][Hide abstract] ABSTRACT: Photonic microdisks with a multilayered structure are designed from photocurable suspensions by step-by-step photolithography. In each step of photolithography, either a colloidal photonic crystal or a magnetic-particle-laden layer is stacked over windows of a photomask. Sequential photolithography enables the creation of multilayered photonic microdisks that have brilliant structural colors that can be switched by an external magnetic field.
[Show abstract][Hide abstract] ABSTRACT: This study examined the serotype distribution and antimicrobial resistance of pneumococcal isolates from invasive infections in children between 2006 and 2010, when the 7-valent pneumococcal conjugate vaccine (PCV7) was offered as an optional vaccine in Korea. Among 140 isolates collected from 8 centers, the common serotypes were 19A (22.9%), 19 F (12.1%), and 6B (8.6%). Between 2006 and 2010, PCV7 serotypes decreased from 62.5% to 21.4% (P = 0.002), whereas 3 PCV13-specific serotypes (3, 6A, and 19A) increased from 18.8% to 42.9% (P = 0.016). Among 102 multidrug-resistant isolates, the proportion of PCV7 serotypes decreased from 65.2% to 21.7% (P = 0.001), and 3 PCV13-specific serotypes increased from 17.4% to 47.8% (P = 0.008). Optional PCV7 vaccination has influenced the proportion of PCV7 serotypes in Korea, resulting in a decrease, whereas the proportions of 3 PCV13-specific serotypes, particularly 19A, have increased.
[Show abstract][Hide abstract] ABSTRACT: Eggerthella lenta is rarely isolated from blood but may occur as an opportunistic pathogen with high morbidity and mortality. We report a case of E. lenta bacteremia after an endoscopic retrograde cholangiopancreatography in an end-stage renal disease patient.
[Show abstract][Hide abstract] ABSTRACT: In general, higher resistance rates are observed among intensive care unit (ICU) isolates than non-ICU isolates. In this study, resistance rates of isolates from ICUs and non-ICUs were compared using the data generated from 20 hospitals in Korea.
[Show abstract][Hide abstract] ABSTRACT: We assessed the accuracy of yeast bloodstream isolate identification performed over a 1-year period at 10 Korean hospitals, using the MALDI-TOF-based VITEK MS system. The overall phenotypic misidentification rate was 3.4% (18/533), with considerable variation between hospitals (0.0% to 19.0%), compared to 1.1% (6/533) for the VITEK MS system.
Journal of clinical microbiology 06/2013; DOI:10.1128/JCM.00945-13 · 3.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Self-assembly of monodisperse colloidal particles into regular lattices has provided relatively simple and economical methods to prepare photonic crystals. The photonic stop band of colloidal crystals appears as opalescent structural colors, which are potentially useful for display devices, colorimetric sensors, and optical filters. However, colloidal crystals have low durability, and an undesired scattering of light makes the structures white and translucent. Moreover, micropatterning of colloidal crystals usually requires complex molding procedures, thereby limiting their practical applications. To overcome such shortcomings, we develop a pragmatic and amenable method to prepare colloidal photonic crystals with high optical transparency and physical rigidity using photocurable colloidal suspensions. The colloidal particles dispersed in a photocurable medium crystallized during capillary force-induced infiltration into a slab, and subsequent photopolymerization of the medium permanently solidifies the structures. Furthermore, conventional photolithography enables micropatterning of the crystal structures. The low index contrast between particles and matrix results in high transparency of the resultant composite structures and narrow reflection peaks, thereby enabling structural color mixing through the overlapping of distinct layers of the colloidal crystals. Multiple narrow peaks in the spectrum provide high selectivity in optical identification, thereby being potentially useful for security materials.
Chemistry of Materials 06/2013; 25(13-13):2684-2690. DOI:10.1021/cm4012603 · 8.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: At present, the clinical breakpoints (CBPs) of both fluconazole and voriconazole are available only for 3 common Candida species in the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) methods. Epidemiological cutoff values (ECVs) were recently applied to both methods to detect the emergence of acquired resistance (i.e., non-wild-type isolates) among 5 common Candida species.
