• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.543-552
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• 2020

For efficient prevention and treatment of enteric colibacillosis, understanding about latest virulence factors and antimicrobial resistance of Escherichia coli is essentially needed. The aim of this study was to survey antimicrobial resistance and determine the prevalence of fimbriae and enterotoxin genes among 118 pathogenic E. coli isolates obtained from Korean pigs with diarrhea between 2016 and 2017. The genes for the toxins and adhesins were amplified by polymerase chain reaction (PCR). The susceptibility of the E. coli isolates to antimicrobials were tested using the standard Kirby-Bauer disk diffusion method. The most prevalent fimbrial antigen was F18 (40.7%), followed by F4 (16.9%), and the most prevalent combinations of toxin genes were Stx2e (21.2%), STb:EAST-1 (19.5%), and STa:STb (16.9%), respectively. Among the pathotypes, enterotoxigenic E. coli (ETEC) was the most predominant (67.8%), followed by Shiga-toxin producing E. coli (STEC, 23.7%). We confirmed high resistance rates to chloramphenicol (88.1%), tetracycline (86.4%), streptomycin (86.4%), and ampicillin (86.4%). And the majorities of isolates (90.7%) showed multi-drug resistance which means having resistance to 3 or more subclasses of antimicrobials. Results of this study can be a source of valuable data for investigating the epidemiology of and control measures for enteric colibacillosis in Korean piggeries.

• Journal of environmental and Sanitary engineering
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• v.22 no.4
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• pp.55-63
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• 2007

We investigated the distribution and drug susceptibility test of V. vulnificus isolated from environmental sources in Incheon. In this survey, total 4,302 samples were obtained from different sites of the Incheon coastal area during the periods from march 2004 to November 2006. Among the 4,302 samples, 310 strains were isolated. The isolation rates of Vibrio vulnificus from fish, shellfish, estuarine water and sediment were 6.7%, 4.7%, 12.4% and 23.2%, respectively. The highest isolation rate was 14.6% in September and in spite of low temperature the isolation rate was 5.1% in November. The highest rate of antibiotic resistance was observed against streptomycin(15.3%), cefazolin(8.5%), cephalothin(8.3%), amikacin(8.3%), cefoxitin(6.7%) and nalidixic acid(6.7%). Seventeen percent of isolates were observed to be resistant to two or more of the antibiotics tested.

• Clinical and Experimental Pediatrics
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• v.51 no.10
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• pp.1031-1037
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• 2008

Macrolide antimicrobial agents including erythromycin, roxithromycin, clarithromycin, and azithromycin are commonly used in the treatment of respiratory tract infections in children. Newer macrolides that have structural modifications of older drug erythromycin show improved change in the spectrum of activity, dosing, and administration. However, recent studies reported that increasing use of macrolide antibiotics is the main force driving the development of macrolide resistance in streptococci. In particular, azithromycin use is more likely to select for macrolide resistance with Streptococcus pneumoniae than is clarithromycin use, a possible reflection of its much longer half life. Recently, erythromycin resistance rates of S. pneumoniae and Streptococcus pyogenes are rapidly increasing in Korea. Two main mechanisms of acquired macrolide resistance have been described, altered binding site on the bacterial ribosome encoded by the ermB gene and active macrolide efflux pump encoded by the mef gene. Relationship between the susceptibility of S. pneumoniae and the response to macrolides has been shown in studies of acute otitis media, but less clear in cases of pneumonia. This article reviews the spectrum of activity, pharmacokinetic properties, mechanisms of action and resistance, and clinical implication of resistance on the treatment of respiratory tract infections in children.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.357-364
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• 2009

Phospholipids are crucially important in a cell membrane function and could thereby influence antibiotic susceptibility. In order to investigate the antifungal mechanism the total lipid was extracted from C. albicans treated with citronellol or thymol in concentration of their minimum inhibiting concentration and the changes in phospholipids composition were analyzed using ketoconazole as control. The cell growth and total lipid synthesis in cell walls of C. albicans were inhibited by treatment with citronellol. The levels of total lipids were decreased by 35.85% compared to the control. They also showed a significant decrease in the contents of phospholipid, phosphatidylcholine(PC), phosphatidyl ethanolamine(PE) and phosphatidylinositol(PI). As the result of GC assay for total fatty acid methyl esters of PC, PE and PI in C. albicans treated with citronellol, it was found that the major fatty acid composed of three phospholipid were palmitic acid, stearic acid and oleic acid. Moreover, the pattern of the fatty acid compositions of PC, PE and PI were changed by the oil. Based on the results, the anti-Candida mechanism of citronellol or thymol might be closely associated with disrupting the permeability barriers of the fungal cell wall composition or construction.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1214-1220
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• 2005

Decreased porin-mediated outer membrane penetration of hydrophilic antibiotics is a common mechanism of antibiotic resistance in Gram-negative bacteria. This study was undertaken to determine whether a null mutation in Pseudomonas putida would suppress porin synthesis, and therefore reduce the susceptibility of the organism to streptomycin, norfloxacin, and tetracycline. Inverse PCR amplification and double-stranded DNA sequencing were used to identify chromosomal genes carrying TnphoA'-1 inserts. Genome database available was used to identify putative homologue genes, one of which encodes protein with homology to domains of the MutS of P. putida, suggesting a crucial role in the multidrug resistance. Increased resistance to streptomycin, norfloxacin, and tetracycline might be due to accumulation of compensatory mutations. Either no growth or slow growth was observed in P. putida KH1027 when grown in minimal medium containing gluconate, glucose, or citrate; however, it is not clear whether the growth patterns contributed to the multidrug resistance.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.69-77
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• 1986

