Publications by authors named "Sahyun Hong"

Objective: Shiga toxin-producing Escherichia coli (STEC) is a water- and food-borne pathogenic agent that causes diarrhea, hemorrhagic colitis, hemolytic uremic syndrome (HUS), and end-stage renal disease. As the annual incidence of STEC increases, disease control is also becoming important in Korea. In this study, we aimed to analyze the incidence trends and characteristics of STEC isolated from diarrheal patients over 10 years.

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Article Synopsis
  • In August 2016, South Korea experienced a cholera outbreak affecting three patients, marking the first domestically linked outbreak in 15 years.
  • Whole genome sequencing of the cholera isolates from the patients and seawater revealed a high genetic similarity, linking it to a previous outbreak in the Philippines in 2011.
  • The study indicates seawater as the likely source and emphasizes the need for regular surveillance of South Korea's coastal areas to prevent future outbreaks.
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is a major foodborne pathogen that is increasingly found worldwide and that is transmitted to humans through meat or dairy products. A detailed understanding of the prevalence and characteristics of in dairy cattle farms, which are likely to become sources of contamination, is imperative and is currently lacking. In this study, a total of 295 dairy cattle farm samples from 15 farms (24 visits) in Korea were collected.

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Sequence type (ST) 33 of Shiga toxin-producing (STEC) strain O91:H14 has been proposed as a potential domestic clone of STEC in Korea because of its high prevalence among human patients with mild diarrhea or asymptomatic carriers. Herein, the clonal diversity of 17 STEC O91:H14 isolates of ST33 during 2003 to 2014 was analyzed by pulsed-field gel electrophoresis, including 14 isolates from human patients and 3 from retail meats. Their virulence characteristics, acid resistance, and antimicrobial susceptibility were also determined.

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Article Synopsis
  • * Epidemiological investigations tracked the spread by examining contacts, seafood, and seawater in the environment.
  • * Microbiological tests revealed that the cholera strains from the patients and seawater were identical, indicating a strong connection between food and environmental sources.
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Objectives: An atypical strain with a plural agglutination pattern [i.e., reacting not only with serum samples containing type antigen II but also with serum samples containing group antigens (3)4 and 7(8)] was selected for genome sequencing, with the aim of obtaining additional comparative information about such strains.

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Objectives: To investigate the prevalence and toxin production characteristics of non-emetic and emetic strains isolated via the laboratory surveillance system in Korea.

Methods: A total of 667 strains were collected by the Korea National Research Institute of Health laboratory surveillance system from 2012 to 2014. The collected strains were analyzed by geographical region, season, patient age, and patient sex.

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Objectives: The aim of this study was to characterize the pathogens responsible for causing diarrhea according to season, region of isolation, patient age, and sex as well as to provide useful data for the prevention of diarrheal disease.

Methods: Stool specimens from 14,886 patients with diarrhea were collected to identify pathogenic bacteria from January 2014 to December 2014 in Korea. A total of 3,526 pathogenic bacteria were isolated and analyzed according to season, region of isolation, and the age and sex of the patient.

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We investigated an October 2014 outbreak of illness caused by Shigella sonnei in a daycare center in the Republic of Korea (South Korea). The outbreak strain was resistant to extended-spectrum cephalosporins and fluoroquinolones and was traced to a child who had traveled to Vietnam. Improved hygiene and infection control practices are needed for prevention of shigellosis.

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An outbreak of extended-spectrum β-lactamase (ESBL)-producing Shigella sonnei infections occurred in a school for disabled children in Gyeongbuk Province, Republic of Korea, in 2008. Five students were affected. Pulsed-field gel electrophoresis (PFGE) analysis revealed that all of the ESBL-producing S.

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Forty domestic and travel-associated Campylobacter jejuni isolates were analyzed by profiling 7 pathogenic genes (cdtB, cadF, Cj0131, ciaB, racR, wlaN, and virB11) along with multilocus sequence typing (MLST) and antimicrobial susceptibility testing. cdtB, cadF, and Cj0131 were present in all isolates, whereas virB11 was not detected in either domestic or travel-associated isolates. ciaB was present in all domestic isolates and 94% of travel-associated isolates.

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Campylobacter jejuni is a major gastrointestinal pathogen in humans. Poultry is a primary reservoir for C. jejuni, and C.

