• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1629-1632
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• 2008

Rapid, real-time detection of pathogenic microorganisms is an emerging and quickly evolving field of research, especially with regard to microorganisms that pose a major threat to public health. Herein, a new method that uses bioimpedance and solid culture medium for the real-time detection of microorganisms is introduced. We fabricated a new impedimetric biosensor by integrating solid media and two plane electrodes attached on two facing sides of an acryl well. During bioelectrical impedance analysis, the solid medium showed the characteristics of a homogenous conductive material. In a real-time impedance measurement, our solid-medium biosensor could monitor bacterial growth in situ with a detection time of ${\sim}4$ hrs. Our data indicate that the solid-medium biosensor is useful for detecting airborne microorganisms, thereby providing a new analytical tool for impedance microbiology.

• 한국산업보건학회지
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• 제22권4호
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• pp.265-275
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• 2012

Objectives: The aim of this study was to investigate the distribution patterns and exposure concentrations of biological hazards in waste handling industries. Methods: We selected 3 recyclable waste sorting plants(RWS), 2 food recycling plants(FR), 1 landfill area(LA) and 1 waste incineration plant(WI). Total airborne bacteria and fungi were measured with single stage impactor and gelatin filters. Endotoxin and glucan were measured with polycarbonate filters in total and respirable dust. Results: The geometric mean of airborne bacterial concentration was the highest in FR($3,273CFU/m^3$), followed by LA, RWS, and WI as 1,334, 934, and $860CFU/m^3$. The fungal concentrations were 6,031, 5,052, 3,307, and $713CFU/m^3$ in RWS, WI, FR, and LA, respectively. By process, WI pit showed the highest concentrations of bacteria, fungi, and endotoxin, followed by inside of bulldozer in LA. The indoor to outdoor ratios of bacteria, fungi, endotoxin and glucan were 2.3, 4.0, 2.3, and 5.0 in RWS, 29.5, 4.9, 7.6, and 5.0 in FR, 5.3, 8.7, 26.8, and 9.5 in WI, respectively. Conclusions: We found that biological hazards, specifically bacteria in FR, fungi in RWS and endotoxin in WI pit and bulldozer at LA, should be controlled to prevent worker's respiratory diseases.

• 한국재난정보학회 논문집
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• 제18권3호
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• pp.566-573
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• 2022

연구목적: 본 연구는 중동호흡기증후군(MERS) 및 코로나바이러스 감염증-19(코로나19)의 국내 유행 이후 늘어난 신종 감염병에 대한 두려움을 해소하기 위하여, 감염취약계층의 집단감염 위험이 있는 초등학교에서 공기살균기 적용에 따른 공기살균효과를 검증하고자 하였다. 연구방법: 서울시 소재의 초등학교의 교실 및 급식실, 화장실에 공기살균기를 각 1대씩 설치하고 공기살균기와 2m 떨어진 거리에서 표면 및 공기 시료를 채취하여 미설치 대조군과 비교하여 세균저감 효과를 분석하였다. 연구결과: 표면에서의 살균효과는 대조군 및 시험군 모두 2log CFU/cm²미만의 결과가 나왔으며, 대조군에 비해 시험군이 54~87% 저감효과가 있는 것으로 나타났다. 또한 공기중에서의 살균효과는 공기살균기 설치 위치에 따라 살균능력이 차이 났으며, 벽면 설치는 대조군에 비해 최대 91%의 저감 효과를 보였으며, 중앙 설치는 최대 93%의 저감 효과를 보였다. 결론: 연구결과 상시적인 소독을 진행하는 초등학교에서 현재의 방역프로그램을 유지하는 한편 공기살균기의 적용하여 상시적인 공기살균을 병행하면 감염병 전파 방지에 상승효과를 볼 수 있을 것으로 보인다. 또한 공기살균기로의 공기유입이 원활할 수 있도록 하는 것이 바람직할 것으로 사료된다.

• 한국유기농업학회지
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• 제7권2호
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• pp.99-106
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• 1999

사과나무에서 발생하는 탄저병에 대한 길항미생물을 찾기 위하여 자연계로부터 유용미생물을 분리하고 사과 탄저 병원균에 대한 길항력 검정과 균주를 동정한 결과는 다음과 같다. 자연계로부터 얻은 1,000여종의 미생물중에서 탄저병원균에 대하여 길항력이 우수한 미생물을 1차적으로 11종 선발하였으며, 이중에서 가장 길항력이 뛰어난 미생물 CH1141을 최종적으로 선발하였다. 길항미생물 CH1141은 분리한 탄저병원균에 대하여 65%의 높은 생장억제력을 보였다. 길항력이 우수한 CH1141의 형태적 성질, 배양적 특성 및 생리 생화학적 성질 등을 조사하여 비교 검토한 결과 Bacillus subtilis와 유사한 균으로 동정되었다.

