Impact of Hydrodynamics on Oral Biofilm Strength

Mechanical removal of oral biofilms is ubiquitously accepted as the best way to prevent caries and periodontal diseases. Removal effectiveness strongly depends on biofilm strength. To investigate the influence of hydrodynamics on oral biofilm strength, we grew single- and multi-species biofilms of Streptococcus oralis J22, Actinomyces naeslundii TV14-J1, and full dental plaque at shear rates ranging from 0.1 to 50 1/sec and measured their compressive strength. Subsequently, biofilm architecture was evaluated by confocal laser scanning microscopy. Multi-species biofilms were stronger than single-species biofilms, with strength values ranging from 6 to 51 Pa and from 5 to 17 Pa, respectively. In response to increased hydrodynamic shear, biofilm strength decreased, and architecture changed from uniform carpet-like to more “fluffy” with higher thickness. S. oralis biofilms grown under variable shear of 7 and 50 1/sec possessed properties intermediate of those measured at the respective single shears.

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Bacterial colonization of enamel in situ investigated using fluorescence in situ hybridization

Journal of Medical Microbiology ◽

10.1099/jmm.0.011213-0 ◽

2009 ◽

Vol 58 (10) ◽

pp. 1359-1366 ◽

Cited By ~ 48

Author(s):

Ali Al-Ahmad ◽

Marie Follo ◽

Ann-Carina Selzer ◽

Elmar Hellwig ◽

Matthias Hannig ◽

...

Keyword(s):

Biofilm Formation ◽

Laser Scanning ◽

Bacterial Colonization ◽

Bacterial Species ◽

Fusobacterium Nucleatum ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Actinomyces Naeslundii ◽

Oral Biofilms

Oral biofilms are one of the greatest challenges in dental research. The present study aimed to investigate initial bacterial colonization of enamel surfaces in situ using fluorescence in situ hybridization (FISH) over a 12 h period. For this purpose, bovine enamel slabs were fixed on buccal sites of individual splints worn by six subjects for 2, 6 and 12 h to allow biofilm formation. Specimens were processed for FISH and evaluated with confocal laser-scanning microscopy, using probes for eubacteria, Streptococcus species, Veillonella species, Fusobacterium nucleatum and Actinomyces naeslundii. The number of adherent bacteria increased with time and all tested bacterial species were detected in the biofilm formed in situ. The general percentage composition of the eubacteria did not change over the investigated period, but the number of streptococci, the most frequently detected species, increased significantly with time (2 h: 17.7±13.8 %; 6 h: 20.0±16.6 %; 12 h: 24.7±16.1 %). However, ≤1 % of the surface was covered with bacteria after 12 h of biofilm formation in situ. In conclusion, FISH is an appropriate method for quantifying initial biofilm formation in situ, and the proportion of streptococci increases during the first 12 h of bacterial adherence.

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Comparison of Cariogenic Characteristics between Fluoride-sensitive and Fluoride-resistant Streptococcus mutans

THE JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY ◽

10.5933/jkapd.2020.47.4.397 ◽

2020 ◽

Vol 47 (4) ◽

pp. 397-405

Author(s):

Seung-Hwan Ong ◽

Jongsoo Kim ◽

Dong-Heon Baek ◽

Seunghoon Yoo

Keyword(s):

Streptococcus Mutans ◽

Biofilm Formation ◽

Laser Scanning ◽

Single Species ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Rt Pcr ◽

Oral Biofilm ◽

Low Levels ◽

Number Of Bacteria

The aim of this study is to compare cariogenic characteristics of fluoride-sensitive Streptococcus mutans [fluoride-sensitive (FS) S. mutans ] and fluoride-resistant Streptococcus mutans [fluoride-resistant (FR) S. mutans] in the presence of sucrose, and to evaluate its effect on cariogenic biofilm formation. S. mutans ATCC 25175 was continuously cultured in trypticase soy broth (TSB) containing NaF (70 ppm) for 40 days to generate FR S. mutans . FS and FR S. mutans were inoculated in TSB with or without 2% sucrose, and optical density and pH were measured every hour. An oral biofilm was formed using saliva bacteria and analyzed through confocal laser scanning microscopy and CFU count. Finally, the expression of glucosyltransferases genes of both S. mutans was investigated through RT-PCR. FR S. mutans exhibited slower growth and lower acidogenicity in the presence of sucrose compared to FS S. mutans . Both cariogenic and single species biofilm formation was lower in the presence of FR S. mutans , along with reduced number of bacteria. FR S. mutans showed significantly low levels of gtfB, gtfC, and gtfD expression compared to FS S. mutans . On the basis of results, FR S. mutans may be less virulent in the induction of dental caries.

