• Journal of Medicine and Life Science
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• 제20권1호
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• pp.43-47
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• 2023

Streptococcus suis (S. suis) is an emerging zoonotic pathogen that causes bacterial meningitis in humans. S. suis is an encapsulated gram-positive facultative anaerobic bacterium and is an important pathogen in pigs. This infectious disease usually manifests in humans as meningitis, endocarditis, septicemia, and arthritis. Most cases originate in Southeast Asia, and human S. suis infections are often reported in countries with a high density of pigs. Meningitis is a common clinical manifestation of S. suis infection. Moreover, hearing loss is a common complication that can be bilateral, profound, and/or permanent. This report presents two cases of bacterial meningitis and hearing loss caused by S. suis in patients without a history of direct exposure to pigs in an intensive pork industry region.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.345-352
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• 2023

Antibacterial activity against foodborne bacteria (Bacillus cereus, Staphylococcus aureus, Salmonella Enteritidis) and inhibitory activity against murine norovirus, a human norovirus surrogate, of 28 extracts from plants endemic to Korea were investigated in this study. All plant extracts showed antibacterial activity only against gram-positive bacteria, B. cereus and S. aureus. Extracts from Callistemon speciosus and Nymphaea tetragona showed inhibition zones of 16.54 and 24.35 mm against B. cereus and S. aureus, respectively, presenting the highest antibacterial activities recorded in this study. Among all samples, Ardisia japonica extract at concentrations of 100 and 200 ㎍/mL showed the highest virucidal activities of 96.6 and 100.0%, respectively. Ardisia japonica, Duchesnea indica, Polygonum aviculare, and Geum japonicum extracts showed high antibacterial and virucidal activity simultaneously without Raw 264.7 cell cytotoxicity. These plant extracts may serve as potential antimicrobials to control foodborne infections.

• Journal of Microbiology and Biotechnology
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• 제28권8호
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• pp.1367-1375
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• 2018

Silver nanoparticles have been widely applied for biomedical areas owing to their potent antiviral and antibacterial activities. Synthesis of silver nanoparticles using biomacromolecules is more efficient, environment-friendly, and cost-saving compared with the traditional approach. In this paper, a novel approach was developed to establish a reaction system with $Ag^+-BH4^--sericin$ to synthesize silver nanoparticles conjugated to sericin (AgNPs-Sericin). Sericin could be as a good dispersant and stabilizing agent, which is able to modify nanoscaled AgNPs, the average diameter of which was only $3.78{\pm}1.14nm$ prepared in a 0.3 mg/ml sericin solution. The characterizations of the AgNPs-Sericin were determined by FTIR, thermogravimetry, and XRD analyses. The results showed that the synthesized AgNPs conjugated with sericin as organic phase. Via SAED and XRD analysis, we showed that these AgNPs formed polycrystalline powder with a face-centered cubic structure of bulk metals. Moreover, we investigated the antiviral and antibacterial activities of AgNPs-Sericin, and the results showed that AgNPs-Sericin exhibited potent anti-HIV-1 activity against CCR5-tropic and CXCR4-tropic strains, but no significant cytotoxicity was found toward human genital epithelial cells compared with free silver ions, which are accepted as a commonly used potent antimicrobial agent. Moreover, its antibacterial activity was determined via flow cytometry. The results showed that AgNPs-Sericin could suppress gram-negative (E. coli) and gram-positive (S. aureus) bacteria, but more was potent for the gram-negative one. We concluded that our AgNPs-Sericin could be a potential candidate as a microbicide or antimicrobial agent to prevent sexually transmitted infections.

