• Journal of Microbiology
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• 제44권4호
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• pp.432-438
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• 2006

Twelve actinomycete strains were isolated from Egyptian soil. The isolated actinomycete strains were then screened with regard to their potential to generate antibiotics. The most potent of the producer strains was selected and identified. The cultural and physiological characteristics of the strain identified. the strain as a member of the genus Streptomyces. The nucleotide sequence of the 16S rRNA gene (1.5kb) of the most potent strain evidenced a 99% similarity with Streptomyces spp. and S. aureofaciens 16S rRNA genes, and the isolated strain was ultimately identified as Streptomyces sp. MAR01. The extraction of the fermentation broth of this strain resulted in the isolation of one major compound, which was active in vitro against gram-positive, gram-negative representatives and Candida albicans. The chemical structure of this bioactive compound was elucidated based on the spectroscopic data obtained from the application of MS, IR, UV, $^1H$ NMR, $^{13}C$ NMR, and elemental analysis techniques. Via comparison to the reference data in the relevant literature and in the database search, this antibiotic, which had a molecular formula of $C_{19}H_{29}NO_2$ and a molecular weight of 303.44, was determined to differ from those produced by this genus as well as the available known antibiotics. Therefore, this antibiotic was designated Meroparamycin.

• KSBB Journal
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• 제26권1호
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• pp.19-26
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• 2011

Of the 500 Actinomycetes isolates obtained from soil, one isolate grown on maltose as the sole carbon source produced compound BHK-P19, which inhibited the growth of multiple drug resistant P. aeruginosa 0245. Ultraviolet radiation mutagenesis curtailed production of BHK-P19. Mutation of the BHK-P19 producer using N-methyl-N'-nitro-N-nitroso-guanidine obviated the antibacterial activity to P. aeruginosa 0245, but not towards P. aeruginosa 0225. The mixing of BHK-P19 and BHK-S5 culture extracts inhibited P. aeruginosa 0254, 0225 and 1113. The combined application of BHK-P19 culture extract and Schizandra chinensis Baillon extract inhibited P. aeruginosa 0254, 0225, 0826, 1113, 1378, 1731 and 2492. Use of various concentrations of BHK-P19 culture extract and ampicillin markedly increased antibacterial activity against multi-drug resistant P. aeruginose 1113.

• 대한수의학회지
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• 제34권3호
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• pp.501-510
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• 1994

This paper deals with the distribution, reservoir and mode of spread of infection on 6 hatcheries in Taegu, Kyungpook and 5 broiler farms in Kyungpook during the period from June 1991 to June 1992. Isolated Salmonella were examined for serotypes, biotyping of Salmonella(S) typhimurtum, antibiotic susceptibility and some biochemical characteristics. Forty two Salmonella strains were isolated from 42(2.7% of 1,577 caecal samples of chicks, and their serotypes were S typhimurium 10, S typhimurium var Copenhagen 5, S infantis 4, S thompson 3, and untypable 20. The isolation rate of Salmonella varied from 0 to 5.1% in 6 hatcheries and that of Salmonella from 5 broiler farms was 10. 5%. Biotypes of 10 S typhimurium and 5 S typhimurium var Copenhagen strains isolated from chicks of hatcheries and broiler farms were biotype 2(86.6%), 8(6.7%), and 10a(6.7%), and 26i(6.7%) according to Duguid's scheme. Antibiotic susceptibility test of Salmonella isolated were performed by agar dilution method, using 9 antibiotics as follows: ampicillin(Am), chloramphenicol(Cm), gentamicin(Gm), kanamycin(Km), nalidixic acid(Na), rifampicin(Rf), streptomycin(Sm), sulfadimethoxine(Su), and tetracycline(Tc), All the strains were sensitive to RF. But 8 strans(23.8%) were resistant to one or more drugs and the most common resistance patterns of transferred R plasmids were SmSuGm and SmSu. Among 42 isolates, one had transferable citrate utilizing plasmid. S typhimurium and S typhimurium var copenhagen strains were resistant to killing by 90% normal guinea pig serum.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1123-1126
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• 2011

The IncP plasmid R995 has been a useful self-transmissible, broad-host-range vector for a number of applications including the recombinase/conjugation-based cloning of large genomic DNA segments. However, R995 derivatives (or related plasmids) expressing a wide range of different resistance markers and Flp recombinase target sites do not exist in the literature. In addition, documented strategies for applying such plasmids in cloning applications that take advantage of conjugation for the convenient isolation and recovery of constructs are extremely limited. Here, we report a new series of R995 plasmids with alternative markers to increase options for applications in backgrounds already expressing resistance to a particular antibiotic(s). These R995 plasmids have been engineered to contain FRT sites that can be used for recombinase-based cloning. We demonstrate the utility of this approach by cloning 20 kb regions from the Salmonella Typhimurium and Escherichia coli genomes and by cloning DNA from an exogenous plasmid source. To our knowledge, this represents the first systematic engineering of an intact, self-transmissible IncP plasmid with a series of alternative antibiotic markers and FRT sites.