We performed a nationwide study to determine the fluconazole and voriconazole susceptibility of Candida bloodstream isolates (BSIs) using both the CLSI and EUCAST methods. A total of 423 BSIs of 5 Candida species were collected from 8 hospitals. The azole susceptibilities were assessed on the basis of the species-specific CBPs and ECVs.
Of the 341 BSIs of 3 common Candida species (i.e., C. albicans, C. tropicalis, and C. parapsilosis), 0.3% and 0.9%, 0.0% and 1.5% of isolates were categorized as fluconazole and voriconazole resistant according to the CLSI and EUCAST CBPs, respectively. Of 423 total BSIs, 1.4% and 2.6% had fluconazole minimum inhibitory concentrations (MICs) exceeding the ECVs according to the CLSI and EUCAST, respectively; 1.0% and 2.1% had voriconazole MICs exceeding the ECVs according to the CLSI and EUCAST, respectively. Categorical agreement between the methods using ECVs was 98.3% for fluconazole and 98.3% for voriconazole.
The EUCAST and CLSI methods using ECVs provide highly concordant results. Moreover, non-wild-type isolates with possibly acquired azole resistance were rare among the BSIs of 5 common Candida species in Korea.
Annals of Laboratory Medicine 05/2013; 33(3):167-73. DOI:10.3343/alm.2013.33.3.167 · 1.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report thermo- and photo-responsive hydrogel capsules, providing controlled encapsulation and triggered release of water-soluble encapsulants. Monodisperse O/W/O (oil-in-water-in-oil) double-emulsion drops are produced in a capillary microfluidic device as templates, which transform into hydrogel capsules upon polymerization of thermo-sensitive monomers in the water phase containing gold nanorods.
Chemical Communications 01/2013; 49(18). DOI:10.1039/c3cc37719a · 6.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to determine antimicrobial susceptibility of recent clinical Stenotrophomonas maltophilia isolates from Korea, and to compare the activity levels of several combinations of antimicrobials. A total of 206 non-duplicate clinical isolates of S. maltophilia was collected in 2010 from 11 university hospitals. Antimicrobial susceptibility testing was performed using the Clinical Laboratory Standards Institute agar dilution method. In vitro activity of antimicrobial combinations was tested using the checkerboard method. The susceptibility rates to trimethoprim-sulfamethoxazole and minocycline were 96% and 99%, respectively. The susceptibility rate to levofloxacin was 64%. All of four antimicrobial combinations showed synergy against many S. maltophilia isolates. A combination of trimethoprim-sulfamethoxazole plus ticarcillin-clavulanate was most synergistic among the combinations. None of the combinations showed antagonistic activity. Therefore, some of the combinations may be more useful than individual drugs in the treatment of S. maltophilia infection. Further clinical studies are warranted to validate our in vitro test results.
Journal of Korean medical science 01/2013; 28(1):62-6. DOI:10.3346/jkms.2013.28.1.62 · 1.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Staphylococcus aureus is a major bacteremia-causing pathogen in hemodialysis patients, frequently colonizing patient skin and mucosa. Active infection control is necessary to prevent methicillin-resistant S. aureus (MRSA) infection in hospitals; however, the spread of community-associated MRSA has recently become a concern for MRSA infection control. We evaluated the nasal colonization of MRSA among hemodialysis patients and the molecular characterization of the MRSA isolates.
[Show abstract][Hide abstract] ABSTRACT: This study was conducted to establish reference intervals (RIs) for serum gamma-glutamyltransferase (GGT), and to evaluate the association between serum GGT levels within RIs and the prevalence of metabolic syndrome (MetS) and type 2 diabetes mellitus (DM) in men and women.
