• Title/Summary/Keyword: selective agar medium

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Isolation and Identification of Pathogenic Microorganisms from Soybean Sprouts

  • Kim, Hye-Jung;Koo, Kyoung-Mo;Kim, Gi-Nahm;Lee, Dong-Sun;Paik, Hyun-Dong
    • Preventive Nutrition and Food Science
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    • v.7 no.3
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    • pp.305-309
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    • 2002
  • Raw soybean sprouts were tested for contamination with the following bacteria which have potential for pathogenesis or food spoilage : Salmonella spp., Escherichia coli O157:H7, Yersinia enterocolitica, Vibrio parahae-molyticus, Aeromonas hydrophila, Plesidomonas shigeloides, Pseudomonas aeruginosa, Staphylococcus aureus, Lis-teria monocytogenes, Bacillus cereus, Clostridium perfringens, Campylobacter jejuni, Erwinia spp., and Fusarium spp. Three of the above strains were isolated from the sprouts, and identified by morphological and biochemical methods including an API kit and ATB automated identification system. The isolate cultured in Cereus selective agar, a selective medium, was a Gram-positive, rod shaped, anaerobic spore former. The biochemical and culture tests revealed the following characteristics: catalase-positive, no growth on Simmon's citrate, NO₂ production and requirement of arginine for growth; the ATB automated identification system gave 99.8 % agreement for the identification of Bacillus cereus to the species level. The isolate cultured in Macconkey agar selective medium was Gram-negative, rod shaped and a gas former; the ATB-system gave 99.9% agreement for the identification of Aeromonas hydrophila to the species level. The isolate found in Pseudomonas isolation agar was Gram-negative, rod shaped, cytochrome oxidase-positive, a reducer of nitrates to nitrogen, and pyocyanin producer; the ATB-system gave 99.9 % agreement for the identification of Pseudomonas aeruginosa to the species level. These results indicate that the three bacteria species present in the soybean sprouts were Bacillus cereus, Aero-monas hydrophila, and Pseudomonas aeruginosa. Salmonella spp., Escherichia coli O157:H7, and Yersinia enter-ocolitica, which are associated with serious disease in humans, were not isolated from soybean sprouts examined in this study.

Development of a Selective Medium for Xanthomonas campestris pv. translucens (맥류 세균성줄무늬병균의 선택배양기 개발)

  • ;David C. Sands
    • Korean Journal Plant Pathology
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    • v.12 no.4
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    • pp.381-388
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    • 1996
  • 맥류세균성 줄무늬병균의 선택배양기(KM-1)를 개발하여 이병식물체 및 토양으로부터 Xanthomonas campestris pv. translucens를 선택적으로 분리할 수 있는 효율성을 검토하였다. KM-1배양기의 구성성분은 증류수 1 L당 lactose 10 g, D(+)trehalose 4.0 g, thiobarbituric acid 0.2 g, K\ulcornerHPO\ulcorner 및 KH\ulcornerPO\ulcorner 각각 0.8 g, yeast extract 30 mg, NH\ulcornerCl 1 g, cycloheximide 100 mg, tobramycin 8.0 mg, ampicillin 1.0 mg 및 Bacto agar 15 g이며 1 N NaOH로 pH 6.6으로 조절하였다. X. c. t.의 균주별 KM-1의 배양효율은 비선택성 농후배지인 Wilbrinks agar에 비하여 1.30정도였으며, 기타 토양전염성식물병원세균 Agrobacterium tumefaciens, Agrobacterium rhizogenes, Erwinia carotovora var. atroseptica, Erwinia carotovora var. carotovora, Corynebacterium insidiosum, 및 기타 토양생존 부생세균 Bacillus cereus, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Pseudomonas putida 등의 생장을 완벽하게 억제하였다. KM-1의 저장기간(shelf-life)도 5$^{\circ}C$에서 2개월 동안 선택성을 유지하였다. 따라서 본 병원균의 전염원의 생존 등 발생생태연구에 활용될 수 있는 가치가 충분히 인정되었다.

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Effects of Oxygen and Salt on the Growth of Bifidus and Anaerobic Bacteria Isolated from Korean Traditional Fermented Foods (산소와 염농도가 한국전통 발효식품에서 생장하는 혐기성 세균과 Bifidus균의 생육에 미치는 영향)

  • 정은영;이진성;배재근;이완규;김병홍
    • Microbiology and Biotechnology Letters
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    • v.21 no.1
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    • pp.82-87
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    • 1993
  • Fourteen samples of kimchies and soy bean pastes were used to isolate strictly anaerobic bacteria on complex BL agar and on a selective BS agar for bifidus bacteria. About $10^7$ ~ $10^8$ colonies per g sample were developed on BL agar under strictly anaerobic conditions, while BS agar supported the growth of $10^3$ ~ $10^6$ colonies per gram sample at the same condition. All colonies developed on BS agar at anaerobic conditions grew in aerobic conditions and did not show fructose6-phosphate phosphoketolase activity. Type cultures of Bifidobacterium did not grow in PYG medium containig more than 3% NaCI. From these results it is conduded that salted fermented food cannot support the growth of strictly anaerobes induding Bifidobactenum.

