Advanced Search

Journal Navigation

Journal Home

Subscriptions

Archive

Contact Us

Table of Contents

Click here to sign up for SAGE Journal Email Alerts today!

Sign In to gain access to subscriptions and/or personal tools.
Journal of Dental Research
This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Saved Citations
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Request Reprints
Right arrow Add to My Marked Citations
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Right arrow Citing Articles via Scopus
Google Scholar
Right arrow Articles by Izano, E.A.
Right arrow Articles by Kaplan, J.B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Izano, E.A.
Right arrow Articles by Kaplan, J.B.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Biological

Detachment and Killing of Aggregatibacter actinomycetemcomitans Biofilms by Dispersin B and SDS

E.A. Izano, H. Wang, C. Ragunath, N. Ramasubbu and J.B. Kaplan*

Department of Oral Biology, New Jersey Dental School, Medical Science Building, Room C-636, 185 S. Orange Ave., Newark, NJ 07103, USA

Correspondence: * corresponding author, kaplanjb{at}umdnj.edu


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS & METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
The periodontopathogen Aggregatibacter actinomycetemcomitans forms tenacious biofilms on abiotic surfaces in vitro. The objective of the present study was to measure the susceptibility of A. actinomycetemcomitans biofilms to detachment and killing by the anionic surfactant sodium dodecyl sulfate (SDS). We found that biofilms formed by a wild-type strain were resistant to detachment by SDS. In contrast, biofilms formed by an isogenic mutant strain that was deficient in the production of PGA (poly-N-acetyl-glucosamine), a biofilm matrix polysaccharide, were sensitive to detachment by SDS. Pre-treatment of wild-type biofilms with dispersin B, a PGA-degrading enzyme, rendered them sensitive to detachment by SDS and resulted in a > 99% increase in SDS-mediated cell killing. We concluded that PGA protects A. actinomycetemcomitans cells from detachment and killing by SDS. Dispersin B and SDS may be useful agents for treating chronic infections caused by A. actinomycetemcomitans and other PGA-producing bacteria.

Key Words: A. actinomycetemcomitans • biofilm matrix • critical micelle concentration • dispersin B • PGA • SDS


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS & METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
The Gram-negative bacterium Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetemcomitans) has been implicated as a causative agent of several forms of destructive periodontal disease, including rapidly progressive adult periodontitis, generalized early-onset periodontitis, and localized aggressive periodontitis (Zambon, 1985; Slots et al., 1986). Fresh clinical isolates of A. actinomycetemcomitans form tenacious biofilms on surfaces such as glass, plastic, and saliva-coated hydroxyapatite in vitro (Fine et al., 1999a; Kaplan et al., 2003a). Mutant strains that fail to form biofilms in vitro are unable to colonize the oral cavity, elicit an immune response, or cause bone loss in a rat model of periodontitis (Fine et al., 2001b; Schreiner et al., 2003). These findings suggest that the biofilm mode of growth contributes to the ability of A. actinomycetemcomitans to colonize the oral cavity and cause disease. A. actinomycetemcomitans biofilms grown in vitro exhibit increased resistance to killing by Listerine®, Meridol®, Plax®, and chlorhexidine, when compared with the resistance exhibited by free-living or "planktonic" cells (Fine et al., 2001a; Haase et al., 2006). This increased resistance may help explain why A. actinomycetemcomitans infections are not easily eradicated by conventional periodontal therapies (Renvert et al., 1990; Takamatsu et al., 1999).

