Distinct molecular evolution of influenza H3N2 strains in the 2016/17 season and its implications for vaccine effectiveness.

Influenza virus is a respiratory pathogen that causes seasonal epidemics by resulting in a considerable number of influenza-like illness (ILI) patients. During the 2016/17 season, ILI rates increased unusually earlier and higher than previous seasons in Korea, and most viral isolates were subtyped as H3N2 strains. Notably, the hemagglutinin (HA) of most Korean H3N2 strains retained newly introduced lysine signatures in HA antigenic sites A and D, compared with that of clade 3C.2a vaccine virus, which affected antigenic distances to the standard vaccine antisera in a hemagglutination inhibition assay. The neuraminidase (NA) of Korean H3N2 strains also harbored amino acid mutations. However, neither consistent amino acid mutations nor common phylogenetic clustering patterns were observed. These suggest that Korean H3N2 strains of the 2016/17 season might be distantly related with the vaccine virus both in genotypic and phenotypic classifications, which would adversely affect vaccine effectiveness.

D-Dimer Levels and Vitamin K Antagonist Therapy in Deep Vein Thrombosis of the Legs.

BACKGROUND: D-dimer levels are closely related to the clinical status of deep vein thrombosis (DVT). This study aimed to investigate the factors which were associated with the normalization of D-dimer level by vitamin K antagonist (VKA) therapy, the maintenance of normal D-dimer levels for 6 months during VKA therapy, and the recurrent elevations of D-dimer above normal level after VKA withdrawal, in DVT of the legs. METHODS: The 469 consecutive patients with first-episode leg swelling were examined. All blood tests were measured from the initially sampled blood before the administration of medications. RESULTS: Of the 469 patients, 288 (61.4%) showed positive D-dimer test. Radiologic examinations, including Doppler ultrasound and computed tomography venography, of the 288 patients revealed positive DVT of the legs in 135 (46.9%) patients and of these, 122 with total follow-up durations of >6 months were enrolled in this study. Linear regression analysis of 100 patients who experienced D-dimer normalization revealed initial D-dimer levels were positively correlated with D-dimer normalization time during VKA therapy (P = 0.010). Logistic regression analysis showed initial D-dimer level was negatively associated with the normalization of D-dimer levels by VKA therapy (P = 0.045), and being a woman (P = 0.005) and having lower protein C (P = 0.002) level had negative impacts on the maintenance of normal D-dimer levels for 6 months during VKA therapy. Finally, after VKA withdrawal, the recurrent elevations of D-dimer above normal level were more likely to occur in women than in men (P = 0.004). CONCLUSIONS: From these observations, it is suggested that higher initial D-dimer level, lower protein C level, and female gender may be the adverse risk factors for the treatment of DVT of the legs using VKA.

Detection, identification, and distribution of fungi in bronchoalveolar lavage specimens by use of multilocus PCR coupled with electrospray ionization/mass spectrometry.

As pulmonary fungal infections continue to increase due to an increasing number of immunocompromised patients, rapid detection and accurate identification of these fungal pathogens are critical. A broad fungal assay was developed by incorporating broad-range multilocus PCR amplification and electrospray ionization/mass spectrometry (PCR/ESI-MS) to detect and identify fungal organisms directly from clinical specimens. The aims of this study were to evaluate the performance of PCR/ESI-MS for detection, identification, and determination of the distribution of fungal organisms in bronchoalveolar lavage (BAL) fluid specimens. The BAL fluid specimens submitted for fungal culture at Vanderbilt University Medical Center between May 2005 and October 2011 were included. Cultures and identification were done using standard procedures. In addition, DNA was extracted from BAL fluid specimens, and fungal DNA amplification/identification were performed by PCR/ESI-MS. The results were compared with those of the standard cultures. A total of 691 nonduplicated BAL fluid specimens with sufficient leftover volume for molecular testing were evaluated using PCR/ESI-MS. Among them, 134 specimens (19.4%) were positive for fungi by both culture and PCR/ESI-MS testing. Of the dual-positive specimens, 125 (93.3%) were positive for Candida and Aspergillus species, with concordances between culture and PCR/ESI-MS results being 84 (67.2%) at the species level and 109 (87.2%) at the genus level. In addition, 243 (35.2%) and 30 (4.3%) specimens were positive only by PCR/ESI-MS or by culture, respectively (odds ratio [OR] = 11.95, 95% confidence interval [CI] = 7.90 to 18.17, P = 0.0000). Codetection of fungal organisms was noted in 23 (3.3%) specimens by PCR/ESI-MS, which was significantly higher than the 4 (0.6%) in which they were noted by culture (OR = 5.91, 95% CI = 1.93 to 20.27, P = 0.0002). Among 53 specimens in which cultures failed because of bacterial overgrowth, at least one fungus was identified in 26 specimens (47.3%) by PCR/ESI-MS. PCR/ESI-MS provides an advanced tool for rapid and sensitive detection, identification, and determination of the distribution of fungal organisms directly from BAL fluid specimens. Moreover, it detected fungal organisms in specimens in which cultures failed because of bacterial overgrowth. The clinical relevance of the significantly higher detection rate of fungal organisms by PCR/ESI-MS merits further investigation.

