Cronobacter sakazakii(C.sakazakii)is a foodborne opportunistic pathogen that can cause life-threatening invasive diseases,such as necrotizing enterocolitis,meningitis,and sepsis in infants.The potential risk of C.saka...Cronobacter sakazakii(C.sakazakii)is a foodborne opportunistic pathogen that can cause life-threatening invasive diseases,such as necrotizing enterocolitis,meningitis,and sepsis in infants.The potential risk of C.sakazakii contamination of powdered infant formula(PIF)is an issue that has attracted considerable attention from manufacturers,regulators,and consumers.C.sakazakii biofilms on the surfaces of equipment and in diverse food-production environments constitute a mode of cell growth that protects the pathogen from hostile environments,and are an important source of persistent contamination of food products.Bacterial biofilms are difficult to remove due to their resistant properties.Conventional cleaning and sterilizing procedures may be insufficient for biofilm control,and may lead to further biofilm development and dispersal.Consequently,novel control strategies are being developed,such as nanotechnology-based delivery systems,interspecies interactions,antimicrobial molecules of microbial origin,natural extracts,and phages.This review focuses on describing the mechanisms underlying the biofilm formation and behavior of C.sakazakii and discussing potential control strategies.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
Vibrio parahaemolyticus, the leading cause of seafood-borne gastroenteritis, has the ability to form biofilms on biotic and abiotic surfaces. Biofilm formation is a complicated process involving many specific structur...Vibrio parahaemolyticus, the leading cause of seafood-borne gastroenteritis, has the ability to form biofilms on biotic and abiotic surfaces. Biofilm formation is a complicated process involving many specific structures and regulatory processes. The most significant of the structures and processes include polar and lateral flagella, mannose-sensitive hemagglutinin typeⅣpili, chitin-regulated pili,capsular polysaccharide (CPS), exopolysaccharide展开更多
Objective:To investigate the in vitro interference of cefotaxime at subinhibitory concentrations [sub-minimal inhibitory concentrations(MIC)] on biofilm formation by nontypeable Haemophilus influenzae(NTHi).Methods:Th...Objective:To investigate the in vitro interference of cefotaxime at subinhibitory concentrations [sub-minimal inhibitory concentrations(MIC)] on biofilm formation by nontypeable Haemophilus influenzae(NTHi).Methods:The interference of subinhibitory concentrations of cefotaxime on biofilm formation of the clinical strong-biofilm forming isolates of NTHi was evaluated by a microtiter plate biofilm formation assay.The effect of sub-MIC cefotaxime on bacterial cell-surface hydrophobicity was determined using a standard microbial adhesion to n-hexadecane test.Additionally,the effects on bacterial adherence to human fibronectin and expression of bacterial adhesins were also investigated.Results:Subinhibitory concentrations of cefotaxime,both at 0.1× and 0.5× MIC levels,efficiently reduced the NTHi biofilm formation,and this effect was independent of decreasing bacterial viability.Sub-MIC cefotaxime also decreased bacterial cell-surface hydrophobicity and reduced adherence to human fibronectin.Inhibition in the P2 and P6 gene expressions upon exposure to sub-MIC cefotaxime was also noted.Conclusions:Taken together,our results indicate that sub-MIC cefotaxime interferes with the formation of NTHi biofilm,and this effect is feasibly related to the interference with cell-surface hydrophobicity,fibronectin-binding activity as well as alteration of the P2 and P6 gene expression.The findings of the present study therefore provide a rationale for the use of subinhibitory concentrations of cefotaxime for treatment of NTHi-related diseases.展开更多
Objective: To investigate anti-quorum sensing(anti-QS) and anti-biofilm formation(antiBF) activities of the ethanol extracts of 388 plants. Methods: The anti-QS activity of the plant extracts was evaluated by disc-dif...Objective: To investigate anti-quorum sensing(anti-QS) and anti-biofilm formation(antiBF) activities of the ethanol extracts of 388 plants. Methods: The anti-QS activity of the plant extracts was evaluated by disc-diffusion assays using the bio-reporter strain, Chromobacterium violaceum CV017. Pseudomonas aeruginosa PAO1, Yersinia enterocolitica ATCC 9610, and Agrobacterium tumefaciens C58, which possess QS systems, were used to evaluate the antiBF activity of the plant extracts. Results: Among 388 plant extracts, the Cornus controversa(C. controversa) and Cynanchum wilfordii extracts exhibited the strongest anti-QS activity. The C. controversa extract exhibited anti-BF activity against Pseudomonas aeruginosa, Yersinia enterocolitica and Agrobacterium tumefaciens, whereas the Cynanchum wilfordii extract exhibited no anti-BF activity against Pseudomonas aeruginosa. In addition, the C. controversa extract suppressed soft rot of cabbage. Conclusions: The C. controversa extract inhibits bacterial QS and BF, and is capable of controlling soft rot. Therefore, this extract has potential for the prevention and treatment of bacterial infections and for the development of alternatives to antibiotics.展开更多
