• 대한임상검사과학회지
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• 제52권3호
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• pp.214-220
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• 2020

세정제로 손을 씻는 것은 감염의 가능성이 있는 미생물을 줄이는 중요한 방법이지만 재사용하는 액체 형 세정제는 외부의 오염에 취약하다. 이 연구의 목적은 공공화장실에서 사용하고 있는 액체 세정제의 오염도를 측정하는 것이다. 저자는 6개 건물에 있는 58개의 공공 화장실에서 액체 형 손 세정제를 조사하였다. 균의 동정은 전통적인 생화학적 검사와 질량분석기를 이용하였으며 항균제 감수성 검사는 Vitek II 시스템을 이용하였다. 58개의 화장실 중 27개(46.55%)의 화장실에서 세정제를 다시 채워 재사용하고 있었으며, 이들 중 25개(92.59%) 화장실의 세정제가 세균에 오염되어 있었다. 오염된 균은 1.6×10³ to 2.7×10⁵ CFU/mL의 범위였으며, Serratia liquefaciens (12 균주), Achromobacter xylosoxidans (9 균주), Serratia marcescens (4 균주), Staphylococcus pastueri (1 균주), Achrombacter spanius (1 균주) 순으로 분리되었다. A. xylosoxidans 1 균주를 제외하고 같은 건물에서 분리된 같은 균 종은 동일한 감수성 양상이었다. 결론적으로 오염된 손 세정제로 손을 씻는 것은 공공보건 시설에서 세균의 전파가능성이 높일 수 있으므로 면역이 감소한 환자들이 이용하는 병원의 화장실은 손 세정제를 재사용하는 것을 제한할 필요가 있다.

• 미생물학회지
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• 제29권1호
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• pp.63-68
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• 1991

Several arsenic compound-resistant bacteria were isolated from Jung-Rang stream. The isolates, D-3, D-12, and D-14 were characterized phenotypically and genetically, and identified as Serratia liquefaciens, Klebsiella oxytoca, and Klebsiella pneumoniae, respectively. A plasmid of 67kb was found in Klebsiella oxytoca D-12 and designated as pMH12. Transfer of this plasmid from D-12 to E. coli HB101 was occurred, and the resulting transconjugant strains expressed the same level of heavy metal resistance as the donor strain. The physical presence of this plasmid in transconjugant was detected with agarose gel electrophoresis. Arsenite-sensitive derivatives of isolate D-12 were obtained with Mitomycin C treatment which cured pMH12. Antibiotics and heavy metal resistances were also examined to be used as a proper marker for the isolates in gene cloning. Isolate D-12 has resistance to several heavy metal ions such as $Cd^{2+}$ , $Zn^{2+}$ and $Hg^{ 2+}$ Also, all the other arsenite resistant isolates showed resistance to several heavy metal ions and antibiotics.

• 한국식품영양과학회지
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• 제30권5호
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• pp.865-869
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• 2001

메밀묵의 부패에 관련된 주요 미생물을 분리 동정하고, chitosan을 농도별(0, 0.5, 1.0, 1.5, 2.0%)로 첨가하여 메밀묵의 저장성과 품질에 미치는 영향을 조사하였다. 그 결과, 묵의 부패에 관여하는 주요균은 Serratia liquefaciens와 Staphylococcus lentus로 간주되었다. 메밀묵을 18$^{\circ}C$에서 6일간 저장시 chitosan의 첨가량이 1.5% 이상일 때는 균의 성장이 상당히 억제되었으며, 수분활성도 chitosan의 첨가량이 1.0% 이상일 때 변화가 적었다. 색상은 대조구와 chitosan 처리구 모두 뚜렷한 차이는 나타나지 않았다. 관능적 평가에서는 1.0% chitosan 처리구가 가장 좋은 것으로 평가되었으며 chitosan 농도가 1.5% 이상에서는 기호도가 떨어졌다. 따라서 메밀묵 제조시 chitosan을 1.0% chitosan 처리구가 가장 좋은 것으로 평가되었으며 chitosan 농도가 1.5% 이상에서는 기호도가 떨어졌다. 따라서 메밀묵 제조시 chitosan을 1.0% 첨가함으로써 대조구에 비하여 관능적 품질 향상뿐만 아니라 저장성도 1~2일정도 연장시킬수 있으리라 여겨졌다.

