Akkermansia muciniphila is one of the commensals residing within the mammalian gut and co-evolving with the host.Numerous studies have demonstrated the benefits of A.muciniphila in ameliorating metabolic disorders,whi...Akkermansia muciniphila is one of the commensals residing within the mammalian gut and co-evolving with the host.Numerous studies have demonstrated the benefits of A.muciniphila in ameliorating metabolic disorders,while little is known about the antimicrobial potential of A.muciniphila against pathogens.Here,we examined the antimicrobial and anti-virulence properties of cell free supernatant(CFS)of A.muciniphila against Salmonella Typhimurium.CFS retarded bacterial growth and inhibited the motility of S.Typhimurium SL1344 and S.Typhimurium 14028.CFS dose-dependently reduced cell hydrophobicity and auto-aggregation of both strains.Also,CFS from A.muciniphila significantly attenuated biofilm formation.Compared with untreated bacteria,CFS-treated bacteria significantly decreased adhesion and invasion to Caco-2 cells,and reduced intracellular survival in macrophages.CFS maintained antimicrobial properties after treatment with high temperatures and various proteases,while it lost its antimicrobial activity after pH neutralization.Gas chromatography-mass spectrometry(GC-MS)confirmed that A.muciniphila produced a certain amount of acetate and propionate,and ultra-high-performance liquid chromatography-mass spectrometry(UHPLCMS)identified other organic acids and metabolites in CFS.In summary,CFS from A.muciniphila exhibited anti-biofilm and anti-virulence properties against Salmonella and could be potentially utilized in the food industry for controlling Salmonella contamination and reducing infection.展开更多
Slightly acidic electrolyzed water(SAEW)has proven to be an efficient and novel sanitizer in food and agriculture field.This study assessed the efficacy of SAEW(30 mg/L)at 40℃on the inactivation of foodbome pathogens...Slightly acidic electrolyzed water(SAEW)has proven to be an efficient and novel sanitizer in food and agriculture field.This study assessed the efficacy of SAEW(30 mg/L)at 40℃on the inactivation of foodbome pathogens and detachment of multi-resistant Staphylococcus aureus(MRSA)biofilm.Furthermore.the underlying mechanism of MRS A biofilm under heated SAEW at 40℃treatment on metabolic profiles was investigated.The results showed that the heated SAEW at 40℃significantly effectively against foodbome pathogens of 1.96-7.56(lg(CFU/g))reduction in pork,chicken,spinach,and lettuce.The heated SAEW at 40℃treatment significantly reduced MRS A biofilm cells by 2.41(lg(CFU/cm^(2))).The synergistic effect of SAEW treatment showed intense anti-biofilm activity in decreasing cell density and impairing biofilm cell membranes.Global metabolic response of MRSA biofilms,treated by SAEW at 40℃,revealed the alterations of intracellular metabolites,including amino acids,organic acid,fatty acid,and lipid.Moreover,signaling pathways involved in amino acid metabolism,energy metabolism,nucleotide synthesis,carbohydrate metabolites,and lipid biosynthesis were functionally disrupted by the SAEW at 40℃treatment.As per our knowledge,this is the first research to uncover the potential mechanism of heated SAEW treatment against MRSA biofilm on food contact surface.展开更多
Biofilm formation is responsible for numerous chronic infections and represents a serious health challenge.Bacteria and the extracellular polysaccharides(EPS)cause biofilms to become adherent,toxic,resistant to antibi...Biofilm formation is responsible for numerous chronic infections and represents a serious health challenge.Bacteria and the extracellular polysaccharides(EPS)cause biofilms to become adherent,toxic,resistant to antibiotics,and ultimately difficult to remove.Inhibition of EPS synthesis can prevent the formation of bacterial biofilms,reduce their robustness,and promote removal.Here,we have developed a framework nucleic acid delivery system with a tetrahedral configuration.It can easily access bacterial cells and functions by delivering antisense oligonucleotides that target specific genes.We designed antisense oligonucleotide sequences with multiple targets based on conserved regions of the VicK protein-binding site.Once delivered to bacterial cells,they significantly decreased EPS synthesis and biofilm thickness.Compared to existing approaches,this system is highly efficacious because it simultaneously reduces the expression of all targeted genes(gtfBCD,gbpB,ftf).We demonstrate a novel nucleic acid-based nanomaterial with multi-targeted inhibition that has great potential for the treatment of chronic infections caused by biofilms.展开更多