[Show abstract][Hide abstract] ABSTRACT: Arcanobacterium haemolyticum, a aerobic Gram-positive rod, has been described as an unusual pathogen causing soft tissue infections such as pharyngotonsillitis, chronic ulcer and cellulitis. In addition, the microorganism causes deep-seated infection and systemic disease including endocarditis, vertebral osteomyelitis and sepsis in patients with predisposing conditions such as diabetes mellitus. Since colonies and microscopic findings of A. haemolyticum might be confused with those of streptococci and coryneform bacteria, and it is usually isolated with other microorganisms, it is often considered to be normal flora or a contaminant in wound infections, resulting in missed or delayed diagnosis. Streptococcus agalactiae infections in neonates and pregnant women have been well recognized. However, invasive S. agalactiae infections in non-pregnant older adults with chronic medical conditions, particularly diabetes mellitus, are increasing. We report a case of diabetic foot ulcer due to A. haemolyticum and S. agalactiae in an uncontrolled diabetes mellitus patient.
[Show abstract][Hide abstract] ABSTRACT: Posterior lumbar interbody fusion (PLIF) using harvested local bone inserted into a polyetheretherketone (PEEK) cage is a commonly used procedure, but the accurate fusion rate of a cage, cage to bone contact area ratio, and the changes in fusion rate with time after surgery are unknown.
The aim was to conduct a quantitative analysis of the fusion rates and the cage to bone contact area ratios at each period of time using a PEEK cage in PLIF using a consecutive three-dimensional (3D) computed tomography (CT) scan.
This was a prospective study using a consecutive 3D thin-section CT scan.
Thirty patients aged between 37 and 73 years set to undergo elective PLIF with PEEK cages and pedicle screw fixation were included in the study.
The assessments included the Korean Oswestry Disability Index (K-ODI), Short Form (SF)-36 questionnaire, Visual Analog Scale (VAS) pain score, and dynamic plane radiographs, preoperatively and at 6 and 12 months after surgery.
Three-dimensional CT scans were performed at 6 and 12 months after surgery. Three-dimensional CT assessments of the following were performed: fusion rate of the cage, cage to bone contact area ratio, and fusion rate of the interbody bone graft besides the cage.
The 6-month fusion rate of the segment was 86.7%, which increased to 90.0% at 12 months. The fusion area ratio between the cage area and end plate showed a significant increase from 52.0% at 6 months to 58.5% at 12 months. Regarding the fusion area ratio between the cage and end plate, the ratio between the lower surface of the cage was significantly higher than that of the upper surface. In addition, the K-ODI, SF-36, and VAS values were similar at 6 and 12 months after surgery.
The fusion rate of the PEEK cage used in PLIF measured at 12 months was higher than that measured at 6 months. Therefore, an assessment on the complete fusion of local bone at 12 months after surgery is more accurate.
The spine journal: official journal of the North American Spine Society 05/2011; 11(7):647-53. DOI:10.1016/j.spinee.2011.04.029 · 2.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Multilocus sequence typing (MLST) has been successfully applied to the epidemiology of Candida albicans isolates not only within the hospital setting but also in multiple locations nationwide. We performed MLST to investigate
the genetic relatedness among bloodstream infection (BSI) isolates of C. albicans recovered from 10 Korean hospitals over a 12-month period. The 156 isolates yielded 112 unique diploid sequence types (DSTs).
While 95 DSTs were each derived from a single isolate, 17 DSTs were shared by 61 isolates (39.1%). Interestingly, 111 (71.1%)
isolates clustered within previously known clades, and 29 (18.6%) clustered within a new clade that includes strains of Asian
origin previously typed as singletons. This MLST study was complemented by restriction endonuclease analysis of genomic DNA
using BssHII (REAG-B) in order to evaluate whether strains with identical DSTs and originating from the same hospital corresponded
to nosocomial clusters. Importantly, only those isolates with a strong epidemiological relationship showed ≥95% identical
REAG-B types. Our results indicate that REAG-B typing can be complementary to MLST but should be limited to the investigation
of isolates of identical DSTs and when interhuman transmission is suspected.