• Bulletin of the Korean Chemical Society
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• 제8권5호
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• pp.418-421
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• 1987

Syntheses of cefotaxime analogs with halosubstituted phenyltetrazolthiomethyl at the $C_{3^-}$position are described. Their in vitro potency was established. The compounds exhibited a broad antibacterial spectrum. Some of these compounds showed activity against Gram-positive bacteria superior to the parent cefotaxime. Against Gram-negative bacteria, these compounds are less effective than cefotaxime.

• Archives of Pharmacal Research
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• 제15권2호
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• pp.187-189
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• 1992

In the preceding paper, we reported the synthessis and biological properties of cephalosporins having quinoliniumthiomethyls at the C-3 position and demonstrated that quinoliniumthiomethylcephalosporins exhibited an extended antibacterial spectrum including antipseudomonal activity, especially strong antiGram-positive activity. With the aim of elaboration to optimize the antibacterial potency of the quaternary ammonium cephalosporins, we have studied the modification of substituents in the pyrrolidine ring of cefepime 1 which is characterized by its potent activity.

• Tuberculosis and Respiratory Diseases
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• 제59권5호
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• pp.522-529
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• 2005

배 경 : 국내에서는 중증지역획득폐렴 원인균의 빈도에 대한 자료가 부족하여, 외국의 항균제 투여 지침을 따르고 있는 실정이다. 이에 본 저자들은 중증지역획득폐렴을 일으키는 원인균과 초기 경험적 항균제 투여 종류에 따른 치료 성적을 분석하여 향후 경험적 항균제 선택에 도움을 주고자 본 연구를 수행하였다. 대상 및 방법 : 2002년 3월부터 2004년 3월 사이에 울산대학교 의과대학 서울아산병원 내과계 중환자실에 입원했던 18세 이상의 성인 환자들 중 지역획득폐렴의 정의를 만족하는 환자를 대상으로 후향적 의무기록 분석을 시행하였다. 세균학적 검사 결과로 원인균의 빈도를 조사하였고, 항균제 투여 종류에 따른 중환자실 재원기간, 중환자실 사망률과 30일 사망률을 비교 분석하였다. 결 과 : 대상 기간 동안 총 116명의 환자가 본 연구 대상에 포함되었다. 대상 환자의 평균 연령은 66.5 (19-89)세 였고, 남자가 95 (81.5%)명으로 다수를 차지하였다. 원인균은 116명의 환자 가운데 54명 (46.5%)에서 동정되었는데, S. pneumoniae 14례, P. aeruginosae 9례, K. pneumoniae 9례, S. aureus 8례, H. influenza 7례 이었다. 비정형 폐렴균은 Legionella 3례, M. pneumoniae 2례 이었다. 총 116명의 환자의 중환자실 평균 재원 일수는 $15.0{\pm}13.7$일 이었으며, 중환자실 사망자 수는 27명 (23.2%), 30일 사망자 수는 33명 (28.4%) 이었다. 전체적으로 항균제 투여 군간의 중환자실 재원일수와 중환자실 사망률 및 30일 사망률은 통계적으로 유의한 차이를 보이지 않았다 (p=0.482, 0.719,0.682). 사망 예후 인자의 다변량 분석에서는 급성호흡곤란증후군, 급성 신부전, K. pneumoniae가 통계적으로 유의한 예후 인자이었다. 결 론 : 본 연구에서 중증지역획득폐렴의 원인균은 S. pneumoniae, P. aeruginosae, K. pneumoniae, S. aureus가 가장 많았고, K. pneumoniae는 높은 사망률을 보여 주었다. 초기 경험적 항균제 종류에 따른 중환자실 재원일수 및 30일 사망률은 차이가 없었다.

• 약학회지
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• 제38권3호
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• pp.322-331
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• 1994

For the development new cephalosporin antibiotics with aminothiazolmethoxyimino moiety in the C-7 position and triazolthiomethyl moiety in the C-3 position of cephem ring, $7{\beta}$-[(z)-2-(2-aminothiasol-4-yl)-2-(methoxyimino)acetamido]-3-[5-(aryl or het.)-4-phenyl-4H-1,2,4-triazol-3-yl]thiomethyl-3-cephem-4-carboxylic acids were synthesized. These compounds were tested for antimicrobial activitiy in vitro against ten species of microorganisms. It showed remarkable antibacterial activity against Bacillus subtilis ATCC 6633, Micrococcus luteus ATCC 9341 and Escherichia coli ESS. The antibacterial activity of most new compounds showed more active than cefazoline, but these compounds were lower active than cefotaxime against Pseudomonas aeruginosa IFO 13130.

