• The Korean Journal of Mycology
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• v.42 no.3
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• pp.225-230
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• 2014

Sclerotinia sclerotiorum, a plant pathogenic fungus, can cause serious yield and quality losses in the winter lettuce field. For biological control of S. sclerotiorum, soil-born microorganisms that inhibit the mycelia growth of S. sclerotiorum and Fusarium oxysporum were isolated from diseased soil. Among the isolates, bacterial isolate, GG95, which was identified as Bacillus subtilis according to the morphological, physiological characteristics and by 16S rRNA similarity, showed the highest level of inhibitory activity. The growth conditions for B. subtilis GG95 were optimized in TSB media (pH 7) by culturing at $28^{\circ}C$ for 24 hrs. Maltose or fructose and peptone were selected as the best carbon and nitrogen sources, respectively. Greenhouse experiment was performed to test effectiveness of B. subtilis GG95 in the control sclerotinia rot. Drench application ($1{\times}10^8cfu/mL$, 3 times) of the bacterial culture broth to lettuce showed an effectiveness value of 88%, suggesting that B. subtilis GG95 would be a promising biocontrol agent for control of sclerotinia rot.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.253-259
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• 1996

To investigate the yeast florae in the traditional and commercial Kochujang, computer identification systems, Vitek, API kit and conventional identification methods were used. Yeast florae of each process were compared and their typical physiological characteristics were also tested. Various process intervals yielded 330 colonies, which resulted in 11 species 184 strains classified. They were identified into Candida glabrata C. guilliermondii. C. humicola. C. rugosa, C. zeylanoides, Cryptococcus uniguttulatus, Pichia farinosa, Rhodotorula glutinis, Saccharomyces cerevisiae and Zygosaccharomyces rouxii. The strains of Candida, Pichia, Saccharomyces and Zygosaccharomyces were existing in both processes. In case of commercial process, the maximum distribution of Z. rouxii and S. cerevisiae were 33% at 15 day fermentation and 13% at 21 day, respectively. The distribution of Candida spp. was gradually decreased throughtout the fermentation period from 40% to 10%. In the traditional process, the maximum distribution of Z. rouxii and S. cerevisiae were 53% after 3 months and 26% after 7 months, respectively, S. cerevisiae and Z. rouxii showed distintive growth pattern at the high concentration of glucose and sodium chloride and played important roles in both processes of fermentation. Physiological tests revealed that only two major yeasts. S. cerevisiae and Z. rouxii, showed vigorous carbon dioxide formation under the tested conditions.

• The Korean Journal of Mycology
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• v.38 no.2
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• pp.146-151
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• 2010

A total of 167,955 microorganisms were isolated from 366,661 clinical specimens. Among them, 6,517 strains of the Candida spp. were isolated from the department of laboratory medicine in "C" hospital from Jan. 1, 2005 to Dec. 31, 2009. All clinical specimens were reviewed by the medical records of patients with Candida by the method of retrospectiveness. From this, we got the some isolated pure cultured yeasts. We identified these yeast by the identification kit system of VITEKII and VITEKII-ID-YST card. The isolation frequencies of Candida spp. were as follows. 56.4%,of C. albicans, 17.7% C tropicalis, 10.7% C glabrata and 9.5% C parapsilosis. The isolated frequency of Candida spp. in 2009 was 1.9 times higher than that in 2005. The clinical materials showing over 10.0% isolation rate were in sputum (30.1%), random urine (25.0%), 15.8% blood (15.8%) and catheterized urine (13.5%) in Candida spp.. The clinical department of showing over 7.0% isolation rate were in pulmonary medicine (20.5%), renal medicine (11.0%), infection disease medicine (10.4%), critical care medicine (10.0%), hematooncology (9.6%), general surgery (7.5%) and gastrointestinal medicine (7.4%) in Candida spp.. In monthly analysis, Candida spp. were most friquency isolated in July (10.6%), but lowest one in February (6.1%). Candida spp. were most frequently isolated in patient of over 50 years old (16.7-40.1%) than those isolated from the patients under the age of 0-49 (1.3-7.5%).

• Korean Journal of Clinical Laboratory Science
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• v.51 no.4
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• pp.428-435
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• 2019