• 미생물학회지
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• 제48권1호
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• pp.8-15
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• 2012

퇴비화 시설과 매립장에서 발생하는 bioaerosol은 작업자 및 주민에게 건강상 위해의 요인이 될 수 있다. 이들 시설에서 공기 중 세균과 진균의 농도 수준을 파악하기 위해 울산시에 위치한 퇴비화 시설과 매립장에서 계절별로 bioaerosol 시료를 포집하였다. 공기중 세균의 농도는 퇴비화 시설에서 평균 $6.5{\times}10^3\;(1.5{\times}10^2-1.5{\times}10^4)\;MPN/m^3$, 퇴비화 시설 출입구에서 평균 $3.9{\times}10^3\;(6.0{\times}10^1-9.3{\times}10^3)\;MPN/m^3$이었는데, 이는 대조군 지점보다 각각 460배와 280배 더 높은 수준이었다. 대장균군 세균은 퇴비화 시설과 출입구에서 모두 검출되었다. 매립장에서 공기중 세균 농도는 평균 $4.9{\times}10^2\;(1.7{\times}10^2-1.0{\times}10^3)\;MPN/m^3$이었고, 퇴비화 시설과 매립장에서 100 m 정도 떨어진 매립장 주차장에서는 평균 $3.7{\times}10^2\;(4.8{\times}10^1-1.3{\times}10^3)\;MPN/m^3$이었으며, 이는 대조군 지점에 비해 각각 35배와 26배 더 높은 수준이었다. 공기중 세균을 분리하여 잠정적으로 동정한 결과 퇴비화 시설에서는 Pseudomonas luteola, 대조군 지점에서는 Micrococcus sp.가 우점하였다. 채취 지점별 공기중 진균의 농도는 평균 $4.8{\times}10^2-7.9{\times}10^2\;MPN/m^3$이었으며, 대조군 지점에 비해 2.1-3.4배 더 높은 수준이었다. 공기중 진균의 경우 Cladosporium, Alternaria, Penicillium의 3속은 모든 지점에서 검출되었으며, Aspergillus 속은 퇴비화 시설의 bioaerosol에서만 확인되었다.

• 한국산업보건학회지
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• 제23권2호
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• pp.84-94
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• 2013

Objectives: The objective of this study is to identify the composition of dominant microorganisms in waste handling industries. Methods: We collected airborne bacteria and fungi by agar plate impaction method in recyclable waste sorting industry, food recycling industry, landfill and incineration. Isolated dominant microorganisms were identified by VITEK system or morphological analysis. Results: We isolated totally 330 microorganisms in the process and outdoor. Bacillus was the most dominant genus in the all industries, and Sphingomonas, Acinetobacter, Staphylococcus, and Proteus was dominant bacterial genus. The dominant genus of fungi was Penicillium, Aspergillus, and Cladosporium in each industries. Enterobacter, Pseudomonas, Klebsiella, and Proteus was identified as the dominant gram negative bacteria. The ratio of bacteria being biosafety levels(class 1 or 2) was 58.3~77.8%. Conclusions: This study has investigated the dominant microorganisms in the waste handling industries. The genus of dominant microorganisms was similar among the industries but the composition was different. We used biosafety levels as qualitative method, but further studies are needed about specific process of qualitative evaluation methods.

• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.367-370
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• 2018

Lysozyme is an antibacterial enzyme that is found in most of body fluids. Lysozyme in tears plays a primary role in protecting eye from harmful environments; if lysozyme is degraded or inhibited, eyes are likely to be more vulnerable to bacterial infection. In this study, lysozyme activity was evaluated according to varying concentrations of heavy metals, copper, zinc, cobalt and manganese and light metal, calcium that are frequently found in airborne particulate matters and was assayed using a dye-quenching lysozyme substrate, Micrococcus lysodeikticus. Less fluorescence intensity was observed with increasing amounts of copper, zinc, manganese and cobalt but not with calcium suggesting that these metals have some affinity with lysozyme and inhibit lysozyme activity. When albumin, the second most common protein in tears, was added on the reaction of lysozyme and metals, lysozyme activity was partially restored. This finding suggests that the albumin might protect damage caused by metals on lysozyme. To identify whether the decrease in enzymatic activity was related to structural changes of lysozyme, SDS-PAGE was conducted and only with copper did lysozyme show marked smearing bands on the SDS-gel, meaning that copper degraded lysozyme consistent with the sharpest activity decrease.