A. actinomycetemcomitans biofilms grown in vitro consist of tightly-packed cells enmeshed in a self-synthesized extracellular polymeric matrix (Kaplan et al., 2003b). The biofilm matrix contains type IV adhesive pili (also known as Flp-1 pili; Kachlany et al., 2001), extracellular DNA (Inoue et al., 2003), and polysaccharide (Kaplan et al., 2004b). A major A. actinomycetemcomitans matrix polysaccharide is poly(β-1,6-N-acetyl-D-glucosamine), also known as PGA (Kaplan et al., 2004b). PGA mediates surface attachment and intercellular adhesion in A. actinomycetemcomitans and other human pathogens, including Escherichia coli, Yersinia pestis, Staphylococcus aureus, and S. epidermidis (Kaplan et al., 2003b, 2004a,Kaplan et al., b; Itoh et al., 2005; Kropec et al., 2005). PGA has also been shown to protect S. aureus and S. epidermidis cells from killing by antimicrobial peptides and human PMNs (Vuong et al., 2004; Kropec et al., 2005). A. actinomycetemcomitans biofilm cells also produce dispersin B, a glycoside hydrolase that depolymerizes PGA into N-acetyl-D-glucosamine monomers (Kaplan et al., 2003b; Itoh et al., 2005; Ramasubbu et al., 2005). Mutant strains that lack dispersin B exhibit a decreased biofilm cell detachment phenotype, suggesting that dispersin B may play a role in biofilm dispersal (Kaplan et al., 2003b). When added to biofilm cultures in vitro, purified dispersin B protein either inhibits biofilm formation or causes biofilm detachment in A. actinomycetemcomitans and other PGA-producing bacteria (Kaplan et al., 2003b, 2004a,Kaplan et al., b; Itoh et al., 2005; Irie et al., 2006).

The anionic surfactant SDS, a common ingredient in dentifrices, exhibits bactericidal activity against numerous oral bacteria (Drake et al., 1992; Wade and Addy, 1992). SDS is thought to kill bacteria by penetrating the cytoplasmic membrane and causing cell lysis (Adair et al., 1979). SDS has been shown to kill planktonic A. actinomycetemcomitans cells at a minimum inhibitory concentration (MIC) of 0.01% (Drake et al., 1992; Wade and Addy, 1992). In this study, we investigated the sensitivity of A. actinomycetemcomitans biofilms to killing by SDS.


   MATERIALS & METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS & METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Reagents
Recombinant dispersin B protein was purified from an over-expressing strain of E. coli as previously described (Kaplan et al., 2003b). The enzyme had a specific activity of ~ 103 units per mg of protein. SDS was purchased from Fluka (St. Gallen, Switzerland). Phosphate-buffered saline (PBS; 138 mM NaCl, 10 mM phosphate, 2.7 mM KCl, pH 7.4) was purchased from Sigma Chemical Company (St. Louis, MO, USA).

Bacterial Strains, Media, and Growth Conditions
A. actinomycetemcomitans strain CU1000 (serotype f) was previously isolated from a 13-year-old African-American female with localized aggressive periodontitis (Fine et al., 1999b). Strain CU1000 exhibits a rough-textured colony morphology on agar and a strong biofilm formation phenotype in broth, both of which are characteristic of fresh clinical isolates (Fine et al., 1999b). We isolated the isogenic PGA mutant strain HW1018 (CU1000 pgaC::IS903{phi}kan) by randomly mutagenizing CU1000 with transposon IS903{phi}kan and selecting mutants that produced white-colonies on Congo red agar, as previously described (Kaplan et al., 2003a, 2004b). Like other pgaC mutant strains, HW1018 was completely deficient in PGA production, but still formed tenacious biofilms on plastic surfaces (Kaplan et al., 2004b). Bacteria were grown in Trypticase Soy broth supplemented with 6 g of yeast extract and 8 g of glucose per liter. Solid medium was supplemented with 15 g of agar per liter. All cultures were incubated statically at 37°C in 10% CO2.

Preparation of Inocula
Approximately 10 colonies from a 48-hour-old agar plate were transferred to a 1.5-mL polypropylene microcentrifuge tube containing 200 µL of fresh broth. The cells were homogenized with 10 strokes of a disposable pellet pestle (Kimble/Kontes, Vineland, NJ, USA), transferred to a 15-mL conical centrifuge tube containing 2 mL of fresh broth, subjected to high-speed vortex agitation for 15 sec, and then passed through a 5-µm-pore-size PVDF syringe filter (Millipore, Billerica, MA, USA). The resulting filtrate (~ 1 mL) contained > 99% single cells at a concentration of 107 to 108 colony-forming units (CFU)/mL (Kaplan and Fine, 2002).

