• 한국식품과학회지
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• 제51권6호
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• pp.604-609
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• 2019

To control pathogenic E. coli in biofilm, bacteriophages were isolated from environmental samples. Seventeen isolates had depolymerase activities by translucent zones at the rims of plaques. To determine biofilm-forming ability, an abiotic plastic surface of polystyrene was used; E. coli O103 showed the highest biofilm formation at 30℃ after 24 h. Moreover, biofilm by E. coli O103 on the biotic surface of lettuce was observed by a scanning electron microscope. The bacteriophage cocktail of ΦNOECP40 and ΦNOECP44 showing depolymerase activities was prepared to eliminate the E. coli inbiofilm. By organic acids, reduction of E. coli in biofilm was insignificant and almost undetectable. However, the abundance of E. coli in biofilm was reduced by 3 log CFU/mL from 7.3 log CFU/mL after 60 min with the bacteriophage cocktail. Therefore, we suggest that bacteriophages with depolymerase could be utilized to effectively control pathogenic E. coli in biofilm.

• 치위생과학회지
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• 제12권1호
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• pp.39-44
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• 2012

본 연구는 치면세균막 관리 프로그램에 의한 치면세균막 감소 효과 및 관리 난이도를 알아보기 위하여 충남지역에 위치한 N대학교 치위생학과에서 2006년부터 2011년까지 학생들이 제출한 임상치위생 증례보고서의 대상자 158명의 기록 가운데 가운데 본 연구에 적절하지 않은 기록을 제외하고 총 131부(82.9%)의 진료기록부를 최종분석에 사용하였다. 1. 치면세균막 관리 프로그램 수행 시 방문 차수에 따른 치면세균막 감소효과를 확인한 결과 2회 방문자(p=0.001), 3회, 4회, 5회, 6회 방문자(p<0.001)는 각각 방문 횟수가 많을수록 치면세균막 지수가 유의하게 감소하였다. 하지만 7회 방문한 대상자의 경우에는 감소된 정도가 통계적으로 유의하지 않았다(p=0.142). 2. 치면세균막 관리 프로그램의 최종방문 시 치아 부위별 치면세균막 지수 평균을 비교하기 위하여 치아 부위를 순/협면, 설/구개면, 인접면으로 분류했을 때에는 설면/구개면의 치면세균막 지수가 26.5%로 가장 높았다. 3. 상/하악의 치면세균막 지수를 측정한 결과 상악과 하악의 치면세균막 지수 간 유의한 차이가 나타났다(t=-2.501, p=0.014). 순/협면, 설/구개면, 인접면의 치면세균막 지수에 대한 분석 결과 순/협면, 설/구개면, 인접면의 치면세균막 지수는 유의한 차이를 보였다(Wilks의 람다=0.686, F=26.329, p<0.001). 육분악의 치면세균막 지수를 확인한 결과 각 부위별로 유의한 차이가 있는 것으로 나타났다(Pillai의 트레이스=0.166, F=4.443, p=0.001).

• 한국식품저장유통학회지
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• 제30권1호
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• pp.42-51
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• 2023

This study aimed to characterize a lytic Salmonella Typhimurium-specific (ST) phage and its biofilm control capability against S. Typhimurium biofilm on polypropylene surface. ST phage was isolated, propagated, and purified from water used in a slaughterhouse. The morphology of ST phage was observed via transmission electron microscopy. Its bactericidal effect was evaluated by determining bacterial concentrations after the phage treatment at various multiplicities of infection (MOIs) of 0.01, 1.0, and 100. Once the biofilm was formed on the polypropylene tube after incubation at 37℃ for 48 h, the phage was treated and its antibiofilm capability was determined using crystal violet staining and plate count method. The phage was isolated and purified at a final concentration of ~11 log PFU/mL. It was identified as a myophage with an icosahedral head (~104 nm) and contractile tail (~90-115 nm). ST phage could significantly decrease S. Typhimurium population by ~2.8 log CFU/mL at an MOI of 100. After incubation for 48 h, biofilm formation on polypropylene surface was confirmed with a bacterial population of ~6.9 log CFU/cm². After 1 h treatment with ST phage, the bacterial population in the biofilm was reduced by 2.8 log CFU/cm². Therefore, these results suggest that lytic ST phage as a promising biofilm control agent for eradicating S. Typhimurium biofilm formed on food contact surfaces.