• 한국동물위생학회지
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• 제19권2호
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• pp.115-125
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• 1996

A total of 315 microorgainisms were isolated from 256 pneumonic lung samples of pig in abattoirs of northern Chungnam area during February to November 1994, and Identified 97 strains as Pusteurella multocida, 89 strains as Staphylococcus spp, 54 strains as Streptococcus spp, 22 strains as Mycoplasma spp, 21 strains as Escherichia coli, 18 strains as Haemophilus parsuis, 11 strains as Corymebacteroi, pyogenes, and 3 strains as Acrinobacillus spp by Gram's and Dienes stain, and biological properties test Involved API system. After that, they were examined anti biotic susceptibility for ampicillin(AM), cephalothin(CF), chloramphenicol(CP), erythromycin(EM), kanamycin(KM), gentamicin(GM), neomycin(NM), penicillin(PC), streptomycin(SM), tetracycline(TE), tiamulin(TIA), tylosin(TYL), methicillin(DP), colistin(CL) and trimet hoprim(SXT). In antibiotics susceptibility test, 293 isolates except Mycoplasma spp 22 strain were highly susceptible to DF(79.2%) and AM(76.2%), but resistant to PC(14.0%), NM(19.5%) and KM (23.2%) The multiple drug resistant patterns were noted in most isolates, whereas only 7 isolates resistant to single drugs.

• 한국식품영양학회지
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• 제11권3호
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• pp.340-346
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• 1998

항생제에 대한 내성균의 출현은 매년 급격하게 증가되고 있으며 이에 대한 약제 개발이 요구되고 있다. 특히 메치실린내성 황색 포도상구균(MRSA)은 여러 항생물질에 대하여 다제내성을 나타내므로 감염증치료에 어려운 문제점으로 남아 있다. 이러한 감염증치료에 사용할 목적으로 임상 가검물에서 분리한 MRSA를 시험균으로 사용하여 항균 활성이 강한 방선균인 YSK-681을 선별하였다. 균주 동정을 위하여 선별된 YSK-681을 형태적, 배양학적, 생리적, 화학적 분석을 하였으며 41개의 단위 항목을 조사하여 TAXON program으로 수리 동정한 결과 주군집 29개에 속하는 Streptomyces lydicus로 동정하였다.

• 한국축산식품학회지
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• 제33권2호
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• pp.239-243
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• 2013

Salmonella Enteritidis is responsible for causing foodborne diseases upon consumption of egg products. While cases of S. Enteritidis isolation from eggs have been reported in other countries, no such cases have previously been reported in Korea. In this study, we report the first isolation and identification of S. Enteritidis from domestically distributed eggs in Korea. Eggs were collected from eight countrywide grocery stores during different seasons between 2011 and 2012. Egg contents and washing solution of egg shells were incubated in buffered peptone water, and the enriched broth was further enriched in tetrathionate broth and Rappaport-Vassiliadis. The secondary enriched broth was streaked on xylose lysine desoxycholate agar. The suspected colonies were confirmed to S. Enteritidis by a biochemical test, serotyping, and PCR test. Genetic relatedness among the isolates was analyzed using Diversilab Salmonella kit. Three strains of S. Enteritidis were isolated from egg contents and egg shells collected from grocery stores of the Eumseong-city in the fall of 2011. All three stains showed resistance to chloramphenicol, streptomycin, nalidixic acid, and ampicillin by the disk diffusion method. In addition, the isolates showed more than 99% DNA homology, indicating that they were presumably identical strains. Therefore, there is a requirement to monitor and control against S. Enteritidis from eggs in Korea.

• Journal of Microbiology and Biotechnology
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• 제30권6호
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• pp.856-867
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• 2020

