• Journal of fish pathology
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• v.13 no.1
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• pp.45-51
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• 2000

Bacterial diseases with mixed infection have recently occurred at land-based flounder farms in Korea. Thus, single antibacterial is not effective for therapy of mixed bacterial diseases of fish because of their different causative bacteria. The purpose of the present study was to obtain basic data for positive usefulness of a combination of antibacterials used for synergism to mixed bacterial diseases of fish. Snergistic interaction in combination of antibacterials was determined by in vitro antimicrobial activity against selected fish-pathogenic bacteria, Vibrio anguillarum, Edwardsiella tarda, Streptococcus sp., Staphylococcus epidermidis, on the basis of Checkerboard assay using fractional inhibitory concentration (FIC) indices. Synergistic interactions were observed in combinations of (oxytetracycline HCL+lincomycin), (tetracycline HCL+florfenicol), (oxytetracycline HCL+florfenicol) against V. anguillarum, (sodium nifurstyrenate+florfenicol), (tetracycline HCL+florfenicol), (sodium nifurstyrenate+oxolinic acid), (oxytetracycline HCL+florfenicol) against E. tarda, (ciprofloxacine+oleandomycin), (oxytetracycline HCL+oleandomycin), (tetracycline HCL+oleandomycin), (oxytetracycline HCL+lincomycin), (oxytetracycline HCL+spiramycin), (oxytetracycline HCL+erythromycin), (doxycycline HCL+oleandomycin), (tetracycline HCL+spiramycin) against Streptococcus sp., and (ciprofloxacine+erythromycin), (florfenicol+erythromycin), (doxycycline HCL+oleandomycin), (ciprofloxacine+oleandomycin) against S. epidermidis.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.211-218
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• 2014

In order to isolate probiotic lactic acid bacteria possessing high inhibitory activities against porcine and zoonotic pathogens, such as enterotoxigenic E. coli, Salmonella Typhimurium, and Clostridium perfringens, a total of 65 anaerobic strains were initially isolated from a variety of sources including cattle rumen fluids, chicken intestines and swine feces. Four Bifidobacterium strains were selected for their high anti-pathogenic bacterial activities. By using the 16S rDNA sequencing method, three B. boum strains and one B. thermophilum were identified. B. thermophilum demonstrated the best adhesive ability to epithelial cells of swine intestine among the isolates. Indeed, B. thermophilum was seen to have superior characteristics as a probiotic for swine, as judged by their high growth inhibitory activities against various pathogens, and high acid- and bile-tolerance.

• Journal of fish pathology
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• v.12 no.1
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• pp.42-48
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• 1999

The disinfectant effects of total residual oxidants (TROs) produced by ozonization of natural sea water were investigated against fish pathogenic bacteria isolated from flounder and red seabream. The concentration of 0.1 mg TROs/liter was stable for 20 min in filtered natural seawater, and those of 0.3 and 0.5 mg TROs/liter were also stable for more 1 hr. Disinfectant effects of TRO against Edwardsiella tarda, Vibrio sp., Streptococcus sp. and Staphylococcus sp. were observed with a concentration of 0.1 mg/liter for 180 sec, and the treatment killed more than 99.9% of bacterial cells. With TROs of 0.3 to 0.5 mg/ liter, the viable cells of the bacteria were reduced by more than 99.99% in 60 sec.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1200-1209
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• 2021

Sepsis is an acute inflammatory response that leads to life-threatening complications if not quickly and adequately treated. Cytolysin, hemolysin, and pneumolysin are toxins produced by gram-positive bacteria and are responsible for resistance to antimicrobial drugs, cause virulence and lead to sepsis. This work assessed the effects of aloe-emodin (AE) and photodynamic therapy (PDT) on sepsis-associated gram-positive bacterial toxins. Standard and antibiotic-resistant Enterococcus faecalis, Staphylococcus aureus, and Streptococcus pneumonia bacterial strains were cultured in the dark with varying AE concentrations and later irradiated with 72 J/cm^-2 light. Colony and biofilm formation was determined. CCK-8, Griess reagent reaction, and ELISA assays were done on bacteria-infected RAW264.7 cells to determine the cell viability, NO, and IL-1β and IL-6 pro-inflammatory cytokines responses, respectively. Hemolysis and western blot assays were done to determine the effect of treatment on hemolysis activity and sepsis-associated toxins expressions. AE-mediated PDT reduced bacterial survival in a dose-dependent manner with 32 ㎍/ml of AE almost eliminating their survival. Cell proliferation, NO, IL-1β, and IL-6 cytokines production were also significantly downregulated. Further, the hemolytic activities and expressions of cytolysin, hemolysin, and pneumolysin were significantly reduced following AE-mediated PDT. In conclusion, combined use of AE and light (435 ± 10 nm) inactivates MRSA, S. aureus (ATCC 29213), S. pneumoniae (ATCC 49619), MDR-S. pneumoniae, E. faecalis (ATCC 29212), and VRE (ATCC 51299) in an AE-dose dependent manner. AE and light are also effective in reducing biofilm formations, suppressing pro-inflammatory cytokines, hemolytic activities, and inhibiting the expressions of toxins that cause sepsis.