Objective To explore the effects of Scutellaria baicalensis on activity and biofilm formation of Klebsiella pneumonia(Kp).Methods The broth and agar dilution methods were carried out to determine minimum inhibitory co...Objective To explore the effects of Scutellaria baicalensis on activity and biofilm formation of Klebsiella pneumonia(Kp).Methods The broth and agar dilution methods were carried out to determine minimum inhibitory concentration and minimum bactericidal concentration of Scutellaria baicalensis for TW518.VITEK-32 system was used to assay TW518 susceptibility to antibiotics.Kp biofilms were formed in vitro and stained with Bac Light Live/Dead stain.The class integron geneⅠ1 m RNA expression was analyzed with RT-PCR.Results The minimum inhibitory concentration of Scutellaria baicalensis on TW518 identified as a Kp colony was 32 mg/ml,and minimum bactericidal concentration was 64 mg/ml.Scutellaria baicalensis and broad-spectrum penicillin,cephalosporin,quinolones,or beta-lactamase had synergistic bactericidal effects.Biofilm formation activity of Kp treated with Scutellaria baicalensis was significantly lower than that of the control group.And class integron geneⅠ1 m RNA expression of TW518 was significantly inhibited by Scutellaria baicalensis.Conclusions Scutellaria baicalensis has sterilization effect on Kp,and Scutellaria baicalensis could effectively inhibit Kp biofilm formation with prolonged treatment.Scutellaria baicalensis might inhibit Kp biofilm formation through down-regulating integron geneⅠ1 expression.展开更多
Biofilms are a constant concern in the food industry;understanding the effect of environmental conditions on biofilm formation is essential to develop effective control strategies.Therefore,this study was conducted to...Biofilms are a constant concern in the food industry;understanding the effect of environmental conditions on biofilm formation is essential to develop effective control strategies.Therefore,this study was conducted to investigate biofilms formation by Staphylococcus epidermidis under various conditions.Biofilms were cultured in nutrient broth containing different carbon source concentrations(0–10 mg/mL)on polystyrene surfaces for 32 h of incubation at 37℃or 55℃,with quantification and enumeration at 8,16,24 and 32 h.S.epidermidis developed biofilms under all tested conditions;achieved the highest yield of biofilm biomass at 2.5 mg/mL for all carbon sources at 37℃.The highest efficiency of extracellular polymeric substance(EPS)molecule production occurred under glucose availability in the growth environment,with a higher yield of biomass and a significantly smaller number of metabolically active cells than under other tested conditions.A condensed ball-shaped structure was observed under the lactose condition.Meanwhile,biofilms in the presence of maltose showed mainly opaque thick rich colonies,while a compact multilayered-shaped structure was exhibited under both glucose and sucrose conditions.These results contribute to a better understanding of the biofilm formation by S.epidermidis in order to reduce contamination and recontamination in the food industry.展开更多
The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. The synthesis of silver nanoparticles was achieved using Bacillus cereus supernatant and1 m ...The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. The synthesis of silver nanoparticles was achieved using Bacillus cereus supernatant and1 m M silver nitrate. 100 m M glucose was found to quicken the rate of reaction of silver nanoparticles synthesis.UV-visible spectrophotometric analysis was carried out to assess the synthesis of silver nanoparticles. The synthesized silver nanoparticles were further characterized by using Nanoparticle Tracking Analyzer(NTA),Transmission Electron Microscope and Energy Dispersive X-ray spectra. These silver nanoparticles showed enhanced quorum quenching activity against Staphylococcus aureus biofilm and prevention of biofilm formation which can be seen under inverted microscope(40 X). The synergistic effect of silver nanoparticles along with antibiotics in biofilm quenching was found to be effective. In the near future, silver nanoparticles could be used in the treatment of infections caused by highly antibiotic resistant biofilm.展开更多
In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was rec...In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.展开更多
