scholarly journals Biofilm Formation by Psychrobacter arcticus and the Role of a Large Adhesin in Attachment to Surfaces

2013 ◽  
Vol 79 (13) ◽  
pp. 3967-3973 ◽  
Author(s):  
Shannon M. Hinsa-Leasure ◽  
Cassandra Koid ◽  
James M. Tiedje ◽  
Janna N. Schultzhaus
Keyword(s):  
Biofilm Formation ◽  
Time Course ◽  
Microtiter Plate ◽  
Bacterial Attachment ◽  
Wild Type ◽  
Microtiter Plate Assay ◽  
Content Type ◽  
Reading Frame ◽  
Transposon Mutants

ABSTRACTPsychrobacter arcticusstrain 273-4, an isolate from a Siberian permafrost core, is capable of forming biofilms when grown in minimal medium under laboratory conditions. Biofilms form at 4 to 22°C when acetate is supplied as the lone carbon source and with 1 to 7% sea salt.P. arcticusis also capable of colonizing quartz sand. Transposon mutagenesis identified a gene important for biofilm formation byP. arcticus. Four transposon mutants were mapped to a 20.1-kbp gene, which is predicted to encode a protein of 6,715 amino acids (Psyc_1601). We refer to this open reading frame ascat1, for cold attachment gene 1. Thecat1mutants are unable to form biofilms at levels equivalent to that of the wild type, and there is no impact on the planktonic growth characteristics of the strains, indicating a specific role in biofilm formation. Through time course studies of the static microtiter plate assay, we determined thatcat1mutants are unable to form biofilms equivalent to that of the wild type under all conditions tested. In flow cell experiments,cat1mutants initially are unable to attach to the surface. Over time, however, they form microcolonies, an architecture very different from that produced by wild-type biofilms. Our results demonstrate that Cat1 is involved in the initial stages of bacterial attachment to surfaces.

scholarly journals Salmonella enterica Serovar Typhimurium Swarming Mutants with Altered Biofilm-Forming Abilities: Surfactin Inhibits Biofilm Formation

2001 ◽  
Vol 183 (20) ◽  
pp. 5848-5854 ◽  
Author(s):  
Joe Robert Mireles ◽  
Adam Toguchi ◽  
Rasika M. Harshey
Keyword(s):  
Polyvinyl Chloride ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Microtiter Plate ◽  
Wild Type ◽  
Swarming Motility ◽  
Microtiter Plate Assay ◽  
Serovar Typhimurium ◽  
Transposon Mutants

ABSTRACT Swarming motility plays an important role in surface colonization by several flagellated bacteria. Swarmer cells are specially adapted to rapidly translocate over agar surfaces by virtue of their more numerous flagella, longer cell length, and encasement of slime. The external slime provides the milieu for motility and likely harbors swarming signals. We recently reported the isolation of swarming-defective transposon mutants of Salmonella enterica serovar Typhimurium, a large majority of which were defective in lipopolysaccharide (LPS) synthesis. Here, we have examined the biofilm-forming abilities of the swarming mutants using a microtiter plate assay. A whole spectrum of efficiencies were observed, with LPS mutants being generally more proficient than wild-type organisms in biofilm formation. Since we have postulated that O-antigen may serve a surfactant function during swarming, we tested the effect of the biosurfactant surfactin on biofilm formation. We report that surfactin inhibits biofilm formation of wild-type S. enterica grown either in polyvinyl chloride microtiter wells or in urethral catheters. Other bio- and chemical surfactants tested had similar effects.

scholarly journals Cellobiose-Specific Phosphotransferase System of Klebsiella pneumoniae and Its Importance in Biofilm Formation and Virulence

2012 ◽  
Vol 80 (7) ◽  
pp. 2464-2472 ◽  
Author(s):  
Meng-Chuan Wu ◽  
Ying-Chun Chen ◽  
Tzu-Lung Lin ◽  
Pei-Fang Hsieh ◽  
Jin-Town Wang
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Type Strain ◽  
Minimal Medium ◽  
Wild Type Strain ◽  
Microtiter Plate ◽  
Wild Type ◽  
Phosphotransferase System ◽  
Microtiter Plate Assay ◽  
Content Type