Flagellar biosynthesis and motility are subject to a four-tiered transcriptional regulatory circuit in Pseudomonas,and the master regulator FleQ appears to be the highest-level regulator in this hierarchical regulator...Flagellar biosynthesis and motility are subject to a four-tiered transcriptional regulatory circuit in Pseudomonas,and the master regulator FleQ appears to be the highest-level regulator in this hierarchical regulatory cascade.Pseudomonas stutzeri A1501 is motile by a polar flagellum;however,the motility and regulatory mechanisms involved in this process are unknown.Here,we searched the A1501 genome for flagella and motility genes and found that approximately 50 genes,which were distributed in three non-contiguous chromosomal regions,contribute to the formation,regulation and function of the flagella.The non-polar mutation of fleQ impaired flagellar biosynthesis,motility and root colonization but enhanced biofilm formation.FleQ positively regulates the expression of flagellar class Ⅱ-Ⅳ genes,suggesting a regulatory cascade that is coordinated similar to that of the well-known P.aeruginosa.Based on our results,we propose that flagellar genes in P.stutzeri A1501 are regulated in a cascade regulated by FleQ and that flagellum-driven motility properties may be necessary for competitive rhizosphere colonization.展开更多
Objective:To investigate the effect of Orostachys(O.)japonicus,a perennial herbaceous plant of the Family Crassulaceae,on biofilm formed by methicillin-resistant Staphylococcus aureus(MRSA).Methods:Powdered O.japonicu...Objective:To investigate the effect of Orostachys(O.)japonicus,a perennial herbaceous plant of the Family Crassulaceae,on biofilm formed by methicillin-resistant Staphylococcus aureus(MRSA).Methods:Powdered O.japonicus was extracted by 95%methanol,concentrated,and then,systematically fractionated with n-hexane,dichloromethane(DCM),ethyl acetate(EtOAc),n-butanol,and H2 O according to polarity.Among them,the flavonoid-rich EtOAc fraction demonstrated the highest antibacterial activity and was used in this study.Using the biofilm inhibition assay,cell-surface attachment assay,confocal laser scanning microscopy,latex agglutination assay,and real time qRT-PCR,we examined whether the EtOAc fraction inhibited the formation of MRSA biofilm.Results:The EtOAc fraction exhibited distinct activity against biofilm formation and cell-surface attachment of MRSA up to 1 mg/m L through down-regulating the expression of mec A gene and the production and agglutination of penicillin-binding protein 2 a as solidly observed in biofilm inhibition assay,cell-suface attachment assay,confocal laser scanning microscopy,latex agglutination assay,and real time qRT-PCR analysis.Conclusions:These results suggest that O.japonicus could be utilized as a potential resource for the development of new antibiofilm formation of MRSA and antibacterial agents in the future.展开更多
Objective: To compare bioi lm formation in trimethoprim/sulfamethoxazole(SXT)-susceptible Escherichia coli(E. coli)(SSEC) and SXT-resistant E. coli(SREC) isolated from patients with urinary tract infections, and study...Objective: To compare bioi lm formation in trimethoprim/sulfamethoxazole(SXT)-susceptible Escherichia coli(E. coli)(SSEC) and SXT-resistant E. coli(SREC) isolated from patients with urinary tract infections, and study the motile ability and physical characteristics of the isolates.Methods: A total of 74 E. coli isolates were tested for antimicrobial susceptibility with the disc diffusion assay. Based on the SXT-susceptibility test, the E. coli isolates were divided into SSEC(N = 30) and SREC(N = 44) groups. All E. coli isolates were examined for motile ability by using a motility test medium, and for checking bioi lm formation a scanning electron microscope was used. Bacterial colony size was measured with a vernier caliper and bacterial cell length was measured under a light microscope. The bacterial growth rate was studied by plotting the cell growth(absorbance) versus the incubation time. Results: The frequencies of non-motility and biofilm formation in the SREC group were signii cantly higher than that in the SSEC group(P < 0.01). The SREC bacterial cell length was shorter than that in the SSEC group [(1.35 ± 0.05) vs.(1.53 ± 0.05) μm, P < 0.05)], whereas the bacterial colony size and mid-log phase of the growth curve were not signii cantly dif erent. Conclusions: The present study indicated that bioi lm formation and phenotypic change of uropathogenic E. coli can be attributed to the mechanism of E. coli SXT resistance.展开更多