This paper presents a study of the effect of the low temperature atmospheric helium dielectric barrier discharge（DBD） on the Streptococcus mutans biofilms formed on tooth surface. Pig jaws were also treated by plasm...This paper presents a study of the effect of the low temperature atmospheric helium dielectric barrier discharge（DBD） on the Streptococcus mutans biofilms formed on tooth surface. Pig jaws were also treated by plasma to detect if there is any harmful effect on the gingiva.The plasma was characterized by using optical emission spectroscopy.Experimental data indicated that the discharge is very effective in deactivating Streptococcus mutans biofilms.It can destroy them with an average decimal reduction time（D-time） of 19 s and about 98%of thein were killed after a treatment time of 30 s.According to the survival curve kinetic an overall 32 s treatment time would be necessary to perform a complete sterilization.The experimental results presented in this study indicated that the helium dielectric barrier discharge,in plan-parallel electrode configuration,could be a very effective tool for deactivation of oral bacteria and might be a promising technique in various dental clinical applications.展开更多
Foodborne pathogen poses a threat to the food industries as many outbreaks have been found to be associated with biofilm formation.The formation of biofilm is a self-protection growth pattern of bacteria,which increas...Foodborne pathogen poses a threat to the food industries as many outbreaks have been found to be associated with biofilm formation.The formation of biofilm is a self-protection growth pattern of bacteria,which increases post-processing contamination and risk to public health.It is difficult to eliminate the biofilm in the food industries,since the biofilm cells have a barrier preventing or lessening the contact with environmental stresses,antimicrobial agents and the host immune system.Bacterial biofilm formation is a complex process,including initial attachment stage,irreversible attachment stage,biofilm development stage,biofilm maturation stage,and biofilm dispersion stage.The genetic mechanism,substratum and bacterial cell surface properties involve in the biofilm formation.The biofilm inhibition methods studied are physical treatment,chemical and biochemical treatment.The potential green and safe biochemical method attracts more attention,especially,the novel strategies using the safe biochemical agents(essential oils,enzymes,biosurfactants,others)constantly emerged.The review emphasized on effective strategies for inhibiting biofilm formation in different stages(initial irreversible attachment,formation,and maturation)by use of biochemical agents,aiming to provide new insight into biofilm control in food industry thus improving food quality and safety.展开更多
In this paper, the interactions between two dielectric barrier discharge(DBD) filaments and three bacterial biofilms are simulated. The modeling of a DBD streamer is studied by means of 2D finite element calculation. ...In this paper, the interactions between two dielectric barrier discharge(DBD) filaments and three bacterial biofilms are simulated. The modeling of a DBD streamer is studied by means of 2D finite element calculation. The model is described by the proper governing equations of air DBD at atmospheric pressure and room temperature. The electric field in the computing domain and the self-consistent transportation of reactive species between a cathode and biofilms on the surface of an apple are realized by solving a Poisson equation and continuity equations. The electron temperature is solved by the electron energy conservation equation. The conductivity and permittivity of bacterial biofilms are considered, and the shapes of the bacterial biofilms are irregular in the uncertainty and randomness of colony growth. The distribution of the electrons suggests that two plasma channels divide into three plasma channels when the streamer are 1 mm from the biofilms. The toe-shapes of the biofilms and the simultaneous effect of two streamer heads result in a high electric field around the biofilms, therefore the stronger ionization facilitates the major part of two streamers combined into one streamer and three streamers arise.The distribution of the reactive oxygen species and the reactive nitrogen species captured by time fluences are non-uniform due to the toe-shaped bacterial biofilms. However, the plasma can intrude into the cavities in the adjacent biofilms due to the μm-scale mean free path. The two streamers case has a larger treatment area and realizes the simultaneous treatment of three biofilms compared with one streamer case.展开更多