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Objectives: We aimed at evaluating the virulence of atypical Shigella flexneri II:(3)4,7(8) by DNA microarray and invasion assay.

Methods: We used a customized S. flexneri DNA microarray to analyze an atypical S.

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Objectives: The aim of this study was to investigate the distribution of Shiga toxin (Stx) gene-positive stool samples from dairy farmer and slaughterhouse workers in Gyeonggi-Do province.

Methods: A total of 621 samples from healthy farmers and 198 samples from slaughterhouse workers were screened by polymerase chain reaction (PCR) for Shiga toxigenic Escherichia coli (STEC) infection on stool samples.

Results: The PCR product of Stx-encoding genes was detected in 21 (3.

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Background: Slaughterhouse workers are in direct contact with cattle nearly every day. The purpose of this study was to survey the presence and distribution of anti-Shiga toxin 1 (Stx1) immunoglobulin G (IgG) in slaughterhouse workers, enabling a study of the serologic response to this toxin while working in an area at high-risk of Stx-producing Escherichia coli (STEC) infection.

Methods: One thousand seven hundred and twenty-nine serum samples from healthy slaughterhouse employees were collected and surveyed by indirect enzyme-linked immunosorbent assay (ELISA).

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Background: Dairy farmers perform various types of work and are in direct contact with dairy cattle nearly every day. The purpose of this study was to assess the prevalence of Shiga toxin-encoding genes (stx) among dairy farmers and to evaluate the relationship between stx and risk factors.

Methods: A questionnaire developed in-house was sent to dairy farmers in Gyeonggi Province, Korea by registered mail.

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Three types of serotypically atypical Shigella flexneri strains were isolated from 2007 to 2008 in patients at the Korea National Institute of Health (NIH). These strains were characterized and compared with serologically typical S.flexneri.

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A total of 1602 stool samples from healthy employees in a slaughter company were screened by PCR for Shiga toxin (Stx)-producing Escherichia coli (STEC). The PCR product of Stx-encoding genes was detected in 90 (5.6%) of 1602 stool samples.

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We previously reported that E7 subunit and DNA vaccines are both capable of inducing antitumor protection through induction of antigen-specific CTL. In this study, we investigated their ability to control established tumors according to tumor size, vaccine doses, and vaccine delivery routes. Antitumor therapeutic efficacy of both vaccine types was dependent on tumor burden.

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An immunosensor for the detection of Vibrio cholerae O1 was developed on the basis of surface plasmon resonance (SPR). A protein G layer was fabricated by means of the chemical coupling between the free amine (-NH2) groups of protein G and the activated carboxyl groups present on a self-assembled monolayer (SAM) consisting of a mixture of 11-mercaptoundecanoic acid (MUA) and hexanethiol (molar ratio of 1:2). A monoclonal antibody, which was confirmed to be specific to V.

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The plaA gene encoding a protein that contains the cytosolic Phospholipase A(2) (cPLA(2)) motif is cloned for the first time from the filamentous fungus, Aspergillus nidulans. The translated 837 amino acid protein product of plaA comprises conserved lipase regions that are present in most mammalian cPLA(2) homologs. High expression of plaA was observed in glucose-lactose medium by Northern blot analyses.

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The expression of matrix metalloproteinases (MMPs) has been implicated in the invasion and metastasis of cancer cells. Here we examined the effect of ascochlorin, a prenyl-phenol anti-tumor compound from the fungus Ascochyta viciae, on the regulation of signaling pathways that control MMP-9 expression in human renal carcinoma (Caki-1) cells. Ascochlorin reduced the invasive activity of Caki-1 cells and inhibited phorbol 12-myristate 13-acetate-induced increases in MMP-9 expression and activity in a dose-dependent manner.

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Mesangial expansion caused by cell proliferation and glomerular extracellular matrix accumulation is one of the earliest renal abnormalities observed at the onset of hyperglycemia in diabetes mellitus. Transcription factor Sp1 is implicated in the transcriptional regulation of a wide range of genes participating in cell proliferation, and is assumed to play an essential role in mesangial expansion. We have generated a phosphorothioated double-stranded Sp1-decoy oligodeoxynucleotide that effectively blocks Sp1 binding to the promoter region for transcriptional regulation of transforming growth factor-beta1 and plasminogen activator inhibitor-1.

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