Vibrio parahaemolyticus is a major gastroenteritis-causing pathogen in many Asian countries. Antimicrobial resistance in V. parahaemolyticus has been recognized as a critical threat to food safety. In this study, we determined the prevalence and incidence of antimicrobial resistance in V. parahaemolyticus in the southern Fujian coast, China. A total of 62 isolates were confirmed in retail aquatic products from June to October of 2018. The serotype O3:K6 strains, the virulence genes tdh and trh, antibiotic susceptibility and molecular typing were investigated. Then plasmid profiling analysis and curing experiment were performed for multidrug-resistant strains. The results showed that the total occurrence of V. parahaemolyticus was 31% out of 200 samples. Five strains (8.1%) out of 62 isolates were identified as the V. parahaemolyticus O3:K6 pandemic clone. A large majority of isolates exhibited higher resistance to penicillin (77.4%), oxacillin (71%), ampicillin (66.1%) and vancomycin (59.7%). Seventy-one percent (44/62) of the isolates exhibited multiple antimicrobial resistance. All 62 isolates were grouped into 7 clusters by randomly amplified polymorphic DNA, and most of the isolates (80.6%) were distributed within cluster A. Plasmids were detected in approximately 75% of the isolates, and seven different profiles were observed. Seventy-six percent (25/33) of the isolates carrying the plasmids were eliminated by 0.006% SDS incubated at 42℃, a sublethal condition. The occurrence of multidrug-resistant strains could be an indication of the excessive use of antibiotics in aquaculture farming. The rational use of antimicrobial agents and the surveillance of antibiotic administration may reduce the acquisition of resistance by microorganisms in aquatic ecosystems.

• Fisheries and Aquatic Sciences
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• 제25권4호
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• pp.202-213
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• 2022

Antibiotic resistant Escherichia coli cases are increasing high especially in Southeast Asia. Illegal use of the antibiotic in the aquaculture farming may become the culprit of the outbreak and spread into environmental source. A study was conducted to: 1) detect the chloramphenicol (CAL)-resistant gene in E. coli isolated from three aquaculture farms and six rivers of northwestern Borneo and 2) investigate the correlation between cat gene with five common antibiotics used. Isolation of E. coli was done on Eosin methylene blue agar and characterized using indole, methyl red, Voges-Proskauer, citrate tests. E. coli isolates were subsequently tested for their susceptibility to five antibiotics commonly used in aqua-farming. The CAL-resistant E. coli were further analyzed for the presence of resistant genes (cat I, cat II, cat III, cat IV) using multiplex polymerase chain reaction. 42 bacterial colonies were isolated from a total of 80 individual water samples, 34 of which were identified as E. coli. Result showed 85.3% of the E. coli isolates were resistant to amoxicillin, 35.3% were resistant to tetracycline, 29.4% were resistant to CAL, 17.6% were resistant to nitrofurantoin and 8.8% were resistant to nalidixic acid. All of the 10 CAL resistant E. coli isolateswere detected with cat II genes; five isolates detected with cat IV genes; three isolates detected with cat III genes; and another two detected with cat I genes. Pearson correlation coefficient shows highly significant relationship between resistance pattern of CAL with amoxicillin; and CAL with tetracycline. Our findings provide the supplementary information of the CAL resistance gene distribution, thereby improving our understanding of the potential risk of antibiotic resistance underlying within this microbial ecosystem.

• The Plant Pathology Journal
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• 제22권1호
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• pp.75-89
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• 2006

The actinomycete strain JK-1 that showed strong inhibitory activity against some plant pathogenic fungi and oomycetes was isolated from Jung-bal Mountain in Ko-yang, Korea. The strain JK-1 produced spores singly borne on sporophores and the spores were spherical and 0.9-1.2 11m in diameter. The cell wall of the strain JK-1 contained meso-diaminopimelic acid. The actinomycete strain JK-1 was identified as the genus Micromonospora based on the morphological, physiological, biochemical and chemotaxonomic characteristics. From the 168 rDNA analysis, the strain JK-1 was assigned to M aurantiaca. The antibiotic MA-1 was purified from the culture broth of M aurantiaca JK-1 using various purification procedures, such as Diaion HP20 chromatography, C18 flash column chromatography, silica gel flash column chromatography and Sephadex LH-20 column chromatography. $^{1}H-$, $^{13}C-NMR$ and EI mass spectral analysis of the antibiotic MA-1 revealed that the antibiotic MA-1 is identical to phenylacetic acid. Phenylacetic acid showed in vitro inhibitory effects against fungal and oomycete pathogens Alternaria mali, Botrytis cinerea, Magnaporthe grisea, Phytophthora capsici and yeast Saccharomyces cerevisiae at < 100 $\mug$ $ml^{-1}$. In addition, phenylacetic, acid completely inhibited the growth of Sclerotinia sclerotiorum, Bacillus subtilis, Candida albicans, Xanthomonas campestris pv. vesicatoria at < $\mug$ $ml^{-1}$. Phenylacetic acid strongly inhibited conidial germination and hyphal growth of M grisea and C. orbiculare. Phenylacetic acid showed significantly high levels of inhibitory' effect against rice blast and cucumber anthracnose diseases at 250 $\mug$ $ml^{-1}$. The control efficacies of phenylacetic acid against the two diseases were similar to those of commercial compounds tricyclazole, iprobenfos and chlorothalonil .n the greenhouse.