Salmonella and their biofilm formation are the primary bacterial causes of foodborne outbreaks and crosscontamination. The objective of the study was to investigate the potential of Salmonella phages as an alternative...Salmonella and their biofilm formation are the primary bacterial causes of foodborne outbreaks and crosscontamination. The objective of the study was to investigate the potential of Salmonella phages as an alternative technology for biofilm removal. In this work, 21 Salmonella phages were isolated from a chicken farm and slaughter plant and the phage(CW1)with the broadest spectrum was characterized. Complete genome sequence analysis revealed that the genomes of phage CW1 is composed of 41 763 bp with 58 open reading frames(ORFs)and a holin-endolysin system and it does not encode any virulence or lysogeny. A phage cocktail consisted of CW1(with the broadest spectrum of 70.49%)and CW11, M4 and M10(with a high lytic activity of more than 67.11%)was established. Treatment with the cocktail reduced the cells in the developing biofilm and mature biofilm by 0.79 lg(CFU/cm~2)and 0.4 lg(CFU/cm~2), respectively. More dead cells and scattered extracellular polymeric substances(EPS)were observed by confocal laser scanning microscopy and scanning electron microscopy. Raman analysis found that carbohydrates and proteins were the identification receptors for scattered EPS. This finding suggests that this phage cockta il has potential applications for the sterilization of Salmonella biofilm during meat processing.展开更多
This study explored the antibiofilm efficacy of 3,3’-diindolylmethane(DIM)on Staphylococcus aureus and its disinfection on common food-contact surfaces.The minimum biofilm inhibitory concentration(MBIC)of DIM on S.au...This study explored the antibiofilm efficacy of 3,3’-diindolylmethane(DIM)on Staphylococcus aureus and its disinfection on common food-contact surfaces.The minimum biofilm inhibitory concentration(MBIC)of DIM on S.aureus was 62.5μmol/L,while it did not impede the bacterial growth evaluated by growth curve and XTT reduction assay.DIM in the concentration range of 31.2-62.5μmol/L demonstrated a dose-dependent antibiofilm activity to S.aureus,as confirmed by light microscopic(LM),confocal laser scanning microscopic(CLSM),and scanning electron microscopic(SEM)analyses.At DIM of62.5μmol/L,the biomass of S.aureus biofilm was significantly reduced by 97%and its average thickness by 58%(P<0.05).DIM of 62.5μmol/L inhibited the bacterial initial adhesion and proliferation,as well as cell motility;the release of extracellular DNA(eDNA)and extracellular polysaccharide(EPS)were reduced by 75%and 69%,respectively.DIM exhibited a strong inhibition to S.aureus biofilm formation on common food-contact surfaces,including 304 stainless steel,glass,and polyvinyl chloride(PVC)but not disperse the mature biofilm.Overall,our investigation identified DIM as a promising antibiofilm agent and its suitability to prevent the biofilm formation of S.aureus on common food-contact surfaces utilized during food processing.展开更多
Fluid flow past the biofilm surface can bring external force to biofilm which could result in biofilm deformation and detachment. The flow velocity have significant effect on determining biofilm deformation and detach...Fluid flow past the biofilm surface can bring external force to biofilm which could result in biofilm deformation and detachment. The flow velocity have significant effect on determining biofilm deformation and detachment. In this work, finite element method was adapted to study the flow induced deformation of biofilm in varied flow conditions.展开更多
基金funded by National Key Research and Development Program of China(2022YFD2100104)Science and Technology Research Program of the Liaoning Department of Education(J2020044)+1 种基金Shaanxi Key Research and Development project(2019SF-259)LiaoNing Revitalization Talents Program(XLYC1807220).
文摘Akkermansia muciniphila is one of the commensals residing within the mammalian gut and co-evolving with the host.Numerous studies have demonstrated the benefits of A.muciniphila in ameliorating metabolic disorders,while little is known about the antimicrobial potential of A.muciniphila against pathogens.Here,we examined the antimicrobial and anti-virulence properties of cell free supernatant(CFS)of A.muciniphila against Salmonella Typhimurium.CFS retarded bacterial growth and inhibited the motility of S.Typhimurium SL1344 and S.Typhimurium 14028.CFS dose-dependently reduced cell hydrophobicity and auto-aggregation of both strains.Also,CFS from A.muciniphila significantly attenuated biofilm formation.Compared with untreated bacteria,CFS-treated bacteria significantly decreased adhesion and invasion to Caco-2 cells,and reduced intracellular survival in macrophages.CFS maintained antimicrobial properties after treatment with high temperatures and various proteases,while it lost its antimicrobial activity after pH neutralization.Gas chromatography-mass spectrometry(GC-MS)confirmed that A.muciniphila produced a certain amount of acetate and propionate,and ultra-high-performance liquid chromatography-mass spectrometry(UHPLCMS)identified other organic acids and metabolites in CFS.In summary,CFS from A.muciniphila exhibited anti-biofilm and anti-virulence properties against Salmonella and could be potentially utilized in the food industry for controlling Salmonella contamination and reducing infection.