ABSTRACTKlebsiella pneumoniaeis a Gram-negative bacillus belonging to the familyEnterobacteriaceae. In the past 20 years,K. pneumoniaehas become the predominant pathogen causing community-acquired pyogenic liver abscess (PLA). The formation of biofilm facilitates bacterial colonization and has been implicated in reduced susceptibility to the host immune response. To investigate genes related to biofilm formation in a PLA-associatedK. pneumoniaestrain, a transposon mutant library was screened by microtiter plate assay to identify isolates impaired for biofilm formation. One of the mutants was disrupted incelB, encoding the putative cellobiose-specific subunit IIC of enzyme II (EIIC) of a carbohydrate phosphotransferase system (PTS). This transmembrane protein is responsible for recognizing and binding specific sugars and transporting them across the cell membrane into the cytoplasm. Deletion and chromosomal complementation ofcelBconfirmed, by microtiter plate and slide culture assays, thatcelBwas indeed responsible for biofilm formation. Cellobiose-specific PTS activities of deletion mutants grown in LB broth and 0.005% cellobiose minimal medium were markedly lower than that of the wild-type strain grown under the same conditions, thereby confirming the involvement ofcelBin cellobiose transport. In 0.005% cellobiose minimal medium, thecelBmutant showed a delay in growth compared to the wild-type strain. In a mouse model of intragastric infection, deletion of thecelBgene increased the survival rate from 12.5% to 87.5%, which suggests that thecelBdeletion mutant also exhibited reduced virulence. Thus, thecelBlocus ofK. pneumoniae may contribute to biofilm formation and virulence through the metabolism of cellobiose.

icaA Gene of Staphylococcus aureus Responds to NaCl, Leading to Increased Biofilm Formation

2018 ◽  
Vol 81 (3) ◽  
pp. 412-416 ◽  
Author(s):  
Soomin Lee ◽  
Sejeong Kim ◽  
Heeyoung Lee ◽  
Jimyeong Ha ◽  
Jeeyeon Lee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Microtiter Plate ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Microtiter Plate Assay ◽  
Nacl Concentration ◽  
Icaa Gene

ABSTRACT The objective of this study was to elucidate the role of the icaA gene in biofilm formation of Staphylococcus aureus exposed to NaCl. The icaA-deletion mutant of S. aureus ATCC 13565 was constructed with the temperature-sensitive plasmid pIMAY. Microtiter plate assays were performed to confirm biofilm formation for both the wild type and the mutant at 0% (control), 2, 4, and 6% NaCl. The microtiter plate assay revealed that biofilm formation by the wild type increased (P < 0.05) as NaCl concentration increased, but biofilm formation of the mutant was not affected by NaCl concentration. Biofilm formation by the mutant was lower (P < 0.05) than that by the wild type. These results indicate that icaA plays an important role in biofilm formation by S. aureus when the pathogen is exposed to NaCl.

scholarly journals Causal Role of Single Nucleotide Polymorphisms within themprFGene of Staphylococcus aureus in Daptomycin Resistance

2013 ◽  
Vol 57 (11) ◽  
pp. 5658-5664 ◽  
Author(s):  
Soo-Jin Yang ◽  
Nagendra N. Mishra ◽  
Aileen Rubio ◽  
Arnold S. Bayer
Keyword(s):  
Staphylococcus Aureus ◽  
Single Nucleotide Polymorphisms ◽  
Point Mutations ◽  
Nucleotide Polymorphisms ◽  
Wild Type ◽  
Single Nucleotide ◽  
Content Type ◽  
Reading Frame ◽  
A Charge

ABSTRACTSingle nucleotide polymorphisms (SNPs) within themprFopen reading frame (ORF) have been commonly observed in daptomycin-resistant (DAPr)Staphylococcus aureusstrains. Such SNPs are usually associated with a gain-in-function phenotype, in terms of either increased synthesis or enhanced translocation (flipping) of lysyl-phosphatidylglycerol (L-PG). However, it is unclear if suchmprFSNPs are causal in DAPrstrains or are merely a biomarker for this phenotype. In this study, we used an isogenic set ofS. aureusstrains: (i) Newman, (ii) its isogenic ΔmprFmutant, and (iii) several intransplasmid complementation constructs, expressing either a wild-type or point-mutated form of themprFORF cloned from two isogenic DAP-susceptible (DAPs)-DAPrstrain pairs (616-701 and MRSA11/11-REF2145). Complementation of the ΔmprFstrain with singly point-mutatedmprFgenes (mprFS295LormprFT345A) revealed that (i) individual and distinct point mutations within themprFORF can recapitulate phenotypes observed in donor strains (i.e., changes in DAP MICs, positive surface charge, and cell membrane phospholipid profiles) and (ii) these gain-in-function SNPs (i.e., enhanced L-PG synthesis) likely promote reduced DAP binding toS. aureusby a charge repulsion mechanism. Thus, for these two DAPrstrains, the definedmprFSNPs appear to be causally related to this phenotype.

