Nanotechnology has provided thousands of novel nano-antimicrobials possessing features uncommon in clinically available antimicrobials.Here,nanocarriers loaded with conventional antimicrobials and responding to enviro...Nanotechnology has provided thousands of novel nano-antimicrobials possessing features uncommon in clinically available antimicrobials.Here,nanocarriers loaded with conventional antimicrobials and responding to environmental changes upon entry into oral biofilms are reviewed.Supra-gingival biofilms are characterized by acidic pH,the presence of bacterial enzymes,and the development of hypoxia in deeper layers.Sub-gingival biofilms are slightly alkaline,with hypoxia occurring over their entire depth.Upon entering biofilms,negatively charged,pH-and/or hypoxia-responsive nanocarriers become positively charged.This charge reversal leads to electrostatic double-layer attraction between positively charged nanocarriers towards negatively charged,waterfilled channel walls in biofilms,enhancing their accumulation in a biofilm.Degradation of bacterial enzyme-responsive nanocarriers causes in-biofilm release of antimicrobial cargo,yielding higher local antimicrobial concentrations than can be achieved through their direct,oral administration without harming soft tissues.Enhanced antibiofilm activity after in-biofilm antimicrobial release from biofilm-responsive micelles and liposomes has been demonstrated in vitro towards single-species Streptococcus mutans and Staphylococcus aureus biofilms or in vivo using specific-pathogen-free rodents inoculated with selected pathogens.This preferential antibacterial activity regulated the microbial composition of ex vivo human oral biofilm towards a more healthy microbiome composition.Although clinical confirmation is limited,the potential benefits of stimuli-responsive,antimicrobial-loaded nanocarriers for oral biofilm control and microbiome restoration are worth further investigation towards clinical translation.展开更多
As a specific spoilage organism of seafood under refrigerated temperature conditions,Shewanella spp.tend to form biofilms that exacerbate the occurrence of seafood spoilage.Biofilm-promoting factor A(BpfA)has been rep...As a specific spoilage organism of seafood under refrigerated temperature conditions,Shewanella spp.tend to form biofilms that exacerbate the occurrence of seafood spoilage.Biofilm-promoting factor A(BpfA)has been reported to promote the adhesion and biofilm formation of Shewanella spp.,but its role in adhesion and biofilm formation of S.putrefaciens under cold stress needs to be further investigated.To better comprehend the effect of BpfA on adhesion and biofilm formation of S.putrefaciens under cold stress(4℃),bacterial adhesion and biofilm phenotype of S.putrefaciens CN32 WT andΔbpfA at 4℃were analyzed and performed transcriptomics.The results showed that the deletion of bpfA had almost no effect on the growth of S.putrefaciens CN32 at 4℃,but weakened the unicellular adhesion capacity of S.putrefaciens CN32 and destabilized the stability of the multicellular adhesion layer.In addition,the biomass of the mature biofilm formed byΔbpfA was merely around 50%of that observed in the mature biofilm of S.putrefaciens CN32 WT,the average thickness and volume of the biofilm decreased by 18%and 27%,respectively,and the composition of the biofilm changed.Transcriptome analysis demonstrated that the deletion of bpfA led to differential expression of genes involved in metabolic pathways such as bacterial chemotaxis,two-component system,tyrosine metabolism,drug metabolism-other enzymes and biofilm formation-Vibrio cholerae,which in turn influenced bacterial adhesion and biofilm formation.Those results advance our acknowledgment of the character of BpfA on adhesion and biofilm formation of S.putrefaciens CN32,which contributes to understanding bacterial adhesion and the control of biofilm formation.展开更多
Background:The bacterial biofilm poses a significant challenge to traditional antibiotic therapy.There is a great need to develop novel antibiofilm agents combined with biofilm disrupting and bacteria-killing without ...Background:The bacterial biofilm poses a significant challenge to traditional antibiotic therapy.There is a great need to develop novel antibiofilm agents combined with biofilm disrupting and bacteria-killing without the dependence of antibiotic.Methods:Herein,we prepared ultrasound/magnetic field-responsive ferroferric oxide nanoparticles(Fe_(3)O_(4))/glucose oxidase microbubbles(FGMB)to form a cascade catalytic system for effective removing methicillin-resistant Staphylococcus aureus biofilms.FGMB were prepared through interfacial self-assembly of Fe_(3)O_(4) nanoparticles(NPs)and glucose oxidase(GOx)at the gas-liquid interface stabilized by surfactants.Under ultrasound/magnetic field stimulation,FGMB disrupted biofilm architecture through microbubble collapse-induced microjets and magnetically driven displacement.Simultaneously,ultrasound-triggered rupture of FGMB released GOx and Fe_(3)O_(4) NPs.Glucose can be oxidized by GOx to generate gluconic acid and hydrogen peroxide which was subsequently catalyzed into hydroxyl radicals by Fe_(3)O_(4) NPs,enabling chemical eradication of biofilm-embedded bacteria.Results:Optical microscopy images demonstrated that FGMB have spherical structure with average size of approximately 17μm.FGMB showed a 65.4%decrease in methicillin-resistant Staphylococcus aureus biofilm biomass and 1.1 log bacterial inactivation efficiency(91.2%),suggesting effective biofilm elimination.In vitro experimental results also indicate that FGMB have good biocompatibility.Conclusion:This antibiofilm strategy integrated dual modes of physical biofilm disruption with chemical bacteria-killing shows great potential as a versatile,non-resistant strategy for bacterial biofilm elimination.展开更多
Probiotics can regulate gut microbes to maintain human health.However,the sensitivity of probiotics to environmental conditions reduces their bioavailability.In contrast,the formation of probiotic biofilm provides a n...Probiotics can regulate gut microbes to maintain human health.However,the sensitivity of probiotics to environmental conditions reduces their bioavailability.In contrast,the formation of probiotic biofilm provides a natural physical barrier against external interference.Our previous study established a dynamic culture system of the biofilm-state Bifidobacterium adolescentis Gr19(B-DC-B.adolescentis Gr19),forming higher density and more structurally stable biofilms,which enhanced its potential probiotic properties in vivo.Thus,the protective effect and mechanism of B-DC-B.adolescentis Gr19 on lipopolysaccharide(LPS)-induced intestinal barrier dysfunction were investigated in this study.The results showed that B-DC-B.adolescentis Gr19 not only had high resistance and adhesion activity,but also improved the intestinal barrier by increasing goblet cells and promoting the expression of tight junction(TJ)-related proteins.Moreover,B-DC-B.adolescentis Gr19 effectively attenuated intestinal barrier injury in Caco-2 cells by improving intestinal permeability and integrity.Remarkably,B-DC-B.adolescentis Gr19 enhanced expression of TJ proteins,restored localization of cytoskeleton and reduced intestinal inflammation by suppressing the Ras homolog family member A/Rho-associated coiled-coil-forming kinases/nuclear factor kappa B/myosin light chain kinase/myosin light chain(RhoA/ROCK/NF-κB/MLCK/MLC)pathway.Therefore,B-DC-B.adolescentis Gr19 plays a key role in mitigating LPS-induced intestinal barrier dysfunction.Overall,the present study provides a theoretical basis for ameliorating intestinal barrier dysfunction and developing novel functional foods by using biofilm-state probiotics under dynamic culture.展开更多
Although activated carbon filters are thought to be the best way to remove per-and polyfluorinated alkyl substances(PFAS),it is yet unknown how biofilms affect PFAS removal.This study first examined how the removal of...Although activated carbon filters are thought to be the best way to remove per-and polyfluorinated alkyl substances(PFAS),it is yet unknown how biofilms affect PFAS removal.This study first examined how the removal of PFAS in full-scale drinking water treatment plants(DWTPs)was impacted by biofilm from biological activated carbon(BAC)of varying depths and carbon ages.PFAS desorption from BAC was visible,but at this point,BAC could still remove dissolved organic matter(DOM)efficiently.Studies have demonstrated that the use of activated carbon filters can dramatically lower the content of PFAS in water,with the amount of PFAS reducing as the filter’s depth grows and its use duration increases.Additionally,pore-clogging becomes more noticeable as the biofilm ages,which reduces BAC’s capacity to eliminate PFAS and hinders PFAS desorption.Furthermore,the adsorption process of PFAS may be impeded by the secretion of biofilms,which are composed of proteins and polysaccharides.Based on the analysis above,it can be the adsorption of PFAS by BAC is significantly inhibited by biofilms,according to another research.This provides theoretical direction for improving the removal effectiveness of PFAS in DWTPs.展开更多