基金supported by Brain Korea (BK)21 Plus Project (4299990913942)funded by the Korean Government,Koreathe Collabo Project funded by the Ministry of SMEs and Startups (C1016120-01-02)the National Research Foundation of Korea (NRF) (2018007551)。
文摘Slightly acidic electrolyzed water(SAEW)has proven to be an efficient and novel sanitizer in food and agriculture field.This study assessed the efficacy of SAEW(30 mg/L)at 40℃on the inactivation of foodbome pathogens and detachment of multi-resistant Staphylococcus aureus(MRSA)biofilm.Furthermore.the underlying mechanism of MRS A biofilm under heated SAEW at 40℃treatment on metabolic profiles was investigated.The results showed that the heated SAEW at 40℃significantly effectively against foodbome pathogens of 1.96-7.56(lg(CFU/g))reduction in pork,chicken,spinach,and lettuce.The heated SAEW at 40℃treatment significantly reduced MRS A biofilm cells by 2.41(lg(CFU/cm^(2))).The synergistic effect of SAEW treatment showed intense anti-biofilm activity in decreasing cell density and impairing biofilm cell membranes.Global metabolic response of MRSA biofilms,treated by SAEW at 40℃,revealed the alterations of intracellular metabolites,including amino acids,organic acid,fatty acid,and lipid.Moreover,signaling pathways involved in amino acid metabolism,energy metabolism,nucleotide synthesis,carbohydrate metabolites,and lipid biosynthesis were functionally disrupted by the SAEW at 40℃treatment.As per our knowledge,this is the first research to uncover the potential mechanism of heated SAEW treatment against MRSA biofilm on food contact surface.
基金the National Key R&D Program of China(2019YFA0110600)National Natural Science Foundation of China(81970916,81671031).
文摘Biofilm formation is responsible for numerous chronic infections and represents a serious health challenge.Bacteria and the extracellular polysaccharides(EPS)cause biofilms to become adherent,toxic,resistant to antibiotics,and ultimately difficult to remove.Inhibition of EPS synthesis can prevent the formation of bacterial biofilms,reduce their robustness,and promote removal.Here,we have developed a framework nucleic acid delivery system with a tetrahedral configuration.It can easily access bacterial cells and functions by delivering antisense oligonucleotides that target specific genes.We designed antisense oligonucleotide sequences with multiple targets based on conserved regions of the VicK protein-binding site.Once delivered to bacterial cells,they significantly decreased EPS synthesis and biofilm thickness.Compared to existing approaches,this system is highly efficacious because it simultaneously reduces the expression of all targeted genes(gtfBCD,gbpB,ftf).We demonstrate a novel nucleic acid-based nanomaterial with multi-targeted inhibition that has great potential for the treatment of chronic infections caused by biofilms.
基金Supported by the Fund of Hubei 2011 Cooperative Innovation Center and project for College Students Innovation and Entrepreneurship(Grant 4)Hubei University of Medicine(201310929004)
文摘Objective To explore the effects of Scutellaria baicalensis on activity and biofilm formation of Klebsiella pneumonia(Kp).Methods The broth and agar dilution methods were carried out to determine minimum inhibitory concentration and minimum bactericidal concentration of Scutellaria baicalensis for TW518.VITEK-32 system was used to assay TW518 susceptibility to antibiotics.Kp biofilms were formed in vitro and stained with Bac Light Live/Dead stain.The class integron geneⅠ1 m RNA expression was analyzed with RT-PCR.Results The minimum inhibitory concentration of Scutellaria baicalensis on TW518 identified as a Kp colony was 32 mg/ml,and minimum bactericidal concentration was 64 mg/ml.Scutellaria baicalensis and broad-spectrum penicillin,cephalosporin,quinolones,or beta-lactamase had synergistic bactericidal effects.Biofilm formation activity of Kp treated with Scutellaria baicalensis was significantly lower than that of the control group.And class integron geneⅠ1 m RNA expression of TW518 was significantly inhibited by Scutellaria baicalensis.Conclusions Scutellaria baicalensis has sterilization effect on Kp,and Scutellaria baicalensis could effectively inhibit Kp biofilm formation with prolonged treatment.Scutellaria baicalensis might inhibit Kp biofilm formation through down-regulating integron geneⅠ1 expression.
基金This work was financially supported by the National Key Research and Development Program of China(2016YFD0400301)the Key Research and Development Program of Zhejiang Province(2017C02015).