• 대한치과의사협회지
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• 제56권8호
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• pp.432-436
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• 2018

Dental caries and periodontitis are the major concerns of oral disease to human, and its etiologic factor is dental biofilm. The aim of this study is to discuss the clinical application method and the meaning of dental biofilm control in the disabled patients. Generally, ultrasonic scaler are likely to generate excessive stimulus to the disabled patients. Rubber cup application using Ni-Ti engine could remove dental biofilm more comfortably to the disabled patients.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2116-2126
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• 2016

Bacterial biofilms are spatially structured communities that contain bacterial cells with a wide range of physiological states. The spatial distribution and speciation of copper in unsaturated Pseudomonas putida CZ1 biofilms that accumulated 147.0 mg copper per g dry weight were determined by transmission electron microscopy coupled with energy dispersive X-ray analysis, and micro-X-ray fluorescence microscopy coupled with micro-X-ray absorption near edge structure (micro-XANES) analysis. It was found that copper was mainly precipitated in a $75{\mu}m$ thick layer as copper phosphate in the middle of the biofilm, while there were two living cell layers in the air-biofilm and biofilm-medium interfaces, respectively, distinguished from the copper precipitation layer by two interfaces. The X-ray absorption fine structure analysis of biofilm revealed that species resembling $Cu_3(PO_4)_2$ predominated in biofilm, followed by Cu-Citrate- and Cu-Glutathione-like species. Further analysis by micro-XANES revealed that 94.4% of copper were $Cu_3(PO_4)_2$-like species in the layer next to the air interface, whereas the copper species of the layer next to the medium interface were composed by 75.4% $Cu_3(PO_4)_2$, 10.9% Cu-Citrate-like species, and 11.2% Cu-Glutathione-like species. Thereby, it was suggested that copper was initially acquired by cells in the biofilm-air interface as a citrate complex, and then transported out and bound by out membranes of cells, released from the copper-bound membranes, and finally precipitated with phosphate in the extracellular matrix of the biofilm. These results revealed a clear spatial pattern of copper precipitation in unsaturated biofilm, which was responsible for the high copper tolerance and accumulation of the biofilm.

• 한국환경과학회지
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• 제30권5호
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• pp.369-378
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• 2021

In this study, we investigated the effects of indole on biofilm formation inhibition in Pantoea agglomerans (P. agglomerans). In the biofilm growth assay, indole inhibited biofilm formation across all the growth time. Depending on biofilm growth stage, indole exhibited biofilm inhibition and anti-bacterial effects on planktonic cells. Through the analysis of the proportion rate between biofilm and Colony Forming Units (CFU) and inhibition rate of indole, we confirmed that depending on the biofilm stage of P. agglomerans, indole treatment timing was more important than the treatment duration. By comparing gene expression rates through rt-qPCR P.agglomerans affected by indole was found to significantly change quorum sensing (pagI/R) and indole transportation (bssS) gene expressions. Throughout all, indole exhibited both antimicrobial and anti-biofilm effects on P. agglomerans. In addition, we confirmed the anti-biofilm effects of indole on mature biofilm. In conclusion, indole as a signal molecule, can exhibit anti-biofilm effects through bacterial quorum sensing inhibition and indole affects. Therefore, indole can regulate biofilm bacteria especially gram-negative opportunistic pathogens.

• Journal of Microbiology and Biotechnology
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• 제33권6호
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• pp.715-723
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• 2023

Microbial biofilms are resilient, immune-evasive, often antibiotic-resistant health challenges, and increasingly the target for research into novel therapeutic strategies. We evaluated the effects of a nutraceutical enzyme and botanical blend (NEBB) on established biofilm. Five microbial strains with known implications in chronic human illnesses were tested: Candida albicans, Staphylococcus aureus, Staphylococcus simulans (coagulase-negative, penicillin-resistant), Borrelia burgdorferi, and Pseudomonas aeruginosa. The strains were allowed to form biofilm in vitro. Biofilm cultures were treated with NEBB containing enzymes targeted at lipids, proteins, and sugars, also containing the mucolytic compound N-acetyl cysteine, along with antimicrobial extracts from cranberry, berberine, rosemary, and peppermint. The post-treatment biofilm mass was evaluated by crystal-violet staining, and metabolic activity was measured using the MTT assay. Average biofilm mass and metabolic activity for NEBB-treated biofilms were compared to the average of untreated control cultures. Treatment of established biofilm with NEBB resulted in biofilm-disruption, involving significant reductions in biofilm mass and metabolic activity for Candida and both Staphylococcus species. For B. burgdorferi, we observed reduced biofilm mass, but the remaining residual biofilm showed a mild increase in metabolic activity, suggesting a shift from metabolically quiescent, treatment-resistant persister forms of B. burgdorferi to a more active form, potentially more recognizable by the host immune system. For P. aeruginosa, low doses of NEBB significantly reduced biofilm mass and metabolic activity while higher doses of NEBB increased biofilm mass and metabolic activity. The results suggest that targeted nutraceutical support may help disrupt biofilm communities, offering new facets for integrative combinational treatment strategies.