Foodborne bacteria produce biofilms and their viable but non-culturable(VBNC)formation,can affect food quality and safety.Studies have shown that these characteristics are regulated by the bacterial quorum sensing(QS)...Foodborne bacteria produce biofilms and their viable but non-culturable(VBNC)formation,can affect food quality and safety.Studies have shown that these characteristics are regulated by the bacterial quorum sensing(QS)system.Quenching the QS system of foodborne bacteria and blocking the expression of the corresponding genes may be an effective way to improve food quality and safety.Therefore,this article reviews the QS systems for foodborne bacteria,the regulatory mechanisms of QS systems in biofilm and VBNC formation and resuscitation,the research progress on quorum sensing inhibitors(QSIs)for Gram-negative and Gram-positive bacteria,and introduces QSIs from various sources.In addition,we have also summarized the current research issues on QS regulation of biofilms and VBNC formation.The systematic study of the QS phenomenon of foodborne bacteria in practical situations,the mechanism of bacterial QS cooperation-cheating,the screening of novel and highly active QSIs,the combination of QSIs and other technologies to improve their bioavailability,and the regulatory network between biofilm and VBNC formation and resuscitation are research directions that need to be paid attention to in the future.展开更多
Objective:To investigate the pattern of antibiotic resistance and biofilm production capabilities of clinical Acinetobacter baumannii(A.baumannii)isolates in this study.Methods:A.baumannii isolates were collected from...Objective:To investigate the pattern of antibiotic resistance and biofilm production capabilities of clinical Acinetobacter baumannii(A.baumannii)isolates in this study.Methods:A.baumannii isolates were collected from Tehran Imam Khomeini Hospital in this cross-sectional study,and the minimum inhibitory concentrations for 16 antibiotics were determined using Vitek2®systems.All isolates were analyzed for biofilm production,then presence of biofilm-associated genes,and class Ⅰ and Ⅱ integron genes.Results:60 non-replicate A.baumannii isolates were included in this study.The resistance rates reached 100%for aztreonam,cefepime,ceftazidime,ciprofloxacin,piperacillin-tazobactam,piperacillin,ticarcillin,and trimethoprim-sulfamethoxazole.A.baumannii isolates were most sensitive to colistin and rifampicin being the most effective treatments.Multi-drug resistant and extensively drug-resistant isolates accounted for 83.3%and 16.7%,respectively.Of the isolates,91.6%formed biofilms,categorized as 10%strong,31.6%moderate,and 50%weak.No correlation was found between antibiotic resistance and biofilm formation.The genes csuE,abaI,and ompA were prevalent,but their distribution was similar across biofilm categories.A relationship between Int1 and biofilm production was noted.Conclusions:The high rates of antibiotic resistance and biofilm formation,alongside the presence of integrons including class Ⅰ and Ⅱ,underscore the necessity for ongoing monitoring of A.baumannii.Notably,classⅠintegron presence was significantly linked to biofilm formation.Further research is needed to explore the connection between antibiotic resistance and biofilm production in A.baumannii.展开更多
Background:Urinary tract infections(UTIs),primarily caused by uropathogenic Escherichia coli(UPEC),are a significant global health concern.The complications arise from antibiotic resistance and biofilm formation,which...Background:Urinary tract infections(UTIs),primarily caused by uropathogenic Escherichia coli(UPEC),are a significant global health concern.The complications arise from antibiotic resistance and biofilm formation,which reduce the effectiveness of conventional treatments.This study aims to evaluate the antibiofilm activity of the homeopathic medicine Terebinthinae oleum in potencies 30C,200C,and 1M against UTI-causing E.coli,and to compare its effectiveness with the standard antibiotic Gentamycin.Methods:An in-vitro biofilm model was employed.E.coli biofilms were cultivated in microtiter plates and treated with Terebinthinae oleum(30C,200C,1M)and Gentamycin.Biofilm biomass was assessed through crystal violet staining,and optical density(OD)was measured using an ELISA microplate reader.Results:Among the tested potencies,Terebinthinae oleum 30C showed the most prominent inhibitory activity on E.coli biofilms.The inhibition percentage was compared with Gentamycin as a control.Terebinthinae oleum 30C demonstrated 41.88%inhibition of biofilm biomass,while Gentamycin exhibited up to 78.98%inhibition.Higher potencies of Terebinthinae oleum(200C and 1M)showed reduced activity(30.15%and 24.81%,respectively).Conclusion:Terebinthinae oleum,especially at 30C potency,exhibits measurable antibiofilm activity against E.coli,although less effective than Gentamycin.These findings support its use as a complementary therapy in managing biofilm-associated UTIs,justifying further clinical and immunological research.展开更多
The effects of disinfectants and plasmid-based antibiotic resistance genes(ARGs)on the growth of microorganisms and the plasmid-mediated transfer of ARGs in the water and biofilm of the drinkingwater distribution syst...The effects of disinfectants and plasmid-based antibiotic resistance genes(ARGs)on the growth of microorganisms and the plasmid-mediated transfer of ARGs in the water and biofilm of the drinkingwater distribution system under simulated conditionswere explored.The heterotrophic plate count of the water in reactors with 0.1 mg/L NaClO and NH_(2)Cl was higher than in the control groups.Therewas no similar phenomenon in biofilm.In thewater of reactors containing NaClO,the aphA and bla geneswere lower than in the antibiotic resistant bacteria group,while both genes were higher in the water of reactors with NH_(2)Cl than in the control group.Chloramine may promote the transfer of ARGs in the water phase.Both genes in the biofilm of the reactors containing chlorine were lower than the control group.Correlation analysis between ARGs and water quality parameters revealed that the copy numbers of the aphA gene were significantly positively correlated with the copy numbers of the bla gene in water and significantly negatively correlated in biofilm(p<0.05).The results of the sequencing assay showed that bacteria in the biofilm,in the presence of disinfectant,were primarily Gram-negative.1.0 mg/L chlorine decreased the diversity of the community in the biofilm.The relative abundance of some bacteria that may undergo transfer increased in the biofilm of the reactor containing 0.1 mg/L chlorine.展开更多
Various chemical irrigants and drugs have been employed for intra-canal disinfection in root canal therapy(RCT).However,due to the complexity of root canal anatomy,many drugs still exhibit poor penetrability and antib...Various chemical irrigants and drugs have been employed for intra-canal disinfection in root canal therapy(RCT).However,due to the complexity of root canal anatomy,many drugs still exhibit poor penetrability and antibiotic resistance,leading to suboptimal treatment outcomes.Thus,it is challenging to remove the organic biofilms from root canals.In recent years,light-responsive therapy,with deeper tissue penetration than traditional treatments,has emerged as an effective RCT modality.Herein,this review summarizes the recent development of light-responsive nanomaterials for biofilm removal in RCT.The light-responsive nanomaterials and the corresponding therapeutic methods in RCT,including photodynamic therapy(PDT),photothermal therapy(PTT),and laser-activated therapy,are highlighted.Finally,the challenges that light-responsive nanomaterials and treatment modalities will encounter to conquer the biofilm in future RCT are discussed.This review is believed to significantly accelerate the future development of light-responsive nanomaterials for RCT from bench to bedside.展开更多
The membrane aeration biofilm reactor(MABR)represents an innovative approach to wastewater treatment,integrating gas separation membranes with biofilm process and demonstrating effectiveness in treating wastewater ric...The membrane aeration biofilm reactor(MABR)represents an innovative approach to wastewater treatment,integrating gas separation membranes with biofilm process and demonstrating effectiveness in treating wastewater rich in ammonia nitrogen.In this system,hollow fiber membranes are essential,serving as a substrate for biofilm attachment while facilitating oxygen transfer to microorganisms through aeration,hydrophobic microporous membranes are utilized in MABR applications.This study focuses on the use of poly-4-methyl-1-pentene(PMP)hollow fiber membranes,which exhibit superior oxygen permeation capabilities compared to traditional hydrophobic microporous membranes.To overcome the challenges posed by the hydrophobic nature and low bubble point of PMP microporous membranes,a hydrophilic modification was conducted using dopamine/poly(ethyleneimine)(DOPA/PEI)co-deposition to enhance microbial adhesion on the membrane surface.The composite membrane modified with DOPA/PEI exhibited an approximately 20%higher NH_(4)^(+)-N removal efficiency than the unmodified membrane.These findings suggest that the incorporation of DOPA/PEI significantly improves MABR performance,underscoring its potential for further research and development in membrane technology for MABR.展开更多