文摘Biofilms are a constant concern in the food industry;understanding the effect of environmental conditions on biofilm formation is essential to develop effective control strategies.Therefore,this study was conducted to investigate biofilms formation by Staphylococcus epidermidis under various conditions.Biofilms were cultured in nutrient broth containing different carbon source concentrations(0–10 mg/mL)on polystyrene surfaces for 32 h of incubation at 37℃or 55℃,with quantification and enumeration at 8,16,24 and 32 h.S.epidermidis developed biofilms under all tested conditions;achieved the highest yield of biofilm biomass at 2.5 mg/mL for all carbon sources at 37℃.The highest efficiency of extracellular polymeric substance(EPS)molecule production occurred under glucose availability in the growth environment,with a higher yield of biomass and a significantly smaller number of metabolically active cells than under other tested conditions.A condensed ball-shaped structure was observed under the lactose condition.Meanwhile,biofilms in the presence of maltose showed mainly opaque thick rich colonies,while a compact multilayered-shaped structure was exhibited under both glucose and sucrose conditions.These results contribute to a better understanding of the biofilm formation by S.epidermidis in order to reduce contamination and recontamination in the food industry.
基金Pravara Institute of Medical Sciences, Loni (MS), India for the financial support
文摘The development of green experimental processes for the synthesis of nanoparticles is a need in the field of nanotechnology. The synthesis of silver nanoparticles was achieved using Bacillus cereus supernatant and1 m M silver nitrate. 100 m M glucose was found to quicken the rate of reaction of silver nanoparticles synthesis.UV-visible spectrophotometric analysis was carried out to assess the synthesis of silver nanoparticles. The synthesized silver nanoparticles were further characterized by using Nanoparticle Tracking Analyzer(NTA),Transmission Electron Microscope and Energy Dispersive X-ray spectra. These silver nanoparticles showed enhanced quorum quenching activity against Staphylococcus aureus biofilm and prevention of biofilm formation which can be seen under inverted microscope(40 X). The synergistic effect of silver nanoparticles along with antibiotics in biofilm quenching was found to be effective. In the near future, silver nanoparticles could be used in the treatment of infections caused by highly antibiotic resistant biofilm.
文摘In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.
基金supported by the National University Research Council,Ministry of Education,Research and Innovation,Romania (Grant PN-II-ID-PCE 2007-2013,nr.446/2009)
文摘This paper presents a study of the effect of the low temperature atmospheric helium dielectric barrier discharge（DBD） on the Streptococcus mutans biofilms formed on tooth surface. Pig jaws were also treated by plasma to detect if there is any harmful effect on the gingiva.The plasma was characterized by using optical emission spectroscopy.Experimental data indicated that the discharge is very effective in deactivating Streptococcus mutans biofilms.It can destroy them with an average decimal reduction time（D-time） of 19 s and about 98%of thein were killed after a treatment time of 30 s.According to the survival curve kinetic an overall 32 s treatment time would be necessary to perform a complete sterilization.The experimental results presented in this study indicated that the helium dielectric barrier discharge,in plan-parallel electrode configuration,could be a very effective tool for deactivation of oral bacteria and might be a promising technique in various dental clinical applications.
基金the Science and Technology Project of Henan Province(212102110320)the Science Foundation of Henan University of Technology(Grant Nos.2020BS013,2019BS029)
文摘Foodborne pathogen poses a threat to the food industries as many outbreaks have been found to be associated with biofilm formation.The formation of biofilm is a self-protection growth pattern of bacteria,which increases post-processing contamination and risk to public health.It is difficult to eliminate the biofilm in the food industries,since the biofilm cells have a barrier preventing or lessening the contact with environmental stresses,antimicrobial agents and the host immune system.Bacterial biofilm formation is a complex process,including initial attachment stage,irreversible attachment stage,biofilm development stage,biofilm maturation stage,and biofilm dispersion stage.The genetic mechanism,substratum and bacterial cell surface properties involve in the biofilm formation.The biofilm inhibition methods studied are physical treatment,chemical and biochemical treatment.The potential green and safe biochemical method attracts more attention,especially,the novel strategies using the safe biochemical agents(essential oils,enzymes,biosurfactants,others)constantly emerged.The review emphasized on effective strategies for inhibiting biofilm formation in different stages(initial irreversible attachment,formation,and maturation)by use of biochemical agents,aiming to provide new insight into biofilm control in food industry thus improving food quality and safety.