Objective:To determine biofilm and hydrophobicity formation ratios in extended spectrum beta lactamases(ESBL) synthesizing Escherichia coli isolates which were isolated from feces samples of 150 cage bird species rand...Objective:To determine biofilm and hydrophobicity formation ratios in extended spectrum beta lactamases(ESBL) synthesizing Escherichia coli isolates which were isolated from feces samples of 150 cage bird species randomly taken from pet shops in Hatay province,Turkey.Methods:In vitro biofilm production of 4 ESBL positive isolates were performed by Congo Red Agar(CRA),Standard Tube(ST) and Microtitre Plate(MP) methods while their hydrophobicity were examined by bacterial adhesion to hydrocarbon(BATH) test.Results:In the examined isolates,while biofilm production was found to be negative by CRA method,highest biofilm producing strain,among 4 bacteria was determined to be A42 by ST and MP methods.The Scanning Electron Microscopy(SEM) also displayed these confirmed findings.The hydrophobicity values of strains were determined to be between 22.45%and 26.42%.Conclusions:As a result,biofilm formation in cage bird feces originated ESBL positive Escherichia coli isolates was performed for the first time in Turkey.In order to present the relation between pathogenicity and biofilm production in animal originated ESBL positive isolates,further studies are required.展开更多
Pig Actinobacillus pleuropneumoniae(App) could induce chronic respiratory tract infection in pigs, which causes major economic losses on pig industry. Bacterial biofilm(BBF) is bacterial community adsorbed on the surf...Pig Actinobacillus pleuropneumoniae(App) could induce chronic respiratory tract infection in pigs, which causes major economic losses on pig industry. Bacterial biofilm(BBF) is bacterial community adsorbed on the surface of biomaterials or body cavity, to protect bacteria escape, and recurrent outbreaks of related infectious diseases and chronic infections resulting therefrom are called bacterial biofilm diseases. App BF belongs to polymers with spatial structure in vitro, and its formation is regulated by multiple genes. Among them, gene deletion of the key component TolC of multidrug efflux pumps and type I secretion systems causes that App BF adhesion weakens; gene deletion of catalytic core ClpP of Clp proteolytic complex induces the inhibition of BF formation; outer membrane lipoprotein VacJ of App promotes BF formation; gene deletion of active enzyme LuxS enhances the formation of App BF and decreases bacterial adhesion ability; gene deletion of Adh obviously declines bacterial accumulation, BF formation and adhesion to host cells. In this paper, BF formation or inhibition mechanism in App is elaborated from molecular level, which could provide reference basis for exploring the prevention of its biofilm diseases.展开更多
Objective:To evaluate the relationship between biofilm formation and incidence of virulence determinants in clinical isolates of Enterococcus.Methods:In this cross-sectional study,the clinical isolates of Enterococcus...Objective:To evaluate the relationship between biofilm formation and incidence of virulence determinants in clinical isolates of Enterococcus.Methods:In this cross-sectional study,the clinical isolates of Enterococcus strains were collected from the university teaching hospitals in Ahvaz,Iran from June 2017 to June 2018.Then,the prevalence of Enterococcus species,antibiotic resistance,virulence factors,and biofilm-producing ability were determined.Results:Of the 119 tested isolates,17(14.3%)were Enterococcus faecalis,72(60.5%)were Enterococcus faecium and 30(25.2%)were other Enterococcus spp.Gelatinase was detected in 97(81.5%)isolates,enterococcal surface protein in 41(34.5%)isolates,serine protease in 39(32.8%)cases,accessory colonization factor in 111(93.3%)cases and pathogenicity islands in 17(14.3%)cases.The biofilm formation ability was observed in 75(63.0%)of all isolates and the association between the presence of enterococcal surface protein gene and biofilm formation was statistically significant.Higher resistance to vancomycin,gentamycin,and teicoplanin was indicated in Enterococcus faecium with 81.8%,58.4%,and 85.7%resistance rate,respectively.All Enterococcus faecalis isolates were sensitive to teicoplanin and vancomycin.Conclusions:The presence of antibiotic-resistance with several virulence factors in Enterococcus spp has become a concern.High prevalence of enterococcal surface protein gene among biofilm-producing isolates suggests a potential relation between biofilm formation and the enterococcal surface protein gene,and further studies are needed to identify the mechanism of biofilm inhibition.展开更多
