• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.36-44
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• 1998

Background: IFN-$\gamma$ is known to activate mononuclear phagocytes and to mediate host defense mechanism against some intracellular microorganisms, but little is known about anti-mycobacterial activity and mechanism of IFN-$\gamma$ in human. In this study, we investigated the role of IFN-$\gamma$ in the pathogenesis of tuberculosis by observing the effect of IFN-$\gamma$ on the phagocytosis of M.tuberculosis(MTB) and on the production of TNF-$\alpha$ by human pulmonary alveolar macrophage. Method: Pulmonary alveolar macrophage(PAM) were prepared with adhesion purification method from bronchoalveolar lavage fluid obtained from 8 persorn without active lung lesion and cultured($1{\times}10^6cells/ml$) with MTB($3{\times}10^7$ bacteria/ml) with or without IFN-$\gamma$(300U/ml), LPS(0.5ug/ml) and autologous serum(10%). After 2 hours, the percentage of PAM-phagocytosed MTB was counted after AFB staining(modified Kynion method). TNF-$\alpha$ production by PAM stimulated by IFN-$\gamma$(300U/ml), MTB($1{\times}10^6bacteria/ml$) and LPS(0.5ug/ml) for 24hours was measured in culture supernatant using ELISA method. The degree of phagocytosis of MTB by PAM stimulated with IFN-$\gamma$(300U/ml) and LPS(0.5ug/ml) for 24hours was also investigated. Results: IFN-$\gamma$ did not influence the phagocytosis of MTB by PAM(percentage of PAM-phagocytosed MTB: control: $22.1{\pm}4.9$, IFN-$\gamma$: $20.3{\pm}5.3$) and did not increase TNF-$\alpha$ production by PAM (control: $21{\pm}38pg/ml$, IFN-$\gamma$: $87{\pm}106pg/ml$), and the degree of phagocytosis of MTB by PAM pre-stimulated with IFN-$\gamma$ for 24 hours, was not increased (control: $24.5{\pm}9.5$, IFN-$\gamma$: $23.4{\pm}10.1$). Conclusion: IFN-$\gamma$ does not influence on the phagocytosis of MTB and TNF-$\alpha$ production by PAM.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.193-200
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• 2019

The study was conducted surveying ultrasound room workers on hospital infection awareness in Daejeon and Choong-chunng region. The contamination of ultrasonic probes used in clinical trials was measured using ATP, and the results were verified after using 70% alcohol sterilization. It was measured on the group's general characteristics and the specific categories such as academic background, job type, having professional certificate and infection education. After the examination, the gel removal and method, disinfection status of the probe and variable correlation analysis were performed to analyze the recognition of the ultrasonic probe disinfection. After examination in ultrasound room, it was found that towels were used the most for cleaning, and the gel container was not replaced for more than three months. After 70% alcohol disinfection, ATP contamination was reduced from $1055.4{\pm}944.2$ to $133.5{\pm}93.2$ and the result was analyzed to be statistically significant.(${\rho}<0.01$) The found bacteria were CNS, Gram positive bacillus, and Micrococcus specs. In order to solve this problem, 70% alcohol sterilization was applied and the bacteria were not detected after the treatment. The research shows that regular training on infection control and efforts to prevent infection are necessary, and that 70% alcohol is effective in disinfect the bacteria. Therefore, the medical institution should provide active hospital infection control education to improve the awareness of hospital infection among workers and contribute to the prevention of patient infection. It is also understood that proper use of the results of this study will help prevent infection by means of ultrasonic probes.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.384-389
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• 2010

Outbreak of contagious diseases to livestock animals is becoming prevalent worldwide and consequently, tremendous numbers of the infected or culled stocks are buried on the ground as the most common disposal method. The buried animals can generate a wide range of detrimental components such as leachate, nutrient salts, and pathogenic bacteria, consequently contaminating the surround environment. This implies that regular investigations are required to monitor any possible detrimental environmental aspect occurred around burial sites. Therefore, the current study was conducted to investigate whether the soil and groundwater nearby the burial sites had been contaminated by the substances originated from the burial sites, which can be applied for the establishment of the ideal burial site construction design and post management scheme. For this, two different burial sites located in Cheonan and Pyeongtaek were selected. Cheonan and Pyeongtaek sites were constructed in 2004 and 2008, respectively and both contained dead poultry infected by avian influenza (AI). Soil and groundwater samples were collected around the sites followed by determination of the nutrient concentrations and bacteria (Salmonella, Camphylobacter, and Bacillus) existence in both soil and groundwater. Some of the soil samples showed higher EC, $NH_4$-N, $NO_3$-N concentration compared to those of the background (control) soils. Also the concentration of $NH_4$-N in some of the groundwater samples appeared to exceed the USEPA guideline value for drinking water (10 mg $L^{-1}$). These results indicated that the soil and groundwater were influenced by the burial site originated nutrients. In the soil, Bacillus was isolated in most soil samples while there were no detections of Salmonella and Camplylobacter. Due to the Bacillus existing mainly as a spore in the soils, it was considered that the frequent detection of Bacillus in the soil samples was attributed to the nutrients originated from the burial sites.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.135-140
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• 2018