Despite their biodegradability and economic advantage, plant leaves used as packaging can constitute a public health problem. The aim of this study was to characterize the microbial diversity contaminating plant leave...Despite their biodegradability and economic advantage, plant leaves used as packaging can constitute a public health problem. The aim of this study was to characterize the microbial diversity contaminating plant leaves used as food packaging. In total, two hundred and forty (240) samples composed of Thaumatococcus daniellii and Musa paradisiaca leaves were collected and analyzed. Microbial diversity was assessed using specific medium and biochemical tests. The resistance profile was determined by the Müeller-Hinton agar diffusion method. The resistance (blaSHV, blaIMP, blaTEM) and biofilm formation (pslA, pelA) genes were searched by PCR method. Plant leaves were contaminated by bacterial (68.7%) and fungal (100%) strains. Extreme bacterial (7.1 log10 cfu/cm2) and fungal (3.5 log10 cfu/cm2) loads were obtained on Thaumatococcus daniellii leaves. Bacterial prevalence was 45.1% (S. aureus), 38.8% (E. coli) and 16.1 (P. aeruginosa). In order of decreasing importance, the prevalence of fungal species was 41.1% (A. flavus), 33.1% (A. fumigattus), 13.7% (A. niger) and 12.1% Candida sp. Resistance of E. coli to penicillins ranges from 31.6% to 87.3% and to cephalosporins from 13.3% to 28%. The P. aeruginosa strains were mainly resistant to aztreonam (87.6%). Those of S. aureus showed resistance to tetracycline (67.6), vancomycin (53), erythromycin (44.6) and levofloxacin (32.7). The blaSHV (14.28% to 18.60%) and blaIMP (9.52% to 16.28%) genes were detected in the bacterial strains. P. aeruginosa strains (19.05%) harbored the pslA and pelA genes. The health safety of these biodegradable plant-based packaging contributes to their valorization.展开更多
Chromium(Cr) contamination in water poses significant health risks,yet advanced remediation methods remain limited.Cr(Ⅵ) reduction catalyzed by palladium nanoparticles(PdNPs) on hydrogen-transfer membranes has shown ...Chromium(Cr) contamination in water poses significant health risks,yet advanced remediation methods remain limited.Cr(Ⅵ) reduction catalyzed by palladium nanoparticles(PdNPs) on hydrogen-transfer membranes has shown potential but requires further optimization.This study investigated the simultaneous microbial-driven and Pd-catalyzed Cr(Ⅵ) reduction,focusing on reduction efficiency and optimal conditions.Two hydrogen-based membrane reactors were compared:a Pd-biofilm reactor incorporating PdNPs associated with a biofilm,and a control biofilm reactor.Continuous experiments demonstrated the superior performance of the Pd-biofilm reactor,achieving immediate Cr(Ⅵ) reduction and effluent Cr(Ⅲ) concentrations below 0.040 mg·L^(-1),compared to 0.3 mg·L^(-1) in the control biofilm reactor.High-throughput sequencing identified Dechloromonas as the dominant microbial species within Pd-biofilm,which plays a critical role in metal ion reduction.The Pd-biofilm reactor maintained high Cr(Ⅵ) reduction flux across varying conditions.When the influent Cr(Ⅵ) loading reached up to10 mg L~(-1),where the co ntrol biofilm reactor experienced inhibitio n,the Pd-bio film reactor achieved a Cr removal of 99%.Increased nitrate loading and hydrogen pressure further enhanced Pd-biofilm reactor performance without compromising Cr(Ⅵ) reduction since Cr(Ⅵ) is the preferential electron acceptor,whereas the biofilm reactor required hydrogen pressures>15 psig(1 psig=6.895 kPa) for similar results.The optimal pH range for Cr(Ⅵ) reduction was 5.0-8.0 in the Pd-biofilm reactor and 7.0 in the biofilm reactor,with alkaline conditions being more inhibitory than acidic ones in both systems.The Pd-biofilm reactor effectively reduced Cr(Ⅵ) concentrations from 1 to 10 mg·L^(-1) to below the maximum contaminant level of 0.1 mg·L^(-1),thus appearing as an efficient technique to treat Cr-contaminated waters.展开更多
Temperature and contact surfaces are critical factors influencing biofilm formation of microbial communities derived from both lab and natural environments.However,there is limited understanding regarding how differen...Temperature and contact surfaces are critical factors influencing biofilm formation of microbial communities derived from both lab and natural environments.However,there is limited understanding regarding how different temperatures impact transfer dynamics of individual microbial species between meat surfaces in dual-species biofilms.In this study,we evaluated the biofilm-forming capabilities of various meat-derived Escherichia coli and Pseudomonas strains on pork surfaces at 15 and 25℃.The results revealed that lower temperature had a significant negative effect on the growth fitness of E.coli compared to Pseudomonas.Two robust biofilm-forming strains,E.coli C-13 and P.fluorescens S_(1-2)3,were selected under both temperature conditions to further explore their interactions in dual-species biofilms on meat surfaces.The results showed that E.coli exhibited a competitive growth advantage at 25℃,while Pseudomonas displayed enhanced growth at 15℃,indicating temperature-dependent competition patterns.Additionally,three established mathematical models were utilized to simulate the transfer dynamics of the two strains within mono-and dual-species biofilms.As anticipated,the numbers of transferred cells progressively declined with increased imprinting reactions between the meat surfaces.Interestingly,the transfer rates of both strains markedly improved in dual-species vs.mono-species biofilms at 15℃,highlighting the influential role of inter-species interactions on transfer dynamics of microbes that may cross-contaminate meats.Our findings advance current understanding of mono-and dual-species biofilm development on meat surfaces under different temperature conditions.They also offer scientific evidence to support strategies for controlling microbial cross-contamination during meat processing to ensure product safety.展开更多
Multidrug-resistant Klebsiella pneumoniae(MDR-KP)is characterized by high mortality and risk of nosocomial transmission,and biofilm constitutes the primary challenge in the treatment of its implant-associated and refr...Multidrug-resistant Klebsiella pneumoniae(MDR-KP)is characterized by high mortality and risk of nosocomial transmission,and biofilm constitutes the primary challenge in the treatment of its implant-associated and refractory pulmonary infections.Notably,the hypoxic microenvironment and the physical barrier of biofilm leading to the increased tolerance of the bacteria to antibiotics.Herein,a hypoxia-responsive hybrid nanoparticle(CHLip@FLD/COL)loaded separately with anti-biofilm candidate fingolimod(FLD)and antibiotic colistin(COL)is achieved targeting antibacterial efficacy against MDR-KP in vitro and in vivo.CHLip@FLD/COL is composed of hybridizing hypoxia-responsive lipids(HLipid)and lipid A targeting materials DSPE-mPEG-COL.HLipid is synthesized by hexadecanedioic acid esterified with nitroimidazole,while DSPE-mPEG is coupling with vector COL via amide reaction.The relative level of extracellular polymeric substances and the NIR-IIb sO2 images of the infection site are used as indicators to establish mature biofilm models.CHLip@FLD/COL readily releases FLD and COL in hypoxic conditions,and its MIC against MDR-KP is only one-sixteenth of that when COL is used alone in vitro.The nanoparticle exhibits bacterial targeting ability and antibacterial effect in the pulmonary infection and biofilm infection mice models.Bacterial loads eliminated by 4 Log10 CFU and 2 Log10 CFU,respectively.The strategy provides a valuable reference for the treatment of refractory infections caused by MDR-KP.展开更多
Objective:To develop chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms and verify their antibacterial performance through animal experiments.Methods:Chitosan,silver nitrate,glacial acetic acid,an...Objective:To develop chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms and verify their antibacterial performance through animal experiments.Methods:Chitosan,silver nitrate,glacial acetic acid,and other chemical reagents were used to synthesize chitosan-silver nanoparticles.The characterization,minimum inhibitory concentration,and biofilm inhibition rate of the chitosan-silver nanoparticles were tested.A total of 40 SD rats were randomly divided into four groups.After routine adaptive feeding,the control group received intraperitoneal injection of normal saline;the model group received intraperitoneal injection of Pseudomonas aeruginosa suspension;the positive group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with ampicillin at a volume ratio of 1∶1;the observation group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with chitosan-silver nanoparticles(at minimum inhibitory concentration)at a volume ratio of 1∶1.Bacterial load,inflammatory factors,and liver and kidney function indicators in tissues were observed and compared among the four groups on the 3^(rd)day after treatment.Results:When the concentration of chitosansilver nanoparticles reached 8μg/mL or above,the OD value of the experimental wells was close to that of the control wells,indicating that 8μg/mL was the minimum inhibitory concentration of the chitosan-silver nanoparticles;at concentrations of 8μg/mL or above,the biofilm inhibition rate was greater than 80%.The bacterial load in the observation group was significantly lower than that in the model and positive groups(P<0.05).The expression levels of interleukin-6,interferon-γ,and tumor necrosis factor-αin the observation group were significantly lower than those in the model and positive groups(P<0.05).There were no statistically significant differences in alanine aminotransferase,aspartate aminotransferase,blood urea nitrogen,and creatinine levels among the four groups(P>0.05).Conclusion:The chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms constructed in this study exhibit good antibacterial effects against Pseudomonas aeruginosa and have good safety.展开更多
