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ABSTRACT: The clinical significance of polymicrobial Staphylococcus aureus bacteremia (SAB) remains unclear. We therefore compared the clinical features and outcomes of polymicrobial and monomicrobial SAB.
A prospective cohort study of patients with SAB was performed during a 20-months. Polymicrobial SAB was defined as the simultaneous isolation of S. aureus and other microorganisms from blood cultures. However, Corynebacterium spp., Bacillus spp., and coagulase-negative staphylococci were considered contaminants unless they were related to device infection and grew in two or more blood cultures.
During the study period, 44 (10%) patients had polymicrobial and 412 (90%) had monomicrobial SAB. A total of 54 microorganisms were isolated from the former, with Enterococcus spp. (22%) being the most common. Independent risk factors for polymicrobial SAB included neutropenia (odds ratio [OR] 3.5, p = 0.02), biliary tract catheters (OR 5.0, p = 0.001), and intra-abdominal infection (OR 10.3, p < 0.001). Clinical outcomes were significantly worse among patients with polymicrobial than monomicrobial SAB, including bacteremia-related and 7-day mortality rates. Independent predictors of bacteremia-related mortality were solid tumors (HR 2.0, p = 0.03) and polymicrobial SAB (HR 2.8, p = 0.007).
Polymicrobial SAB is associated with more severe illness than monomicrobial SAB, with neutropenia, biliary tract catheters and intra-abdominal infection being significant risk factors for polymicrobial SAB.
The Journal of infection 03/2012; 65(2):119-27. · 4.13 Impact Factor
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Seong Yeon Park,
Chaehun Lim,
Sang-Oh Lee,
Sang-Ho Choi,
Yang Soo Kim,
Jun Hee Woo,
Jae-Woo Song,
Mi Young Kim,
Eun Jin Chae,
Kyung-Hyun Do,
Koun-Sik Song,
Joon Beom Seo,
Sung-Han Kim
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ABSTRACT: We evaluated CT findings and their prognostic value in non-neutropenic transplant recipients with invasive pulmonary aspergillosis (IPA) compared with neutropenic patients with IPA.
All adult patients during a 27-month who met the criteria for proven or probable IPA according to the 2008 EORTC/MSG criteria were retrospectively enrolled. Initial CT findings were reviewed by two radiologists blinded to the patients' demographics and clinical outcomes.
A total of 50 non-neutropenic transplant recipients and 60 neutropenic patients were enrolled. Consolidation-or-mass, halo signs, and angio-invasive form were observed less often in non-neutropenic transplant recipients than in neutropenic patients: (56%, 26%, and 32%) versus (78%, 55%, and 60%, p = 0.01, p = 0.002, and p = 0.003, respectively). Multivariate analysis revealed that macronodules (HR 0.31, p = 0.001), multiple infarct-shaped consolidations (HR 4.26, p < 0.001), renal replacement therapy (HR 5.62, p < 0.001) and persistence of a positive serum galactomannan (HR 7.14, p < 0.001) were independently associated with 90-day mortality.
Our data indicate that CT findings in non-neutropenic transplant recipients with IPA are similar to those in neutropenic patients with IPA except that consolidation-or-mass, halo sings, and angio-invasive form are less frequent, and certain CT findings such as macronodules and multiple infarct-shaped consolidations have prognostic implications in IPA.
The Journal of infection 08/2011; 63(6):447-56. · 4.13 Impact Factor
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Oh-Hyun Cho,
Ki-Ho Park,
Su-Jin Park,
Sun-Mi Kim, Seong Yeon Park,
Song Mi Moon,
Yong Pil Chong,
Mi-Na Kim,
Sang-Oh Lee,
Sang-Ho Choi,
Jun Hee Woo,
Yang Soo Kim,
Sung-Han Kim
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ABSTRACT: The utility of a newly-developed Mycobacterium tuberculosis-specific enzyme-linked immunosorbent spot (ELISPOT) assay for diagnosis of tuberculous peritonitis (TBP) has not been fully assessed.
All patients with suspected TBP in a tertiary care hospital in an intermediate TB burden country were prospectively enrolled over a 30-month period. ELISPOT assays were performed on peripheral mononuclear cells (PBMC) and mononuclear cells from peritoneal fluid (PF-MC).