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Antibacterial activity of moxifloxacin on bacteria associated with periodontitis within a biofilm

Journal of Medical Microbiology ◽

10.1099/jmm.0.065441-0 ◽

2014 ◽

Vol 63 (2) ◽

pp. 284-292 ◽

Cited By ~ 12

Author(s):

Phoebus Tsaousoglou ◽

Sandor Nietzsche ◽

Georg Cachovan ◽

Anton Sculean ◽

Sigrun Eick

Keyword(s):

Laser Scanning ◽

Single Species ◽

Mixed Population ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Topical Formulation ◽

Single Strain ◽

Mechanical Removal ◽

Multispecies Biofilms

The activity of moxifloxacin was compared with ofloxacin and doxycycline against bacteria associated with periodontitis within a biofilm (single strain and mixed population) in vitro. MICs and minimal bactericidal concentrations (MBCs) of moxifloxacin, ofloxacin and doxycyline were determined against single strains and mixed populations in a planktonic state. Single-species biofilms of two Porphyromonas gingivalis and two Aggregatibacter actinomycetemcomitans strains and a multispecies biofilm consisting of 12 species were formed for 3 days. The minimal biofilm eradication concentrations (MBECs) were determined after exposing the biofilms to the antibacterials (0.002–512 µg ml−1) for 18 h, addition of nutrient broth for 3 days and subsequent subcultivation. Photographs were taken using confocal laser-scanning microscopy and scanning electron microscopy. The MICs and MBCs did not differ between ofloxacin and moxifloxacin against A. actinomycetemcomitans, whilst moxifloxacin was more active than the other tested antibacterials against anaerobes and the mixed population. The single-species biofilms were eradicated by moderate concentrations of the antibacterials, and the lowest MBECs were always found for moxifloxacin (2–8 µg ml−1). MBECs against the multispecies biofilms were 128, >512 and >512 µg ml−1 for moxifloxacin, ofloxacin and doxycycline, respectively. In summary, moxifloxacin in a topical formulation may have potential as an adjunct to mechanical removal of the biofilms.

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Low-Temperature Plasma as an Approach for Inhibiting a Multi-Species Cariogenic Biofilm

Applied Sciences ◽

10.3390/app11020570 ◽

2021 ◽

Vol 11 (2) ◽

pp. 570

Author(s):

Leandro W. Figueira ◽

Beatriz H. D. Panariello ◽

Cristiane Y. Koga-Ito ◽

Simone Duarte

Keyword(s):

Low Temperature ◽

Laser Scanning ◽

Single Species ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Low Temperature Plasma ◽

Temperature Plasma ◽

Plasma Device ◽

Negative Controls ◽

Promising Source

This study aimed to determine how low-temperature plasma (LTP) treatment affects single- and multi-species biofilms formed by Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii formed on hydroxyapatite discs. LTP was produced by argon gas using the kINPen09™ (Leibniz Institute for Plasma Science and Technology, INP, Greifswald, Germany). Biofilms were treated at a 10 mm distance from the nozzle of the plasma device to the surface of the biofilm per 30 s, 60 s, and 120 s. A 0.89% saline solution and a 0.12% chlorhexidine solution were used as negative and positive controls, respectively. Argon flow at three exposure times (30 s, 60 s, and 120 s) was also used as control. Biofilm viability was analyzed by colony-forming units (CFU) recovery and confocal laser scanning microscopy. Multispecies biofilms presented a reduction in viability (log10 CFU/mL) for all plasma-treated samples when compared to both positive and negative controls (p < 0.0001). In single-species biofilms formed by either S. mutans or S. sanguinis, a significant reduction in all exposure times was observed when compared to both positive and negative controls (p < 0.0001). For single-species biofilms formed by S. gordonii, the results indicate total elimination of S. gordonii for all exposure times. Low exposure times of LTP affects single- and multi-species cariogenic biofilms, which indicates that the treatment is a promising source for the development of new protocols for the control of dental caries.