BACKGROUND: The Asian hornet (Vespa velutina nigrithorax), a wasp species, has attacked honey bee populations and affected the beekeeping industry in Korea over the past 15 years. However, little research has been done with this invasive species. In this study, we investigated the intestine bacterial microbiota of Asian hornets and honey bees to design an attractive trap for Asian hornets. METHODS AND RESULTS: Genomic DNAs isolated from the intestine microorganisms of Asian hornets and honey bees were utilized to amplify bacterial 16S rDNA for the comparative sequence analysis. The next generation sequencing analysis identified that the orders Flavobacteriales as the most abundant intestinal microorganisms in Asian hornets, showing a clear difference compared to honey bees in which Aeromonadales are dominant. We also report five newly identified 16S rDNA sequences of Asian hornet intestinal bacteria. According to the sequence blast search, these five bacteria belong to the genera Thalassomonas, Caedobacter, Vampirovibrio, Alkaliphilus and Calothrix. CONCLUSION: While Asian hornets and honey bees show similar intestine bacterial diversity, the relative ratio of bacterial populations is different. providing useful information to design pest control agents specifically targeting Asian hornets.

• Tuberculosis and Respiratory Diseases
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• v.64 no.1
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• pp.22-27
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• 2008

Background: Staphylococcus aureus frequently colonizes and infects hospitalized patients. Respiratory infections with Staphylococcus aureus are common in patients with compromised airway defenses. However the mechanisms of S. aureus invasion from colonization to the epithelium are unclear. Cell invasion by S. aureus would require destruction of the extracellular matrix, which is believed to be the result of increased matrix metalloproteinases (MMP) activity. Methods: In this study, respiratory epithelial cells were infected with S. aureus. After removing the extracellular bacteria by washing, the internalized bacteria in the cells were assessed by counting the colonized forming units (CFUs). The cell adhesion proteins, dysadherin and E-cadherin, were evaluated by Western blotting. The MMPs in the bacterial invasion were evaluated by pretreating the cells with GM6001, a MMP inhibitor. Results: The internalization of S. aureus was found to be both time and dose dependent, and the increase in MMP 2 and 9 activity was also dependent on the incubation time and the initial amount of bacterial inoculation. The invasion of S. aureus was attenuated by GM6001 after 12 hours incubation with a multiply of infection (MOI)=50. The expression of dysadherin, a membrane protein, was increased in a time and dose dependent manner, while the expression of E-cadherin was decreased. Conclusion: MMPs may mediate the invasion of S. aureus into epithelial cells.

• Korean Journal of Medicinal Crop Science
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• v.26 no.3
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• pp.248-253
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• 2018

Background: Dazomet are widely used as soil fumigant to solve soilborne problems, and the degradation intermediates are toxic to nematodes, fungi, bacteria, insects and weeds. Methods and Results: The effects of cultivation of green manure crop, maize before and after soil fumigation on the control of ginseng root rot disease were compared using soil where 6-years-old ginseng was harvested. Fumigant (dazomet) were used for soil fumigation in May and September, respectively. Maize was grown for soil management before and after soil fumigation. After May fumigation, the sowing date of maize was delayed by 15 days and thus its dry weight was decreased significantly. Maize cultivation after May fumigation increased pH but decreased EC, $NO_3$, $P_2O_5$, and K significantly. Maize cultivation after May fumigation decreased fungi population and the ratio of fungi and bacteria. Growth of 2-years-old ginseng was improved and the incidence of ginseng root rot was significantly decreased by maize cultivation after May fumigation. After harvesting 2-years-old ginseng, the population of Cylindrocarpon destructans was not different between treatment of May and September, but Fusarium solani showed a significant increase in September fumigation after maize cultivation. Conclusions: Maize cultivation after soil fumigation was effective in inhibiting ginseng root rot by the amendment of mineral composition and microorganism in fumigated soil.