• 한국가축번식학회지
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• 제19권1호
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• pp.1-7
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• 1995

This study was accomplished to illuminate factors of contamination of microbes in the culture medium and effect of antibiotics on prevention of contamination in the medium when bovine follicular oocyte was matured, fertilized and developed in vitro. 1. When washed or unwashed semen diluted with TCM 199 was incubated for 24∼72hr, contamination was come out. 2. When diluted semen with TCM 199 which has penicillin, streptomycin, gentamycin, kanamycin or nystatin was incubated for 24∼72hr, contamination was not come out only in kanamycin. 3. When imported semen which was diluted in TCM 199 with penicillin, streptomycin, gentamycin, kanamycin or nystatin was incubated for 24∼72hr, contamination was not come out in all treatments. 4. When semen which was diluted in BO, CZB, Ham's F10 or TCM 199 was incubated for 24∼72hr, kanamycin showed no contamination in all treatments, but gentamycin showed contamination in CZB, Ham's F10 and TCM 199. 5. When the semen diluted in BO was moved at 24hr after incubation into BO and incubated for 72hr, contamination was not come out, but when it was moved into the TCM 199 and incubated for 72hr, contamination was come out at 48 to 72hr of incubation. 6. When the semen diluted in BO, BO＋BSA or BO＋FBS containing gentamycin, kanamycin or nystatin was incubated for 24∼72hr, the diluted semen in BO or BO＋BSA showed no contamination in all antibiotics but the diluted semen in BO＋FBS showed no contamination only in kanamycin. 7.The Pseudomonas cepacia, Serratia liquefaciens, Klebsiella pneumaniae was respectively isolated in the semen of A, B, and C bull and the microbes are highly affected by amikacin, tobramycin and kanamycin. 8. When bovine folicular oocyte was in vitro matured, fertilized and developed in the simple medium with kanamycin, 26.6% was developed to over 32cell stage embryo.

• 한국식품영양과학회지
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• 제38권4호
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• pp.502-508
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• 2009

Paper disc법을 통하여 항균력을 측정한 결과, 물 추출물에서는 항균효과가 나타나지 않았으나, 4 mg/mL 농도의 에탄올 추출물에서는 그람 음성균 중 S. liquefaciens, S. Typhimurium 및 P. aerogenosa에 대해 항균효과를 보였으며, 실험에 사용된 모든 그람 양성균에 대해 항균효과를 보였다. 특히, B. subtilis, C. perfringens 및 L. monocytogens에 대해 높은 항균력을 보였다. 또한 A. niger 및 P. expansum에는 항진균 효과가 없었으나 S. cerevisae에 대해서는 4 mg/mL 농도에서 항진균 활성을 보였다. 지충이 에탄올 조추출물에 대한 MIC test를 실시한 결과, 그람 음성균에 대한 MIC 값은 $0.6{\sim}0.8%$로 약한 항균활성을 보였으나, 그람 양성 균주 중 C. perfringens와 L. monocytogenes에 대해서는 0.01 및 0.1%에서 두 균주의 생육을 효과적으로 억제하였다. 열 및 pH 안정성 실험 결과, 지충이 에탄올 추출물은 $121^{\cir}C$에서 15분간의 열처리와 pH $2{\sim}8$ 처리에도 항균활성에 변화가 없어 이들 추출물 유래의 항균물질은 열 및 pH 변화에 안정한 물질임을 알 수 있었다. 지충이 에탄올 추출물의 silica gel column chromatography 분획물을 2개 또는 3개씩 1:1(또는 1:1:1)의 비율로 혼합한 후 항균력을 측정한 결과, 클로로포름 및 에탄올 분획 혼합물과 클로로포름, 에틸아세테이트 및 에탄올 분획 혼합물에서 조 추출물 이상의 항균활성이 나타났다.

• 한국축산식품학회지
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• 제26권3호
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• pp.402-409
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• 2006

Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.