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Effect of Etching Procedures on the Adhesion of Biofilm-Coated Dentin

Materials ◽

10.3390/ma13122762 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2762

Author(s):

Bo-Kyung Jeon ◽

Chang-Ha Lee ◽

A Reum Kim ◽

Seung Hyun Han ◽

Hyun-Jung Kim ◽

...

Keyword(s):

Bond Strength ◽

Biofilm Formation ◽

Laser Scanning ◽

Failure Modes ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Acid Etching ◽

Dentin Surface ◽

Biofilm Removal ◽

Oral Biofilms

Oral biofilms coat all surfaces in the oral cavity including the exposed dentin surface. This study aimed to investigate biofilm removal by acid etching procedures and the effects of the residual biofilm on dentin surfaces on composite–dentin adhesion. Dentin discs were assigned to five groups: no biofilm formation (C); biofilm formation and no surface treatment (BF); biofilm formation and acid etching (BF-E); biofilm formation and acid etching followed by chlorhexidine soaking (BF-EC); and biofilm formation and rubbing with pumice, followed by acid etching (BF-RE). Biofilms were formed on saliva-precoated dentin discs by soaking the discs in Streptococcus mutans (S. mutans) suspension. Biofilm removal from the dentin surface was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and scanning electron microscopy, respectively. To compare the bond strength of the biofilm-coated dentin discs with the surface treatments, specimens were assigned to four groups: no biofilm formation and acid etching (C-E); BF-E; BF-EC; and BF-RE. Assessments of the micro-shear bond strength and subsequent failure modes were performed. BF-E and BF-EC did not remove the biofilm, whereas BF-RE partially removed the biofilm attached to the dentin (p < 0.05). The bond strength of BF-RE was significantly higher than those of BF-E and BF-EC, but lower than that of C-E (p < 0.05). In conclusion, mechanical biofilm removal is recommended before etching procedures to enhance adhesion to the biofilm-coated dentin.

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Actinomyces naeslundii in initial dental biofilm formation

Microbiology ◽

10.1099/mic.0.027706-0 ◽

2009 ◽

Vol 155 (7) ◽

pp. 2116-2126 ◽

Cited By ~ 73

Author(s):

I. Dige ◽

M. K. Raarup ◽

J. R. Nyengaard ◽

M. Kilian ◽

B. Nyvad

Keyword(s):

Biofilm Formation ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Oral Appliances ◽

Dental Biofilm ◽

Actinomyces Naeslundii ◽

Combined Use ◽

Notable Increase

The combined use of confocal laser scanning microscopy (CLSM) and fluorescent in situ hybridization (FISH) offers new opportunities for analysis of the spatial relationships and temporal changes of specific members of the microbiota of intact dental biofilms. The purpose of this study was to analyse the patterns of colonization and population dynamics of Actinomyces naeslundii compared to streptococci and other bacteria during the initial 48 h of biofilm formation in the oral cavity. Biofilms developed on standardized glass slabs mounted in intra-oral appliances worn by ten individuals for 6, 12, 24 and 48 h. The biofilms were subsequently labelled with probes against A. naeslundii (ACT476), streptococci (STR405) or all bacteria (EUB338), and were analysed by CLSM. Labelled bacteria were quantified by stereological tools. The results showed a notable increase in the number of streptococci and A. naeslundii over time, with a tendency towards a slower growth rate for A. naeslundii compared with streptococci. A. naeslundii was located mainly in the inner part of the multilayered biofilm, indicating that it is one of the species that attaches directly to the acquired pellicle. The participation of A. naeslundii in the initial stages of dental biofilm formation may have important ecological consequences.

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New Evidences of Antibacterial Effects of Cranberry Against Periodontal Pathogens

Foods ◽

10.3390/foods9020246 ◽

2020 ◽

Vol 9 (2) ◽

pp. 246 ◽

Cited By ~ 1

Author(s):

María C. Sánchez ◽

Honorato Ribeiro-Vidal ◽

Begoña Bartolomé ◽

Elena Figuero ◽

M. Victoria Moreno-Arribas ◽

...