• Journal of Veterinary Science
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• 제23권3호
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• pp.37.1-37.8
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• 2022

Background: Avian pathogenic Escherichia coli (APEC) causes colibacillosis, resulting in significant economic losses in the poultry industry. Objectives: In this study, the molecular characteristics of two extended-spectrum beta-lactamase (ESBL)-producing APEC isolates were compared with previously reported ESBL-producing E. coli isolates. Methods: The molecular characteristics of E. coli isolates and the genetic environments of the ESBL genes were investigated using whole genome sequencing. Results: The two ESBL-producing APEC were classified into the phylogenetic groups C and B1 and ST410 and ST162, respectively. Moreover, the ESBL genes of the two isolates were harbored in different Inc plasmids. The EC1809182 strain, harboring the bla_CTX-M-55 gene on the plasmid, exhibited extensive homology to IncFIB (98.4%) and IncFIC(FII) (95.8%). The EC1809191 strain, harboring the bla_CTX-M-1 gene, was homologous to IncI1-I (Gamma) (99.3%). All chromosomes carried the multidrug transporter, mdf(A) gene. Mobile genetic elements, adjacent to CTX-M genes, facilitated the dissemination of genes in the two isolates, analogous to other ESBL-producing E. coli isolates. Conclusions: This study clarifies the transmission dynamics of CTX-M genes and supports strengthened surveillance to prevent the transmission of the antimicrobial-resistant genes to humans via the food chain.

• Pediatric Infection and Vaccine
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• 제7권2호
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• pp.225-232
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• 2000

목 적 : 올바른 항생제의 사용을 위해서는 우선 항생제 사용 실태의 파악과 함께 검사실의 확충, 의료진의 협조 등 다양한 노력과 보완이 요구된다. 본 연구는 적절한 항생제 사용의 기반을 마련하고자 현재 시행되고 있는 항생제 사용 실태를 조사하였다. 방 법 : 전북대학교병원에 입원한 환자 총 1,833명을 대상으로 의무기록을 통하여 항생제의 사용 여부, 종류, 사용 기간, 용량, 항생제의 투약 시작 시기 및 투여 목적을 조사하였다. 결 과 : 전체 조사 대상 환자 1,833명 중 입원 기간 중 항생제를 사용한 환자는 1,231명으로 67.2%였으며, 계별로 살펴보면 내과계는 전체 1,014명 중 497명(49.0%)이 항생제를 사용하였고, 외과계는 819명 중 734명(89.6%)에서 항생제를 사용하였다. 전체 항생제를 사용한 환자 1,231명 중 706명(57.4%)에서 예방 목적으로 사용하였고, 525명(42.6%)에서 치료 목적으로 사용하였다. 항생제를 사용한 환자의 경우 사용된 항생제의 갯수를 살펴보면 총 1,231명 중 1가지 항생제를 사용한 경우는 125명(10.2%)이었으며, 2가지를 사용한 경우는 311명(25.3%), 3가지를 사용한 경우는 562명(45.6%), 4가지 이상을 사용한 경우는 233명(18.9%)으로, 70% 이상의 환자에서 3가지 이상의 항생제가 사용하였다. 사용 항생제의 종류는 ${\beta}$-lactam, aminoglycoside, quinolone, macrolide, 항진균제, metronidazole, clindamycin, trimethoprim-sulfamethoxazole, glycopeptide, 그리고 fosfomycin 등으로 아주 다양하였다. 전체적인 그룹별 사용률을 보면 ${\beta}$-lactam은 57.0%, aminoglycoside는 34.5%, quinolone은 3.6% 그리고 기타 그룹은 4.9%로, ${\beta}$-lactam과 aminoglycoside가 가장 많이 사용되었다. 결 론 : 대부분의 환자에서 2가지 이상의 항생제의 병합요법이 보편화되어 있다는 점은 진지하게 검토되어야 할 것으로 생각된다. 아울러 임상적으로 전신 세균 감염이 확실한 경우에도 원인 병원체를 찾아내기 위한 적극적인 노력이 부족한 경우도 상당수 있어 이에 대해서도 검사실과 함께 적극적인 개선의 노력이 필요할 것으로 생각된다. 수술 환자의 예방적 화학 요법에 대해서도 개선이 필요할 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.115-122
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• 2021