Biofilm Cultures
Biofilms were grown in 17-mm x 100-mm culture tubes (untreated polystyrene; Falcon #352051, BD Biosciences, San Jose, CA, USA) or 96-well microtiter plates (tissue-culture-treated polystyrene, flat bottoms; Falcon #353072). Culture vessels were inoculated with a 1:10 dilution of inoculum in fresh broth (1 mL for tubes or 200 µL for microplates) and incubated for 24 hrs.

Crystal Violet Assay
Biofilm biomass was visualized and quantitated by means of a crystal violet binding assay as previously described (Kaplan et al., 2004a). Briefly, biofilms were rinsed with water to remove loosely attached cells, stained for 1 min with Gram’s crystal violet (200 µL for microplates and 1 mL for tubes), rinsed, dried, and photographed. For quantitation of biofilms grown in microplates, biofilms were de-stained with 200 µL of 33% acetic acid for 5 min, and the absorbance of the crystal violet solution was measured directly in the plate by means of a BioRad Benchmark microtiter plate-reader set at 590 nm.

Biofilm Detachment Assay
Biofilms were rinsed with water and treated with 200 µL (for microplates) or 1 mL (for tubes) of dispersin B (20 µg/mL in PBS) or SDS (0.001–1% in PBS). After a five- or 30-minute incubation at 37°C, biofilms were rinsed with water and stained with crystal violet as described above. In some assays, biofilms were first treated with dispersin B for 5 or 30 min, rinsed, and then treated with SDS. All detachment assays were performed in duplicate wells or tubes. All assays were performed on at least 3 separate occasions, with similar results.

Biofilm Killing Assay
Biofilms grown in polystyrene tubes as described above were washed 3 times with sterile PBS and then treated with 1 mL of SDS (0.01% in PBS). After 5 min, the biofilms were rinsed 3 times with PBS to remove the SDS, and then treated with 1 mL of dispersin B (20 µg/mL in PBS) for 5 min to detach the cells. Tubes were vortexed for 10 sec, and 20-µL aliquots of the detached biofilms were transferred to the wells of a flat-bottomed 96-well microtiter plate containing 180 µL of fresh broth. Five serial decimal dilutions (20 µL into 180 µL) were performed directly into adjacent wells. Plates were incubated for 48 hrs and then rinsed and stained with crystal violet as described above. Wells containing 30–300 biofilm colonies were photographed under a dissecting microscope and counted. In some assays, biofilms were pre-treated with 1 mL of dispersin B (20 µg/mL in PBS) for 5 min prior to the SDS treatment. In these assays, a 100-µL quantity of SDS in PBS (at 10 times the test concentration) was added directly to the dispersin-B-treated cell suspension and mixed. After 5 min, tubes were vortexed briefly, and 20-µL aliquots of culture were enumerated as described above. Killing assays were performed in duplicate tubes on at least 5 separate occasions, with similar results.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS & METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Detachment of Biofilms by SDS and Dispersin B
We used crystal violet dye to visualize A. actinomycetemcomitans biofilm growth and detachment in polystyrene tubes and 96-well microtiter plates (Fig. 1Go). Crystal violet binds to bacterial biofilms, but not to polystyrene (O’Toole and Kolter, 1998). Both wild-type and PGA mutant strains formed uniform biofilms that covered the bottom surface of the tube or microplate well after 24 hrs (Figs. 1A, 1BGo). In all cultures, the broth remained optically clear and contained < 1% of the total CFUs after 24 hrs.


Figure 1
View larger version (73K):
[in this window]
[in a new window]

  		Figure 1. Biofilm growth and detachment of A. actinomycetemcomitans strains CU1000 (wild-type) and HW1018 (PGA mutant) in polystyrene tubes and 96-well microtiter plates. All tubes and microplate wells were stained with crystal violet. (A,B) Biofilm formation at 0 hrs and 24 hrs in tubes (panel A) and microplates (panel B). The biofilms on the right were rinsed with water and treated with SDS (0.1% in PBS) or dispersin B (DspB; 20 µg/mL in PBS) for 5 min prior to crystal violet staining. (C) Detachment of CU1000 biofilms from microplates by SDS. Wells on the bottom were pre-treated with dispersin B for 30 min prior to the SDS treatment.

