• 한국미생물·생명공학회지
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• 제28권4호
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• pp.189-194
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• 2000

Microorganisms causing bovine mastitis, swine diarrhea and swine pneumonia were isolated from farms in Chungbuk and Kyunggi Province and the isolates were identified using microbial identification system(MIS). The most common isolates from bovine mastitis were Staphylococcus sp.,Streptococcus sp., and Corynebacterium sp., those from swine diarrhea were Escherichia coli, Salmonella sp., and Clostridium perfringens, those from swine pneumonia were Bordetella bronchiseptica and Pasteurella multocida. Examination of 16 antibiotics against these pathogens revealed that the incidence of antibiotic-resistant microoganisms were very high and that many of these isolates had multiple resistance to various commercially available antibiotics such as penicillin, ampicillin, erythromycin, streptomycin, norfloxacin, and tetracycline. These results suggest that the use of antibiotics in a farm should be controlled in order to decrease the number of antibiotic-resistant microorganisms were very high and that many of these isolates had multiple resistance to various commercially available antibiotics such as penicillin, ampicillin, erythromycin, streptomycin, norfloxacin, and tetracycline. These results suggest that the use of antibiotics in a farm should be controlled in order to decrease the number of antibiotic-resistant microorganisms.

• Asian-Australasian Journal of Animal Sciences
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• 제17권8호
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• pp.1076-1079
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• 2004

Antibiotics are common additives in culture media during in vitro embryo development, but their effects on oocyte maturation in vitro have not been tested. The effects of penicillin, streptomycin and gentamicin on the maturational competence and subsequent development potential of goat follicular oocytes were examined after parthenogenetic activation in vitro. Maturation rates at 24 h after in vitro maturation, and parthenogenetic development at 48 h after activation, were evaluated by observing the protruding first polar body and the 4 cell stage cleavage, respectively. When streptomycin was present in the maturation medium, the percentages of matured oocytes 24 h after activation were significantly (p<0.01) lower than those from the other groups (42.5-45.7% vs. 69.1-73.8%). Penicillin and gentamicin treatment did not affect the maturation rates or the percentages reaching the 4 cell stage 48 h after activation. There was no significant difference in cleavage rates among the different antibiotic treatments 48 h after activation. Therefore, streptomycin suppresses the in vitro maturation of immature goat oocytes, but does not influence their subsequent development.

• Journal of Microbiology
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• 제35권2호
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• pp.103-108
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• 1997

To improve the detection of methicillin resistant staphylococci, lowered incubation temperature (30.deg.) and inclusion of sodium chloride in media have been empirically recommended. However, in this study, we found that sodium chloride in Peptone-Yeast Extract-K$\_$2/HPO$\_$4/ (PYK) medium decreased methicillin minimum inhibitory concentrations. Divalent cations were shown to restore the expression of staphylococcal methicillin resistance. However, when it was determined by efficiency of plating, sodium chloride increased methicillin resistance expression on agar medium in which higher divalent cations were contained in the agar medium. The decrease of minimum inhibitory concentrations at 30.deg.C by sodium chloride occurred in Brain Heart Infusion but did not occur in other media investigated. Interestingly, both PYK and Brain Heart Infusion media had peptone, which contain cholic acids having detergent activities. Inclusion of sodium chloride in PYK caused a higher rate of autolysis. Penicillin binding protein 2a that has a low affinity to beta-lactam antibiotics, was highly inducible in methicillin resistant Staphylococcus epidermidis strains. In this study, we found that autolysins that are activated by the sodium chloride decreased the minimum inhibitory concentration at 30.deg.C, and peptidoglycan is weakened due to the presence of methicillin. Peptone in the media may aggravate the fragile cells. However, stabilization due to the presence of divalent cations and production of penicilin binding protein 2a increase the survival of staphylococci.

• Advances in Traditional Medicine
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• 제5권1호
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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.

• Asian-Australasian Journal of Animal Sciences
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• 제16권3호
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• pp.425-429
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• 2003

Staphylococcus aureus is a major pathogen for cattle, causing various forms of subclinical and clinical mastitis and could be a causative agent of food poisoning, it produces various superantigenic exotoxins which have a great public health significance. A total of 72 S. aureus clinical isolates from dairy farms located in Kyunggi Province Korea were examined for the species identification by biochemical method, and for the detection of $\beta$-lactamase, enterotoxin and other exotoxins genes by PCR. The results of species identification by biochemical method agreed with those of PCR done with species specific primer STA-AU. $\beta$-lactamase is an enzyme closely associated with the resistance to antibiotic penicillin, which is an important means of treatment of mastitis, all the isolates were positive for the presence of genes encoding $\beta$-lactamase, which were reproduced in penicillin susceptibility disc assay. Six types of toxin genes, Staphylococcal enterotoxin (SE)A, SEB, SEC, SEE, toxic shock syndrome toxin (TSST-1) and exfoliative toxin A (ET A) were detected in 72 isolates by PCR associated genotypic method in this study, none of the isolates carried the genes for enterotoxin D (SED) and exfoliative toxin B (ETB). The occurrence rate of exotoxin genes rated as 12.5%, and the precision of the PCR identification results has been confirmed using the reference strains.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.534-540
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• 1999

