Microbial Pathogenesis and Biofilm Development

Abstract Ion exchanger beads are explored as aids in accelerating the development of anaerobic biofilms for use in advanced anaerobic reactors. Initial adhesion and subsequent changes in adhesion and growth of anaerobic biofilms (as reflected in total supported biomass and metabolic activity) were monitored on different ion exchangers (strong cation, strong anion and weak anion) over a period of 12 days. Metabolic activity was recorded for the first time in this type of study using ATP biolumininescence assays which allowed monitoring of rapid changes in the biofilm development. Results indicate that the strong cation exchanger is a better overall substratum for anaerobic biofilm development due to its favorable property of dialent cation binding and adsorption of volatile fatty acid substrate for methanogens.

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Influence of Seeding Conditions on Initial Biofilm Development during the Startup of Anaerobic Fluidized Bed Reactors

Water Science & Technology ◽

10.2166/wst.1989.0219 ◽

1989 ◽

Vol 21 (4-5) ◽

pp. 157-165 ◽

Cited By ~ 2

Author(s):

F. Ehlinger ◽

J. M. Audic ◽

G. M. Faup

Keyword(s):

Fluidized Bed ◽

Future Development ◽

Protein Concentration ◽

Specific Activity ◽

Fluidized Bed Reactor ◽

Fluidized Bed Reactors ◽

Support Material ◽

Biofilm Development ◽

Initial Biofilm

The characterization of the biofilm of an anaerobic fluidized-bed reactor was completed under standard conditions. The distribution of the fixed protein concentration depended on the level in the reactor. The protein concentration reached 1520 µg.g−1 of support at the top of the reactor and only 1200 µg.g−1 at the bottom after 504 hours of operation but the specific activity of the biofilm was 33×10−4 µM acetate.h−1.mg−1 proteins at the bottom and only 26×10−4 µM.h−1.mg−1 at the top. The efficiency of a fluidized bed reactor and the composition of the biofilm changed with an increase of the pH from 7 to 8.5 during the seeding of the support material. Future development of the biofilm and the specific activity of the support were affected.

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Use of a dynamic gassing-out method for activity and oxygen diffusion coefficient estimation in biofilms

Water Science & Technology ◽

10.2166/wst.1998.0611 ◽

1998 ◽

Vol 37 (4-5) ◽

pp. 171-175

Author(s):

Artem Khlebnikov ◽

Falilou Samb ◽

Paul Péringer

Keyword(s):

Diffusion Coefficient ◽

Oxygen Uptake ◽

Oxygen Diffusion ◽

Fixed Bed ◽

Biofilm Reactor ◽

Strictly Aerobic ◽

Comamonas Testosteroni ◽

Respiration Activity ◽

Oxygen Diffusion Coefficient ◽

Biofilm Development

p-toluenesulphonic acid degradation by Comamonas testosteroni T-2 in multi-species biofilms was studied in a fixed bed biofilm reactor. The polypropylene static mixer elements (Sulzer Chemtech Ltd., Switzerland) were used as a support matrix for biofilm formation. Biofilm respiration was estimated using the dynamic gassing-out oxygen uptake method. A strong relation between oxygen uptake and reactor degradation efficiency was observed, because p-toluenesulphonate degradation is a strictly aerobic process. This technique also allowed us to estimate the thickness of the active layer in the studied system. The mean active thickness was in order of 200 μm, which is close to maximum oxygen penetration depth in biofilms. A transient mathematical model was established to evaluate oxygen diffusitivity in non-steady-state biofilms. Based on the DO concentration profiles, the oxygen diffusion coefficient and the maximum respiration activity were calculated. The oxygen diffusion coefficient obtained (2 10−10-1.2 10−9 m2 s−1) is in good agreement with published values. The DO diffusion coefficient varied with biofilm development. This may be, most likely, due to the biofilm density changes during the experiments. The knowledge of diffusivity changes in biofilms is particularly important for removal capacity estimation and appropriate reactor design.

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Antimicrobial Potential of Benzamides and Derived Nanosystems for Controlling in vitro Biofilm Development on Medical Devices

Current Organic Chemistry ◽

10.2174/1385272811317020013 ◽

2013 ◽

Vol 17 (2) ◽

pp. 162-175 ◽

Cited By ~ 2

Author(s):

Carmen Limban ◽

Alexandru Mihai Grumezescu ◽

Mariana Chirea ◽

Lilia Matei ◽

Mariana Carmen Chifiriuc

Keyword(s):

Medical Devices ◽

Antimicrobial Potential ◽

Biofilm Development

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Bifunctional Composites for Biofilms Modulation on Cervical Restorations

Journal of Dental Research ◽

10.1177/00220345211018189 ◽

2021 ◽

pp. 002203452110181

Author(s):

A.A. Balhaddad ◽

I.M. Garcia ◽

L. Mokeem ◽

M.S. Ibrahim ◽

F.M. Collares ◽

...

Keyword(s):

Free Energy ◽

Surface Free Energy ◽

Contact Angles ◽

Bacterial Biofilm ◽

Dental Composite ◽

Log P ◽

Rrna Gene ◽

Cervical Lesions ◽

Biofilm Growth ◽

Biofilm Development

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM–20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log ( P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM–20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations’ life span.

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