文摘In this paper, the interactions between two dielectric barrier discharge(DBD) filaments and three bacterial biofilms are simulated. The modeling of a DBD streamer is studied by means of 2D finite element calculation. The model is described by the proper governing equations of air DBD at atmospheric pressure and room temperature. The electric field in the computing domain and the self-consistent transportation of reactive species between a cathode and biofilms on the surface of an apple are realized by solving a Poisson equation and continuity equations. The electron temperature is solved by the electron energy conservation equation. The conductivity and permittivity of bacterial biofilms are considered, and the shapes of the bacterial biofilms are irregular in the uncertainty and randomness of colony growth. The distribution of the electrons suggests that two plasma channels divide into three plasma channels when the streamer are 1 mm from the biofilms. The toe-shapes of the biofilms and the simultaneous effect of two streamer heads result in a high electric field around the biofilms, therefore the stronger ionization facilitates the major part of two streamers combined into one streamer and three streamers arise.The distribution of the reactive oxygen species and the reactive nitrogen species captured by time fluences are non-uniform due to the toe-shaped bacterial biofilms. However, the plasma can intrude into the cavities in the adjacent biofilms due to the μm-scale mean free path. The two streamers case has a larger treatment area and realizes the simultaneous treatment of three biofilms compared with one streamer case.
基金funded by grants from the National Natural Science Foundation of China (31872911)the National Key Research Program of China (2018YFC1603800)。
文摘Salmonella and their biofilm formation are the primary bacterial causes of foodborne outbreaks and crosscontamination. The objective of the study was to investigate the potential of Salmonella phages as an alternative technology for biofilm removal. In this work, 21 Salmonella phages were isolated from a chicken farm and slaughter plant and the phage(CW1)with the broadest spectrum was characterized. Complete genome sequence analysis revealed that the genomes of phage CW1 is composed of 41 763 bp with 58 open reading frames(ORFs)and a holin-endolysin system and it does not encode any virulence or lysogeny. A phage cocktail consisted of CW1(with the broadest spectrum of 70.49%)and CW11, M4 and M10(with a high lytic activity of more than 67.11%)was established. Treatment with the cocktail reduced the cells in the developing biofilm and mature biofilm by 0.79 lg(CFU/cm~2)and 0.4 lg(CFU/cm~2), respectively. More dead cells and scattered extracellular polymeric substances(EPS)were observed by confocal laser scanning microscopy and scanning electron microscopy. Raman analysis found that carbohydrates and proteins were the identification receptors for scattered EPS. This finding suggests that this phage cockta il has potential applications for the sterilization of Salmonella biofilm during meat processing.
基金supported by the National Key Research and Development Projects(2019YFE0103800)Sichuan Science and Technology Program(2019YFH0113,2021YFH0060,2021YFH0072,2021ZHFP0045,2021YFN0092)the Fundamental Research Funds for the Central Universities(2018CDLZ-07,2018CDPZH-9,2019CDPZH-23,2020CDLZ-17)。
文摘This study explored the antibiofilm efficacy of 3,3’-diindolylmethane(DIM)on Staphylococcus aureus and its disinfection on common food-contact surfaces.The minimum biofilm inhibitory concentration(MBIC)of DIM on S.aureus was 62.5μmol/L,while it did not impede the bacterial growth evaluated by growth curve and XTT reduction assay.DIM in the concentration range of 31.2-62.5μmol/L demonstrated a dose-dependent antibiofilm activity to S.aureus,as confirmed by light microscopic(LM),confocal laser scanning microscopic(CLSM),and scanning electron microscopic(SEM)analyses.At DIM of62.5μmol/L,the biomass of S.aureus biofilm was significantly reduced by 97%and its average thickness by 58%(P<0.05).DIM of 62.5μmol/L inhibited the bacterial initial adhesion and proliferation,as well as cell motility;the release of extracellular DNA(eDNA)and extracellular polysaccharide(EPS)were reduced by 75%and 69%,respectively.DIM exhibited a strong inhibition to S.aureus biofilm formation on common food-contact surfaces,including 304 stainless steel,glass,and polyvinyl chloride(PVC)but not disperse the mature biofilm.Overall,our investigation identified DIM as a promising antibiofilm agent and its suitability to prevent the biofilm formation of S.aureus on common food-contact surfaces utilized during food processing.
文摘Fluid flow past the biofilm surface can bring external force to biofilm which could result in biofilm deformation and detachment. The flow velocity have significant effect on determining biofilm deformation and detachment. In this work, finite element method was adapted to study the flow induced deformation of biofilm in varied flow conditions.
