Introduction to the second issue on Biofilms
0
Citation
0
Reference
10
Related Paper
Extracellular polymeric substance
Cite
Citations (229)
This paper presented the influence of Al(III) on biodegradability, micromorphology, composition and functional groups characteristics of the biofilm extracellular polymeric substances (EPS) during different growth phases. The sequencing batch biofilm reactors were developed to cultivate biofilms under different Al(III) dosages. The results elucidated that Al(III) affected biofilm development adversely at the beginning of biofilm growth, but promoted the biofilm mass and improved the biofilm activity with the growth of the biofilm. The micromorphological observation indicated that Al(III) led to a reduction of the filaments and promotion of the EPS secretion in growth phases of the biofilm, also Al(III) could promote microorganisms to form larger colonies for mature biofilm. Then, the analysis of EPS contents and components suggested that Al(III) could increase the protein (PN) of tightly bound EPS (TB-EPS) which alleviated the metal toxicity inhibition on the biofilm during the initial phases of biofilm growth. The biofilm could gradually adapt to the inhibition caused by Al(III) at the biofilm maturation moment. Finally, through the Fourier transform infrared spectroscopy, it was found that Al(III) was beneficial for the proliferation and secretion of TB-EPS functional groups, especially the functional groups of protein and polysaccharides.
Extracellular polymeric substance
Bacterial growth
Cite
Citations (12)
In the present study, biofilm formation was quantified in UTI isolates of Pseudomonas aeruginosa (n = 22) using the crystal violet assay and was categorized into; strong (n = 16), weak (n = 4), and moderate (n = 2) biofilm producers. Further experiments were done using strong (n = 4) and weak (n = 4) biofilm producers. Biofilm formation was greater in Luria broth followed by natural urine and artificial urine on silicone and silicone-coated latex. Cell adhesion and twitching motility were greater in strong biofilm producers. The presence of thick biofilm with an increased number of dead and total number of cells of strong biofilm producers was observed using CLSM. The concentrations of exopolymeric substances (eDNA, protein, and pel polysaccharide) were high in strong biofilm producers. FEG-SEM visualization of biofilm produced by strong biofilm producers showed more cells encased in thick biofilm matrix than weak ones. Overall results provide evidence for increased cell adhesion and twitching motility in strong biofilm producers.
Crystal violet
Extracellular polymeric substance
Cite
Citations (17)
In this study, multiple roles of biofilm EPS were assessed with respect to the resistance of biofilm and detached biofilm clusters to chlorine disinfection. Strains from an opportunistic pathogen, Pseudomonas aeruginosa (wild type, EPS- and EPS+) with altered extracellular polymeric substances (EPS) secretion capabilities were tested. The impact of biofilm EPS quantity on disinfection was evaluated by monitoring biofilm viability, biofilm structure, removal of dissolved organic matter (DOM), and viability of detached biofilm simultaneously during chlorine disinfection. The obtained results suggested that the presence of EPS increased biofilm and detached biofilm resistance to chlorine in both presence and absence of DOM. The quantity of EPS had an effect on biofilm structure and the structural characteristics were closely related to both overall biofilm viability and the spatial distribution of viable cells within the biofilm. Additionally, the increased amount of EPS influenced selective removal of DOM with polar functional groups. However the DOM removal did not have a significant impact on the viability of biofilm cells during chlorine disinfection. Meanwhile, the viability of detached biofilm clusters, particularly the EPS overproducing strain, was significantly increased in the presence of DOM. The combined results suggested that biofilm EPS played multiple roles toward influencing the resistance of both biofilm and detached biofilm to disinfectant.
Extracellular polymeric substance
Biofouling
Disinfectant
Cite
Citations (149)
Introduction. Bacterial cell hydrophobicity and adherence to a substrate are one of the most important factors in biofilm formation. Group A streptococcus is an unstable and low biofilm productor. Importance of biofilm production in streptococcal pathogenesis is still unknown. Objective. The aim of this study was to determine the impact of hydrophobicity and adherence on the biofilm production of group A streptococcal invasive and noninvasive isolates, and also to evaluate the stability of biofilm production in time function. Methods. Adherence, hydrophobicity and biofilm production were investigated in a total of 172 isolates divided into three groups: noninvasive, low invasive and highly invasive. Adherence to uncoated and laminin-coated microtiter plates and biofilm production after 12, 24 and 48 hours of incubation was determined using the method described by Stepanovic et al. Hydrophobicity was measured using the MATH test by Rosenberg and SAT test by Lindhal. Results. Correlation between adherence and biofilm production was detected in the group of noninvasive isolates. These isolates were stable biofilm productors during all three time periods of biofilm production. In the groups of invasive and noninvasive isolates no statistical correlation was detected among the analysed variables. The invasive isolates were unstable biofilm productors. Conclusion. Noninvasive isolates were stable biofilm producers; as detected, they showed a direct correlation between adherence and biofilm production, and a negative impact of hydrophobicity on the biofilm production. Invasive isolates were unstable biofilm productors; it was observed that there was no correlation between adherence and hydrophobicity with biofilm production.
Cite
Citations (0)
The Impact of Biofilm Formation Detrimental Biofilms Beneficial Biofilms Processes Governing the Formation and Persistence of Biofilms Initial Events Biofilm Cell Metabolic Processes Biofilm Removal Processes Net Accumulation of Biofilm Recent Advances in Biofilm Research Advances in Biofilm Experimental Techniques Transport Phenomena in Biofilms Molecular Processes in Biofilm Communities Novel Biofilm Removal Strategies Bibliography
Cite
Citations (0)
Homoserine
Extracellular polymeric substance
Cite
Citations (25)
Many bacteria grow on surfaces forming biofilms. In this structure, they are well protected and often high dosages of antibiotics cannot clear infectious biofilms. The formation and stabilization of biofilms are mediated by diffusible autoinducers (e.g. N-acyl homoserine lactones, small peptides, furanosyl borate diester). Metabolites interfering with this process have been identified in plants, animals and microbes, and synthetic analogues are known. Additionally, this seems to be not the only way to control biofilms. Enzymes capable of cleaving essential components of the biofilm matrix, e.g. polysaccharides or extracellular DNA, and thus weakening the biofilm architecture have been identified. Bacteria also have mechanisms to dissolve their biofilms and return to planktonic lifestyle. Only a few compounds responsible for the signalling of these processes are known, but they may open a completely novel line of biofilm control. All these approaches lead to the destruction of the biofilm but not the killing of the pathogens. Therefore, a combination of biofilm-destroying compounds and antibiotics to handle biofilm infections is proposed. In this article, different approaches to combine biofilm-controlling compounds and antibiotics to fight biofilm infections are discussed, as well as the balance between biofilm formation and virulence.
Autoinducer
Extracellular polymeric substance
Homoserine
Cite
Citations (67)
Disinfectant
Cite
Citations (34)
Biofilms are complex microbial communities consisting of microcolonies embedded in a matrix of self-produced polymer substances. Biofilm cells show much greater resistance to environmental challenges including antimicrobial agents than their free-living counterparts. The biofilm mode of life is believed to significantly contribute to successful microbial survival in hostile environments. Conventional treatment, disinfection and cleaning strategies do not proficiently deal with biofilm-related problems, such as persistent infections and contamination of food production facilities. In this review, strategies to control biofilms are discussed, including those of inhibition of microbial attachment, interference of biofilm structure development and differentiation, killing of biofilm cells and induction of biofilm dispersion.
Cite
Citations (178)