• Journal of Life Science
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• v.17 no.10
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• pp.1374-1380
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• 2007

The development of polymerase chain reaction (PCR) technology has the potential to solve for isolating pathogenic microorganisms from environmental samples than traditional plate counting methods. We have been detected pathogenic bacteria from raw water and water treatment process in Busan metropolitan city by PCR method. According to the result of survey from July 2004 to October 2005, 80 out of 92(87.0%) were positive for bacterial pathogens in raw water samples and positive rate of Shigella spp., Yersinia spp., Salmonella spp. and Legionella spp. were 46.2%, 40.7%, 17.6% and 9.9%, respectively. Pathogenic bacteria in raw water was mainly distributed through the lately Autumn to the winter and more highly detected Maeri than Mulgum region. During the period of survey in water treatment process, Shigella spp. was highly detected but all of bacterial pathogens were entirely removed after in post-ozonation step. These suggest that waters supplied in Busan metropolitan city may be safe against the pathogenic bacteria.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.341-348
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• 2010

Antifungal and antibacterial activities of wood vinegars were investigated in this study in order to apply for the natural fungicides and food preservatives. The antifungal activities of wood vinegars were measured as a hyphal growth inhibition rate using four plant pathogenic, four wood rot and one mushroom pathogenic fungi. Inhibition effect on the fungi growth was explicitly observed at the concentrations higher than 0.5% of unrefined wood vinegar and higher than 1.0% of refined wood vinegar, respectively, suggesting that unrefined wood vinegars showed the higher antifungal activities than that of refined wood vinegars. The highest inhibition effect on the fungi growth was shown in Libertella betulina which is a mushroom pathogenic fungus. In addition, the wood vinegars from Pinus densiflora showed the higher antifungal activities against the plant pathogenic and wood rot fungi than that from Quercus spp.. On the other hand, the antibacterial activities of wood vinegars were determined by a paper disc method using the three gram positive and five gram negative bacteria. The unrefined wood vinegars showed a prominent effect on the suppression of bacteria growth at the concentration of 10%, while the suppression of bacteria growth was not observed in the refined wood vinegars. These results also suggest that the unrefined wood vinegars showed the higher antibacterial activities than the refined wood vinegars. The antibacterial activities of wood vinegars against gram positive bacteria were higher than those of wood vinegars against gram negative bacteria. From these results, it can be inferred that the wood vinegars has the strong antimicrobial activities and can be applied as the natural fungicides and food preservatives.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.349-354
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• 2006

Furaneol, a key aroma compound found in strawberry, pineapple, and processed foodstuffs, has been known to possess various biological activities on animal models. In this study, the antimicrobial effects of furaneol against human pathogenic microorganisms were investigated. The results indicated that furaneol displayed a broad spectrum of antimicrobial activities against Gram-positive and Gram-negative bacteria and fungi without hemolytic activity on human erythrocyte cells. To confirm the antifungal activity of furaneol, we examined the accumulation of intracellular trehalose as a stress response marker on toxic agents and its effect on dimorphic transition of Candida albicans. The results demonstrated that furaneol induced significant accumulation of intracellular trehalose and exerted its antifungal effect by disrupting serum-induced mycelial forms. These results suggest that furaneol could be a therapeutic agent having a broad spectrum of antimicrobial activity on human pathogenic microorganisms.

• Journal of fish pathology
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• v.7 no.2
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• pp.113-117
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• 1994

The antimicrobial activity of Artemisia princeps var. orientalis essential oil against a partial fish pathogenic bacteria was examined. The growth of Aeromonas hydrophila, Aeromonas salomonicida, Aeromonas sorbia, Edwardsiella tarda and Streptococcus sp. (yellowtail) were inhibited at concentrations of 1,000 to 2,000 ppm. The A. salmonicida was inhibited at 1,000 ppm, A. hydrophila, A. sorbia, E, tarda and Streptococcus sp. (yellowtail) at 1,500 ppm, but Vibrio anguillarum, Vibrio ordalii, Edwardsiella ictaluri and Streptococcus sp. (SF 1) were grown on 100-2,000 ppm.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.479-491
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• 2015

Lactobacillus species have been shown to enhance intestinal epithelial barrier function, modulate host immune responses, and suppress the growth of pathogenic bacteria, yeasts, molds, and viruses. Thus, lactobacilli have been used as probiotics for treating various diseases, including intestinal disorders, and as biological preservatives in the food and agricultural industries. However, the molecular mechanisms used by lactobacilli to suppress pathogenic bacterial infections have been poorly characterized. We previously isolated Lactobacillus plantarum JSA22 from buckwheat sokseongjang, a traditional Korean fermented soybean food, which possessed high enzymatic, fibrinolytic, and broad-spectrum antimicrobial activity against foodborne pathogens. In this study, we investigated the effects of L. plantarum JSA22 on the growth of S. Typhimurium and S. Typhimurium-induced cytotoxicity by stimulating the host immune response in intestinal epithelial cells. The results showed that coincubation of S. Typhimurium and L. plantarum JSA22 with intestinal epithelial cells suppressed S. Typhimurium infection, S. Typhimurium-induced NF-κB activation, and IL-8 production, and lowered the phosphorylation of both Akt and p38. These data indicated that L. plantarum JSA22 has probiotic properties, and can inhibit S. Typhimurium infection of intestinal epithelial cells. Our findings can be used to develop therapeutic and prophylactic agents against pathogenic bacteria.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.67-71
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• 2017

This study examined the antimicrobial activity of flaxseed meal extract (FME) against Staphylococcus aureus and Escherichia coli O157:H7 inoculated on red mustard. With the treatment of 0.7% FME for 3 min, the reduction levels of S. aureus and E. coli O157:H7 populations were 1.23 and 1.83 log CFU/g, respectively. In addition, the combined treatment of 0.7% FME at $50^{\circ}C$ for 3 min reduced the populations of the pathogenic bacteria by 2.28 and 2.41 log CFU/g, respectively. The color and the vitamin C content were not significantly different between treatments. Thus, FME can be used as a novel antimicrobial agent in fresh-cut vegetables.