• 한국환경보건학회지
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• 제41권6호
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• pp.397-404
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• 2015

Objectives: The aim of this study is to investigate microbial contamination in the school food service environment for the assessment of microbial food safety. Methods: We collected both swab samples from tables and desks and airborne bacterial samples from an elementary school (School A) and a high school (School B). Heterotrophic plate count, total coliform, Staphylococcus aureus, and Bacillus cereus were measured with selective media to quantify microbial concentration. PCR assay targeting 16S rRNA genes was performed to identify the strains of S. aureus and B. cereus isolated. In addition, we made a food service checklist for the locations to evaluate the food service environment. A Wilcoxon test was employed to examine the differences in microbial concentration between before lunchtime and afterwards. Results: Heterotrophic plate counts showed higher levels after-lunch compared to before-lunch at School B. However, levels of S. aureus were higher in the after-lunch period (p<0.05) in both classrooms and in the cafeteria in School A. B. cereus was only sparsely detected in School B. Several samples from food dining carts were found to be contaminated with bacteria, and facilities associated with food delivery were found to be vulnerable to bacterial contamination. Although microbial concentrations in the air showed little difference between before- and after-lunchtime in the cafeteria in School A, those in classrooms were greater after-lunchtime at both schools. Conclusion: Our results suggested that the microbial safety in schools after lunchtime of concern. Necessary preventive measures such as hygiene education for students and food handlers should be required to minimize microbial contamination during food service processes in schools.

• 한국환경보건학회지
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• 제48권2호
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• pp.116-122
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• 2022

Background: The recent COVID-19 pandemic is one of the worst disease outbreaks of the 21th century. Due to a lack of reliable antiviral therapeutics, wearing face masks is recommended to prevent airborne infection originating from virus-contaminated bioaerosols. Objectives: The aim of this study was to evaluate the filtration efficiencies of face masks that are commercially available in South Korea for a biological aerosol of Staphylococcus aureus (S. aureus) and murine coronavirus, a well-known surrogate for human coronaviruses. Methods: We collected six different kinds of commercial masks: two Korea Filter (KF)94 (KF94-1, KF94-2) masks, one surgical (Surgical-1) mask, one anti-droplet (KF-AD-1) mask, and two dust (Dust-1, Dust-2) face masks. S. aureus (ATCC 6538), a well-performing test bacteria and murine coronavirus (ATCC VR-764) were prepared under a suitable culture condition. Then, a mask biological filtration tester was used to examine the microbial filtration efficiencies of masks. Test microorganisms were quantitatively measured via cultivation methods and microbial filtration efficiencies were calculated appropriately. Results: All face masks showed over 99.6% filtration efficiency for S. aureus or murine coronavirus. There were no significant differences among the bacterial filtration efficiencies of the face masks. KF94-1 (99.97±0.08%) and Dust-1 mask (99.97±0.07%) showed the highest (over 99.9%) filtration efficiency for murine coronavirus. KF94-1 or Dust-1 masks showed a significant virus filtration efficiency compared to Surgical-1 mask (p<0.05; Mann-Whitney U test). Conclusions: All the commercially available face masks used in this study can filter S. aureus or murine coronavirus in bioaerosols efficiently, regardless of the mask type. Therefore, our results suggest that wearing a certified face mask is a reliable means to prevent the transmission of infectious airborne diseases via biological aerosols.

• 사물인터넷융복합논문지
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• 제6권2호
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• pp.19-24
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• 2020

본 연구에서, 세균의 생물학적 정보와 이산화염소 가스의 생화학적 정보들을 활용하여, 그람 양성 세균인 Alloiococcus otitis, Erysipelothrix rhusiopathiae, Staphylococcus caprae, Staphylococcus lentus 및 그람 음성 세균인 Acinetobacter baumannii complex, Aeromonas salmonicida, Brucella melitensis, Oligella ureolytica에 대한 이산화염소가스의 성장 억제 효과를 분석하였다. 전체적으로, 이산화염소 가스는 10 CFU 미만으로 세균의 성장을 약 99 % 억제하였다. 하지만, 그람 양성인 Alloiococcus otitis 및 그람 음성인 Aeromonas salmonicida는 약 50 CFU 이상인 것으로 밝혀졌다. 여러 세균과의 실험 결과를 비교할 때, 이산화염소 가스의 농도는 세균 억제에 대해 10 ppm 내지 400 ppm 일 것이라고 제안한다. 이 연구의 결과는 이산화염소 가스의 임상적 유용성을 평가하기 위한 기본 데이터로 사용될 수 있을 것이다. 이 연구가 임상에 있는 근무자가 병원에서 감염을 일으키는 미생물의 존재를 인식하고 예방하는 사전 지식에 도움이 되는 경우, 융합분야 중, 임상에서처럼 환자 치료와 같은 활동에 도움이 될 것이다. 향후에, 이산화염소 가스에 대해 억제되는 미생물들의 정보의 데이터를 활용하여, 환자에게 감염된 미생물들을 신속히 억제하는데 기초가되는 연구결과가 될 것으로 사료된다.