Sixty-four patients with suspected TBP were enrolled. Of these, 30 (47%) were classified as having TBP (27 confirmed and 3 probable cases), and 25 (39%) were classified as not having active tuberculosis. The remaining 9 (14%) with possible TBP were excluded from the final analysis. Five (8%) of the total 64 patients gave indeterminate PBMC ELISPOT results and 7 (18%) of 39 patients who underwent PF-MC ELISPOT assay revealed indeterminate PF-MC ELISPOT results. The sensitivity and specificity, respectively, of the tested methods for diagnosing TBP were as follows: PBMC ELISPOT (≥ 6 spots), 86% and 67%; PF-MC ELISPOT (≥ 14 spots), 92% and 86%; PF-MC ELISPOT/PBMC ELISPOT ratio (≥ 2), 75% and 93%; and PF ADA levels (≥ 38 IU/L), 95% and 100%. The areas under the receiver operating characteristics curves were as follows: PF-MC ELISPOT, 0.96; PF ADA, 0.96; PBMC ELISPOT, 0.88; and PF-MC ELISPOT/PBMC ELISPOT ratio, 0.87, respectively.
Although the ELISPOT assay does not outperform PF ADA, the ELISPOT assay using PBMC and PF-MC is a useful adjunct for diagnosing TBP, especially for a rule-in test when PF/MC/PBMC ELISPOT ratio (≥ 2) is used. However, the relatively high proportion of indeterminate results limits test utility, so further studies are needed to develop an optimized assay prototype.
The Journal of infection 06/2011; 62(6):462-71. · 4.13 Impact Factor
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Seong Yeon Park,
Sang-Oh Lee,
Sang-Ho Choi,
Jin-Yong Jeong,
Heungsup Sung,
Mi-Na Kim,
Chang-Min Choi,
Sang-Bum Hong,
Yeon-Mok Oh,
Tae-Sun Shim,
Chae-Man Lim,
Younsuck Koh,
Dong Soon Kim,
Yang Soo Kim,
Jun Hee Woo,
Sung-Han Kim
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ABSTRACT: The sensitivities of the serum and bronchoalveolar lavage galactomannan (GM) assays in 48 patients with pulmonary aspergilloma were 38% (13 of 34; 95% confidence interval [CI], 22%-56%) and 92% (33 of 36; 95% CI, 78%-98%), respectively. The positivity of serum GM assays was significantly higher in patients with hemoptysis than in those without hemoptysis (52% vs 9%; P=.02).
Clinical Infectious Diseases 04/2011; 52(7):e149-52. · 9.15 Impact Factor
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Hyun Jung Park,
Shin Na, Seong Yeon Park,
Song Mi Moon,
Oh-Hyun Cho,
Ki-Ho Park,
Yong Pil Chong,
Sung-Han Kim,
Sang-Oh Lee,
Yang Soo Kim,
Jun Hee Woo,
Mi-Na Kim,
Sang-Ho Choi
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ABSTRACT: Of 522 patients with Propionibacterium acnes bacteremia (PAB), 18 (3.5%) had clinically significant PAB. Of these 18 patients, 10 (55.6%) had hospital-acquired bacteremia and 6 (33.3%) had undergone invasive procedures before development of PAB. One patient with a ventricular septal defect presented with infective endocarditis. After the exclusion of 1 patient whose outcome was not available, the overall mortality rate was 5.9% (1/17).
Journal of clinical microbiology 02/2011; 49(4):1598-601. · 4.16 Impact Factor
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Seong Yeon Park,
Sang-Oh Lee,
Sang-Ho Choi,
Heungsup Sung,
Mi-Na Kim,
Chang-Min Choi,
Sang-Bum Hong,
Yeon-Mok Oh,
Tae Sun Shim,
Younsuck Koh,
Yang Soo Kim,
Jun Hee Woo,
Sung-Han Kim
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ABSTRACT: A recently developed bronchoalveolar lavage (BAL) galactomannan (GM) assay shows promising results. We evaluated the diagnostic performance of this assay and analyzed risk factors for false-positive results.
A prospective cohort study was performed in a tertiary hospital over a 9-month period. We reviewed all adult patients who underwent GM assays of BAL. Patients were categorized with proven, probable, or possible invasive pulmonary aspergillosis (IPA) according to revised EORTC/MSG definitions. Each patient with a false-positive BAL GM result was matched with three patients with true-negative BAL GM result, and the risk factors for false-positive BAL GM results were determined.
Of 359 enrolled patients, 22 (6%) were diagnosed with IPA (1 proven, 17 probable, and 4 possible). Of the 22 patients with IPA, 17 (77%) had already received antifungal agents before the BAL GM assay was conducted. At an index cutoff value of ≥0.5, the BAL GM assay had a sensitivity of 64% (95% CI 41%-83%) and a specificity of 89% (95% CI 85%-92%). However, at an index cutoff value of ≥0.2, the BAL GM assay had a sensitivity of 86% (95% CI 65%-97%) and a specificity of 74% (95% CI 69%-79%). Of the 52 patients with positive BAL GM assay (≥0.5), 25 (7%) were false-positives. Univariate and multivariate analysis revealed that treatment with piperacillin-tazobactam or ampicillin-sulbactam was associated with false-positive BAL GM results.