Foot infections resulting from biofilm producers and multi-drug resistant organisms is one of the most important complications of diabetes mellitus, as it can impede the wound healing process. This study was carried o...Foot infections resulting from biofilm producers and multi-drug resistant organisms is one of the most important complications of diabetes mellitus, as it can impede the wound healing process. This study was carried out in order to determine the antibiotic resistance pattern and the biofilm production in diabetic foot ulcers isolates. Clinical samples were collected from patients suffering from diabetic foot ulcers by using sterile swabs. Antibiotic susceptibility test was done using disk diffusion method on Mueller Hinton Agar. Biofilm formation was assessed by Crystal Violet Staining Method. <i>Staphylococcus aureus</i> isolates were resistant to ofloxacin (83.3%), ciprofloxacin (75.0%), trimethoprim-sulphamethoxazole (75.0%), and gentamicin (58.8%) but very sensitive to oxacillin (100.0%) and vancomycin (91.7%). <i>Pseudomonas aeruginosa</i> isolates showed resistance to the commonly used antibiotics such as ofloxacin, cefotaxime, ampicillin (81.8%), ceftazidime and imipenem (72.7%). The majority of bacteria studied were biofilm producers. This study showed that bacteria isolated from diabetic foot ulcers were biofilm producers and presented resistance to commonly used antibiotics. Knowledge on antibiotic sensitivity pattern and biofilm phenotype of the isolates will be helpful in determining the drugs for the treatment of diabetic ulcers.展开更多
Ethanol extract of Venenum Bufonis has shown many valuable bioactivities, but little is known about its effect on biofilm formation of Staphylococcus aureus. In this study, biofilm formation of S. aureus NCTC8325 with...Ethanol extract of Venenum Bufonis has shown many valuable bioactivities, but little is known about its effect on biofilm formation of Staphylococcus aureus. In this study, biofilm formation of S. aureus NCTC8325 with or without ethanol extract of Venenum Bufonis was tested using microtitre plate assay and Confocal Laser Scanning Microscope (CLSM) system. Results show that the biofilm formation of S. aureus with ethanol extract of Venenum Bufonis was significantly lower than that of the control group without ethanol extract of Venenum Bufonis. Meanwhile, the reduction degree was correlated to the concentration of ethanol extract of Venenum Bufonis positively. With CLSM system we can observe that looser and less biomass of the biofilm structure of the experimental group appeared than that of the control group. These results suggested that ethanol extract of Venenum Bufonis has inhibitory effect on biofilm formation of S. aureus.展开更多
How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies d...How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies described as volcano-like. The formative developmental process of this morphotype has been presented as a suitable experimental model for the study of 3D patterning in macrocolony biofilms. Here, we report the optical microscopy observations and genetic analysis that have unveiled the existence of a novel autoaggregative behaviour which generates massive lumpiness over the surface of the volcano-like macrocolonies. These lumpy formations are generated by the autoaggregation and strong interaction of tightly packed bacterial cells in structures with a chondrule-like appearance which give the colony’s surface its characteristic microscopic lumpy phenotype. Furthermore, they exhibit different levels of maturation from the edge to the center of the colony. Hence, its generation appears to follow a spatiotemporal program of development during the macrocolony’s morphogenesis. Interestingly, the agar’s hardness influences the morphology exhibited by these formations, with high agar concentration (1.5%, 15 g/L) suppressing its development. This new auto-aggregative E. coli’s behaviour does not require the activity of the biofilm master regulator CsgD, the adhesiveness of flagella, pili type 1, adhesin Ag43, β-1,6-N-acetyl-D-glucosamine polymer-PGA, cellulose or colanic acid, but it is under glucose repression and the control of cAMP receptor protein (CRP). The possible physiological role of these chondrule-like formations in the adaptability of the colony to different stressful environmental conditions is discussed.展开更多
基金financial support of National Key Research and Development Program of China(2017YFC1601200)the Science and Technology Planning Project of Guangdong Province(2017A070702018)+1 种基金the Science and Technology Planning Project of Guangzhou(201604020003)Guangdong Academy of Sciences Special Project of Science and Technology Development(2017GDASCX-0201).