scholarly journals Motility-Independent Formation of Antibiotic-TolerantPseudomonas aeruginosaAggregates

2019 ◽  
Vol 85 (14) ◽  
Author(s):  
Sally Demirdjian ◽  
Hector Sanchez ◽  
Daniel Hopkins ◽  
Brent Berwin
Keyword(s):  
Biofilm Formation ◽  
Bacterial Pathogen ◽  
Aggregate Formation ◽  
Flagellar Motility ◽  
Wild Type ◽  
Chronic Infections ◽  
Content Type ◽  
Temporal Adaptation ◽  
Bacterial Aggregates

ABSTRACTPseudomonas aeruginosais a bacterial pathogen that causes severe chronic infections in immunocompromised individuals. This bacterium is highly adaptable to its environments, which frequently select for traits that promote bacterial persistence. A clinically significant temporal adaptation is the formation of surface- or cell-adhered bacterial biofilms that are associated with increased resistance to immune and antibiotic clearance. Extensive research has shown that bacterial flagellar motility promotes formation of such biofilms, whereupon the bacteria subsequently become nonmotile. However, recent evidence shows that antibiotic-tolerant nonattached bacterial aggregates, distinct from surface-adhered biofilms, can form, and these have been reported in the context of lung infections, otitis media, nonhealing wounds, and soft tissue fillers. It is unclear whether the same bacterial traits are required for aggregate formation as for biofilm formation. In this report, using isogenic mutants, we demonstrate thatP. aeruginosaaggregates in liquid cultures are spontaneously formed independent of bacterial flagellar motility and independent of an exogenous scaffold. This contrasts with the role of the flagellum to initiate surface-adhered biofilms. Similarly to surface-attached biofilms, these aggregates exhibit increased antibiotic tolerance compared to planktonic cultures. These findings provide key insights into the requirements for aggregate formation that contrast with those for biofilm formation and that may have relevance for the persistence and dissemination of nonmotile bacteria found within chronic clinical infections.IMPORTANCEIn this work, we have investigated the role of bacterial motility with regard to antibiotic-tolerant bacterial aggregate formation. Previous work has convincingly demonstrated thatP. aeruginosaflagellar motility promotes the formation of surface-adhered biofilms in many systems. In contrast, aggregate formation byP. aeruginosawas observed for nonmotile but not for motile cells in the presence of an exogenous scaffold. Here, we demonstrate that both wild-typeP. aeruginosaand mutants that genetically lack motility spontaneously form antibiotic-tolerant aggregates in the absence of an exogenously added scaffold. Additionally, we also demonstrate that wild-type (WT) and nonmotileP. aeruginosabacteria can coaggregate, shedding light on potential physiological interactions and heterogeneity of aggregates.

scholarly journals Role of Flagellin-Homologous Proteins in Biofilm Formation by Pathogenic Vibrio Species

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
You-Chul Jung ◽  
Mi-Ae Lee ◽  
Kyu-Ho Lee
Keyword(s):  
Biofilm Formation ◽  
Specific Binding ◽  
Biological Significance ◽  
Wild Type ◽  
Forming Process ◽  
Homologous Proteins ◽  
Content Type ◽  
Pathogenic Vibrio ◽  
Biofilm Matrix