Two cases of peritonitis caused by Kocuria marina in patients undergoing continuous ambulatory peritoneal dialysis.

Kocuria spp. are members of the Micrococcaceae family that are frequently found in the environment and on human skin. Few human infections have been reported. We describe what appear to be the first two cases of Kocuria marina peritonitis in patients undergoing continuous ambulatory peritoneal dialysis.

The effects of hemodilution on acute inflammatory responses in a bleomycin-induced lung injury model.

Acute normovolemic hemodilution (ANH) can be used in acute lung injury (ALI) patients who refuse blood transfusions. To investigate the effects of hemodilution on the acute inflammatory response in lung injury, the authors studied the effects of ANH in a rat model of bleomycin-induced lung injury. Bleomycin (10 mg/kg) was used to induce lung injury in 2 groups of rats. The treatment groups included a lung injury group with hemodilution (HI), a lung injury group without hemodilution (NHI), and a control group. Hemodilution was performed by removing blood and substituting the same amount of hydroxyethyl starch solution targeted to 7.0 g/dL via the right and left internal jugular veins. At day 3 after bleomycin instillation, systemic hemoglobin concentration was 9.5 +/- 1.1 g/dL. Tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 levels measured in the bronchoalveolar lavage fluid (BALF), blood, and lung tissue were not significantly different between the HI and NHI groups 3 days after lung injury. Microscopic findings showed fibrosis and inflammation in the HI and NHI groups 28 days after lung injury, but no significant differences were found between the 2 groups. Hemodilution after bleomycin administration did not further affect the acute inflammatory response or lung injury.

Blocking of monocyte-associated B7-H1 (CD274) enhances HCV-specific T cell immunity in chronic hepatitis C infection.

The establishment of a chronic hepatitis C (CHC) infection is associated with defective HCV-specific T cell responses. Recent studies suggest that negative T cell regulators such as programmed death 1 (PD-1) contribute to the impairment of virus-specific T cell functions in chronic viral infections. However, the implication of peripheral monocytes from CHC patients in the inhibition of HCV-specific T cell responses is only partially defined. In this study, we found that B7-H1, a ligand of PD-1, was significantly up-regulated on monocytes of CHC patients. Proliferation of T cells in response to anti-CD3 antibody was directly suppressed by B7-H1+CD14+ monocytes, and this suppression was reversed by addition of antagonistic B7-H1 mAb. Furthermore, blocking of monocyte-associated B7-H1 (moB7-H1) significantly enhanced the frequency of IFN-gamma-producing, HCV-specific CD4+ and CD8+ effector T cells and the production of Th1 cytokines, such as IL-2 but not Th2 cytokines, including IL-4 and IL-10. Upon B7-H1 blockade, production of perforin was also increased in CD8+ T cells stimulated with HCV peptides. Our findings suggest that moB7-H1 inhibits HCV-specific CD4+ and CD8+ T lymphocyte proliferation and suppresses Th1 cytokine production and perforin secretion. Blockade of the B7-H1 pathway thus represents an attractive approach in the treatment of chronic HCV infection.

Screening and identification of unexpected red cell antibodies by simultaneous LISS/Coombs and NaCl/Enzyme gel methods.

We evaluated the clinical usefulness of simultaneous LISS/Coombs and NaCl/Enzyme testing using the gel method for screening and identification of unexpected antibodies in 15,014 samples. When unexpected antibodies were detected by either screening test, those antibodies were identified using both the LISS/Coombs and the NaCl/Enzyme gel test. The positive screening rates of the LISS/Coombs, NaCl/Enzyme, and combined tests (excluding 25 autoantibody cases) were 0.48%, 1.29%, and 1.39%, respectively. Among the 57 samples positive by both screening methods, the antibodies in 19.3% could be identified only by the NaCl/Enzyme method. Among the 137 samples positive only by NaCl/Enzyme screening, 74.5% showed positive results in antibody identification only by the NaCl/Enzyme test, although 7.3% were also positive in the LISS/Coombs test. The NaCl/Enzyme method thus showed about threefold higher detection rates than the LISS/Coombs method, especially in screening for Rh antibodies, and higher exact identification rates and discriminatory power for identifying mixed antibodies. Addition of the NaCl/Enzyme method to routine laboratory procedures may detect and identify considerable numbers of significant antibodies that might be missed if only the LISS/Coombs method is used.