文摘Cronobacter sakazakii(C.sakazakii)is a foodborne opportunistic pathogen that can cause life-threatening invasive diseases,such as necrotizing enterocolitis,meningitis,and sepsis in infants.The potential risk of C.sakazakii contamination of powdered infant formula(PIF)is an issue that has attracted considerable attention from manufacturers,regulators,and consumers.C.sakazakii biofilms on the surfaces of equipment and in diverse food-production environments constitute a mode of cell growth that protects the pathogen from hostile environments,and are an important source of persistent contamination of food products.Bacterial biofilms are difficult to remove due to their resistant properties.Conventional cleaning and sterilizing procedures may be insufficient for biofilm control,and may lead to further biofilm development and dispersal.Consequently,novel control strategies are being developed,such as nanotechnology-based delivery systems,interspecies interactions,antimicrobial molecules of microbial origin,natural extracts,and phages.This review focuses on describing the mechanisms underlying the biofilm formation and behavior of C.sakazakii and discussing potential control strategies.
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supported by the National Natural Science Foundation of China [81601809]the Natural Science Foundation of Jiangsu Province [BK20160505]
文摘Vibrio parahaemolyticus, the leading cause of seafood-borne gastroenteritis, has the ability to form biofilms on biotic and abiotic surfaces. Biofilm formation is a complicated process involving many specific structures and regulatory processes. The most significant of the structures and processes include polar and lateral flagella, mannose-sensitive hemagglutinin typeⅣpili, chitin-regulated pili,capsular polysaccharide (CPS), exopolysaccharide
基金Supported by the National Research Council of Thailand through the Annual Research Fund of Naresuan University(Grant No.R2557B011)
文摘Objective:To investigate the in vitro interference of cefotaxime at subinhibitory concentrations [sub-minimal inhibitory concentrations(MIC)] on biofilm formation by nontypeable Haemophilus influenzae(NTHi).Methods:The interference of subinhibitory concentrations of cefotaxime on biofilm formation of the clinical strong-biofilm forming isolates of NTHi was evaluated by a microtiter plate biofilm formation assay.The effect of sub-MIC cefotaxime on bacterial cell-surface hydrophobicity was determined using a standard microbial adhesion to n-hexadecane test.Additionally,the effects on bacterial adherence to human fibronectin and expression of bacterial adhesins were also investigated.Results:Subinhibitory concentrations of cefotaxime,both at 0.1× and 0.5× MIC levels,efficiently reduced the NTHi biofilm formation,and this effect was independent of decreasing bacterial viability.Sub-MIC cefotaxime also decreased bacterial cell-surface hydrophobicity and reduced adherence to human fibronectin.Inhibition in the P2 and P6 gene expressions upon exposure to sub-MIC cefotaxime was also noted.Conclusions:Taken together,our results indicate that sub-MIC cefotaxime interferes with the formation of NTHi biofilm,and this effect is feasibly related to the interference with cell-surface hydrophobicity,fibronectin-binding activity as well as alteration of the P2 and P6 gene expression.The findings of the present study therefore provide a rationale for the use of subinhibitory concentrations of cefotaxime for treatment of NTHi-related diseases.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(2015R1A6A1A03031413)Rural Development Administration,Republic of Korea(PJ00743703)
文摘Objective: To investigate anti-quorum sensing(anti-QS) and anti-biofilm formation(antiBF) activities of the ethanol extracts of 388 plants. Methods: The anti-QS activity of the plant extracts was evaluated by disc-diffusion assays using the bio-reporter strain, Chromobacterium violaceum CV017. Pseudomonas aeruginosa PAO1, Yersinia enterocolitica ATCC 9610, and Agrobacterium tumefaciens C58, which possess QS systems, were used to evaluate the antiBF activity of the plant extracts. Results: Among 388 plant extracts, the Cornus controversa(C. controversa) and Cynanchum wilfordii extracts exhibited the strongest anti-QS activity. The C. controversa extract exhibited anti-BF activity against Pseudomonas aeruginosa, Yersinia enterocolitica and Agrobacterium tumefaciens, whereas the Cynanchum wilfordii extract exhibited no anti-BF activity against Pseudomonas aeruginosa. In addition, the C. controversa extract suppressed soft rot of cabbage. Conclusions: The C. controversa extract inhibits bacterial QS and BF, and is capable of controlling soft rot. Therefore, this extract has potential for the prevention and treatment of bacterial infections and for the development of alternatives to antibiotics.