ABSTRACT The pathogenic bacterium Vibrio vulnificus exhibits the ability to form biofilm, for which initiation is dependent upon swimming motility by virtue of a polar flagellum. The filament of its flagellum is composed of multiple flagellin subunits, FlaA, -B, -C, and -D. In V. vulnificus genomes, however, open reading frames (ORFs) annotated by FlaE and -F are also present. Although neither FlaE nor FlaF is involved in filament formation and cellular motility, they are well expressed and secreted to the extracellular milieu through the secretion apparatus for flagellar assembly. In the extrapolymeric matrix of V. vulnificus biofilm, significant levels of FlaEF were detected. Mutants defective in both flaE and flaF formed significantly decreased biofilms compared to the wild-type biofilm. Thus, the potential role of FlaEF during the biofilm-forming process was investigated by exogenous addition of recombinant FlaEF (rFlaEF) to the biofilm assays. The added rFlaE and rFlaF were predominantly incorporated into the biofilm matrix formed by the wild type. However, biofilms formed by a mutant defective in exopolysaccharide (EPS) biosynthesis were not affected by added FlaEF. These results raised a possibility that FlaEF specifically interact with EPS within the biofilm matrix. In vitro pulldown assays using His-tagged rFlaEF or rFlaC revealed the specific binding of EPS to rFlaEF but not to rFlaC. Taken together, our results demonstrate that V. vulnificus FlaEF, flagellin-homologous proteins (FHPs), are crucial for biofilm formation by directly interacting with the essential determinant for biofilm maturation, EPS. Further analyses performed with other pathogenic Vibrio species demonstrated both the presence of FHPs and their important role in biofilm formation. IMPORTANCE Flagellar filaments of the pathogenic Vibrio species, including V. vulnificus, V. parahaemolyticus, and V. cholerae, are composed of multiple flagellin subunits. In their genomes, however, there are higher numbers of the ORFs encoding flagellin-like proteins than the numbers of flagellin subunits required for filament assembly. Since these flagellin-homologous proteins (FHPs) are well expressed and excreted to environments via a flagellin transport channel, their extracellular role in the pathogenic Vibrio has been enigmatic. Their biological significance, which is not related with flagellar functions, has been revealed to be in maturation of biofilm structures. Among various components of the extracellular polymeric matrix produced in the V. vulnificus biofilms, the exopolysaccharides (EPS) are dominant constituents and crucial in maturation of biofilms. The enhancing role of the V. vulnificus FHPs in biofilm formation requires the presence of EPS, as indicated by highly specific interactions among two FHPs and three EPS.

scholarly journals Characterization of Biofilm Formation and the Role of BCR1 in Clinical Isolates of Candida parapsilosis

2013 ◽  
Vol 13 (4) ◽  
pp. 438-451 ◽  
Author(s):  
Srisuda Pannanusorn ◽  
Bernardo Ramírez-Zavala ◽  
Heinrich Lünsdorf ◽  
Birgitta Agerberth ◽  
Joachim Morschhäuser ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Candida Parapsilosis ◽  
Clinical Isolates ◽  
Wild Type ◽  
Content Type ◽  
Initial Adhesion ◽  
High Level ◽  
Increased Susceptibility

ABSTRACT In Candida parapsilosis , biofilm formation is considered to be a major virulence factor. Previously, we determined the ability of 33 clinical isolates causing bloodstream infection to form biofilms and identified three distinct groups of biofilm-forming strains (negative, low, and high). Here, we establish two different biofilm structures among strains forming large amounts of biofilm in which strains with complex spider-like structures formed robust biofilms on different surface materials with increased resistance to fluconazole. Surprisingly, the transcription factor Bcr1, required for biofilm formation in Candida albicans and C. parapsilosis , has an essential role only in strains with low capacity for biofilm formation. Although BCR1 leads to the formation of more and longer pseudohyphae, it was not required for initial adhesion and formation of mature biofilms in strains with a high level of biofilm formation. Furthermore, an additional phenotype affected by BCR1 was the switch in colony morphology from rough to crepe, but only in strains forming high levels of biofilm. All bcr1 Δ/Δ mutants showed increased proteolytic activity and increased susceptibility to the antimicrobial peptides protamine and RP-1 compared to corresponding wild-type and complemented strains. Taken together, our results demonstrate that biofilm formation in clinical isolates of C. parapsilosis is both dependent and independent of BCR1 , but even in strains which showed a BCR1 -independent biofilm phenotype, BCR1 has alternative physiological functions.

scholarly journals The CpAL Quorum Sensing System Regulates Production of Hemolysins CPA and PFO To Build Clostridium perfringens Biofilms