Acute infectious peritonitis caused by Vibrio fluvialis.

Vibrio fluvialis is a Gram-negative, oxidase-producing, halophilic bacterium that, as a pathogen, has been implicated mainly as a cause of gastroenteritis. We describe a case of V. fluvialis peritonitis after a traffic accident that is, to our knowledge, the 1st report of non-continuous ambulatory peritoneal dialysis-related acute peritonitis caused by this organism.

Prevalence, identification, and antimicrobial susceptibility of Staphylococcus lugdunensis from various clinical specimens in Korea.

Staphylococcus lugdunensis is an unusually virulent coagulase-negative staphylococcus (CoNS) that can cause many types of infection. All culture specimens were collected from patients at Inje University Busan Paik Hospital between October 2005 and March 2006. S. lugdunensis was identified using the phenotypic biochemical tests and 16S rDNA sequencing. Among 358 CoNS, three strains were identified as S. lugdunensis. All three isolates showed positive results in the clumping factor testing, but the L-pyrrolidonyl-beta-naphthylamide hydrolysis test was positive in only one and the ornithine decarboxylase test in two. Two of the three isolates were correctly identified by API Staph, but none of them was identified correctly by the Vitek I system. All three strains were penicillin resistant secondary to beta-lactamase production. S. lugdunensis was an unrecognized but infrequent cause of infection.

Improvement of neutralizing activity of human scFv antibodies against hepatitis B virus binding using CDR3 V(H) mutant library.

CDR3 of the heavy-chain variable region of immunoglobulin is a region in which somatic mutation occurs heavily after secondary antibody response, resulting in an affinity maturation of antibodies in vivo. The aim of this study was to improve the affinity of a human single-chain variable fragment (scFv) specific for pre-S1 of hepatitis B virus (HBV) by introducing random mutagenesis in CDR3 variable region of heavy chain (V(H)) of the parental scFv clone 1E4. By using a BIAcore for panning and screening, we have selected three clones (A9, B2, and B9) with lower highest affinity (K(D)) than 1E4. Affinities of selected clones ranged from 1.7 x 10(7) mol/L to 6.3 x 10(8) mol/L, which were increased by factors of 1.4 to 4.0, respectively, compared to the parental clone. Binding inhibition assay using flow cytometry and polymerase chain reaction revealed that B2 (6.4 x 10(8) mol/L) had a higher neutralizing activity against pre-S1 or HBV virion binding to liver cell line. This anti-pre-S1 scFv can be considered as a potential therapeutic tool for a passive immunotherapy for HBV infection.

Current status of therapeutic plasma exchange in Korea.

A nationwide survey on the status of plasma exchange in Korea was performed during the 2 year period 2001-02. Data from 496 patients were collected from 15 major hospitals. The most common indication was myasthenia gravis (15.3%), followed by thrombotic thrombocytopenic purpura (14.5%) and hemolytic uremic syndrome (9.7%). Clinical improvement was noted in 70.1% of the 415 cases. Plasma exchange by centrifugation alone accounted for 92.4%. Postcentrifugal filtration was carried out in 5.6% and double filtration in 2.0% of treatments. The most common instruments for the centrifugation were Cobe Spectra (71.3%) and Fenwal CS3000 (15.8%). Filtration was performed by either Kuraray KM8300 or Kuraray KM8800. The overall frequency of complications was 11.1% (293/2647 cases), of which symptomatic hypocalcemia was the most common (2.3%).

Coombs negative autoimmune hemolytic anemia in Crohn's disease.