Microalgae possess significant advantages in nitrogen and phosphorus removal from nutrient-richwastewater that are highly efficient and independent of the C/N ratio.However,challenges such as low biomass productivity,...Microalgae possess significant advantages in nitrogen and phosphorus removal from nutrient-richwastewater that are highly efficient and independent of the C/N ratio.However,challenges such as low biomass productivity,high variability in nutrient removal under different trophic types,and difficulty in harvesting biomass limits the large-scale application of microalgae wastewater treatment.This study attempted to employmixotrophic microalgae biofilm to address these issues.The biomass production,microalgal activity,and nutrient removal of Chlorella pyrenoidosa biofilms with different trophic types were compared for nutrient-rich wastewater treatment.The results showed that the biomass productivity of the mixotrophic microalgal biofilm(0.215 g/(L·d))was 2.3,8.6,and 6.0 times higher than that of photoautotrophic microalgal biofilm,heterotrophic microalgal biofilm,and photoautotrophic suspended microalga,respectively.Additionally,the dehydrogenase activity(DHA),indicating microalgal activity,of the mixotrophic biofilm was 2.3 and 16.5 times higher than that of photoautotrophic and heterotrophic biofilms,respectively.Meanwhile,the mixotrophic biofilm removed 96.0%of NH_(4)^(+)-N and 99.2%of PO_(4)^(3-)-P,more efficient than that with other types of biofilms and suspended microalgae.In an open-ended air-lift photobioreactor,the mixotrophic microalgal biofilm produced biomass at 0.12 g/(L·d)and removed 90.0%of NH_(4)^(+)-N and 97.6%of PO_(4)^(3-)-P.This study suggests that the mixotrophic microalgal biofilm shows promise in treating nutrient-rich wastewater and producing microalgal biomass for value-added products.展开更多
In the fight against bacterial infections,it is critical to effectively disrupt biofilms.However,disruption of biofilms becomes exceptionally difficult due to the low permeability of therapeutic agents.Herein,we prese...In the fight against bacterial infections,it is critical to effectively disrupt biofilms.However,disruption of biofilms becomes exceptionally difficult due to the low permeability of therapeutic agents.Herein,we present a self-propelled nanovesicle(PCL-PLG@CHX)strategy for eliminating biofilms and further expediting the healing of wounds.PCL-PLG@CHX is synthesized by assembling vesicles from amphiphilic polymers,which incorporate both poly-ε-caprolactone and guanidinated-poly-ε-lysine(PCL-PLG)and are infused with chlorhexidine(CHX).Upon application to sites of bacterial infection,PCL-PLG@CHX,abundant in guanidinium structures,effectively accumulates on the negatively charged surface of biofilms.It interacts with reactive oxygen species(ROS)within the biofilm,leading to nitric oxide(NO)production.The generated NO cannot only propel the nanovesicle to penetrate deeper into the biofilm,but also act as a signaling molecule to disperse the biofilm,working in conjunction with the subsequent release of CHX for an enhanced antibacterial impact.Following the eradication of bacteria,the residual guanidine component continues to produce small quantities of NO,facilitating angiogenesis and epithelial growth,thereby accelerating the healing of wounds.Together,our study shows that PCL-PLG@CHX utilizes the potential of guanidine moieties to efficiently break down biofilms and support tissue restoration,tackling the pivotal challenge of biofilm-related diseases.展开更多
Background:Houttuynia cordata injection(HCI),made from fresh Houttuynia cordata,exerts heat-clearing,detoxifying and diuretic effects.It is indicated for various infections including lung abscess,fever,leucorrhea,urin...Background:Houttuynia cordata injection(HCI),made from fresh Houttuynia cordata,exerts heat-clearing,detoxifying and diuretic effects.It is indicated for various infections including lung abscess,fever,leucorrhea,urinary tract infection and carbuncle.Candida albicans is a common opportunistic pathogen in immunocompromised individuals.This pathogenic fungus colonizes in skin,mucosa membrane and digestive tract,potentially progressing from localized mucosal infections to systemic disease.Methods:The minimum inhibitory concentration(MIC)of HCI against C.albicans strain was determined by the microdilution method.The hyphal status of C.albicans was observed after incubation in the liquid medium and evaluated by Gram staining.The biofilm formation ability was measured using XTT reduction assay and assessed by Calcofluor White staining.The expression of virulence-related genes was detected with quantitative RT-PCR.Results:The MIC of HCI against C.albicans strain was determined to be 0.5 g/mL.At this concentration,HCI exhibited inhibitory effects on hyphal formation,as confirmed by both liquid medium observation and Gram staining.HCI at the MIC also effectively inhibited C.albicans biofilm formation,which was verified through XTT reduction assay and Calcofluor White staining.Additionally,gene expression analysis revealed that HCI significantly suppressed the expression of virulence-related genes in C.albicans.Conclusion:HCI demonstrates inhibitory effects on C.albicans growth and biofilm development.It inhibits hyphal formation,affecting the yeast-to-hyphal transition.This study investigated the antifungal effects of HCI,providing potent experimental evidence for its mechanism of action against C.albicans.展开更多
Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as we...Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as well as a carrier of pollutants like heavy metals.However,the dynamic changes of bacterial communities attached to EPS and their interaction with heavy metals are still poorly unknown.In this study,a one-year field exposure experiment was conducted at an aquaculture farm near Donghai Island,in Leizhou Bay,Zhanjiang,Guangdong,in South China Sea.The bacterial communities attached to EPS MPs were examined by 16S r DNA high-throughput sequencing,and the relationships between bacterial biofilms and heavy metals were explored.The results show that there were notable seasonal variations in the bacterial diversity of EPS MPs.Species biodiversity was the highest in summer and the lowest in winter.The greatest number of bacterial species and lowest level of uniformity were observed in the spring.The bacterial community structure changed with exposure time,and the most significant difference in the 12-month group (P<0.05) was found.The dominant bacterial species attached to EPS MPs were mainly Proteobackteria and Firmicutes at the phylum level,and Pseudomonas and Exiguobacterium were dominant at the genus level.Furthermore,EPS MPs acted as transport carriers for potential pathogenic bacteria.High correlations were found between bacterial species and the total concentration of heavy metals on EPS MPs,as well as their speciation fractions.Different chemical speciation of heavy metals migrated and altered over seasons within biofilms,which would further exacerbate the ecological risks.展开更多
基金supported by the National Science Fund for Excellent Young Scholars (32322044)the CQMU Program for Youth Innovation in Future Medicine (W0077)+1 种基金the Program for Scientific and Technological Innovation Leader of Chongqing (CQYC20220303655)the Young Scientists Fund of the National Natural Science Foundation of China (82301144)。
文摘Nanotechnology has provided thousands of novel nano-antimicrobials possessing features uncommon in clinically available antimicrobials.Here,nanocarriers loaded with conventional antimicrobials and responding to environmental changes upon entry into oral biofilms are reviewed.Supra-gingival biofilms are characterized by acidic pH,the presence of bacterial enzymes,and the development of hypoxia in deeper layers.Sub-gingival biofilms are slightly alkaline,with hypoxia occurring over their entire depth.Upon entering biofilms,negatively charged,pH-and/or hypoxia-responsive nanocarriers become positively charged.This charge reversal leads to electrostatic double-layer attraction between positively charged nanocarriers towards negatively charged,waterfilled channel walls in biofilms,enhancing their accumulation in a biofilm.Degradation of bacterial enzyme-responsive nanocarriers causes in-biofilm release of antimicrobial cargo,yielding higher local antimicrobial concentrations than can be achieved through their direct,oral administration without harming soft tissues.Enhanced antibiofilm activity after in-biofilm antimicrobial release from biofilm-responsive micelles and liposomes has been demonstrated in vitro towards single-species Streptococcus mutans and Staphylococcus aureus biofilms or in vivo using specific-pathogen-free rodents inoculated with selected pathogens.This preferential antibacterial activity regulated the microbial composition of ex vivo human oral biofilm towards a more healthy microbiome composition.Although clinical confirmation is limited,the potential benefits of stimuli-responsive,antimicrobial-loaded nanocarriers for oral biofilm control and microbiome restoration are worth further investigation towards clinical translation.