 
A solution of 0.1% SDS had no effect on the attachment of wild-type biofilms, but caused the rapid detachment of PGA mutant biofilms, in both tubes and microplate wells (Figs. 1A, 1BGo). In contrast, a solution of 20 µg/mL of dispersin B caused the rapid detachment of wild-type biofilms from tubes, but not from microplate wells. Dispersin B had no effect on the attachment of PGA mutant biofilms grown in either culture vessel. Microscopic analyses of biofilms grown in tubes indicated that dispersin B caused the biofilms to disaggregate into uniformly turbid suspensions containing > 99% single cells, with very few small clusters of cells (data not shown). Detachment of biofilms from microplate wells could be achieved if higher dispersin B concentrations and longer incubation times were used (Kaplan et al., 2003b).

Pre-treatment of wild-type biofilms with dispersin B rendered them sensitive to detachment by SDS in microplate wells (Fig. 1CGo). To measure the concentration of SDS needed to detach A. actinomycetemcomitans biofilms from microplate wells, we treated biofilms with 0.001–1% SDS for 5 min and then quantitated biofilm biomass by measuring the amount of bound crystal violet dye (Fig. 2Go). Wild-type biofilms were resistant to detachment at all concentrations of SDS. A slight, but reproducible, increase in crystal violet staining was exhibited by biofilms treated with 0.04–0.11% SDS. In contrast, wild-type biofilms pre-treated with dispersin B were resistant to detachment only at SDS concentrations < 0.04%. When the concentration of SDS was increased from 0.04 to 0.07%, biofilms underwent a transition from SDS-resistant to SDS-sensitive. This concentration of SDS (1.4–2.4 mM) is very close to the critical micelle concentration (CMC) of SDS in physiologic saline at 37°C (Helenius et al., 1979). PGA mutant biofilms exhibited a nearly identical transition from SDS-resistant to SDS-sensitive between 0.04 and 0.07% SDS (data not shown).


Figure 2
View larger version (15K):
[in this window]
[in a new window]

  		Figure 2. Detachment of CU1000 (wild-type) biofilms from 96-well microtiter plates by SDS. Biofilms were pre-treated with PBS (mock pre-treatment) or dispersin B (20 µg/mL in PBS) for 30 min, and then treated with increasing concentrations of SDS for 5 min. Biofilms were then rinsed and stained with crystal violet. We quantitated the amount of bound crystal violet dye, which is proportional to biofilm biomass, by measuring its absorbance at 590 nm. Values indicate the mean absorbance for duplicate wells. Error bars indicate range.

 
Dispersin B Increases the Sensitivity of Biofilms to Killing by SDS
We tested the sensitivity of A. actinomycetemcomitans biofilms to killing by 0.01% SDS, which corresponds to the MIC against A. actinomycetemcomitans planktonic cells (Drake et al., 1992; Wade and Addy, 1992), but which is below the concentration required for biofilm detachment (Fig. 2Go). Biofilms grown in tubes were pre-treated with PBS (mock pre-treatment) or dispersin B for 5 min or 30 min, and then treated with SDS for 5 min. PBS, dispersin B, or SDS alone did not significantly kill A. actinomycetemcomitans biofilms (Fig. 3Go). However, SDS caused a 2-log-unit decrease in the number of CFUs in tubes pre-treated with dispersin B for 5 min, and a 4-log-unit decrease in tubes pre-treated for 30 min.


Figure 3
View larger version (26K):
[in this window]
[in a new window]

  		Figure 3. Pre-treatment of A. actinomycetemcomitans CU1000 (wild-type) biofilms with dispersin B increased their sensitivity to killing by SDS. Biofilms grown in polystyrene tubes were rinsed with PBS and treated with 1 mL of PBS (mock pre-treatment) or dispersin B (20 µg/mL in PBS) for 5 min (black bars) or 30 min (gray bars), and then treated with PBS (-) or SDS (0.01% in PBS; +) for 5 min. CFUs were enumerated by dilution plating. Values indicate the log10 of the mean number of CFUs per tube for duplicate tubes. Error bars indicate range.