The rapid increase and dissemination of carbapene mases, such as Klebsiella pneumoniae carbapenemase (KPC), has become a major problem within the field of healthcare-related infection. There are few antibiotics to treat carbapenem-resistant Enterobacteriaceae (CRE) infections, so the identification of resistant bacterial mechanisms is critical to initiate infection control and conduct epidemiological research. A rapid and effective method for detecting KPC-producing bacteria is needed to avoid therapeutic failures and introduce measures to prevent and control the dissemination of these multi-resistant bacteria. During the study period, 31 isolates (seven isolates of Acinetobacter spp., six isolates of Morganella morganii, five isolates of Pseudomonas aeruginosa, five isolates of Proteus mirabilis, one isolate of Proteus vulgaris, two isolates of Enterobacter cloacae, one isolate of Enterobacter aerogenes, one isolate of Klebsiella pneumoniae, one isolate of Klebsiella oxytoca, one isolate of Serratia marcescens and one isolate of Escherichia coli) were identified by the VITEK. Gram negative rod bacteria were the most frequently isolated from urine (35.5%), blood (19.4%), sputum (16.1%), pus (9.7%), ascitic fluid (9.7%), tracheal aspirates (6.5%) and bile juice (3.2%). Analysis using the PCR method identified the bla_KPC gene in the K. oxytoca1 strain, but the bla_IMP, bla_VIM and bla_OXA-48 genes are not amplified. In conclusion, diagnosis using the PCR method can accurately and quickly diagnose KPC, thus establishing quick preventive measures to prevent the spread of KPC in hospitals.

• Food Science and Preservation
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• v.16 no.4
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• pp.567-572
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• 2009

We evaluated the microbiological quality of a facility in which freshly cut onions were prepared. The total plate counts on walls, equipment, and raw materials were ND (not detected) to $10^1$ CFU/100 $cm^2$, $10^0{\sim}10^3$ CFU/100 $cm^2$, and $10^3{\sim}10^4$ CFU/g, respectively. No coliforms were detected on walls however, coliforms were detected at concentrations of ND to $10^3$ CFU/100 $cm^2$ and $10^3{\sim}10^4$ CFU/g on equipment and raw materials, respectively. The total plate counts for falling and floating bacteria in the processing plant were ND to $10^0$CFU/plate and $10^1{\sim}10^2$ $CFU/m^3$, respectively. Pathogenic microorganisms such as Escherichia coli, Salmonella spp, Staphylococcus aureus, and Listeria monocytogenes were not detected on walls, equipment, or raw materials. Overall, the results of the study indicate that hygiene control at the fresh-cut processing plant should be improved.

• Journal of Environmental Health Sciences
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• v.47 no.5
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• pp.479-485
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• 2021

Background: Vibrio vulnificus has been frequently detected in seawater, fish, and shellfish mainly in the coastal areas of Chungcheongnam-do Province. Objectives: This study was conducted to investigate the analyzed biochemical properties, genetic characteristics, and distribution of Vibrio vulnificus isolated from environmental sources in coastal areas of Chungcheongnam-do Province from 2019 to 2020. Methods: A total of 1,510 samples were obtained from six different sites in Chungcheongnam-do Province. Isolated strains from the samples were identified by a VITEK 2 system and MALDI-TOF. Antibiotic susceptibility testing for 85 isolates was done by microdilution minimum inhibitory concentration methods, and 11 isolates were analyzed for 16s rRNA sequences in multiple alignments. Results: Among the 1,510 samples taken during the investigation period, 306 strains were isolated and the detection rate of V. vulnificus was 20.3%. One hundred eighty-eight strains (24.6%) from seawater and 118 strains (15.8%) from mud flats were isolated. It was mainly detected in July (17.3%), August (36.5%), and September (28.8%), and the proportion was 82.0%. Based on the CLSI-recommended breakpoints, V. vulnificus isolates were all susceptible to amoxicillin/clavulanic acid, amikacin, gentamicin, ciprofloxacin and trimethoprim/sulfamethoxazole. However, nonsusceptible isolates to ampicillin, ampicillin/sulbactam, cefazolin, cefoxitin, imipenem, tetracycline and chloramphenicol were identified. In the analysis of the nucleotide sequences for 16s rRNA of V. vulnificus isolates, it was confirmed that mutations frequently occurred between nucleotide number 922 and 952, and 98.2% to 100% nucleotide identities between isolates was verified. Conclusions: The results of this study can be used as a basic data for infection control and prevention of Vibrio vulnificus infection by describing the distribution and characteristics of Vibrio vulnificus strains isolated in coastal areas of Chungcheongnam-do Province.

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.182-191
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• 2021

Objective: This study was performed to detect indicator bacteria in drinking spring water samples in Gwangju City and to identify their genus using the VITEK-II system. Methods: The subjects were ten drinking spring water sites in Gwangju. Samples of spring water were taken every month from September 2019 to August 2020. We analyzed for the indicator bacteria Yersinia and microorganisms isolated from the spring water. Result: According to the research results on indicator bacteria, general bacteria in st1-st7 with sterilization facilities in the spring and summer were investigated in the range of 0-2 CFU/mL and 0-12 CFU/mL. In st9, where a sterilization facility was not installed, the most general bacteria were detected (160 CFU/mL). Total coliform and fecal coliform showed unsatisfied rates of 16.7 and 11.1% in spring and 14.7 and 11.8% in summer, respectively. The unsatisfied rates of total coliform for the designated and non-designated spring water facilities were 3.8 and 47.1%, respectively, and for the fecal coliform group they were 2.5 and 35.3%. The difference was confirmed according to the presence of a sterilization facility. Yersinia spp. was not detected in all drinking spring water. Forty-one strains in 25 species were isolated from ten sites. The results classified as major dominant species are Pseudomonas spp. 14.6%, Pantoea spp. 9.8%, Serratia spp. 9.8%, Acinetobacter spp. 9.8%, Citrobacter spp. 7.3%, Bordetella spp. 7.3%, Delftia spp. 4.9%, and Enterobacter spp. 4.9%. Conclusions: Based on the result that various species derived from fecal pollution and artificial pollutants were detected in the non-specified public spring water facilities that many people use, the facilities need institutional complements such as continuous management or complete shutdowns.