基金funded by the National Natural Science Foundation of China(32472401).
文摘As a specific spoilage organism of seafood under refrigerated temperature conditions,Shewanella spp.tend to form biofilms that exacerbate the occurrence of seafood spoilage.Biofilm-promoting factor A(BpfA)has been reported to promote the adhesion and biofilm formation of Shewanella spp.,but its role in adhesion and biofilm formation of S.putrefaciens under cold stress needs to be further investigated.To better comprehend the effect of BpfA on adhesion and biofilm formation of S.putrefaciens under cold stress(4℃),bacterial adhesion and biofilm phenotype of S.putrefaciens CN32 WT andΔbpfA at 4℃were analyzed and performed transcriptomics.The results showed that the deletion of bpfA had almost no effect on the growth of S.putrefaciens CN32 at 4℃,but weakened the unicellular adhesion capacity of S.putrefaciens CN32 and destabilized the stability of the multicellular adhesion layer.In addition,the biomass of the mature biofilm formed byΔbpfA was merely around 50%of that observed in the mature biofilm of S.putrefaciens CN32 WT,the average thickness and volume of the biofilm decreased by 18%and 27%,respectively,and the composition of the biofilm changed.Transcriptome analysis demonstrated that the deletion of bpfA led to differential expression of genes involved in metabolic pathways such as bacterial chemotaxis,two-component system,tyrosine metabolism,drug metabolism-other enzymes and biofilm formation-Vibrio cholerae,which in turn influenced bacterial adhesion and biofilm formation.Those results advance our acknowledgment of the character of BpfA on adhesion and biofilm formation of S.putrefaciens CN32,which contributes to understanding bacterial adhesion and the control of biofilm formation.
基金supported by the National Natural Science Foundation of China(22375101)the Natural Science of Colleges and Universities in Jiangsu Province(24KJB430027).
文摘Background:The bacterial biofilm poses a significant challenge to traditional antibiotic therapy.There is a great need to develop novel antibiofilm agents combined with biofilm disrupting and bacteria-killing without the dependence of antibiotic.Methods:Herein,we prepared ultrasound/magnetic field-responsive ferroferric oxide nanoparticles(Fe_(3)O_(4))/glucose oxidase microbubbles(FGMB)to form a cascade catalytic system for effective removing methicillin-resistant Staphylococcus aureus biofilms.FGMB were prepared through interfacial self-assembly of Fe_(3)O_(4) nanoparticles(NPs)and glucose oxidase(GOx)at the gas-liquid interface stabilized by surfactants.Under ultrasound/magnetic field stimulation,FGMB disrupted biofilm architecture through microbubble collapse-induced microjets and magnetically driven displacement.Simultaneously,ultrasound-triggered rupture of FGMB released GOx and Fe_(3)O_(4) NPs.Glucose can be oxidized by GOx to generate gluconic acid and hydrogen peroxide which was subsequently catalyzed into hydroxyl radicals by Fe_(3)O_(4) NPs,enabling chemical eradication of biofilm-embedded bacteria.Results:Optical microscopy images demonstrated that FGMB have spherical structure with average size of approximately 17μm.FGMB showed a 65.4%decrease in methicillin-resistant Staphylococcus aureus biofilm biomass and 1.1 log bacterial inactivation efficiency(91.2%),suggesting effective biofilm elimination.In vitro experimental results also indicate that FGMB have good biocompatibility.Conclusion:This antibiofilm strategy integrated dual modes of physical biofilm disruption with chemical bacteria-killing shows great potential as a versatile,non-resistant strategy for bacterial biofilm elimination.
基金funded by Beijing Natural Science Foundation(6252001)Guangdong Basic and Applied Basic Research Foundation(2022A1515140021)Natural Science Foundation of China(31871772).
文摘Probiotics can regulate gut microbes to maintain human health.However,the sensitivity of probiotics to environmental conditions reduces their bioavailability.In contrast,the formation of probiotic biofilm provides a natural physical barrier against external interference.Our previous study established a dynamic culture system of the biofilm-state Bifidobacterium adolescentis Gr19(B-DC-B.adolescentis Gr19),forming higher density and more structurally stable biofilms,which enhanced its potential probiotic properties in vivo.Thus,the protective effect and mechanism of B-DC-B.adolescentis Gr19 on lipopolysaccharide(LPS)-induced intestinal barrier dysfunction were investigated in this study.The results showed that B-DC-B.adolescentis Gr19 not only had high resistance and adhesion activity,but also improved the intestinal barrier by increasing goblet cells and promoting the expression of tight junction(TJ)-related proteins.Moreover,B-DC-B.adolescentis Gr19 effectively attenuated intestinal barrier injury in Caco-2 cells by improving intestinal permeability and integrity.Remarkably,B-DC-B.adolescentis Gr19 enhanced expression of TJ proteins,restored localization of cytoskeleton and reduced intestinal inflammation by suppressing the Ras homolog family member A/Rho-associated coiled-coil-forming kinases/nuclear factor kappa B/myosin light chain kinase/myosin light chain(RhoA/ROCK/NF-κB/MLCK/MLC)pathway.Therefore,B-DC-B.adolescentis Gr19 plays a key role in mitigating LPS-induced intestinal barrier dysfunction.Overall,the present study provides a theoretical basis for ameliorating intestinal barrier dysfunction and developing novel functional foods by using biofilm-state probiotics under dynamic culture.
基金supported by the National Key Research and Development Program of China(No.2022YFC3203703)the National Natural Science Foundation of China(No.52270013).