 

   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS & METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Our findings showed that A. actinomycetemcomitans biofilms grown in polystyrene tubes were rapidly and efficiently detached by dispersin B. In contrast, higher concentrations of enzyme and longer incubation times were necessary to achieve only partial detachment of CU1000 biofilms grown in tissue-culture-treated polystyrene microtiter plates (Kaplan et al., 2003b). The observed surface-dependent differences in sensitivity to detachment by dispersin B may result from the presence of additional matrix adhesins that bind with higher avidity to the hydrophilic surfaces of tissue-culture-treated polystyrene microplates, vs. the more hydrophobic untreated polystyrene surfaces of tubes.

Biofilms formed by a PGA mutant strain of A. actinomycetemcomitans were more sensitive than wild-type biofilms to detachment by SDS. In addition, pre-treatment of wild-type biofilms with dispersin B rendered them sensitive to detachment by SDS, but only at SDS concentrations greater than the critical micelle concentration. Since SDS causes protein unfolding at concentrations above its critical micelle concentration (Otzen, 2002), these findings suggest that SDS-mediated biofilm detachment results from the denaturation of proteinaceous matrix adhesins. Since PGA mutant strains still form tenacious biofilms, it is possible that the PGA molecule itself, and not biofilm formation alone, may mediate resistance to killing by SDS. PGA may act as a diffusion barrier that prevents SDS from entering the biofilm. Alternately, PGA, which is positively charged due to the presence of a small fraction of N-deacetylated N-acetyl-D-glucosamine residues (Itoh et al., 2005), may bind directly to the negatively charged SDS molecule. It is also possible that PGA binds to and stabilizes extracellular DNA, a biofilm matrix adhesin that has been shown to mediate SDS-resistance in Pseudomonas aeruginosa (Allesen-Holm et al., 2006). Our findings suggest that dispersin B may be a useful agent for sensitizing A. actinomycetemcomitans biofilms to detachment and killing by SDS and other antimicrobial agents.


   ACKNOWLEDGMENTS
 
We thank Daniel Kadouri for helpful comments. This work was supported by NIH grants DE15124 (to J.B.K.) and DE16291 (to N.R.).