• Research in Plant Disease
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• v.24 no.4
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• pp.332-338
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• 2018

In August of 2011, a wilting disease of ginseng was observed at Bongwha, Gyeongbuk province, Korea. Affected plants initially show withering symptoms on leaves of ginseng. As the disease progresses, withering leaves spread downward, eventually encompassing the whole plant. Leaves lose vigor but remain pale green. Symptoms of roots were brown, and soft rots characterized by moist and watery decay of the whole ginseng root, which initiated as small brown, water-soaked lesions of hairy roots and enlarged to the entire roots. The causal organism isolated from the infected roots was identified as Serratia plymuthica based on its physiological and biochemical characteristics, by cellular fatty acid composition (GC-FAME), the utilization of carbon sources (BioLog System), and 16S rRNA sequence of the isolated bacterium were 99% homologous to those of Serratia plymuthica strains. Artificial inoculation of the bacterium produced the same brown or soft rot symptoms on the ginseng roots, from which the same bacterium was isolated. This is the first report of bacterial root rot caused by the Serratia plymuthica in ginseng in Korea. Serratia plymuthica has been used as antagonistic microorganism for biological control on several crop plants. But it was proved pathogen of ginseng at humid condition in this study.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.343-351
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• 2020

BACKGROUND: Irrigation water is known to be one of the major sources of bacterial contamination in agricultural products. In addition, anti-microbial resistance (AMR) bacteria in food products possess serious threat to humans. This study was aimed at investigating the prevalence of foodborne bacteria in irrigation water and evaluating their anti-microbial susceptibility. METHODS AND RESULTS: Surface water (n = 66 sites) and groundwater (n = 40 sites) samples were collected from the Gyeongi and Gangwon provinces of South Korea during April, July, and October 2019. To evaluate the safety of water, fecal indicators (Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were examined. E. coli isolates from water were further tested for antimicrobial susceptibility using VITEK2 system. Overall, detection rate of foodborne pathogens in July was highest among three months. The prevalence of pathogenic E. coli (24%), Salmonella (3%), and L. monocytogenes (3%) was higher in surface water, while only one ground water site was contained with pathogenic E. coli (2.5%). Of the 343 E. coli isolates, 22.7% isolates were resistant to one or more antimicrobials (ampicillin (18.7%), trimethoprim-sulfamethoxazole (7.0%), and ciprofloxacin (6.7%)). CONCLUSION: To enhance the safety of agricultural products, it is necessary to frequently monitor the microbial quality of water.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.66-72
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• 2024

Background: Vibrio vulnificus is a serious opportunistic human pathogen that has a worldwide distribution in a variety of marine and estuarine environments. Objectives: For this reason, we investigated the distribution of Vibrio vulnificus in coastal areas of Gyeonggido Province from 2018 to 2022. Also, we analyzed the correlation between V. vulnificus leading to infection and two marine environmental factors (water temperature and salinity). Methods: We collected a total of 266 samples from six coastal area points (i.e., seawater, mudflats). Specimens were isolated using selective plating media and isolated strains were identified by a VITEK 2 system. To find the relevance of the isolation rates of V. vulnificus and number of cases of V. vulnificus infection, we summarized the data on 48 cases of V. vulnificus infection from the open data of the Korea Disease Control and Prevention Agency. Results: Among the 266 samples taken during the investigation period, 47 strains were isolated, and the separation rates of V. vulnificus were 17.7%. The monthly isolation rates of V. vulnificus were ranked in the order of August (53.8%), September (33.3%), June (28.6%), and July (21.1%). There was a positive correlation with the temperature of seawater, but salinity was not significant. The number of cases of V. vulnificus infection reported in Gyeonggi-do Province were 18 (37.5%) in September, 14 (29.2%) in August, and eight (16.7%) in October. The proportion was 83.3%. It was relevant to the isolation rates of V. vulnificus in the marine environmental sources. Conclusions: Our data showed that the number of V. vulnificus infection cases could be affected by changes in the distribution of V. vulnificus due to rise the temperature of seawater in the marine environment.