文摘Although activated carbon filters are thought to be the best way to remove per-and polyfluorinated alkyl substances(PFAS),it is yet unknown how biofilms affect PFAS removal.This study first examined how the removal of PFAS in full-scale drinking water treatment plants(DWTPs)was impacted by biofilm from biological activated carbon(BAC)of varying depths and carbon ages.PFAS desorption from BAC was visible,but at this point,BAC could still remove dissolved organic matter(DOM)efficiently.Studies have demonstrated that the use of activated carbon filters can dramatically lower the content of PFAS in water,with the amount of PFAS reducing as the filter’s depth grows and its use duration increases.Additionally,pore-clogging becomes more noticeable as the biofilm ages,which reduces BAC’s capacity to eliminate PFAS and hinders PFAS desorption.Furthermore,the adsorption process of PFAS may be impeded by the secretion of biofilms,which are composed of proteins and polysaccharides.Based on the analysis above,it can be the adsorption of PFAS by BAC is significantly inhibited by biofilms,according to another research.This provides theoretical direction for improving the removal effectiveness of PFAS in DWTPs.
基金financially supported by the National Natural Science Foundation of China(32202191)and(32272279)the Key R&D Project of Shandong Province(2023CXPT007 and 2024CXPT014)the Key R&D Project of Qingdao Science and Technology Plan(24-2-3-4-zyyd-jch).
文摘Foodborne bacteria produce biofilms and their viable but non-culturable(VBNC)formation,can affect food quality and safety.Studies have shown that these characteristics are regulated by the bacterial quorum sensing(QS)system.Quenching the QS system of foodborne bacteria and blocking the expression of the corresponding genes may be an effective way to improve food quality and safety.Therefore,this article reviews the QS systems for foodborne bacteria,the regulatory mechanisms of QS systems in biofilm and VBNC formation and resuscitation,the research progress on quorum sensing inhibitors(QSIs)for Gram-negative and Gram-positive bacteria,and introduces QSIs from various sources.In addition,we have also summarized the current research issues on QS regulation of biofilms and VBNC formation.The systematic study of the QS phenomenon of foodborne bacteria in practical situations,the mechanism of bacterial QS cooperation-cheating,the screening of novel and highly active QSIs,the combination of QSIs and other technologies to improve their bioavailability,and the regulatory network between biofilm and VBNC formation and resuscitation are research directions that need to be paid attention to in the future.
基金This study was financially supported by the Vice Chancellor for Research Affairs,Ilam University of Medical Sciences,Ilam,Iran(Project No.1326).
文摘Objective:To investigate the pattern of antibiotic resistance and biofilm production capabilities of clinical Acinetobacter baumannii(A.baumannii)isolates in this study.Methods:A.baumannii isolates were collected from Tehran Imam Khomeini Hospital in this cross-sectional study,and the minimum inhibitory concentrations for 16 antibiotics were determined using Vitek2®systems.All isolates were analyzed for biofilm production,then presence of biofilm-associated genes,and class Ⅰ and Ⅱ integron genes.Results:60 non-replicate A.baumannii isolates were included in this study.The resistance rates reached 100%for aztreonam,cefepime,ceftazidime,ciprofloxacin,piperacillin-tazobactam,piperacillin,ticarcillin,and trimethoprim-sulfamethoxazole.A.baumannii isolates were most sensitive to colistin and rifampicin being the most effective treatments.Multi-drug resistant and extensively drug-resistant isolates accounted for 83.3%and 16.7%,respectively.Of the isolates,91.6%formed biofilms,categorized as 10%strong,31.6%moderate,and 50%weak.No correlation was found between antibiotic resistance and biofilm formation.The genes csuE,abaI,and ompA were prevalent,but their distribution was similar across biofilm categories.A relationship between Int1 and biofilm production was noted.Conclusions:The high rates of antibiotic resistance and biofilm formation,alongside the presence of integrons including class Ⅰ and Ⅱ,underscore the necessity for ongoing monitoring of A.baumannii.Notably,classⅠintegron presence was significantly linked to biofilm formation.Further research is needed to explore the connection between antibiotic resistance and biofilm production in A.baumannii.
文摘Background:Urinary tract infections(UTIs),primarily caused by uropathogenic Escherichia coli(UPEC),are a significant global health concern.The complications arise from antibiotic resistance and biofilm formation,which reduce the effectiveness of conventional treatments.This study aims to evaluate the antibiofilm activity of the homeopathic medicine Terebinthinae oleum in potencies 30C,200C,and 1M against UTI-causing E.coli,and to compare its effectiveness with the standard antibiotic Gentamycin.Methods:An in-vitro biofilm model was employed.E.coli biofilms were cultivated in microtiter plates and treated with Terebinthinae oleum(30C,200C,1M)and Gentamycin.Biofilm biomass was assessed through crystal violet staining,and optical density(OD)was measured using an ELISA microplate reader.Results:Among the tested potencies,Terebinthinae oleum 30C showed the most prominent inhibitory activity on E.coli biofilms.The inhibition percentage was compared with Gentamycin as a control.Terebinthinae oleum 30C demonstrated 41.88%inhibition of biofilm biomass,while Gentamycin exhibited up to 78.98%inhibition.Higher potencies of Terebinthinae oleum(200C and 1M)showed reduced activity(30.15%and 24.81%,respectively).Conclusion:Terebinthinae oleum,especially at 30C potency,exhibits measurable antibiofilm activity against E.coli,although less effective than Gentamycin.These findings support its use as a complementary therapy in managing biofilm-associated UTIs,justifying further clinical and immunological research.
基金supported by the Natural Science Foundation of China(No.52070145,51778453).
文摘The effects of disinfectants and plasmid-based antibiotic resistance genes(ARGs)on the growth of microorganisms and the plasmid-mediated transfer of ARGs in the water and biofilm of the drinkingwater distribution system under simulated conditionswere explored.The heterotrophic plate count of the water in reactors with 0.1 mg/L NaClO and NH_(2)Cl was higher than in the control groups.Therewas no similar phenomenon in biofilm.In thewater of reactors containing NaClO,the aphA and bla geneswere lower than in the antibiotic resistant bacteria group,while both genes were higher in the water of reactors with NH_(2)Cl than in the control group.Chloramine may promote the transfer of ARGs in the water phase.Both genes in the biofilm of the reactors containing chlorine were lower than the control group.Correlation analysis between ARGs and water quality parameters revealed that the copy numbers of the aphA gene were significantly positively correlated with the copy numbers of the bla gene in water and significantly negatively correlated in biofilm(p<0.05).The results of the sequencing assay showed that bacteria in the biofilm,in the presence of disinfectant,were primarily Gram-negative.1.0 mg/L chlorine decreased the diversity of the community in the biofilm.The relative abundance of some bacteria that may undergo transfer increased in the biofilm of the reactor containing 0.1 mg/L chlorine.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20200092)。
文摘Various chemical irrigants and drugs have been employed for intra-canal disinfection in root canal therapy(RCT).However,due to the complexity of root canal anatomy,many drugs still exhibit poor penetrability and antibiotic resistance,leading to suboptimal treatment outcomes.Thus,it is challenging to remove the organic biofilms from root canals.In recent years,light-responsive therapy,with deeper tissue penetration than traditional treatments,has emerged as an effective RCT modality.Herein,this review summarizes the recent development of light-responsive nanomaterials for biofilm removal in RCT.The light-responsive nanomaterials and the corresponding therapeutic methods in RCT,including photodynamic therapy(PDT),photothermal therapy(PTT),and laser-activated therapy,are highlighted.Finally,the challenges that light-responsive nanomaterials and treatment modalities will encounter to conquer the biofilm in future RCT are discussed.This review is believed to significantly accelerate the future development of light-responsive nanomaterials for RCT from bench to bedside.
基金supported by the National Key Research and Development Program of China(2023YFB3810502)the National Natural Science Foundation of China(22078146)the Key Research and Development program of Anhui Province(2023h11020004).
文摘The membrane aeration biofilm reactor(MABR)represents an innovative approach to wastewater treatment,integrating gas separation membranes with biofilm process and demonstrating effectiveness in treating wastewater rich in ammonia nitrogen.In this system,hollow fiber membranes are essential,serving as a substrate for biofilm attachment while facilitating oxygen transfer to microorganisms through aeration,hydrophobic microporous membranes are utilized in MABR applications.This study focuses on the use of poly-4-methyl-1-pentene(PMP)hollow fiber membranes,which exhibit superior oxygen permeation capabilities compared to traditional hydrophobic microporous membranes.To overcome the challenges posed by the hydrophobic nature and low bubble point of PMP microporous membranes,a hydrophilic modification was conducted using dopamine/poly(ethyleneimine)(DOPA/PEI)co-deposition to enhance microbial adhesion on the membrane surface.The composite membrane modified with DOPA/PEI exhibited an approximately 20%higher NH_(4)^(+)-N removal efficiency than the unmodified membrane.These findings suggest that the incorporation of DOPA/PEI significantly improves MABR performance,underscoring its potential for further research and development in membrane technology for MABR.