2015 ◽  
Vol 83 (6) ◽  
pp. 2430-2442 ◽  
Author(s):  
Jorge E. Vidal ◽  
Joshua R. Shak ◽  
Adrian Canizalez-Roman
Keyword(s):  
Quorum Sensing ◽  
Clostridium Perfringens ◽  
Biofilm Formation ◽  
Extracellular Dna ◽  
Wild Type ◽  
Content Type ◽  
Type C ◽  
Enteritis Necroticans ◽  
Biofilm Structure

Clostridium perfringensstrains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by theC. perfringensAgr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. AlthoughC. perfringensstrains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrBmutant strains were not able to produce biofilms, a ΔluxSmutant produced wild-type levels. The transcript levels of CpAL-regulatedcpaandpfoAgenes, but notcpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpaand ΔpfoAmutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpbmade wild-type levels. Biofilm formation was restored in complemented Δcpa/cpaand ΔpfoA/pfoAstrains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation inC. perfringensby increasing levels of certain toxins required to build biofilms.

scholarly journals Cell Surface Attachment Structures Contribute to Biofilm Formation and Xylem Colonization by Erwinia amylovora

2011 ◽  
Vol 77 (19) ◽  
pp. 7031-7039 ◽  
Author(s):  
Jessica M. Koczan ◽  
Bryan R. Lenneman ◽  
Molly J. McGrath ◽  
George W. Sundin
Keyword(s):  
Biofilm Formation ◽  
Time Course ◽  
Erwinia Amylovora ◽  
Critical Role ◽  
Gene Clusters ◽  
Type I ◽  
Content Type ◽  
Type Iv ◽  
Attachment Structures

ABSTRACTBiofilm formation plays a critical role in the pathogenesis ofErwinia amylovoraand the systemic invasion of plant hosts. The functional role of the exopolysaccharides amylovoran and levan in pathogenesis and biofilm formation has been evaluated. However, the role of biofilm formation, independent of exopolysaccharide production, in pathogenesis and movement within plants has not been studied previously. Evaluation of the role of attachment inE. amylovorabiofilm formation and virulence was examined through the analysis of deletion mutants lacking genes encoding structures postulated to function in attachment to surfaces or in cellular aggregation. The genes and gene clusters studied were selected based onin silicoanalyses. Microscopic analyses and quantitative assays demonstrated that attachment structures such as fimbriae and pili are involved in the attachment ofE. amylovorato surfaces and are necessary for the production of mature biofilms. A time course assay indicated that type I fimbriae function earlier in attachment, while type IV pilus structures appear to function later in attachment. Our results indicate that multiple attachment structures are needed for mature biofilm formation and full virulence and that biofilm formation facilitates entry and is necessary for the buildup of large populations ofE. amylovoracells in xylem tissue.

scholarly journals In VivoEfficacy of Antimicrobials against Biofilm-Producing Pseudomonas aeruginosa

2015 ◽  
Vol 59 (8) ◽  
pp. 4974-4981 ◽  
Author(s):  
Vinay Pawar ◽  
Uliana Komor ◽  
Nadine Kasnitz ◽  
Piotr Bielecki ◽  
Marina C. Pils ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Transcriptional Profiling ◽  
Tumor Model ◽  
Experimental System ◽  
Wild Type ◽  
Content Type ◽  
Transposon Mutants ◽  
High Disease Severity

ABSTRACTPatients suffering from cystic fibrosis (CF) are commonly affected by chronicPseudomonas aeruginosabiofilm infections. This is the main cause for the high disease severity. In this study, we demonstrate thatP. aeruginosais able to efficiently colonize murine solid tumors after intravenous injection and to form biofilms in this tissue. Biofilm formation was evident by electron microscopy. Such structures could not be observed with transposon mutants, which were defective in biofilm formation. Comparative transcriptional profiling ofP. aeruginosaindicated physiological similarity of the bacteria in the murine tumor model and the CF lung. The efficacy of currently available antibiotics for treatment ofP. aeruginosa-infected CF lungs, such as ciprofloxacin, colistin, and tobramycin, could be tested in the tumor model. We found that clinically recommended doses of these antibiotics were unable to eliminate wild-typeP. aeruginosaPA14 while being effective against biofilm-defective mutants. However, colistin-tobramycin combination therapy significantly reduced the number ofP. aeruginosaPA14 cells in tumors at lower concentrations. Hence, we present a versatile experimental system that is providing a platform to test approved and newly developed antibiofilm compounds.

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