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Identification of Enterococcus faecalis on MSB Medium Selective for Mutans Streptococci

  • Lee, Seung-Hoon;Yoo, So-Young;Kim, Hwa-Sook;Kang, Sook-Jin;Lim, Sung-Hoon;Kim, Kwang-Won;Park, Jung-Min;Shin, Yong-Kook;Shin, Jeong-Hwan;Baek, Dong-Heon;Choe, Son-Jin;Kook, Joong-Ki
    • International Journal of Oral Biology
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    • v.31 no.1
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    • pp.7-10
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    • 2006
  • Mitis-salivarius sucrose bacitracin(MSB) medium is widely used in the selective isolation of mutans streptococci(MS), a designation for a group of oral cariogenic species. Recently, we have isolated three bacterial strains grown on MSB agar from human dental plaques. The three strains exhibited biochemical characteristics similar to those of the biotype IV of MS, with the exception that they manifested a positive reaction for arginine deaminase. The objective of this study was to identify and characterize these three clinical isolates. The bacteria were identified with biochemical tests as well as by 16S rDNA cloning and sequencing. In order to compare the antibiotics susceptibility of the clinical isolates with that of type strain, the minimum inhibitory concentrations of 9 antibiotics were determined using broth dilution assays. The results identified all of our three clinical isolates as Enterococcus faecalis. All E. faecalis strains were found to be susceptible to penicillin G, amoxicillin, augmentin, and vancomycin, but were resistant to ciprofloxacin, cefuroxim axetil, and clindamycin. Our findings indicate that E. faecalis is capable of growing on MSB agar, and suggest that the MSB medium be improved so that only MS should be recoverable on the medium, as originally devised for their selection.

Reisolation Frequency of Soil Actinomycetes on Multiple Isolation Media (다수 배지의 사용에 따른 방선균의 중복 분리빈도)

  • Kim, Chang-Jin;Lee, Kang-Hyun;Shimazu, Akira;Yoo, Ick-Dong
    • Microbiology and Biotechnology Letters
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    • v.22 no.3
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    • pp.329-331
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    • 1994
  • For effective screening research, to isolate many different strains not duplicated would be essential. Three kinds of media were used for selective isolation of actinomycetes to test the reisolation frequency. Sixty species were isolated on Bennet's agar, 47 were on glycerol-asparagine agar and 77 were on humic acid-vitamin agar from 10 domestic soil samples. All of these isolates were identified to the genus level based on morphological characters and examined the sameness on each medium. The reisolation frequency between two different media was 10% or so(8.3~16.7%) and among three different media was 25% or so(22.1~27.7%).

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Changes in the Oral Microflora in Patients with Acute Myeloid Leukemia during the Period of Induction Therapy (항암 화학요법중인 급성 골수성 백혈병 환자의 구강내 세균변화에 관한 연구)

  • Byul-Hee Lee;Chong-Youl Kim
    • Journal of Oral Medicine and Pain
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    • v.18 no.1
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    • pp.73-82
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    • 1993
  • To investigate the changes in aerobic and facultative anaerobic oral microflora during remission-induction chemotherapy in patients with acute myeloid leukemia, 10 consecutive patients were studied during a period of 28 days. One day before, during and after the induction therapy, patients were given 10% Betadine solution for mouthrinses after breakfast and kept from eating and drinking. After 3 hours, paraffin-stimulated whole saliva was obtained for 2 minutes and transported to the laboratory. The samples were dispersed and homogenized by use of vortex mixer for 20 seconds. From these samples 10-fold serial dilutions (from 10-1 through 10-3) were prepared. Each dilution of 0.1 ml was plated on duplicate set of one nonselective medium (Blood agar) and four selective media (Sabourauds dextrose agar, Mannitol salt agar, Mac-Conkey agar, SF medium ) using applicator woods. All agar plate were incubated at 37$^{\circ}C$ for 48 hours. The total number of microorganisms was calculated and the percentage distribution of the various microorganisms from each specimen was drawn. 1. The salivary flow rate decreased by 66%, going from 5.38 ml/2min to 1.81 ml/2min over two days during the chemotherapy. 2. The total number of microorganisms in saliva increased by 22%, going from 4.88$\times$105/ml to 6.00$\times$105/ml over two days during the chemotherapy. 3. The salivary flow rate and the total number of microorganisms in saliva were recovered within 28 days after the chemotherapy. 4. The quantitative alteration in oral Enterobacteria, Enterococci, Staphylococci, Cndida during the chemotherapy had no statistical significance. 5. In saliva of the patients with acute myeloid leukemia who ahd intraoral ulcer, Enterobacteria was quantitatively predominent. Our study suggests that chemotherapy-induced transient xerostomia may induce acute oral infection. Consequently, the use of saliva substitute, the removal of intraoral infection source and the consistent oral hygiene care seem to be required to avoid the transmission of potential pathogenes in this group of patients.

