• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.3-13
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• 2020

Pseudomonas aeruginosa is a ubiquitous gram-negative bacterium causing serious infections. The P. aeruginosa T3SS is a syringe-like apparatus on the bacterial surface, with 4 effector toxins: ExoS, ExoT, ExoY, and ExoU. Here, we investigated the effect of ExoS and ExoT of the T3SS of P. aeruginosa K strain (PAK). The type three secretion system (T3SS) is a major virulence system of Pseudomonas aeruginosa (P. aeruginosa). The effector protein Exotoxin S (ExoS) produced by P. aeruginosa is secreted into the host cells via the T3SS. For the purpose of screening the inhibitors with regard to ExoS secretion, we developed the sandwich-type enzyme-linked immunosorbent assay (ELISA) system. PAK clinical strains induce proinflammatory cytokine production through the T3SS, and this involves NF-κB activation in pneumonia mouse models. We tried to confirm the role of the NF-κB transcription factor in ExoS- and ExoT-induced pneumonia mouse models. pro-inflammatory cytokines induction in response to ExoS and ExoT infection relied on NF-κB activation. Our findings highlight the roles of natural poduct in inhibiting proinflammatory cytokine expression during ExoS and ExoT exposure in PAK infections, paving the way for a novel therapeutic approach for the treatment of pulmonary infections.

• Journal of Life Science
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• v.22 no.9
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• pp.1268-1276
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• 2012

The emergence and dissemination of carbapenem-resistant bacteria have resulted in limitations of antibiotic treatment and potential outbreaks of metallo-${\beta}$-lactamase (MBL) producing Pseudomonas aeruginosa resistant to carbapenems. In this study, we conducted molecular characterization of the MBL genes of the ${\beta}$-lactam drug-resistant P. aeruginosa and prepared basic data for treatment and prevention of proliferation of antimicrobial-resistant bacterial infections. Forty-two P. aeruginosa isolates of 254 were resistant to imipenem or meropenem. Among the 42 isolates, 28 isolates were positive for the Hodge test, and 23 isolates were positive for the EDTA-disk synergy test (EDST). MBLs were detected in 59.5% (25/42) of P. aeruginosa isolates. Eight isolates harbored $bla_{IMP-6}$, whereas 17 isolates harbored $bla_{VIM-2}$. The $bla_{IMP-6}$ gene was in a class 1 integron containing five gene cassettes: $bla_{IMP-6}$, qac, aacA4, $bla_{OXA-1}$, and aadA1. Some strains that produce IMP-6 and VIM-2 showed epidemiological relationships. The $bla_{IMP-6}$ gene in carbapenem-resistant P. aeruginosa showed an identical pattern to a gene cassette that was reported at a hospital in Daegu, Korea. Therefore, MBL-producing P. aeruginosa is already endemic in the community. We are concerned that the existence of carbapenem-resistant bacteria containing the blaMBL gene may increase pressure on antibiotic selection when treating infections. We believe that we should select appropriate antibiotics based on the antibiotic susceptibility test and continue the research to prohibit the emergence and spread of antibiotics resistant bacteria.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.294-302
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• 2007

This study was to evaluate microcystin production by Microcystis aeruginosa in response to three different levels of indirect (0, 10, 50% of fish cultured media filtrate; control, FCMF1 and FCMF2) exposures to omnivorous and planktivorous fish (Carassius gibelio langsdorfi and Hypophthalmichthys molitrix, CCMF and HCMF, repectively). The cell biomass, intracellular microcystin (MC) and extracellular MC were measured everyday. The intracellular MC contents of all treatments were significantly increased than the controls (CCMF1, P=0.015; CCMF2, P<0.001; HCMF1, P<0.001; HCMF2, P<0.001). The intracellular MC contents of M. aeruginosa were significantly higher in CCMF2 than in CCMF1 (P=(0.023), Those of M, aeruginosa in HCMF2 were significantly higher than that in HCMF1 (P<0.001). The extracellular MC contents were not significantly different between control and CCMFs but those of M, aeruginosa in HCMF1 and HCMF2 were significantly higher than that in control (HCMF1, P=0.003; HCMF2, P<0.001). This study strongly supports that induced-defensive MC production (intra and extracellular MC) of potentially toxic cyanobacteria in response to kairomone concentration and this results can consider the biomanipulation of eutrophic waters as well as an information concerning strategies for recovering eutrophic waters.