• 미생물학회지
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• 제54권1호
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• pp.77-78
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• 2018

포도상구균(Staphylococcus aureus)은 그람양성이고 구형의 박테리아로 Firmicutes 문에 속하며, 피부나 호흡기 감염 그리고 식중독의 주요 감염원 중에 하나이다. 포도상구균을 감염시키는 박테리오파지는 포도상구균 감염에 효과적인 처방으로 쓰일 수 있다. 본 연구에서는 충청남도에 위치한 가축 농장의 오수에서 분리된 포도상구균 박테리오파지 SA7 균주의 유전체 초안을 분석하였다. 본 균주는 G + C 비율이 34.1%이며, 34,730 bp 로 구성된 dsDNA 를 지니고 있었다. 염색체에서 53 개의 단백질 코딩 유전자가 확인되었으며, 이 중 23 개의 유전자는 BLASTp 분석으로부터 기능을 가지고 있다고 추정되었다. 나머지는 가설 단백질 혹은 보존 단백질이었다.

• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.500-505
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• 2019

Staphylococcus aureus is a round-shaped, gram-positive bacterium that can cause numerous infectious diseases ranging from mild infections such as skin infections and food poisoning to life-threatening infections such as sepsis, endocarditis and toxic shock syndrome. Various antibiotic-resistant strains of S. aureus have frequently emerged, threatening human lives significantly. Despite much research on the genetics of S. aureus, many of its genes remain unknown functionally and structurally. To counteract its toxins and to prevent the antibiotic resistance of S. aureus, our understanding of S. aureus should be increased at the proteomic scale. SAV0927 was first sequenced in an antibiotic resistant S. aureus strain. The gene is a conserved hypothetical protein, and its homologues appear to be restricted to Firmicutes. In this study, we determined the crystal structure of SAV0927 at $2.5{\AA}$ resolution. The protein was primarily dimeric both in solution and in the crystals. The asymmetric unit contained five dimers that are stacked linearly with ${\sim}80^{\circ}$ rotation by each dimer, and these interactions further continued in the crystal packing, resulting in a long linear polymer. The crystal structures, together with the network analysis, provide functional implications for the SAV0927-mediated protein network.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1820-1826
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• 2017

Lipoteichoic acid (LTA), a cell wall component of gram-positive bacteria, is recognized by Toll-like receptor 2, expressed on certain mammalian cell surfaces, initiating signaling cascades that include nuclear factor kappa-light-chain-enhancer of activated B cells (NF-${\kappa}B$) and mitogen-activated protein kinase. There are many structural and functional varieties of LTA, which vary according to the different species of gram-positive bacteria that produce them. In this study, we examined whether LTA isolated from Staphylococcus aureus (aLTA) affects the expression of junction proteins in keratinocytes. In HaCaT cells, tight junction-related gene expression was not affected by aLTA, whereas adherens junction-related gene expression was modified. High doses of aLTA induced the phosphorylation of extracellular signal-regulated protein kinases 1 and 2, which in turn induced the epithelial-mesenchymal transition (EMT) of HaCaT cells. When cells were given a low dose of aLTA, however, NF-${\kappa}B$ was activated and the total cell population increased. Taken together, our study suggests that LTA from S. aureus infections in the skin may contribute both to the outbreak of EMT-mediated carcinogenesis and to the genesis of wound healing in a dose-dependent manner.

• Journal of Microbiology and Biotechnology
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• 제30권9호
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• pp.1305-1309
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• 2020

Insects possess biological defense systems that can effectively combat the invasion of external microorganisms and viruses, thereby supporting their survival in diverse environments. Antimicrobial peptides (AMPs) represent a fast-acting weapon against invading pathogens, including various bacterial or fungal strains. A 37-residue antimicrobial peptide, papiliocin, derived from the swallowtail butterfly Papilio xuthus larvae, showed significant antimicrobial activities against several human pathogenic bacterial and fungal strains. Jelleines, isolated as novel antibacterial peptides from the Royal Jelly (RJ) of bees, exhibit broad-spectrum protection against microbial infections. In this study, we developed a novel antimicrobial peptide, PAJE (RWKIFKKPFKISIHL-NH₂), which is a hybrid peptide prepared by combining 1-7 amino acid residues (RWKIFKK-NH₂) of papiliocin and 1-8 amino acid residues (PFKISIHL-NH₂) of Jelleine-1 to alter length, charge distribution, net charge, volume, amphipaticity, and improve bacterial membrane interactions. This novel peptide exhibited increased hydrophobicity and net positive charge for binding effectively to the negatively charged membrane. PAJE demonstrated antimicrobial activity against both gram-negative and gram-positive bacteria, with very low toxicity to eukaryotic cells and an inexpensive process of synthesis. Collectively, these findings suggest that this novel peptide possesses great potential as an antimicrobial agent.