基金supported by grants from the National Basic Research(973) Program of China(2015CB755700)the National High-Tech R&D(863) Program of China (2012AA02A703)+2 种基金the National Natural Science Foundation of China(31170081)the Special Fund for Agro-scientific Research in the Public Interest,China(201103007)the Guangdong Innovative and Entrepreneurial Research Team Program,China(2013S033).
文摘Flagellar biosynthesis and motility are subject to a four-tiered transcriptional regulatory circuit in Pseudomonas,and the master regulator FleQ appears to be the highest-level regulator in this hierarchical regulatory cascade.Pseudomonas stutzeri A1501 is motile by a polar flagellum;however,the motility and regulatory mechanisms involved in this process are unknown.Here,we searched the A1501 genome for flagella and motility genes and found that approximately 50 genes,which were distributed in three non-contiguous chromosomal regions,contribute to the formation,regulation and function of the flagella.The non-polar mutation of fleQ impaired flagellar biosynthesis,motility and root colonization but enhanced biofilm formation.FleQ positively regulates the expression of flagellar class Ⅱ-Ⅳ genes,suggesting a regulatory cascade that is coordinated similar to that of the well-known P.aeruginosa.Based on our results,we propose that flagellar genes in P.stutzeri A1501 are regulated in a cascade regulated by FleQ and that flagellum-driven motility properties may be necessary for competitive rhizosphere colonization.
基金supported by the 2016 creative research program of Inje University.
文摘Objective:To investigate the effect of Orostachys(O.)japonicus,a perennial herbaceous plant of the Family Crassulaceae,on biofilm formed by methicillin-resistant Staphylococcus aureus(MRSA).Methods:Powdered O.japonicus was extracted by 95%methanol,concentrated,and then,systematically fractionated with n-hexane,dichloromethane(DCM),ethyl acetate(EtOAc),n-butanol,and H2 O according to polarity.Among them,the flavonoid-rich EtOAc fraction demonstrated the highest antibacterial activity and was used in this study.Using the biofilm inhibition assay,cell-surface attachment assay,confocal laser scanning microscopy,latex agglutination assay,and real time qRT-PCR,we examined whether the EtOAc fraction inhibited the formation of MRSA biofilm.Results:The EtOAc fraction exhibited distinct activity against biofilm formation and cell-surface attachment of MRSA up to 1 mg/m L through down-regulating the expression of mec A gene and the production and agglutination of penicillin-binding protein 2 a as solidly observed in biofilm inhibition assay,cell-suface attachment assay,confocal laser scanning microscopy,latex agglutination assay,and real time qRT-PCR analysis.Conclusions:These results suggest that O.japonicus could be utilized as a potential resource for the development of new antibiofilm formation of MRSA and antibacterial agents in the future.