文摘Despite their biodegradability and economic advantage, plant leaves used as packaging can constitute a public health problem. The aim of this study was to characterize the microbial diversity contaminating plant leaves used as food packaging. In total, two hundred and forty (240) samples composed of Thaumatococcus daniellii and Musa paradisiaca leaves were collected and analyzed. Microbial diversity was assessed using specific medium and biochemical tests. The resistance profile was determined by the Müeller-Hinton agar diffusion method. The resistance (blaSHV, blaIMP, blaTEM) and biofilm formation (pslA, pelA) genes were searched by PCR method. Plant leaves were contaminated by bacterial (68.7%) and fungal (100%) strains. Extreme bacterial (7.1 log10 cfu/cm2) and fungal (3.5 log10 cfu/cm2) loads were obtained on Thaumatococcus daniellii leaves. Bacterial prevalence was 45.1% (S. aureus), 38.8% (E. coli) and 16.1 (P. aeruginosa). In order of decreasing importance, the prevalence of fungal species was 41.1% (A. flavus), 33.1% (A. fumigattus), 13.7% (A. niger) and 12.1% Candida sp. Resistance of E. coli to penicillins ranges from 31.6% to 87.3% and to cephalosporins from 13.3% to 28%. The P. aeruginosa strains were mainly resistant to aztreonam (87.6%). Those of S. aureus showed resistance to tetracycline (67.6), vancomycin (53), erythromycin (44.6) and levofloxacin (32.7). The blaSHV (14.28% to 18.60%) and blaIMP (9.52% to 16.28%) genes were detected in the bacterial strains. P. aeruginosa strains (19.05%) harbored the pslA and pelA genes. The health safety of these biodegradable plant-based packaging contributes to their valorization.
基金financially supported by the National Natural Science Foundation of China (52400008,52470049)。
文摘Chromium(Cr) contamination in water poses significant health risks,yet advanced remediation methods remain limited.Cr(Ⅵ) reduction catalyzed by palladium nanoparticles(PdNPs) on hydrogen-transfer membranes has shown potential but requires further optimization.This study investigated the simultaneous microbial-driven and Pd-catalyzed Cr(Ⅵ) reduction,focusing on reduction efficiency and optimal conditions.Two hydrogen-based membrane reactors were compared:a Pd-biofilm reactor incorporating PdNPs associated with a biofilm,and a control biofilm reactor.Continuous experiments demonstrated the superior performance of the Pd-biofilm reactor,achieving immediate Cr(Ⅵ) reduction and effluent Cr(Ⅲ) concentrations below 0.040 mg·L^(-1),compared to 0.3 mg·L^(-1) in the control biofilm reactor.High-throughput sequencing identified Dechloromonas as the dominant microbial species within Pd-biofilm,which plays a critical role in metal ion reduction.The Pd-biofilm reactor maintained high Cr(Ⅵ) reduction flux across varying conditions.When the influent Cr(Ⅵ) loading reached up to10 mg L~(-1),where the co ntrol biofilm reactor experienced inhibitio n,the Pd-bio film reactor achieved a Cr removal of 99%.Increased nitrate loading and hydrogen pressure further enhanced Pd-biofilm reactor performance without compromising Cr(Ⅵ) reduction since Cr(Ⅵ) is the preferential electron acceptor,whereas the biofilm reactor required hydrogen pressures>15 psig(1 psig=6.895 kPa) for similar results.The optimal pH range for Cr(Ⅵ) reduction was 5.0-8.0 in the Pd-biofilm reactor and 7.0 in the biofilm reactor,with alkaline conditions being more inhibitory than acidic ones in both systems.The Pd-biofilm reactor effectively reduced Cr(Ⅵ) concentrations from 1 to 10 mg·L^(-1) to below the maximum contaminant level of 0.1 mg·L^(-1),thus appearing as an efficient technique to treat Cr-contaminated waters.
基金supported by the National Natural Science Foundation of China(32072287,32202121).
文摘Temperature and contact surfaces are critical factors influencing biofilm formation of microbial communities derived from both lab and natural environments.However,there is limited understanding regarding how different temperatures impact transfer dynamics of individual microbial species between meat surfaces in dual-species biofilms.In this study,we evaluated the biofilm-forming capabilities of various meat-derived Escherichia coli and Pseudomonas strains on pork surfaces at 15 and 25℃.The results revealed that lower temperature had a significant negative effect on the growth fitness of E.coli compared to Pseudomonas.Two robust biofilm-forming strains,E.coli C-13 and P.fluorescens S_(1-2)3,were selected under both temperature conditions to further explore their interactions in dual-species biofilms on meat surfaces.The results showed that E.coli exhibited a competitive growth advantage at 25℃,while Pseudomonas displayed enhanced growth at 15℃,indicating temperature-dependent competition patterns.Additionally,three established mathematical models were utilized to simulate the transfer dynamics of the two strains within mono-and dual-species biofilms.As anticipated,the numbers of transferred cells progressively declined with increased imprinting reactions between the meat surfaces.Interestingly,the transfer rates of both strains markedly improved in dual-species vs.mono-species biofilms at 15℃,highlighting the influential role of inter-species interactions on transfer dynamics of microbes that may cross-contaminate meats.Our findings advance current understanding of mono-and dual-species biofilm development on meat surfaces under different temperature conditions.They also offer scientific evidence to support strategies for controlling microbial cross-contamination during meat processing to ensure product safety.
基金granted by National Key Research and Development Program of China(2021YFD1800900)Science and Technology Innovation Key R&D Program of Chongqing(CSTB2024TIAD-STX0038)+3 种基金National Natural Science Foundation of China(82574334,32501226)Chongqing Science and Technology Commission(CSTB2023NSCQ-JQX0002)Special Fund for Youth Team of Southwest University(SWU-XJLJ202306)Chongqing Natural Science Foundation(CSTB2024NSCQ-MSX0547).
文摘Multidrug-resistant Klebsiella pneumoniae(MDR-KP)is characterized by high mortality and risk of nosocomial transmission,and biofilm constitutes the primary challenge in the treatment of its implant-associated and refractory pulmonary infections.Notably,the hypoxic microenvironment and the physical barrier of biofilm leading to the increased tolerance of the bacteria to antibiotics.Herein,a hypoxia-responsive hybrid nanoparticle(CHLip@FLD/COL)loaded separately with anti-biofilm candidate fingolimod(FLD)and antibiotic colistin(COL)is achieved targeting antibacterial efficacy against MDR-KP in vitro and in vivo.CHLip@FLD/COL is composed of hybridizing hypoxia-responsive lipids(HLipid)and lipid A targeting materials DSPE-mPEG-COL.HLipid is synthesized by hexadecanedioic acid esterified with nitroimidazole,while DSPE-mPEG is coupling with vector COL via amide reaction.The relative level of extracellular polymeric substances and the NIR-IIb sO2 images of the infection site are used as indicators to establish mature biofilm models.CHLip@FLD/COL readily releases FLD and COL in hypoxic conditions,and its MIC against MDR-KP is only one-sixteenth of that when COL is used alone in vitro.The nanoparticle exhibits bacterial targeting ability and antibacterial effect in the pulmonary infection and biofilm infection mice models.Bacterial loads eliminated by 4 Log10 CFU and 2 Log10 CFU,respectively.The strategy provides a valuable reference for the treatment of refractory infections caused by MDR-KP.