• Pediatric Infection and Vaccine
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• 제17권1호
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• pp.36-48
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• 2010

목 적 : 항암 화학 요법을 받는 소아 혈액 종양 환아들에서의 균혈증은 예후에 큰 영향을 미칠 수 있어 이에 대한 신속한 경험적인 항생제 치료는 매우 중요하다. 이러한 경험적 치료의 근거를 마련하기 위하여 소아 혈액 종양 환아들의 균혈증의 임상 양상, 검사 소견, 위험 인자, 원인균의 분포 및 임상경과에 대한 최근 경향에 대한 정보를 파악하고자 하였다. 방 법: 2005년 7월부터 2008년 6월까지 한양대학교병원 소아청소년과 혈액 종양 분과에서 치료받은 환아들에게서 발생한 총 212 발열례의 의무 기록을 후향적으로 분석하였다. 이들을 균혈증이 발생한 군과 균혈증이 발생하지 않은 군으로 나눠서 호중구 감소증 여부 및 정도, 이식 여부 및 종류, 중심 정맥관 유무 및 종류 등을 비교하였고, 원인균의 종류, 항생제 감수성 및 임상경과를 조사하였다. 결 과: 3년 동안 총 63명의 소아 혈액 종양 분과 환아에서 212 발열례가 발생하였으며, 40례(18.9%)에서 균혈증이 발생하였다. 발열례 중 호중구 감소증이 동반된 경우는 157례였고 37례(23.6%)의 균혈증이 발생하였다. 동정된 총 균주는 45균주로 그람 양성균 23균주(51.1%), 그람 음성균 20균주(44.4%), 진균 2균주(4.4%)였다. 그람 양성균 중 가장 흔하게 분리된 균주는 Coagulase-negative Staphylococcus (46.7%)였으며, 그람 음성균 중에는Acinetobacter species (15.6%)가 가장 분리율이 높았다. 호중구 감소증이 있는 환자들에 게서 호중구 감소증이 없는 환자들보다 균혈증이 유의하게 많이 발생하였다(P =0.002). 13례의 균혈증은 이식을 시행받은 환자들에게 발생하였으며, 호중구 감소증을 보인 환자 중에서 이식환자가 이식을 받지 않은 환자보다 균혈증이 많이 발생하였다(P =0.008). 제대혈이식을 시행받은 군에서 기타 다른 형태의 이식을 받은 군에 비해 균혈증의 발생률이 유의하게 많았다(P =0.001). 균혈증 환자들의 사망률은 균에 따른 차이를 나타내지 않았다. 하지만 다제내성균의 경우에는 사망률이 상대적으로 높은 경향을 보였지만 이는 통계적 유의성은 없었다. (P =0.335). 중심 정맥관을 지닌 환자에서 발열이 발생한 경우 Chemoport를 지닌 환자에서 Hickman 도관을 지닌 환자에서보다 균혈증의 발생이 많았으며(P =0.029), Chemoport를지닌군에서 그람 양성균이, Hickman 도관을 지닌 군에서는 그람 음성군이 유의하게 많은 비율로 배양되었다(P =0.001). 항생제 감수성 검사에서 그람양성균은 모두 penicillin과 oxacillin에 내성을 보였고, vancomycin과 teicoplanin에는 모두 감수성을나타내었다. 그람 음성균에서는 amikacin, gentamicin, imipenem, piperacillin/tazobactam에 대한 내성률이 각각 45.0%, 30.0%, 20.0% 및 20.0%였다. 결 론 : 본 연구는 소아 혈액 종양 환자들에서 발열례의 균혈증의 빈도 및 감염원의 분포와 호중구 감소, 이식, 및 중심 정맥관의 종류가 균혈증 발생에 미치는 영향과, 동정된 원인균의 항생제 내성률을 밝혔으며 이러한 자료는 향후 발열을 동반한 호중구 감소증을 가지는 환자에서 적절한 경험적 항생제 선택에 고려되어야 할 것이다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권4호
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• pp.420-429
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• 2000