Phenol-soluble modulins (PSMs) are responsible for regulating biofilm formation, persister cell formation, pmtR expression, host cell lysis, and anti-bacterial effects. To determine the effect of psm deletion on methicillin-resistant Staphylococcus aureus, we investigated psm deletion mutants including Δpsmα, Δpsmβ, and Δpsmαβ. These mutants exhibited increased β-lactam antibiotic resistance to ampicillin and oxacillin that was shown to be caused by increased N-acetylmannosamine kinase (nanK) mRNA expression, which regulates persister cell formation, leading to changes in the pattern of phospholipid fatty acids resulting in increased anteiso-C15:0, and increased membrane hydrophobicity with the deletion of PSMs. When synthetic PSMs were applied to Δpsmα and Δpsmβ mutants, treatment of Δpsmα with PSMα1-4 and Δpsmβ with PSMβ1-2 restored the sensitivity to oxacillin and slightly reduced the biofilm formation. Addition of a single fragment showed that α1, α2, α3, and β2 had an inhibiting effect on biofilms in Δpsmα; however, β1 showed an enhancing effect on biofilms in Δpsmβ. This study demonstrates a possible reason for the increased antibiotic resistance in psm mutants and the effect of PSMs on biofilm formation.

• 대한의생명과학회지
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• 제18권3호
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• pp.299-306
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• 2012

Recently, the prevalence of 16S rRNA methylase conferring high-level resistance to aminoglycosides has been increasing in Gram-negative bacilli globally. We determined the prevalence and genotype of these methylase-producing bacteria, and characterized the co-resistance to ${\beta}$-lactam antibiotics and quinolone in Gram-negative clinical isolates collected in 2010 at a hospital in Korea. Among 65 amikacin-resistant isolates screened from 864 Gram-negative bacilli (GNB), 16S rRNA methylase genes were detected from 49 isolates, including Acinetobacter baumannii (43), Klebsiella pneumoniae (2), Proteus mirabilis (2) and Serratia marcescens (1), Empedobacter brevis (1). All of the 16S rRNA methylase genotype was armA and no variant sequences of amplified PCR products for armA were noted. The 16S rRNA methylase producing bacteria showed much higher resistance to aminoglycoside for Enterobacteriaceae and glucose non-fermenting (NF)-GNB and to imipenem for glucose NF-GNB, than the non-producing isolates. All of the 16S rRNA methylase producing Enterobacteriaceae had the extended-spectrum-${\beta}$-lactamase. In addition, two K. pneumoniae concurrently produced both plasmid-mediated AmpC ${\beta}$-lactamase and qnrB gene. All of the amikacin-resistant A. baumannii (43) co-harbored armA 16S rRNA methylase and $bla_{OXA-23}$ carbapenemase. In conclusion, 16S rRNA methylase producing bacteria were very prevalent among GNB in South Korea, and were commonly associated with co-resistance, including carbapenem and quinolone.

• 대한의생명과학회지
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• 제13권4호
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• pp.293-304
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• 2007

The emergence of extended spectrum $\beta$-lactamase (ESBL) producing bacteria is worldwide concern. Until recently, the most frequently identified strains in the Republic of Korea were E. coli and Klebsiella spp. The incidence of resistance to extended spectrum $\beta$-lactam antibiotics is increasing in Wonju city, Korea. Total 57 strains of ESBL producing E. coli and Klebsiella species were isolated from Wonju Christian Hospital during a 9 month-period from April to December, 2003. To determine the prevalence and genotypes of the ESBL producing clinical isolates, antibiotic susceptibility and ESBL activity test by VITEK system and double disk synergy (DDS) test, and PCR based genotyping were performed. Fourteen (82%) isolates of 17 ESBL producing E. coli were found to have $bla_{TEM}$ gene and 5 (29%) isolates were found to have $bla_{CTX-M}$ gene by polymerase chain reaction (PCR). Thirty (75%) isolates of 40 ESBL producing Klebsiella species with $bla_{TEM}$ gene, 38 (95%) isolates with $bla_{SHV}$ gene, and 7 (20%) isolates with $bla_{CTX-M}$ type gene were also identified. Enterobacterial repetitive intergenic consensus (ERIC) PCR and similarity index by dendrogram for genetical similarity to band pattern of each clinical isolates were examined. ESBL producing E. coli were grouped into 6 clusters up to 84% of similarity index and Klebsiella species were grouped into 12 clusters up to 76% of similarity index. In conclusion, ESBL producing clinical isolates were characterized with the results from antimicrobial resistance pattern and genetical similarity using ERiC PCR.

• Archives of Pharmacal Research
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• 제17권1호
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• pp.21-25
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• 1994

Physico-chemical characterization of human renal dipeptidase was carried out. It was a glycoprotein with a subunit MW of approximately 47,700 dalton. The pH optimum was at 8 and its stable conformation was retained between pH 5 and 12. The kinetic parameters determined with imipenem, a noval ${\beta}-lactam$ antibiotic, were Vmax, $5.21\;\mu{mol/min/mg}$; km, 4.35 mM ; and Ki with cilastatin, $0.25\;\mu{M}$ Cilastatin demonstrated reversible competitive inhibition.