Received for publication November 30, 2006. Revision received February 7, 2007. Accepted for publication March 8, 2007.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS & METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  • Adair FW, Geftic SG, Heymann H (1979). Lytic effect of di- or tricarboxylic acids plus sodium dodecyl sulfate against Pseudomonas aeruginosa. Antimicrob Agents Chemother 16:417–420.[Abstract/Free Full Text]
  • Allesen-Holm M, Barken KB, Yang L, Klausen M, Webb JS, Kjelleberg S, et al. (2006). A characterization of DNA release in Pseudomonas aeruginosa cultures and biofilms. Mol Microbiol 59:1114–1128.[CrossRef][Medline] [Order article via Infotrieve]
  • Drake DR, Chung J, Grigsby W, Wu-Yuan C (1992). Synergistic effect of pyrophosphate and sodium dodecyl sulfate on periodontal pathogens. J Periodontol 63:696–700.[Medline] [Order article via Infotrieve]
  • Fine DH, Furgang D, Kaplan JB, Charlesworth J, Figurski DH (1999a). Tenacious adhesion of Actinobacillus actinomycetemcomitans strain CU1000 to salivary-coated hydroxyapatite. Arch Oral Biol 44:1063–1076.[CrossRef][Medline] [Order article via Infotrieve]
  • Fine DH, Furgang D, Schreiner HC, Goncharoff P, Charlesworth J, Ghazwan G, et al. (1999b). Phenotypic variation in Actinobacillus actinomycetemcomitans during laboratory growth: implications for virulence. Microbiology 145:1335–1347.[Abstract/Free Full Text]
  • Fine DH, Furgang D, Barnett ML (2001a). Comparative antimicrobial activities of antiseptic mouthrinses against isogenic planktonic and biofilm forms of Actinobacillus actinomycetemcomitans. J Clin Periodontol 28:697–700.[CrossRef][Medline] [Order article via Infotrieve]
  • Fine DH, Goncharoff P, Schreiner H, Chang KM, Furgang D, Figurski D (2001b). Colonization and persistence of rough and smooth colony variants of Actinobacillus actinomycetemcomitans in the mouths of rats. Arch Oral Biol 46:1065–1078.[CrossRef][Medline] [Order article via Infotrieve]
  • Haase EM, Bonstein T, Palmer RJ, Scannapieco FA (2006). Environmental influences on Actinobacillus actinomycetemcomitans biofilm formation. Arch Oral Biol 51:299–314.[CrossRef][Medline] [Order article via Infotrieve]
  • Helenius A, McCaslin DR, Fries E, Tanford C (1979). Properties of detergents. Methods Enzymol 56:734–749.[Medline] [Order article via Infotrieve]
  • Inoue T, Shingaki R, Sogawa N, Sogawa CA, Asaumi J, Kokeguchi S, et al. (2003). Biofilm formation by a fimbriae-deficient mutant of Actinobacillus actinomycetemcomitans. Microbiol Immunol 47:877–881.[Medline] [Order article via Infotrieve]
  • Irie Y, Preston A, Yuk MH (2006). Expression of the primary carbohydrate component of the Bordetella bronchiseptica biofilm matrix is dependent on growth phase but independent of Bvg regulation. J Bacteriol 188:6680–6687.[Abstract/Free Full Text]
  • Itoh Y, Wang X, Hinnebusch BJ, Preston JF III, Romeo T (2005). Depolymerization of beta-1,6-N-acetyl-D-glucosamine disrupts the integrity of diverse bacterial biofilms. J Bacteriol 187:382–387.[Abstract/Free Full Text]
  • Kachlany SC, Planet PJ, DeSalle R, Fine DH, Figurski DH, Kaplan JB (2001). flp-1, the first representative of a new pilin gene subfamily, is required for non-specific adherence of Actinobacillus actinomycetemcomitans. Mol Microbiol 40:542–554.[CrossRef][Medline] [Order article via Infotrieve]
  • Kaplan JB, Fine DH (2002). Biofilm dispersal of Neisseria subflava and other phylogenetically diverse oral bacteria. Appl Environ Microbiol 68:4943–4950.[Abstract/Free Full Text]
  • Kaplan JB, Meyenhofer MF, Fine DH (2003a). Biofilm growth and detachment of Actinobacillus actinomycetemcomitans. J Bacteriol 185:1399–1404.[Abstract/Free Full Text]
  • Kaplan JB, Ragunath C, Ramasubbu N, Fine DH (2003b). Detachment of Actinobacillus actinomycetemcomitans biofilm cells by an endogenous beta-hexosaminidase activity. J Bacteriol 185:4693–4698.[Abstract/Free Full Text]
  • Kaplan JB, Ragunath C, Velliyagounder K, Fine DH, Ramasubbu N (2004a). Enzymatic detachment of Staphylococcus epidermidis biofilms. Antimicrob Agents Chemother 48:2633–2636.[Abstract/Free Full Text]
  • Kaplan JB, Velliyagounder K, Ragunath C, Rohde H, Mack D, Knobloch JK, et al. (2004b). Genes involved in the synthesis and degradation of matrix polysaccharide in Actinobacillus actinomycetemcomitans and Actinobacillus pleuropneumoniae biofilms. J Bacteriol 186:8213–8220.[Abstract/Free Full Text]
  • Kropec A, Maira-Litrán T, Jefferson KK, Grout M, Cramton SE, Götz F, et al. (2005). Poly-N-acetylglucosamine production in Staphylococcus aureus is essential for virulence in murine models of systemic infection. Infect Immun 73:6868–6876.[Abstract/Free Full Text]
  • O’Toole GA, Kolter R (1998). Initiation of biofilm formation in Pseudomonas fluorescens WCS365 proceeds via multiple, convergent signalling pathways: a genetic analysis. Mol Microbiol 28:449–461.[CrossRef][Medline] [Order article via Infotrieve]
  • Otzen DE (2002). Protein unfolding in detergents: effect of micelle structure, ionic strength, pH and temperature. Biophys J 83:2219–2230.[Medline] [Order article via Infotrieve]
  • Ramasubbu N, Thomas LM, Ragunath C, Kaplan JB (2005). Structural analysis of dispersin B, a biofilm-releasing glycoside hydrolase from the periodontopathogen Actinobacillus actinomycetemcomitans. J Mol Biol 349:475–486.[CrossRef][Medline] [Order article via Infotrieve]
  • Renvert S, Wikström M, Dahlén G, Slots J, Egelberg J (1990). Effect of root debridement on the elimination of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis from periodontal pockets. J Clin Periodontol 17:345–350.[Medline] [Order article via Infotrieve]
  • Schreiner HC, Sinatra K, Kaplan JB, Furgang D, Kachlany SC, Planet PJ, et al. (2003). Tight-adherence genes of Actinobacillus actinomycetemcomitans are required for virulence in a rat model. Proc Natl Acad Sci USA 100:7295–7300.[Abstract/Free Full Text]
  • Slots J, Bragd L, Wikström M, Dahlén G (1986). The occurrence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius in destructive periodontal disease in adults. J Clin Periodontol 13:570–577.[CrossRef][Medline] [Order article via Infotrieve]
  • Takamatsu N, Yano K, He T, Umeda M, Ishikawa I (1999). Effect of initial periodontal therapy on the frequency of detecting Bacteroides forsythus, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans. J Periodontol 70:574–580.[CrossRef][Medline] [Order article via Infotrieve]
  • Vuong C, Voyich JM, Fischer ER, Braughton KR, Whitney AR, Deleo FR, et al. (2004). Polysaccharide intercellular adhesin (PIA) protects Staphylococcus epidermidis against major components of the human innate immune system. Cell Microbiol 6:269–275.[CrossRef][Medline] [Order article via Infotrieve]
  • Wade WG, Addy M (1992). Antibacterial activity of some triclosan-containing toothpastes and their ingredients. J Periodontol 63:280–282.[Medline] [Order article via Infotrieve]
  • Zambon JJ (1985). Actinobacillus actinomycetemcomitans in human periodontal disease. J Clin Periodontol 12:1–20.[CrossRef][Medline] [Order article via Infotrieve]