• ALGAE
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• v.32 no.4
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• pp.275-284
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• 2017

Microcystis aeruginosa causes harmful algal blooms in the Nakdong River of Korea. We studied the effect of different concentrations and ratios of ammonium ($NH_4{^+}$), nitrate ($NO_3{^-}$), and phosphate ($PO{_4}^{3-}$) on growth of this species in BG-11 medium: each nutrient alone, $NO_3{^-}:NH_4{^+}$ ratio, the N : P ratio with fixed total N (TN), and the N : P ratio with fixed total P (TP). The single nutrient experiments indicated that M. aeruginosa had the highest growth rate at $NH_4{^+}$ and $NO_3{^-}$ concentrations of $500{\mu}M$, and at a $PO{_4}^{3-}$ concentration of $5{\mu}M$. The $NO_3{^-}:NH_4{^+}$ ratio experiments showed that M. aeruginosa had the highest growth rate at a ratio of 1 : 1 when TN was $100{\mu}M$ and $250{\mu}M$, and the lowest growth rate at a ratio of 1 : 1 when the TN was $500{\mu}M$. The N : P ratio with fixed TN experiments indicated that M. aeruginosa had the highest growth rates at 50 : 1, 20 : 1, and 100 : 1 ratios when the TN was 100, 250, and $500{\mu}M$, respectively. In contrast, the N : P ratio with fixed TP experiments showed that M. aeruginosa had the highest growth rates at 200 : 1 ratio at all tested TP concentrations. In conclusion, our results imply that the $NO_3{^-}:NH_4{^+}$ ratio and the $PO{_4}^{3-}$ concentration affect the early stage of growth of M. aeruginosa. In particular, our results suggest that the maximum growth of M. aeruginosa is not simply affected by the $NO_3{^-}:NH_4{^+}$ ratio and the N : P ratio, but is determined by the TN concentration if a certain minimum $PO{_4}^{3-}$ concentration is present.

• Archives of Plastic Surgery
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• v.36 no.4
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• pp.372-379
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• 2009

Purpose: The purpose of this study was to compare the effect on antibacterial activities and wound healing effect of silver containing dressings with which of Betadine against Staphylococcus aureus and Pseudomonas aeruginosa. Methods: One full thickness skin defects in rats(n=72) were developed on the back and were given rise to infection with S. aureus(n=36) and P. aeruginosa(n=36). The 72 mice were divided into 6 groups : Acticoat$^{(R)}$, Aquacel$^{(R)}$-Ag, Medifoam silver$^{(R)}$, Polymen silver$^{(R)}$, Ilvadon$^{(R)}$ and Betadine(control group) dressing groups. Five silver containing dressings and Betadine were assesed on infected wound. Measurement of wound size change, bacterial colonies count and histologic findings was applied. Antibacterial activity was analyzed with bacterial restricted zone in Mueller Hinton agar. Results: On S. aureus, wound size was more decreased in all treated groups as compared with betadine, however Ilvadon$^{(R)}$ was less decreased on P. aeruginosa. In histologic findings, experimental group showed more effective findings than others on S. aureus, however on P. aeruginosa, which was showed similar. Acticoat$^{(R)}$ was best effective in wound healing against S. aureus and P. aeruginosa. The bacterial colonies count was increased in all treated groups except Acticoat$^{(R)}$ as compared with the control group on S. aureus, which was decreased in Acticoat$^{(R)}$ and Ilvadon$^{(R)}$ group on P. aeruginosa. There were not statistical differences. The restricted zone was shown in Mueller - Hinton agar of all groups except Medifoam silver$^{(R)}$ group on S. aureus, which was shown of all groups on P. aeruginosa. There were statistical differences. Conclusion: This study suggests that silver containing dressings may have not better potential than Betadine in assisting management of wounds at risk of infection on S. aureus and P. aeruginosa. However, which have better antibacterial activity on S. aureus and P. aeruginosa.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.92-98
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• 1994

The bacteria which secrete surface-active agent and decrease the surface tension of culture broth were isolated from soil samples. Among them, biosurfactant producing strain KK-7 was selected and emulsification was also detected. The KK-7 produced biosurfactant not only lipid but also glucose by using carbon source. Taxonomical characterization tests have demostrated the strain KK-7 to be Pseudomonas aeruginosa. The media composition of the P. aeruginosa KK-7 for the biosurfactant production was 1% glucose, 0.5% tryptone, 0.2% yeast extract, 0.15% potas sium phosphate mono-dibasic, 0.05% MgSO$_{4}$, initial pH 8.5, at 30$\circ $C for 2 days. In this condition, the concentration of biosurfactant was reached CMC 5 in the culture broth. Surface active material was produced maximum at stationary8 phase, but emulsification power was higher at log phase than stationary phase. It was considered that P. aeruginosa KK-7 produced biosurfactant more than one type having defferent properties and each maximum production time was different. The minimun surface tension of biosurfactant in 50 mM Tris buffer (pH8.0) was 28 dyn/cm, and CMC was 1 g/L.