The purpose of this study was the examination for presence of K99 antigen (K99), enterotoxigenicity, 0-groups, colicin and antibiotic susceptibility among E. coil isolated from calves and cows. A total of 49(18.7%) among 262 strains, isolated from 30(26.5%) out of 113 calves and cows, possesed K99, and thirty three of 49 $K99^+$ strains produced ST. Of the strains of diarrheal calf origin which less than 15 days old, a high correlation was observed between enterotoxigenic ability and K99: 92.3% of the $K99^+$ strains produced heat stable enterotoxin(ST). In O group typing of 33 $ST^+$ strains, they belonged to O20(48.4%), O8(9.1%), O9(6.1%), O139(6.1%), O149(6.1%), O101(3.0%), O115(3.0%), except six which were untypable or autoagglutinable. Of 262 E. coil isolates, 30 strains(13.3%) produced colicin and K99 were detected in 6 strains. One hundred eighty eight strains(71.8%) of 262 E. coil isolates were resistance to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, alone or in combination thereof. One hundred and fourteen(60.6%) out of 188 drug resistance strains carried R factor($R^+$) which were transferable to the recipients by conjugation. Sixty five $R^+$ strains(57.0%) carried thermo-sensitive R plasmid.

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.287-295
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• 1990

The purpose of this study was the examination for presence of pilus antigen, O serogroups, colicin production, antibiotic susceptibility and plasmid profiles among E coli isolated from diarrheal piglets and fattening pigs in Taegu province. Of 145 E coli isolated, 98 strains (67.4%) possesed pilus antigens which belonged to either K88 (47.6%), K99 (11.7%) or 987P (8.3%) types. Fifty-nine strains (40.7%) were classified into tenO serogroups and their types were O8 (22.0%), O20(16.9%), O141(15.3%), O9(10.2%), O45(10.2%), O139(8.5%), O064(6.8%), O149(5.0%), O157(3.4%), and O115(1.7%). Thirty-three strains (22.8%) were colicinogenic and 6 strains (4.1%) were hemolytic. One hundred and thirty-nine strains (95.9%) of 145 E coli isolates were resistant to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, rifampicin and nalidixic acid, alone or in combination thereof. Ninety strains (64.7%) of 139 drug resistant strains carried R factor (R) which were transferable to the recipient by conjugation. In gel electrophoresis for the isolation of plasmid DNA, the number of plasmid DNA band varied from 2 to 11 in 16 E coli with pilus antigen. It's molecular weight ranged from 1.0 to 60.0 megadalton.

• Advances in Traditional Medicine
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• v.5 no.1
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• pp.57-61
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• 2005

Ethanol and aqueous extracts of Cassia auriculata were tested in vitro against fungi (Candida albicans and Microsporum canis) and bacteria (Escherichia coli, Salmonella enteriditis, Staphylococcus aureus and Bacillus subtilis). M. canis showed dose-dependent susceptibility only towards ethanol leaf and bark extracts. C. albicans, were resistant to all types of plant extracts. Results were statistically smaller to antifungal drug ketoconazole and miconazole at equivalent concentration. Both ethanol and aqueous extracts of Cassia auriculata leaves and barks exhibit antibacterial activity against S. aureus and only the ethanol extracts of leaf and bark were detected against Bacillus subtilis. The results were compared to antibacterial drugs chloramphenicol, ampicillin, penicillin G, and enrofloxacin. The antibacterial activity was statistically similar to penicillin G. Based on the current findings, it can be concluded that this plant has antimicrobial activity, which is as potent as standard antimicrobial drugs.

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.104-110
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• 2009

Phenylketonuria (PKU) is an inherited metabolic disorder caused by mutations in the phenylalanine catabolic enzyme, phenylalanine hydroxylase (PAH). The use of phenylalanine ammonia-lase (PAL) by oral and parenteral routes as a therapeutic drug for PKU has been severely limited due to inactivation by intestinal proteolysis and immune reactions. PEGylation was applied to PAL to reduce the degrees of antigenicity and proteolytic inactivation. Kinetic experiments with native PAL and pegylated PALs were performed, and pH stability, temperature stability, and protease susceptibility were evaluated. Enzyme linked immunosorbent assay (ELISA) was carried out to measure the immune complex between pegylated PALs and antiserum that had been extracted from a PAL-immunized mouse. Pegylated PAL, especially branched pegylated PAL (10 kDa, 1:32), was more active for phenylalanine and more stable in pancreatic proteases than native PAL. Native PAL was optimal at pH 8.5, corresponding to the average pH range of the small intestine; the same finding was noted for pegylated PALs. All linear and branched pegylated PALs had low reactivity with mouse antiserum, especially the 1:16 formulation with linear 5-kDa PEG and the 1:32 formulation with branched 10-kDa PEG. Therefore, we suggest the 1:32 formulation with branched 10-kDa PEG as the most promising formulation for enzyme replacement therapy.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.103-107
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• 1985

A variety of plasmid curing agents such as sodium dodecyl sulfate, acriflavine, ethidium bromide, and mitomycin-C were used to cure Bacillus subtilis cells of streptomycin resistant factor. The drug susceptibility was increased by 0.1％ sodim dodecyl sulfate at stationary growth phase. The curing frequency was obtained highly at 4 $\mu\textrm{g}$/$m\ell$ of acriflavine, 10 $\mu\textrm{g}$/$m\ell$ of ethidium bromide, and 200 $\mu\textrm{g}$/$m\ell$ of mitomycin-C. respectively. Curing action occurred competitively for the streptomycin and terramycin resistant factors in B. subtilis.