基金Supported by Incubation Research Project-2012 grant,Khon Kaen University,Thailand
文摘Objective: To compare bioi lm formation in trimethoprim/sulfamethoxazole(SXT)-susceptible Escherichia coli(E. coli)(SSEC) and SXT-resistant E. coli(SREC) isolated from patients with urinary tract infections, and study the motile ability and physical characteristics of the isolates.Methods: A total of 74 E. coli isolates were tested for antimicrobial susceptibility with the disc diffusion assay. Based on the SXT-susceptibility test, the E. coli isolates were divided into SSEC(N = 30) and SREC(N = 44) groups. All E. coli isolates were examined for motile ability by using a motility test medium, and for checking bioi lm formation a scanning electron microscope was used. Bacterial colony size was measured with a vernier caliper and bacterial cell length was measured under a light microscope. The bacterial growth rate was studied by plotting the cell growth(absorbance) versus the incubation time. Results: The frequencies of non-motility and biofilm formation in the SREC group were signii cantly higher than that in the SSEC group(P < 0.01). The SREC bacterial cell length was shorter than that in the SSEC group [(1.35 ± 0.05) vs.(1.53 ± 0.05) μm, P < 0.05)], whereas the bacterial colony size and mid-log phase of the growth curve were not signii cantly dif erent. Conclusions: The present study indicated that bioi lm formation and phenotypic change of uropathogenic E. coli can be attributed to the mechanism of E. coli SXT resistance.
文摘Objective:To determine biofilm and hydrophobicity formation ratios in extended spectrum beta lactamases(ESBL) synthesizing Escherichia coli isolates which were isolated from feces samples of 150 cage bird species randomly taken from pet shops in Hatay province,Turkey.Methods:In vitro biofilm production of 4 ESBL positive isolates were performed by Congo Red Agar(CRA),Standard Tube(ST) and Microtitre Plate(MP) methods while their hydrophobicity were examined by bacterial adhesion to hydrocarbon(BATH) test.Results:In the examined isolates,while biofilm production was found to be negative by CRA method,highest biofilm producing strain,among 4 bacteria was determined to be A42 by ST and MP methods.The Scanning Electron Microscopy(SEM) also displayed these confirmed findings.The hydrophobicity values of strains were determined to be between 22.45%and 26.42%.Conclusions:As a result,biofilm formation in cage bird feces originated ESBL positive Escherichia coli isolates was performed for the first time in Turkey.In order to present the relation between pathogenicity and biofilm production in animal originated ESBL positive isolates,further studies are required.
基金Supported by Tianjin Natural Science Foundation Project(07JCYBJC16000)Key Technologies Integration and Students' Comprehensive Ability Improvement Project of Animal Hospital Affiliated to Tianjin Agricultural University(ZH004901)
文摘Pig Actinobacillus pleuropneumoniae(App) could induce chronic respiratory tract infection in pigs, which causes major economic losses on pig industry. Bacterial biofilm(BBF) is bacterial community adsorbed on the surface of biomaterials or body cavity, to protect bacteria escape, and recurrent outbreaks of related infectious diseases and chronic infections resulting therefrom are called bacterial biofilm diseases. App BF belongs to polymers with spatial structure in vitro, and its formation is regulated by multiple genes. Among them, gene deletion of the key component TolC of multidrug efflux pumps and type I secretion systems causes that App BF adhesion weakens; gene deletion of catalytic core ClpP of Clp proteolytic complex induces the inhibition of BF formation; outer membrane lipoprotein VacJ of App promotes BF formation; gene deletion of active enzyme LuxS enhances the formation of App BF and decreases bacterial adhesion ability; gene deletion of Adh obviously declines bacterial accumulation, BF formation and adhesion to host cells. In this paper, BF formation or inhibition mechanism in App is elaborated from molecular level, which could provide reference basis for exploring the prevention of its biofilm diseases.
基金Our study was a part of a research project(No.96s35)which was approved and financially supported by Deputy of Vice-Chancellor for Research Affairs and Student Research Committee of Ahvaz Jundishapur University of Medical Sciences,Ahvaz,Iran,and the authors thank all of them.