Keyword(s):

Laser Scanning ◽

Periodontal Diseases ◽

Quantitative Polymerase Chain Reaction ◽

Chemical Characterization ◽

Fusobacterium Nucleatum ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Periodontal Pathogens ◽

Bacteria Adhesion

The worrying rise in antibiotic resistances emphasizes the need to seek new approaches for treating and preventing periodontal diseases. The purpose of this study was to evaluate the antibacterial and anti-biofilm activity of cranberry in a validated in vitro biofilm model. After chemical characterization of a selected phenolic-rich cranberry extract, its values for minimum inhibitory concentration and minimum bactericidal concentration were calculated for the six bacteria forming the biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans). Antibacterial activity of the cranberry extract in the formed biofilm was evaluated by assessing the reduction in bacteria viability, using quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA), and by confocal laser scanning microscopy (CLSM), and anti-biofilm activity by studying the inhibition of the incorporation of different bacteria species in biofilms formed in the presence of the cranberry extract, using qPCR and CLSM. In planktonic state, bacteria viability was significantly reduced by cranberry (p < 0.05). When growing in biofilms, a significant effect was observed against initial and early colonizers (S. oralis (p ≤ 0.017), A. naeslundii (p = 0.006) and V. parvula (p = 0.010)) after 30 or 60 s of exposure, while no significant effects were detected against periodontal pathogens (F. nucleatum, P. gingivalis or A. actinomycetemcomitans (p > 0.05)). Conversely, cranberry significantly (p < 0.001 in all cases) interfered with the incorporation of five of the six bacteria species during the development of 6 h-biofilms, including P. gingivalis, A. actinomycetemcomitans, and F. nucleatum. It was concluded that cranberry had a moderate antibacterial effect against periodontal pathogens in biofilms, but relevant anti-biofilm properties, by affecting bacteria adhesion in the first 6 h of development of biofilms.

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Bacteria on Catheters in Patients Undergoing Peritoneal Dialysis

Peritoneal Dialysis International ◽

10.3747/pdi.2011.00320 ◽

2013 ◽

Vol 33 (1) ◽

pp. 51-59 ◽

Cited By ~ 13

Author(s):

Maria Pihl ◽

Julia R. Davies ◽

Ann-Cathrine Johansson ◽

Gunnel Svensäter

Keyword(s):

Peritoneal Dialysis ◽

Laser Scanning ◽

Close Association ◽

Bacterial Species ◽

Clinical Signs ◽

Single Species ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Rrna Gene ◽

Micro Organisms

♦BackgroundPeritonitis is the leading cause of morbidity for peritoneal dialysis (PD) patients, and microbial biofilms have previously been identified on catheters from infected patients. However, few studies of catheters from patients without clinical signs of infection have been undertaken. The aim of the present study was to investigate the extent to which bacteria are present on catheters from PD patients with no symptoms of infection.♦MethodsMicrobiologic culturing under aerobic and anaerobic conditions and confocal laser scanning microscopy were used to determine the distribution of bacteria on PD catheters from 15 patients without clinical signs of infection and on catheters from 2 infected patients. The 16S rRNA gene sequencing technique was used to identify cultured bacteria.♦ResultsBacteria were detected on 12 of the 15 catheters from patients without signs of infection and on the 2 catheters from infected patients. Single-species and mixed-microbial communities containing up to 5 species were present on both the inside and the outside along the whole length of the colonized catheters. The bacterial species most commonly found were the skin commensals Staphylococcus epidermidis and Propionibacterium acnes, followed by S. warneri and S. lugdunensis. The strains of these micro-organisms, particularly those of S. epidermidis, varied in phenotype with respect to their tolerance of the major classes of antibiotics.♦ConclusionsBacteria were common on catheters from patients without symptoms of infection. Up to 4 different bacterial species were found in close association and may represent a risk factor for the future development of peritonitis in patients hosting such micro-organisms.