文摘Objective:To develop chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms and verify their antibacterial performance through animal experiments.Methods:Chitosan,silver nitrate,glacial acetic acid,and other chemical reagents were used to synthesize chitosan-silver nanoparticles.The characterization,minimum inhibitory concentration,and biofilm inhibition rate of the chitosan-silver nanoparticles were tested.A total of 40 SD rats were randomly divided into four groups.After routine adaptive feeding,the control group received intraperitoneal injection of normal saline;the model group received intraperitoneal injection of Pseudomonas aeruginosa suspension;the positive group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with ampicillin at a volume ratio of 1∶1;the observation group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with chitosan-silver nanoparticles(at minimum inhibitory concentration)at a volume ratio of 1∶1.Bacterial load,inflammatory factors,and liver and kidney function indicators in tissues were observed and compared among the four groups on the 3^(rd)day after treatment.Results:When the concentration of chitosansilver nanoparticles reached 8μg/mL or above,the OD value of the experimental wells was close to that of the control wells,indicating that 8μg/mL was the minimum inhibitory concentration of the chitosan-silver nanoparticles;at concentrations of 8μg/mL or above,the biofilm inhibition rate was greater than 80%.The bacterial load in the observation group was significantly lower than that in the model and positive groups(P<0.05).The expression levels of interleukin-6,interferon-γ,and tumor necrosis factor-αin the observation group were significantly lower than those in the model and positive groups(P<0.05).There were no statistically significant differences in alanine aminotransferase,aspartate aminotransferase,blood urea nitrogen,and creatinine levels among the four groups(P>0.05).Conclusion:The chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms constructed in this study exhibit good antibacterial effects against Pseudomonas aeruginosa and have good safety.
基金supported by the Natural Science Foundation of Guangdong Province(No.2020A1515011113)the Applied Basic Research Project of Guangzhou(No.202002030455)Zhongshan Science and Technology Plan Project(No.2020AG021).
文摘Microalgae possess significant advantages in nitrogen and phosphorus removal from nutrient-richwastewater that are highly efficient and independent of the C/N ratio.However,challenges such as low biomass productivity,high variability in nutrient removal under different trophic types,and difficulty in harvesting biomass limits the large-scale application of microalgae wastewater treatment.This study attempted to employmixotrophic microalgae biofilm to address these issues.The biomass production,microalgal activity,and nutrient removal of Chlorella pyrenoidosa biofilms with different trophic types were compared for nutrient-rich wastewater treatment.The results showed that the biomass productivity of the mixotrophic microalgal biofilm(0.215 g/(L·d))was 2.3,8.6,and 6.0 times higher than that of photoautotrophic microalgal biofilm,heterotrophic microalgal biofilm,and photoautotrophic suspended microalga,respectively.Additionally,the dehydrogenase activity(DHA),indicating microalgal activity,of the mixotrophic biofilm was 2.3 and 16.5 times higher than that of photoautotrophic and heterotrophic biofilms,respectively.Meanwhile,the mixotrophic biofilm removed 96.0%of NH_(4)^(+)-N and 99.2%of PO_(4)^(3-)-P,more efficient than that with other types of biofilms and suspended microalgae.In an open-ended air-lift photobioreactor,the mixotrophic microalgal biofilm produced biomass at 0.12 g/(L·d)and removed 90.0%of NH_(4)^(+)-N and 97.6%of PO_(4)^(3-)-P.This study suggests that the mixotrophic microalgal biofilm shows promise in treating nutrient-rich wastewater and producing microalgal biomass for value-added products.
基金supported by the Wenzhou Major Scientific and Technological Innovation Project(No.ZY2022020)the Zhejiang Provincial Science and Technology Project for Public Welfare(No.LGF22H140010)the Science and Technology Plan of Wenzhou(No.H20210008)。
文摘In the fight against bacterial infections,it is critical to effectively disrupt biofilms.However,disruption of biofilms becomes exceptionally difficult due to the low permeability of therapeutic agents.Herein,we present a self-propelled nanovesicle(PCL-PLG@CHX)strategy for eliminating biofilms and further expediting the healing of wounds.PCL-PLG@CHX is synthesized by assembling vesicles from amphiphilic polymers,which incorporate both poly-ε-caprolactone and guanidinated-poly-ε-lysine(PCL-PLG)and are infused with chlorhexidine(CHX).Upon application to sites of bacterial infection,PCL-PLG@CHX,abundant in guanidinium structures,effectively accumulates on the negatively charged surface of biofilms.It interacts with reactive oxygen species(ROS)within the biofilm,leading to nitric oxide(NO)production.The generated NO cannot only propel the nanovesicle to penetrate deeper into the biofilm,but also act as a signaling molecule to disperse the biofilm,working in conjunction with the subsequent release of CHX for an enhanced antibacterial impact.Following the eradication of bacteria,the residual guanidine component continues to produce small quantities of NO,facilitating angiogenesis and epithelial growth,thereby accelerating the healing of wounds.Together,our study shows that PCL-PLG@CHX utilizes the potential of guanidine moieties to efficiently break down biofilms and support tissue restoration,tackling the pivotal challenge of biofilm-related diseases.
基金sponsored by the projects funded by the Natural Science Foundation(Key project)of University in Anhui province(grant numbers 2023AH050727,2023AH040114,2023AH052278).
文摘Background:Houttuynia cordata injection(HCI),made from fresh Houttuynia cordata,exerts heat-clearing,detoxifying and diuretic effects.It is indicated for various infections including lung abscess,fever,leucorrhea,urinary tract infection and carbuncle.Candida albicans is a common opportunistic pathogen in immunocompromised individuals.This pathogenic fungus colonizes in skin,mucosa membrane and digestive tract,potentially progressing from localized mucosal infections to systemic disease.Methods:The minimum inhibitory concentration(MIC)of HCI against C.albicans strain was determined by the microdilution method.The hyphal status of C.albicans was observed after incubation in the liquid medium and evaluated by Gram staining.The biofilm formation ability was measured using XTT reduction assay and assessed by Calcofluor White staining.The expression of virulence-related genes was detected with quantitative RT-PCR.Results:The MIC of HCI against C.albicans strain was determined to be 0.5 g/mL.At this concentration,HCI exhibited inhibitory effects on hyphal formation,as confirmed by both liquid medium observation and Gram staining.HCI at the MIC also effectively inhibited C.albicans biofilm formation,which was verified through XTT reduction assay and Calcofluor White staining.Additionally,gene expression analysis revealed that HCI significantly suppressed the expression of virulence-related genes in C.albicans.Conclusion:HCI demonstrates inhibitory effects on C.albicans growth and biofilm development.It inhibits hyphal formation,affecting the yeast-to-hyphal transition.This study investigated the antifungal effects of HCI,providing potent experimental evidence for its mechanism of action against C.albicans.
基金Supported by the Hainan Province Science and Technology Special Fund (No.ZDYF2022SHFZ317)the Guangdong Province Key Laboratory of Applied Marine Biology (No.2023B1212060047)the Program for Scientific Research Start-up Funds of Guangdong Ocean University (No.060302332301)。
文摘Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as well as a carrier of pollutants like heavy metals.However,the dynamic changes of bacterial communities attached to EPS and their interaction with heavy metals are still poorly unknown.In this study,a one-year field exposure experiment was conducted at an aquaculture farm near Donghai Island,in Leizhou Bay,Zhanjiang,Guangdong,in South China Sea.The bacterial communities attached to EPS MPs were examined by 16S r DNA high-throughput sequencing,and the relationships between bacterial biofilms and heavy metals were explored.The results show that there were notable seasonal variations in the bacterial diversity of EPS MPs.Species biodiversity was the highest in summer and the lowest in winter.The greatest number of bacterial species and lowest level of uniformity were observed in the spring.The bacterial community structure changed with exposure time,and the most significant difference in the 12-month group (P<0.05) was found.The dominant bacterial species attached to EPS MPs were mainly Proteobackteria and Firmicutes at the phylum level,and Pseudomonas and Exiguobacterium were dominant at the genus level.Furthermore,EPS MPs acted as transport carriers for potential pathogenic bacteria.High correlations were found between bacterial species and the total concentration of heavy metals on EPS MPs,as well as their speciation fractions.Different chemical speciation of heavy metals migrated and altered over seasons within biofilms,which would further exacerbate the ecological risks.