文摘Objective:To evaluate the relationship between biofilm formation and incidence of virulence determinants in clinical isolates of Enterococcus.Methods:In this cross-sectional study,the clinical isolates of Enterococcus strains were collected from the university teaching hospitals in Ahvaz,Iran from June 2017 to June 2018.Then,the prevalence of Enterococcus species,antibiotic resistance,virulence factors,and biofilm-producing ability were determined.Results:Of the 119 tested isolates,17(14.3%)were Enterococcus faecalis,72(60.5%)were Enterococcus faecium and 30(25.2%)were other Enterococcus spp.Gelatinase was detected in 97(81.5%)isolates,enterococcal surface protein in 41(34.5%)isolates,serine protease in 39(32.8%)cases,accessory colonization factor in 111(93.3%)cases and pathogenicity islands in 17(14.3%)cases.The biofilm formation ability was observed in 75(63.0%)of all isolates and the association between the presence of enterococcal surface protein gene and biofilm formation was statistically significant.Higher resistance to vancomycin,gentamycin,and teicoplanin was indicated in Enterococcus faecium with 81.8%,58.4%,and 85.7%resistance rate,respectively.All Enterococcus faecalis isolates were sensitive to teicoplanin and vancomycin.Conclusions:The presence of antibiotic-resistance with several virulence factors in Enterococcus spp has become a concern.High prevalence of enterococcal surface protein gene among biofilm-producing isolates suggests a potential relation between biofilm formation and the enterococcal surface protein gene,and further studies are needed to identify the mechanism of biofilm inhibition.
文摘Foot infections resulting from biofilm producers and multi-drug resistant organisms is one of the most important complications of diabetes mellitus, as it can impede the wound healing process. This study was carried out in order to determine the antibiotic resistance pattern and the biofilm production in diabetic foot ulcers isolates. Clinical samples were collected from patients suffering from diabetic foot ulcers by using sterile swabs. Antibiotic susceptibility test was done using disk diffusion method on Mueller Hinton Agar. Biofilm formation was assessed by Crystal Violet Staining Method. <i>Staphylococcus aureus</i> isolates were resistant to ofloxacin (83.3%), ciprofloxacin (75.0%), trimethoprim-sulphamethoxazole (75.0%), and gentamicin (58.8%) but very sensitive to oxacillin (100.0%) and vancomycin (91.7%). <i>Pseudomonas aeruginosa</i> isolates showed resistance to the commonly used antibiotics such as ofloxacin, cefotaxime, ampicillin (81.8%), ceftazidime and imipenem (72.7%). The majority of bacteria studied were biofilm producers. This study showed that bacteria isolated from diabetic foot ulcers were biofilm producers and presented resistance to commonly used antibiotics. Knowledge on antibiotic sensitivity pattern and biofilm phenotype of the isolates will be helpful in determining the drugs for the treatment of diabetic ulcers.
文摘Ethanol extract of Venenum Bufonis has shown many valuable bioactivities, but little is known about its effect on biofilm formation of Staphylococcus aureus. In this study, biofilm formation of S. aureus NCTC8325 with or without ethanol extract of Venenum Bufonis was tested using microtitre plate assay and Confocal Laser Scanning Microscope (CLSM) system. Results show that the biofilm formation of S. aureus with ethanol extract of Venenum Bufonis was significantly lower than that of the control group without ethanol extract of Venenum Bufonis. Meanwhile, the reduction degree was correlated to the concentration of ethanol extract of Venenum Bufonis positively. With CLSM system we can observe that looser and less biomass of the biofilm structure of the experimental group appeared than that of the control group. These results suggested that ethanol extract of Venenum Bufonis has inhibitory effect on biofilm formation of S. aureus.
文摘How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies described as volcano-like. The formative developmental process of this morphotype has been presented as a suitable experimental model for the study of 3D patterning in macrocolony biofilms. Here, we report the optical microscopy observations and genetic analysis that have unveiled the existence of a novel autoaggregative behaviour which generates massive lumpiness over the surface of the volcano-like macrocolonies. These lumpy formations are generated by the autoaggregation and strong interaction of tightly packed bacterial cells in structures with a chondrule-like appearance which give the colony’s surface its characteristic microscopic lumpy phenotype. Furthermore, they exhibit different levels of maturation from the edge to the center of the colony. Hence, its generation appears to follow a spatiotemporal program of development during the macrocolony’s morphogenesis. Interestingly, the agar’s hardness influences the morphology exhibited by these formations, with high agar concentration (1.5%, 15 g/L) suppressing its development. This new auto-aggregative E. coli’s behaviour does not require the activity of the biofilm master regulator CsgD, the adhesiveness of flagella, pili type 1, adhesin Ag43, β-1,6-N-acetyl-D-glucosamine polymer-PGA, cellulose or colanic acid, but it is under glucose repression and the control of cAMP receptor protein (CRP). The possible physiological role of these chondrule-like formations in the adaptability of the colony to different stressful environmental conditions is discussed.