• Membrane and Water Treatment
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• 제14권1호
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• pp.35-45
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• 2023

Biofilms significantly affect the performance of wastewater treatment processes in which biodegradability of numerous microorganisms are actively involved, and various technologies have been applied to secure microbial biofilms. Understanding changes in biofilm characteristics by regulating expression of signaling molecules is important to control and regulate biofilms in membrane bioreactor, i.e., biofouling. This study investigated effects of addition of acyl-homoserine lactones (AHL) as a controllable factor for the microbial signaling system on biofilm formation of Pseudomonas aeruginosa PAO1 and multiple strains in membrane bioreactor. The addition of three AHL, i.e., C4-, C6-, and C8-HSL, at a concentration of 200 ㎍/L, enhanced the formation of the PAO1 biofilm and the degree of increases in the biofilm formation of PAO1 were 70.2%, 76.6%, and 72.9%, respectively. The improvement of biofilm formation of individual strains by C4-HSL was an average of 68%, and the microbial consortia increased by approximately 52.1% in the presence of 200 ㎍/L C4-HSL. CLSM images showed that more bacterial cells were present on the membrane surface after the AHL application. In the COMSTAT results, biomass and thickness were increased up to 2.2 times (PAO1) and 1.6 times (multi-strains) by C4-HSL. This study clearly showed that biofilm formation was increased by the application of AHL to individual strain groups, including PAO1 and microbial consortia, and significant increases were observed when 50 or 100 ㎍/L AHL was administered. This suggests that AHL application can improve the biofilm formation of microorganisms, which could yield an enhancement in efficiency of biofilm control, such as in various biofilm reactors including membrane bioreactor and bioflocculent systems in water/wastewater treatment processes.

• 한국축산식품학회지
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• 제40권4호
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• pp.668-674
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• 2020

Manuka honey (MH) has been shown anti-bacterial activity against several pathogenic bacteria. However, the inhibitory effect of MH on biofilm formation by Escherichia coli O157:H7 has not yet been examined. In this study, MH significantly reduced E. coli O157:H7 biofilm. Moreover, pre- and post-treatment with MH also significantly reduced E. coli O157:H7 biofilm. Cellular metabolic activities exhibited that the viability of E. coli O157:H7 biofilm cells was reduced in the presence of MH. Further, colony forming unit of MH-treated E. coli O157:H7 biofilm was significantly reduced by over 70%. Collectively, this study suggests the potential of anti-biofilm properties of MH which could be applied to control E. coli O157:H7.

• 한국미생물·생명공학회지
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• 제44권4호
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• pp.535-539
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• 2016

제주도 넙치 양식장에서 주로 발생하는 어류질병세균인 S. parauberis, S. iniae, E. tarda에 대한 피해를 줄이고자 갈륨을 이용하여 어류질병세균을 억제하고자 한다. 본 연구진은 Sp, Si, Et의 생육도와 biofilm 형성능을 확인하였으며, 세균의 성장도와 biofilm 형성능간의 특정한 패턴은 없었으며 세균의 성장도가 높다 하더라도 biofilm을 활발히 형성하지 않음을 알 수 있었다. 어류질병세균이 형성하는 biofilm을 저해하기 위해 갈륨을 2.0, 4.0, 8.0 mg/ml로 첨가하여 저해능을 확인한 결과 72시간째 biofilm의 형성이 크게 저해되는 것을 확인하였다. 또한 biofilm을 저해하는 동시에 균주의 사멸능을 확인하기 위해 resazurin assay와 propidium iodide를 이용하여 염색한 결과 갈륨의 농도에 따라 균주의 사멸이 증가하는 것을 확인하였다. 이에 따라 in vitro 상에서 갈륨이 어류질병세균의 biofilm을 억제하는 동시에 균주를 사멸시키는 물질로서 가치가 있다고 사료된다.