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Novel Model for Multispecies Biofilms That Uses Rigid Gas-Permeable Lenses

Applied and Environmental Microbiology ◽

10.1128/aem.00039-11 ◽

2011 ◽

Vol 77 (10) ◽

pp. 3413-3421 ◽

Cited By ~ 21

Author(s):

Rebecca Peyyala ◽

Sreenatha S. Kirakodu ◽

Jeffrey L. Ebersole ◽

Karen F. Novak

Keyword(s):

Laser Scanning ◽

Bacterial Species ◽

Disease Process ◽

Laser Scanning Microscopy ◽

Host Cells ◽

Confocal Laser ◽

Content Type ◽

Oral Biofilms ◽

Multispecies Biofilms

ABSTRACTOral biofilms comprise complex multispecies consortia aided by specific inter- and intraspecies interactions occurring among commensals and pathogenic bacterial species. Oral biofilms are primary initiating factors of periodontal disease, although complex multifactorial biological influences, including host cell responses, contribute to the individual outcome of the disease. To provide a system to study initial stages of interaction between oral biofilms and the host cells that contribute to the disease process, we developed a novelin vitromodel system to grow biofilms on rigid gas-permeable contact lenses (RGPLs), which enable oxygen to permeate through the lens material. Bacterial species belonging to early- and late-colonizing groups were successfully established as single- or three-species biofilms, with each group comprisingStreptococcus gordonii,Streptococcus oralis, andStreptococcus sanguinis;S. gordonii,Actinomyces naeslundii, andFusobacterium nucleatum; orS. gordonii,F. nucleatum, andPorphyromonas gingivalis. Quantification of biofilm numbers by quantitative PCR (qPCR) revealed substantial differences in the magnitude of bacterial numbers in single-species and multispecies biofilms. We evaluated cell-permeable conventional nucleic acid stains acridine orange, hexidium iodide, and Hoechst 33258 and novel SYTO red, blue, and green fluorochromes for their effect on bacterial viability and fluorescence yield to allow visualization of the aggregates of individual bacterial species by confocal laser scanning microscopy (CLSM). Substantial differences in the quantity and distribution of the species in the multispecies biofilms were identified. The specific features of these biofilms may help us better understand the role of various bacteria in local challenge of oral tissues.

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Novel Broad-Spectrum Antimicrobial Photoinactivation ofIn SituOral Biofilms by Visible Light plus Water-Filtered Infrared A

Applied and Environmental Microbiology ◽

10.1128/aem.02490-14 ◽

2014 ◽

Vol 80 (23) ◽

pp. 7324-7336 ◽

Cited By ~ 34

Author(s):

L. Karygianni ◽

S. Ruf ◽

M. Follo ◽

E. Hellwig ◽

M. Bucher ◽

...

Keyword(s):

Visible Light ◽

Laser Scanning ◽

Treatment Approach ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Pharmaceutical Treatment ◽

Oral Biofilms ◽

Biofilm Bacteria ◽

Bovine Enamel

ABSTRACTAntimicrobial photodynamic therapy (APDT) has gained increased attention as an alternative treatment approach in various medical fields. However, the effect of APDT using visible light plus water-filtered infrared A (VIS + wIRA) on oral biofilms remains unexplored. For this purpose, initial and mature oral biofilms were obtainedin situ; six healthy subjects wore individual upper jaw acrylic devices with bovine enamel slabs attached to their proximal sites for 2 h or 3 days. The biofilms were incubated with 100 μg ml−1toluidine blue O (TB) or chlorin e6 (Ce6) and irradiated with VIS + wIRA with an energy density of 200 mW cm−2for 5 min. After cultivation, the CFU of half of the treated biofilm samples were quantified, whereas following live/dead staining, the other half of the samples were monitored by confocal laser scanning microscopy (CLSM). TB- and Ce6-mediated APDT yielded a significant decrease of up to 3.8 and 5.7 log10CFU for initial and mature oral biofilms, respectively. Quantification of the stained photoinactivated microorganisms confirmed these results. Overall, CLSM revealed the diffusion of the tested photosensitizers into the deepest biofilm layers after exposure to APDT. In particular, Ce6-aided APDT presented elevated permeability and higher effectiveness in eradicating 89.62% of biofilm bacteria compared to TB-aided APDT (82.25%) after 3 days. In conclusion, antimicrobial photoinactivation using VIS + wIRA proved highly potent in eradicating oral biofilms. Since APDT excludes the development of microbial resistance, it could supplement the pharmaceutical treatment of periodontitis or peri-implantitis.

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