• The Journal of the Korean Society for Microbiology
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• v.35 no.4
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• pp.289-297
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• 2000

Background: Staphylococcus aureus (s. aureus) and Escherichia coli (E. coli) are major pathogens in community and hospital. And they sometimes cause the outbreak in hospital in the immunocompromised patients. Pulsed-field gel electrophoresis (PFGE) has been regarded as a standard method for genotyping in epidemiologic studies, but it is laborious and time-consuming. Infrequent restriction site-polymerase chain reaction (IRS-PCR), a new genotyping methods, was performed to compare the applicability with PFGE. Methods: We performed PFGE and IRS-PCR on S. aurues (n=120) and E. coli (n=117) which were collected clinically in 4 different hospitals. We assessed each method in terms of discriminatory power, quality, and efficiency. Results: In E. coli, the discriminatory power of IRS-PCR was $46.7{\sim}86.7%$, and that of PFGE was $88.9{\sim}96.7%$ according to hospital. But in S. aurues, the discriminatory power of IRS-PCR was $20{\sim}56.7%$, and that of PFGE was $40{\sim}90%$ according to hospital. The typablity and reproducibility of IRS-PCR were 100% of each. PFGE needed four days to complete the procedure, but IRS-PCR could be performed within one day, IRS-PCR showed better resolution than PFGE. Conclusion: In case of gram negative bacteria (like E. coli), IRS-PCR could be a reliable alternative for epidemiologic typing due to better efficiency and comparable discriminatory power. But in the case of gram positive bacteria (like S. aureus), IRS-PCR does not seem to be suitable for the strain-to-strain differentiation. More trials and changes of restriction enzymes or primers could reveal the efficacy of IRS-PCR in the field of molecular typing.

• Korean Journal of Medicinal Crop Science
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• v.24 no.2
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• pp.143-151
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• 2016

Background: The public has increasing concerns about herbal crops owing to insufficient information on biological hazards such as foodborne pathogens. Therefore, the objective of this study is the development of a herbal crop quality control system through monitoring with biological hazard analysis. Today, it is estimated that millions of people become ill every year from food contamination. The public demands agricultural products of stable and consistent quality. Governments have the responsibility of establishing the standards, legislation and enforcement programs necessary to control food quality and safety. However, research on the biosafety of herbal crop products is still insufficient. Therefore, the implementation of monitoring systems with high standards is critical for public safety. Methods and Results: In this study, we collected 52 samples of herbal crop products, and conducted both quantitative and qualitative biological hazard analysis. With biological hazard analysis, aerobic bacteria, Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. could be detected. Conclusions: Herbal crops were found to be contaminated with aerobic bacteria at $3.69{\pm}0.32log\;CFU/g$. Staphylococcus aureus, Salmonella spp., Escherichia coli, Coliforms, and Listeria spp. were not detected in any of the samples. This research suggests that continuous monitoring of biological hazards is required to improve the quality of herbal crops.

• Journal of Environmental Health Sciences
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• v.48 no.2
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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.

• Journal of Veterinary Science
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• v.23 no.6
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• pp.12.01-12.10
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• 2022

Background: Staphylococcus aureus and Streptococcus agalactiae are the main cause of clinical mastitis in dairy cattle in Argentina, whereas coagulase-negative staphylococci (CNS) and environmental streptococci are the main cause of subclinical mastitis. Bacteria isolated from infected animals show increasing antimicrobial resistance. Objectives: This study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci. Methods: Isolation was performed on blood agar and identification was based on biochemical reactions. Antimicrobial susceptibility was according to the Clinical and Laboratory Standards Institute guidelines. The antimicrobial resistance genes, SCCmec type and spa type were detected by the polymerase chain reaction method. Results: We isolated a total of 185 staphylococci and 28 streptococci from 148 milk samples. Among the staphylococcal isolates, 154 were identified as CNS and 31 as S. aureus. Among the 154 CNS, 24.6% (n = 38) were resistant to penicillin, 14.9% (n = 23) to erythromycin, 17.5% (n = 27) to clindamycin, 6.5% (n = 10) to cefoxitin and oxacillin. Among the S. aureus isolates, 16.1% (n = 5) were resistant to penicillin, 3.2% (n = 1) to cefoxitin and oxacillin (MRSA). Six MR isolates (5 CNS and 1 MRSA) were positive to the mecA gene, and presented the SCCmec IVa. The MRSA strain presented the sequence type 83 and the spa type 002. Among the 28 streptococcal isolates, 14.3% (n = 4) were resistant to penicillin, 10.7% (n = 3) to erythromycin and 14.3% (n = 4) to clindamycin. Conclusions: The present findings of this study indicate a development of antimicrobial resistance in main bacteria isolated from cows with mastitis in Argentina.