The BAL GM assay appears promising for the diagnosis of IPA. However, treatment with certain antibiotics may interfere with the results of the BAL GM assay.
The Journal of infection 12/2010; 61(6):492-8. · 4.13 Impact Factor
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ABSTRACT: Of 149 patients with suspected cytomegalovirus (CMV) gastrointestinal disease, 51 (36%) confirmed cases, 6 (4%) probable cases, and 64 (45%) instances of non-CMV gastrointestinal disease were analyzed using the CMV antigenemia assay; 22 patients (5%) with indeterminate gastrointestinal disease were excluded. The sensitivity and specificity of the CMV antigenemia assay (defined as detection of > or =1 positive cells per 200,000 leukocytes) for diagnosis of CMV gastrointestinal disease were 54% (95% confidence interval, 41%-68%) and 88% (95% confidence interval, 77%-94%), respectively.
Clinical Infectious Diseases 06/2009; 48(12):e121-4. · 9.15 Impact Factor
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Young-Kook Kim,
Jieun Yu,
Tae Su Han, Seong-Yeon Park,
Bumjin Namkoong,
Dong Hyuk Kim,
Keun Hur,
Moon-Won Yoo,
Hyuk-Joon Lee,
Han-Kwang Yang,
V Narry Kim
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ABSTRACT: microRNAs (miRNAs) play integral roles in diverse processes including tumorigenesis. miRNA gene loci are often found in close conjunction, and such clustered miRNA genes are transcribed from a common promoter to generate polycistronic primary transcript. The primary transcript (pri-miRNA) is then processed by two RNase III proteins to release the mature miRNAs. Although it has been speculated that the miRNAs in the same cluster may play related biological functions, this has not been experimentally addressed. Here we report that the miRNAs in two clusters (miR-106b approximately 93 approximately 25 and miR-222 approximately 221) suppress the Cip/Kip family members of Cdk inhibitors (p57(Kip2), p21(Cip1) and p27(Kip1)). We show that miR-25 targets p57 through the 3'-UTR. Furthermore, miR-106b and miR-93 control p21 while miR-222 and miR-221 regulate both p27 and p57. Ectopic expression of these miRNAs results in activation of Cdk2 and facilitation of G1/S phase transition. Consistent with these results, both clusters are abnormally upregulated in gastric cancer tissues compared to the corresponding normal tissues. Ectopic expression of miR-222 cluster enhanced tumor growth in the mouse xenograft model. Our study demonstrates the functional associations between clustered miRNAs and further implicates that effective cancer treatment may require a combinatorial approach to target multiple oncogenic miRNA clusters.
Nucleic Acids Research 02/2009; 37(5):1672-81. · 8.03 Impact Factor
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ABSTRACT: The tumor suppressor p53 is central to many cellular stress responses. Although numerous protein factors that control p53 have been identified, the role of microRNAs (miRNAs) in regulating p53 remains unexplored. In a screen for miRNAs that modulate p53 activity, we find that miR-29 family members (miR-29a, miR-29b and miR-29c) upregulate p53 levels and induce apoptosis in a p53-dependent manner. We further find that miR-29 family members directly suppress p85 (the regulatory subunit of PI3 kinase) and CDC42 (a Rho family GTPase), both of which negatively regulate p53. Our findings provide new insights into the role of miRNAs in the p53 pathway.
Nature Structural & Molecular Biology 12/2008; 16(1):23-29. · 12.71 Impact Factor
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ABSTRACT: Small RNA-mediated gene silencing (RNA silencing) has emerged as a major regulatory pathway in eukaryotes. Identification of the key factors involved in this pathway has been a subject of rigorous investigation in recent years. In humans, small RNAs are generated by Dicer and assembled into the effector complex known as RNA-induced silencing complex (RISC) by multiple factors including hAgo2, the mRNA-targeting endonuclease, and TRBP (HIV-1 TAR RNA-binding protein), a dsRNA-binding protein that interacts with both Dicer and hAgo2. Here we describe an additional dsRNA-binding protein known as PACT, which is significant in RNA silencing. PACT is associated with an approximately 500 kDa complex that contains Dicer, hAgo2, and TRBP. The interaction with Dicer involves the third dsRNA-binding domain (dsRBD) of PACT and the N-terminal region of Dicer containing the helicase motif. Like TRBP, PACT is not required for the pre-microRNA (miRNA) cleavage reaction step. However, the depletion of PACT strongly affects the accumulation of mature miRNA in vivo and moderately reduces the efficiency of small interfering RNA-induced RNA interference. Our study indicates that, unlike other RNase III type proteins, human Dicer may employ two different dsRBD-containing proteins that facilitate RISC assembly.
The EMBO Journal 03/2006; 25(3):522-32. · 9.20 Impact Factor