Thirty-seven strains of Bacillus thuringiensis were isolated from Korean soil and examined for H-antigen serotyping, toxicity, and different spectra of biological activities. The isolate HL-175 bore a specific H-antigen, different from the 51 known serotypes, a spherical $\delta$-endotoxin crystal, and minor different biochemical characteristics. It was resistant to ampicillin, colistin, and penicillin G. Therefore, it was classified as a new serotype, H52, with the name kim. The other 36 isolates also produced endotoxin crystals and endospores. The crystal shape of eight strains was cuboidal while the others were bipyramidal. Biochemical characteristics of the isolates were only slightly different from the known serotypes of B. thuringiensis. The flagellar (H) antigens of the 36 isolates were identified as: one colmeri (H21), three galleriae (H5a,5b); two pakistani (H13); one toumanoffi (H11a, 11b); and twenty-nine kurstaki (H3a,3b). All 36 isolates were resistant to ampicillin, colistin, penicillin, cephalothin, and chloramphenicol.

• International Journal of Oral Biology
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• 제33권4호
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• pp.197-203
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• 2008

It has been reported that the antimicrobial susceptibility patterns of viridans streptococci vary according to geographical region. Although several studies on the antibiotic resistance of viridans streptococci in foreign countries have been reported, little is known about the distribution of resistance among viridans streptococci in Korea. In this study, 88 isolates of viridans streptococci from Korean students' dental plaque were identified as 12 different species. The susceptibility of these isolates to 8 antibiotics was investigated. The in vitro antibiotic activity of penicillin G, ampicillin, vancomycin, streptomycin, gentamicin, erythromycin, amoxicillin, and tetracycline was measured by the broth microdilution method. The range of the minimum inhibitory concentrations (MIC), MIC50, MIC90, and the percentage of the susceptible isolates were determined. Streptococcus mutans and Streptococcus salivarius were susceptible to the 8 antibiotics. Isolates with resistance to vancomycin, streptomycin, and amoxicillin were not found. The overall resistance rates of the 88 isolates to penicillin G, ampicillin, gentamicin, erythromycin, and tetracycline were 12.5%, 62.5%, 62.5%, 26.1%, and 26.1%, respectively.

• 한국균학회지
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• 제8권1호
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• pp.63-68
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• 1980

${\beta}-Lactamase$ was isolated from the culture filtrate of the penicillin producing strain, Penicillium chrysogenum Q176. When the pH of the medium was adjusted to 5.0 at the start of culture, a rapid increase in pH accompanied by the synthesis of penicillin was observed in the first $2{\sim}4$ days. When the pH of medium was brought to 6.0 or 7.0 the opposite was observed: high yield of the enzyme and little of the antibiotics in the medium. The optimum enzyme activi­ty was at a temperature of $40^{\circ}C$ and around pH 7.0. A partially purified enzyme was assayed on several different substrates including penicillins V and G, 6-aminopenicillanic acid, cephalospo­rin C. The V max values calculated were 24.5, 20.4, 7.6, and 6.1 mmoles/hour, and the $K_m$, values were 16.4, 12.6, 7.5, and 6.9 mM in the order given.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권3호
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• pp.200-204
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• 2001

In this study, nanofiltration was applied to the concentration of the 6-aminopenicillinic acid (6-APA) from bioconverted penicillin solution and also to its mother liquor. The 6-APA in the solution was concentrated from 0.211 mol/L to 0.746 mol/L by nanofiltration. The final maximum concentration was 3.6 times higher than the initial concentration an the recovery yield was 97% to 99% of the original 6-APA. The concentrated solution was crystallized with the yields of 88.9-90.2% and the purity of the crystallized product was about 98%. The concentration of 6-APA in the mother liquor after crystallization was 0.014 mol/L and thus was concentrated 20-30 fold by nanofiltration and crystallization. The recovery of 6-APA was over 98%. The salts contained in the mother liquor, such as NH$_4$Cl and KCl, could be removed by allowing them to permeate through the membrane.

• 한국미생물·생명공학회지
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• 제43권1호
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• pp.84-90
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• 2015

젓갈로부터 분리된 ampicillin 감수성, coagulase 음성 Staphylococcus 속 17 균주의 항생물질내성 및 위해성을 평가하였다. 15 균주는 한 종류 이상의 항생물질에 대한 내성을 나타내었고, penicillin G 내성 균주가 가장 높은 빈도로 검출되었다. PCR 증폭에 의한 항생물질내성 유전자 존재 확인 결과, trimethoprim 내성 관련 dfrA 유전자와 tetracycline 내성 관련 tetK 유전자를 각각 보유한 두 균주가 확인되었다. α 형 용혈활성은 검출되지 않았지만, 다섯 균주가 δ 형의 용혈을 나타내었고, 그 중 두 균주는 β 형 용혈활성을 나타냈으며, 12 균주가 biofilm을 형성하였다. 본 실험에서 수행한 모든 안전성 평가 결과는 균주 특이적으로 나타났다.