BACKGROUND: Anemia is a common, important extraintestinal complication of Crohn's disease. The main types of anemia in patients with Crohn's disease are iron deficiency anemia and anemia of chronic disease. Although patients with Crohn's disease may experience various type of anemia, autoimmune hemolytic anemia (AIHA) in patients with Crohn's disease, especially Coombs-negative AIHA, is very rare. CASE REPORT: A 41-year-old woman with Crohn's disease presented to our emergency room (ER) with dark urine, dizziness, and shortness of breath. The activity of Crohn's disease had been controlled, with Crohn's disease activity index (CDAI) score below 100 point. On physical examination, the patient had pale conjunctivae and mildly icteric sclerae. Serum bilirubin was raised at 3.1 mg/dL, lactate dehydrogenase (LDH) level was 1418 U/L and the haptoglobin level was <3 mg/dL. Results of direct and the indirect Coombs tests were all negative. We then measured the RBC-IgG to evaluate the possibility of Coombs-negative AIHA. The result revealed that RBC-IgG level was 352 IgG molecules/cell, with the cut-off value at 78.5 IgG molecules/cell. CONCLUSIONS: We report a case of Coombs-negative AIHA in a patient with Crohn's disease with chronic anemia, diagnosed by red blood cell-bound immunoglobulin G (RBC-IgG) and treated with steroids therapy.

Clinical characterization of DISP1 haploinsufficiency: A case report.

Chromosome 1q41q42 microdeletions have been classified as a syndrome consisting of significant developmental delay, seizures, and characteristic dysmorphic features. They harbor different breakpoints and their smallest region of overlap at 1q41q42 involves several genes, including DISP1. Deletion or variants of DISP1 have been proposed as a candidate for the midline defects in this syndrome but may not be responsible for its major features in some cases. We report here a patient with a 183-kb deletion in chromosome 1q41, representing the smallest deletion identified among cases of the 1q41q42 microdeletion syndrome. The involved genes are DISP1 and TLR5. This patient developed seizures and developmental delay but showed no facial dysmorphism or organ defects. This deleted region was inherited from a phenotypically normal parent. This case may help define the role of the DISP1 haploinsufficiency in phenotype and support the suggestion that DISP1 mutation or deletion may reveal incomplete penetrance.

Serotyping and antimicrobial susceptibility of Salmonella spp.: nationwide multicenter study in Korea.

The study aimed to investigate the prevalence of various serotypes and extended-spectrum ß-lactamase-producing features of Salmonella strains and to determine the antimicrobial susceptibility of 256 Salmonella strains other than Salmonella serotype Typhi, which were isolated at 12 university hospitals in Korea. We identified 46 serotypes of Salmonella spp. Serogroup D was the most common (39.5%), followed by B (32.4%), C (22.7%), E (2.7%), A (2.3%), and G (0.4%). The three most common Salmonella serotypes were Enteritidis (36.3%), Typhimurium (16.8%), and Infantis (7.8%). Six strains that belonged to serotype Paratyphi A and nine that belonged to serotype Paratyphi B were also detected. The 256 Salmonella strains had a 38.7% rate of resistance to ampicillin, 23.0% to chloramphenicol, 8.2% to cefotaxime, 8.6% to ceftriaxone, and 6.3% to trimethoprim-sulfamethoxazole. The antimicrobial resistance rates of Salmonella serogroups B and D were higher than those of the other serogroups. Seven isolates carried blaCTX-M: four CTX-M-15, two CTX-M-14, and one CTX-M-3.

Evaluation of DNA extraction methods and their clinical application for direct detection of causative bacteria in continuous ambulatory peritoneal dialysis culture fluids from patients with peritonitis by using broad-range PCR.

BACKGROUND: The aims of this study were to compare several DNA extraction methods and 16S rDNA primers and to evaluate the clinical utility of broad-range PCR in continuous ambulatory peritoneal dialysis (CAPD) culture fluids. METHODS: Six type strains were used as model organisms in dilutions from 10(8) to 10(0) colony-forming units (CFU)/mL for the evaluation of 5 DNA extraction methods and 5 PCR primer pairs. Broad-range PCR was applied to 100 CAPD culture fluids, and the results were compared with conventional culture results. RESULTS: There were some differences between the various DNA extraction methods and primer sets with regard to the detection limits. The InstaGene Matrix (Bio-Rad Laboratories, USA) and Exgene Clinic SV kits (GeneAll Biotechnology Co. Ltd, Korea) seem to have higher sensitivities than the others. The results of broad-range PCR were concordant with the results from culture in 97% of all cases (97/100). Two culture-positive cases that were broad-range PCR-negative were identified as Candida albicans, and 1 PCR-positive but culture-negative sample was identified as Bacillus circulans by sequencing. Two samples among 54 broad-range PCR-positive products could not be sequenced. CONCLUSIONS: There were differences in the analytical sensitivity of various DNA extraction methods and primers for broad-range PCR. The broad-range PCR assay can be used to detect bacterial pathogens in CAPD culture fluid as a supplement to culture methods.