Publications by authors named "Chi Hwan Choi"

Article Synopsis
  • - The study focused on analyzing the genomes of monkeypox virus isolates from patients in the Republic of Korea to understand how the virus spreads and evolves over time.
  • - Eight monkeypox virus isolates were classified into Clade IIb, with notable lineages identified including B.1.1, A.2.1, and B.1.3, with B.1.3 being prevalent among isolates from 2023.
  • - The findings suggest that the unique genetic characteristics of these Far East isolates indicate a possible start of local transmission of the B.1.3 lineage in early 2023, particularly among six patients with no recent travel history.
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Following the worldwide surge in mpox (monkeypox) in 2022, cases have persisted in Asia, including South Korea, and sexual contact is presumed as the predominant mode of transmission, with a discernible surge in prevalence among immunocompromised patients. Drugs such as tecovirimat can result in drug-resistant mutations, presenting obstacles to treatment. This study aimed to ascertain the presence of tecovirimat-related resistant mutations through genomic analysis of the monkeypox virus isolated from a reported case involving prolonged viral shedding in South Korea.

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Ticks are important vectors of the tick-borne encephalitis virus (TBEV). In Kyrgyzstan, the livestock farming trade and nomadic lifestyle enable tick-borne diseases to be imported from neighboring countries, but there are few relevant studies. In this study, we collected 40 ticks from cattle in Kyrgyzstan.

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We report the complete genome sequence of the monkeypox virus strain MPXV-ROK-P1-2022, isolated from the first patient diagnosed with monkeypox in the Republic of Korea in June 2022. The virus was fully sequenced on the Illumina MiSeq instrument, and the phylogenetic tree showed that the strain belongs to lineage B.1.

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Objectives: Monkeypox outbreaks in nonendemic countries have been reported since early May 2022. The first case of monkeypox in the Republic of Korea was confirmed in a patient who traveled to Europe in June 2022, and an attempt was made to isolate and identify the monkeypox virus (MPXV) from the patient's specimens.

Methods: Clinical specimens from the patient were inoculated in Vero E6 cells.

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Francisella tularensis is the etiological agent of the zoonosis tularemia. Here, we report the draft genome sequence of F. tularensis subsp.

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To understand the origin of variants and their evolutionary history in the early stage of the COVID-19 pandemic, time-scaled phylogenetic and gene variation analyses were performed. The mutation patterns and evolution characteristics were examined using the Bayesian Evolutionary Analysis Sampling Trees (BEAST) with 349 whole-genome sequences available by March 2020. The results revealed five phylogenetic clusters (Groups A-E), with 408 nucleotide variants.

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A Gram-positive, aerobic, rod-shaped bacterium, designated as strain 1605-214, was isolated from the blood sample of a patient with cholangitis. Based on its 16S rRNA gene sequence, the strain 1605-214 belonged to the genus Cohnella and exhibited 97.9% sequence identity with Cohnella luojiensis DSM 24270 (GQ214052).

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Botulism is a neuroparalytic disease caused by a neurotoxin produced by . This study aimed to genetically characterize strain isolated from the first case of infant botulism in Korea reported on June 17, 2019. We isolated strain CB-27 from a stool sample of the patient and analyzed the toxin types and toxin gene cluster compositions of the strain using a mouse bioassay, real-time PCR, and genome sequencing.

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In this study, the complete genome sequences of strains NCCP 15687 and NCCP 16831 were determined and deposited in the National Culture Collection for Pathogens (NCCP) of South Korea. Genomic DNA was isolated from blood samples from patients infected with .

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High-throughput sequencing can produce hundreds of thousands of 16S rRNA sequence reads corresponding to different organisms present in the environmental samples. Typically, analysis of microbial diversity in bioinformatics starts from pre-processing followed by clustering 16S rRNA reads into relatively fewer operational taxonomic units (OTUs). The OTUs are reliable indicators of microbial diversity and greatly accelerate the downstream analysis time.

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Purpose: The aim of this study was to identify clinical predictive factors for tumor response after preoperative chemoradiotherapy (CRT) in rectal cancer.

Materials And Methods: The study involved 51 patients who underwent preoperative CRT followed by surgery between January 2005 and February 2012. Radiotherapy was delivered to the whole pelvis at a dose of 45 Gy in 25 fractions, followed by a boost of 5.

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