• Journal of Microbiology and Biotechnology
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• 제30권10호
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• pp.1516-1524
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• 2020

Climate change is expected to affect not only availability and quality of water, the valuable resource of human life on Earth, but also ultimately public health issue. A six-year monitoring (total 20 times) of Escherichia coli O157, Salmonella enterica, Legionella pneumophila, Shigella sonnei, Campylobacter jejuni, and Vibrio cholerae was conducted at five raw water sampling sites including two lakes, Hyundo region (Geum River) and two locations near Water Intake Plants of Han River (Guui region) and Nakdong River (Moolgeum region). A total 100 samples of 40 L water were tested. Most of the targeted bacteria were found in 77% of the samples and at least one of the target bacteria was detected (65%). Among all the detected bacteria, E. coli O157 were the most prevalent with a detection frequency of 22%, while S. sonnei was the least prevalent with a detection frequency of 2%. Nearly all the bacteria (except for S. sonnei) were present in samples from Lake Soyang, Lake Juam, and the Moolgeum region in Nakdong River, while C. jejuni was detected in those from the Guui region in Han River. During the six-year sampling period, individual targeted noxious bacteria in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five Korea's representative water environments make it necessary to establish the chemical and biological analysis for noxious bacteria and sophisticated management systems in response to climate change.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.323-326
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• 2002

To detect whole ammonia-oxidizing bacteria in the activated sludge, group-specific primers targeting the 16S-rRNA gene of ammonia-oxidizing bacteria were used. The electrophoresis pattern of the PCR products seemed to produce a single band of approximately 1.0 k bp for the bacteria in activated sludge and Nitrosomonas europaea. No band was observed for nitrite-oxidizer Nitrobacter winogradskyi and heterotrophs such as Pseudomonas putida. Then direct measurement of the PCR product was made by fluorometry using the reagent Hoechist 33258, so that the fluorescent intensity was in proportional to the cell number of the sample up to 240. Total time required for the test was about 4 h including DNA extraction. The DNA fragments produced were cloned and their sequences showed high similarity to those of Nitrosomonas spp. This study showed the feasibility to detect ammonia-oxidizing bacteria and to esti-mate their population rapidly for the control of the nitrogen elimination process.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권6호
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• pp.395-399
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• 2000

Five different freeze-dried recombinant bioluminescent bacteria were used for the detection of cellular stresses caused by endocrine disrupting chemicals. These strains were DPD2794 (recA::luxCDABE), which is sensitive to DNA damage, DPD2540 (fabA::luxCDABE), sensitive to cellular membrane damage, DPD2511 (katG::luxCDABE), sensitive to oxidative damage, and TV1061 (grpE::luxCDABE), sensitive to protein damage. GC2, which emits bioluminescence constitutively, was also used in this study. The toxicity of several chemicals was measured using GC2. Damage caused by known endocrine disrupting chemicals, such as nonyl phenol, bisphenol A, and styrene, was detected and classified according to toxicity mode, while others, such as phathalate and DDT, were not detected with the bacteria. These results suggest that endocrine disrupting chemicals are toxic in bacteria, and do not act via an estrogenic effect, and that toxicity monitoring and classification of some endocrine disrupting chemicals may be possible in the field using these freeze-dried recombinant bioluminescent bacteria.

• 한국환경과학회지
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• 제26권1호
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• pp.11-21
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• 2017

In this study, bacterial growth was assessed by flow cytometry analysis of fluorescent probes-stained bacteria. Flow cytometry has many advantages of rapid analytical time, a low standard deviation, and highly sensitive detection of live and Dead E.coli over colony forming assay. When untreated bacteria were stained by using Thiazole Orange (TO) and Propidium Iodide (PI), double staining had a short analytical time as compared with that of single staining while its error rate was similar to that of single staining. Through double staining experiments, it was determined that optimal concentrations for TO and PI staining were 420 nM and $9.6{\mu}M$, respectively.

• Journal of Microbiology and Biotechnology
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• 제31권5호
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• pp.705-709
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• 2021

Porphyromonas gingivalis (P. gingivalis) is a major bacterial pathogen that causes periodontitis, a chronic inflammatory disease of tissues around the teeth. Periodontitis is known to be related to other diseases, such as oral cancer, Alzheimer's disease, and rheumatism. Thus, a precise and sensitive test to detect P. gingivalis is necessary for the early diagnosis of periodontitis. The objective of this study was to optimize a rapid visual detection system for P. gingivalis. First, we performed a visual membrane immunoassay using 3,3',5,5'-tetramethylbenzidine (TMB; blue) and coating and detection antibodies that could bind to the host laboratory strain, ATCC 33277. Antibodies against the P. gingivalis surface adhesion molecules RgpB (arginine proteinase) and Kgp (lysine proteinase) were determined to be the most specific coating and detection antibodies, respectively. Using these two selected antibodies, the streptavidin-horseradish peroxidase (HRP) reaction was performed using a nitrocellulose membrane and visualized with a detection range of 10³-10⁵ bacterial cells/ml following incubation for 15 min. These selected conditions were applied to test other oral bacteria, and the results showed that P. gingivalis could be detected without cross-reactivity to other bacteria, including Streptococcus mutans and Escherichia fergusonii. Furthermore, three clinical strains of P. gingivalis, KCOM 2880, KCOM 2803, and KCOM 3190, were also recognized using this optimized enzyme immunoassay (EIA) system. To conclude, we established optimized conditions for P. gingivalis detection with specificity, accuracy, and sensitivity. These results could be utilized to manufacture economical and rapid detection kits for P. gingivalis.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.582.2-582
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• 2001

Black-pigmented bacteria anaerobes have been implicated in the endodontic infections. This group of microorganisms includes Porphyromonas endodontalis, Porphyromonas gingivalis, prevotella intermedia, and Prevotella nigrescens. The organisms display a wide variety of virulence factors that may be pertinent to acute endodontic infections.(omitted)

• 한국환경보건학회지
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• 제13권1호
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• pp.63-65
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• 1987

A study on detection rates of acid-fast bacteria in urine by three sampling methods was performed on 898 cases randomly sampled from peoples who visited Dr. Chung's Health Lab. from January to December, 1983. Positive rate by 5 times sampling of motring urine was 7.0% and 12.5% higher than that of 24 hours sampling. Therefore, 5 times sampling of morning urine method was considered to be desirable method for the test of ambulatory cases.

• Safe Food
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• 제1권4호
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• pp.5-15
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• 2006

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 1999년도 춘계학술대회 논문집
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• pp.176-177
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• 1999

• Journal of Microbiology and Biotechnology
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• 제31권11호
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• pp.1481-1489
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• 2021

Early and accurate detection of pathogens is important to improve clinical outcomes of bloodstream infections (BSI), especially in the case of drug-resistant pathogens. In this study, we aimed to develop a culture-independent digital PCR (dPCR) system for multiplex detection of major sepsis-causing gram-negative pathogens and antimicrobial resistance genes using plasma DNA from BSI patients. Our duplex dPCR system successfully detected nine targets (five bacteria-specific targets and four antimicrobial resistance genes) through five reactions within 3 hours. The minimum detection limit was 50 ag of bacterial DNA, suggesting that 1 CFU/ml of bacteria in the blood can be detected. To validate the clinical applicability, cell-free DNA samples from febrile patients were tested with our system and confirmed high consistency with conventional blood culture. This system can support early identification of some drug-resistant gram-negative pathogens, which can help improving treatment outcomes of BSI.