Journal of Dental Research, Vol. 86, No. 7, 618-622 (2007)
DOI: 10.1177/154405910708600707
Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:


Home page
 J Antimicrob ChemotherHome page
R. O. Darouiche, M. D. Mansouri, P. V. Gawande, and S. Madhyastha
Antimicrobial and antibiofilm efficacy of triclosan and DispersinB(R) combination
J. Antimicrob. Chemother., July 1, 2009; 64(1): 88 - 93.
[Abstract] [Full Text] [PDF]

Home page
 Infect. Immun.Home page
J. J. Amarasinghe, F. A. Scannapieco, and E. M. Haase
Transcriptional and Translational Analysis of Biofilm Determinants of Aggregatibacter actinomycetemcomitans in Response to Environmental Perturbation
Infect. Immun., July 1, 2009; 77(7): 2896 - 2907.
[Abstract] [Full Text] [PDF]

Home page
 Appl. Environ. Microbiol.Home page
E. A. Izano, M. A. Amarante, W. B. Kher, and J. B. Kaplan
Differential Roles of Poly-N-Acetylglucosamine Surface Polysaccharide and Extracellular DNA in Staphylococcus aureus and Staphylococcus epidermidis Biofilms
Appl. Envir. Microbiol., January 15, 2008; 74(2): 470 - 476.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Saved Citations
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Request Reprints
Right arrow Add to My Marked Citations
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Right arrow Citing Articles via Scopus
Google Scholar
Right arrow Articles by Izano, E.A.
Right arrow Articles by Kaplan, J.B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Izano, E.A.
Right arrow Articles by Kaplan, J.B.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?