• Korean Journal of Veterinary Research
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• v.61 no.2
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• pp.16.1-16.6
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• 2021

Pseudomonas aeruginosa is one of the most common pathogenic species associated with canine otitis externa (OE). Their resilience is achieved by forming a biofilm, which allows these bacteria to evade even the harshest of treatments. This study evaluated the in vitro synergistic efficacy of N-acetylcysteine (NAC) with different antimicrobial agents against P. aeruginosa isolated from dogs with OE to develop an effective treatment against P. aeruginosa. The antimicrobial activity was evaluated by the minimum inhibitory concentration test using the microdilution method. The efficacy of antibiofilm formation was evaluated using a crystal violet stain method. The treatment solutions included NAC alone, and in synergy with enrofloxacin, polymyxin B, and gentamicin. NAC alone exhibited antimicrobial and antibiofilm abilities. On the other hand, the combination of NAC and the antibiotics did not show any significant synergistic effects against P. aeruginosa.

• Journal of Pharmacopuncture
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• v.26 no.1
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• pp.53-59
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• 2023

Objectives: The most prominent microorganisms that cause hospital infections and acquire antibiotic resistance are Staphylococcus aureus and Pseudomonas aeruginosa. The present study aimed to compare the phenolic and flavonoid compounds of various Allium ampeloprasum and Allium porrum extracts and evaluate the antibacterial effects of these extracts against these two microorganisms. Methods: The total phenolic and flavonoid contents of the acetone, methanol, aqueous, and hexane leeks extracts from A. ampeloprasum and A. porrum were measured. The antibacterial activity of these extracts against S. aureus and P. aeruginosa was tested using the disk diffusion method for 24, 48, and 72 hours. Further, the minimum inhibitory concentrations and the minimum bactericidal concentrations of these extracts for these two bacteria were evaluated and compared with those of common antibiotics. Results: The aqueous extracts showed the highest phenolic and flavonoid contents and at concentrations of 35 and 40 mg per disk, showed the most antibacterial activity against S. aureus and P. aeruginosa; P. aeruginosa showed more sensitivity to the aqueous extracts than S. aureus. Conclusion: Aqueous A. ampeloprasum and A. porrum extracts may prevent the growth of hospital pathogens, especially P. aeruginosa; our findings will aid the discovery of new antimicrobial substances against antibiotic-resistant bacteria.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.145-152
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• 2020

In this study, the antimicrobial activity was tested by Ethanol extract(ET), Ethyl acetate fraction(EA) and Butanol fraction(BT) of Rhus javanica L fruit as natural preservatives. The antimicrobial activity were tested by Paper disc method and minimum inhibitory concentration (MIC) for microorganisms (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida Albicans). As a result of the antimicrobial activities of P. aeruginosa fruit extracts have shown the clear zone that S. aureus, S. epidermidis, E. coli, and P. aeruginosa. In BT, additional clear zones were observed for the Candida. The MIC results showed that EA samples showed the lowest concentrations for S. aureus S. epidermidis, E. coli, and P. aeruginosa. Accordingly, it can be concluded that these Rhus javanica L fruit extracts have the potential for antimicrobial materials for the cosmetic industry.

• Journal of Life Science
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• v.29 no.1
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• pp.84-89
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• 2019

Previous screening of novel antibacterial agents revealed that some bacterial isolates exhibited antibiotic activity against both gram-positive and gram-negative bacteria and that they showed antibacterial activity, even against methicillin-resistant Staphylococcus aureus (MRSA). Among these isolates, one bacterial strain, BCNU 1204, was identified as Pseudomonas aeruginosa using phenetic and phylogenetic analysis, based on 16S ribosomal RNA gene sequences. The maximum productivities of antimicrobial substances of BCNU 1204 were obtained after being cultured at $35^{\circ}C$ and pH 7.0 for 4 d in King's medium B (KMB). Dichloromethane (DCM) and ethylacetate (EA) extracts of P. aeruginosa BCNU 1204 exhibited strong antimicrobial activity, particularly against gram-positive bacteria. The EA extracts exhibited broad-spectrum activity against antibiotic resistant strains. Fraction 5-2, was obtained by recycling preparative liquid chromatography (LC) and preparative thin-layer chromatography (TLC) and was identified as phenazine-1-carboxylic acid belonging to phenazines using gas chromatography and mass spectrometry (GC/MS). Its minimum inhibitory concentration (MIC) values were $25{\mu}g/ml$, $50{\mu}g/ml$, ${\geq}25{\mu}g/ml$, and ${\geq}50{\mu}g/ml$ for MRSA CCARM 3089, 3090, 3091, and 3095 strains, respectively. P. aeruginosa BCNU 1204 may be a potential resource for the development of anti-MRSA antibiotics. Additional research is required to identify the active substance from P. aeruginosa BCNU 1204.