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Studies on the m-Toluate Degradating Plasmid in Pseudomonas (m-Tluate를 분해하는 Peudomonas의 분리 및 Dgradative Pasmid와의 연관성에 관하여)

  • 박순희;하영칠;홍순우
    • Korean Journal of Microbiology
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    • v.17 no.1
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    • pp.25-41
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    • 1979
  • A strain able to grow up m-toluate minimal medium has been isolated after selective enrichment and given the name T81X, which was later identified as pseudomonase putida according to its morphological and biochemical characteristics. After treatment with plasmied specific curing agent, mitomycin C, followed by replica plating on m-toluate and xylene minimal agar plate, T81Xstrain has been shown to harbour a curable plasmid relating to the m-toluate and xylene metabolism. Spontaneous curing frquency of this plasmid was also greatly enhanced by growing on benzoate minimal medium. After then, it was also xylene metabogrowing on benzoate minimal medium. After then, it was found to be conjugally nontransmissible. From the comparative investigation of catechol 1,2-oxygenase and catechol 2,3-oxygenase activities in wild type and cured strain on various growth substrate, it appeared that T81X strain has both of these two enzymes while cured strain has catechol 1,2-oxygenase only. Growing on m-toluate minimal medium T81X strain should carry the genetic information necessary for coding the catechol 1,2-oxygense induced by m-toluate or benzoate, on that curable plasmid.

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Identification of Non-mutans Streptococci Organisms in Dental Plaques Recovering on Mitis-Salivarius Bacitracin Agar Medium

  • Yoo So Young;Kim Pyung Sik;Hwan Ho Keel;Lim Seong Hoon;Kim Kwang Won;Choe Son Jin;Min Byung Moo;Kook Joong Ki
    • Journal of Microbiology
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    • v.43 no.2
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    • pp.204-208
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    • 2005
  • The objective of this study was to both isolate and identify non-mutans streptococci organisms (non­MSO) from dental plaques recovered on mitis-salivarius sucrose bacitracin agar (MSB) plates. The dental plaque samples, which had been collected from 63 human subjects, were diluted and plated on MSB. The bacteria growing on the MSB plates were then identified with biochemical tests, as well as with 16S rDNA cloning and sequencing techniques. Our data indicated that bacteria from 30 subjects had been recovered on the MSB plates. Among the 21 typical colonies selected from the 30 subjects, 12 colonies, derived from 10 subjects, were identified as non-MSO. These 12 colonies were determined to be Streptococcus anginosus (8 colonies), S. sanguinis (1 colony), and Pantoea agglomerans (3 colonies). These results strongly suggest that a new selective medium will be required for the reliable isolation of mutans streptococci.

Screening of Organo Phosphorus Insecticide Fenitrothion-Degrading Microorganisms (유기인계 살충제 fenitrothion 분해미생물 탐색)

  • Choi, Hyuek;Kim, Bok-Jin;Bae, Do-Yong;Lee, Young-Deuk;Kang, Sun-Chul
    • Korean Journal of Environmental Agriculture
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    • v.17 no.3
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    • pp.279-285
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    • 1998
  • Fenitrothion-degrading microorganisms were isolated from 124 sampling sites of paddy, upland, forest and polluted soil, and wastewater. A total of 1,071 strains were isolated from each selective medium supplemented with 50mg/l of fenitrothion - nutrient agar (NA) 601, potato dextrose agar (PDA) 201, Actinomycetes isolation agar (AIA) 168 and basal salt medium (BSM) 101, respectively. Twenty-eight effective strains of them, which showed more than 80% degradation of fenitrothion by the gasliquid chromatography(GLC) analysis. were successfully selected from each liquid culture supplemented with 50mg/l of fenitrothion - NB 12(upland soil 3, paddy soil 3, forest soil 2, polluted soil 4), PDB 8(upland soil 1, paddy soil 2, forest soil 2, polluted soil 3) and PSB 8(upland soil 1, forest soil 1, polluted soil 6), respectively. Four strains - NPal, NFol, PFol and BPol, which have the most powerful degradation activity were finally selected among 28 fenitrothion-degrading microorganisms based on the degradation rate at the concentration of 100mg/l fenitrothion in enrichment media.

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Usefulness of microwave to melt rehydrated media and to remove oxygen from anaerobic tube media (Microwave를 이용한 배지 융해와 공기 제거)

  • 정윤섭;이귀녕;이삼열
    • Korean Journal of Microbiology
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    • v.18 no.3
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    • pp.148-152
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    • 1980
  • The microwave of 2450 MHz, generated by a household cooking oven, was evaluated for its applicability to melt various rehydrated media and to remove dissolved oxygen from tubed media for anaerobic culture. The effect on the sterilization of E. coli in selective media was also evaluated. The following results were obtained. 10 The microwave oven was useful in saving time for melting media and in eliminating heat and combustion gas from the laboratory, which were inevitable by-products in the conventional flame method. 2) Dissolved oxygen could be removed without boiling over by exposing the tubes of anaerobic culture medium after putting them in a wire basket in a beaker with water. 30 The count of E. coli during the melting of MacConkey and EMB agar were similar to those treated with open flame. The microwave treatment was not considered a possible mean to replace autoclaving even in these selective media.

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