Oral & maxillofacial infections are most commonly odontogenic in origin. Although such infections are usually self-limiting, they may occasionally spread deeply into fascial spaces or planes far from the initial site of involvement. If early diagnosis and appropriate therapy is delayed, complications such as mediastinal extension, retropharyngeal spread and airway obstruction could happen to the patients. For the study of the microbiology, we have retrospectively analysed the oral & maxillofacial infected patients in the Dept. of Oral & Maxillofacial Surgery. In-Ha University Hospital from 1997 September to 2000 April. The results were as follows 1. The male patients were more common than female, with male 61.9% and female 38.1%. 2. Dental originated infections were most common cause with the incidence of 62%. 3. Most common fascial space involved was buccal space 42cases(37.2%) followed by submandibular space 13cases(11.5%), infraorbital space 13cases(11.5%), masseteric space 11cases(9.7%), periapical abscess 11cases(9.7%). 4. The causative organisms isolated from the pus culture were Gram Positive Bacterial species, which were 46cases(31.9%) of Streptococcus viridans, 16cases(8.6%) of ${\alpha}$ and ${\beta}-hemolytic$ streptococcus, 4cases(3.1%) of Strep.-group D non enterococci, 7cases(5.1%) of Staphylococcus Coa. neg., 5cases(3.9%) of Staphylococcus aureus, 3cases(2.3%) of Enterococcus faecalis, 1case(0.8%) of Bacillus species, 1case(0.8%) of Peptostreptococcus, 1case(0.8%) of Clostridium and Gram negative bacterial species, which were 4cases(3.1%) of Acinetobacter baumannii, 2cases(1.6%) of Pseudomonas aeruginosa, 2cases(1.6%) of Burkholderia cepacia, 1case(0.8%) of Neisseria species, 1case(0.8%) of Klebsiella pneumoniae, 1case(0.8%) of Klebsiella oxytoca, 1case(0.8%) of Escherichia coli. 5. In drug sensitivity test, high resistant tendency was found in Penicillin system(Penicillin G 83.3%, Ampicillin 60%) and Aminoglycosides (Gentamycin 50%, Tobramycin 45.5%), but tertiary Cephalosporin system(Cefoperazone 9.1%, Ceftazidime 18.2%), and glycopeptides system (Teicoplanin 0%, Vancomycin 0%) showed lower resistancy.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권3호
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• pp.296-301
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• 2008

Actinomyces is a part of the normal oral flora, but under certain circumstances it may become pathogenic. Actinomycosis is a chronic granulomatous infective disease caused by microaerophilic Gram-positive bacteria of the genus actinomyces. It can involve almost any system, but principally affects the head and neck. Because the lesions in the submandibular region and the angle of the jaw give the face a swollen, indurated appearance, actinomycosis of mandible can be easily misdiagnosed in its acute or early state of infection. In these cases the disease usually presented as a swelling suggestive of an abscess or mimicking a neoplasm. The yield from standard cultures was poor and repeated sampling and anaerobic culture may be needed to obtain a positive culture. So actinomycosis should always be considered in a differential diagnosis of all infections of the cervicofacial area. Diagnosis of actinomycosis is made based on the histopathology, the clinical presentation and past dental history. We experienced a case of actinomycosis in the masseter muscle and present the case with review of literature.