scholarly journals Comparison between a Conventional Anti-Biofouling Compound and a Novel Modified Low-Fouling Polyethersulfone Ultrafiltration Membrane: Bacterial Anti-Attachment, Water Quality and Productivity

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 227
Author(s):  
Norhan Nady ◽  
Noha Salem ◽  
Ranya Amer ◽  
Ahmed El-Shazly ◽  
Sherif H. Kandil ◽  
...  

In this work, the efficiency of a conventional chlorination pretreatment is compared with a novel modified low-fouling polyethersulfone (PES) ultrafiltration (UF) membrane, in terms of bacteria attachment and membrane biofouling reduction. This study highlights the use of membrane modification as an effective strategy to reduce bacterial attachment, which is the initial step of biofilm formation, rather than using antimicrobial agents that can enhance bacterial regrowth. The obtained results revealed that the filtration of pretreated, inoculated seawater using the modified PES UF membrane without the pre-chlorination step maintained the highest initial flux (3.27 ± 0.13 m3·m−2·h−1) in the membrane, as well as having one and a half times higher water productivity than the unmodified membrane. The highest removal of bacterial cells was achieved by the modified membrane without chlorination, in which about 12.07 × 104 and 8.9 × 104 colony-forming unit (CFU) m−2 bacterial cells were retained on the unmodified and modified membrane surfaces, respectively, while 29.4 × 106 and 0.42 × 106 CFU mL−1 reached the filtrate for the unmodified and modified membranes, respectively. The use of chlorine disinfectant resulted in significant bacterial regrowth.

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1423
Author(s):  
Nicola Mangieri ◽  
Roberto Foschino ◽  
Claudia Picozzi

Shiga toxin-producing Escherichia coli are pathogenic bacteria able to form biofilms both on abiotic surfaces and on food, thus increasing risks for food consumers. Moreover, biofilms are difficult to remove and more resistant to antimicrobial agents compared to planktonic cells. Bacteriophages, natural predators of bacteria, can be used as an alternative to prevent biofilm formation or to remove pre-formed biofilm. In this work, four STEC able to produce biofilm were selected among 31 different strains and tested against single bacteriophages and two-phage cocktails. Results showed that our phages were able to reduce biofilm formation by 43.46% both when used as single phage preparation and as a cocktail formulation. Since one of the two cocktails had a slightly better performance, it was used to remove pre-existing biofilms. In this case, the phages were unable to destroy the biofilms and reduce the number of bacterial cells. Our data confirm that preventing biofilm formation in a food plant is better than trying to remove a preformed biofilm and the continuous presence of bacteriophages in the process environment could reduce the number of bacteria able to form biofilms and therefore improve the food safety.


2020 ◽  
Author(s):  
Maria Chiara Sportelli ◽  
Giada Caniglia ◽  
Ruggiero Quarto ◽  
Rosaria Anna Picca ◽  
Antonio Valentini ◽  
...  

<p>Biofilms are considered a major cause of serious health issues in human medicine and food industry, due to their resistance against harsh conditions and pharmacological treatment [1]. Biofilms are defined as three-dimensional structures encasing bacterial communities rooted in extracellular polymeric substances (EPS). These complex systems are strongly influenced by a variety of parameters including biofilm age, external conditions, nutrient deficiency, attack of exogenous agents [2]. Moreover, bacterial colonies may activate survival strategies when subjected to stress such as the presence of antimicrobial agents. Even cannibalistic behavior may occur [3], which involves the secretion of cannibalism toxins inducing the generation of lysed cells providing nutrients.</p> <p>Several methodologies were developed for or adapted to biofilm formation studies enabling a more comprehensive understanding of biofilm physiology, structure, and composition. This information should facilitate the development of more effective eradication strategies. Infrared spectroscopy in attenuated total reflectance (IR-ATR) mode provides in-situ and close to real time monitoring of biofilm lifecycles providing molecular information on the various stages of biofilm formation. Given the antibiotic resistance of biofilms [4], it is of increasing importance to develop innovative methodologies for the treatment of biofilm-related infections. While our research team has shown the generic utility of antimicrobial nanoparticles (NPs) such as ZnONPs, AgNPs, CuNPs, etc. in the past [5], the current study focuses on AgNPs embedded within fluoropolymer matrices with tunable loading of the NPs. Next to morphological studies by TEM and AFM, detailed XPS investigations revealed the surface chemical composition. In addition, the kinetics of antimicrobial ion release enabled correlating the behavior of the nanocomposite to its swelling properties and 3D modification after immersion in liquids. Biofilm growth and inhibition was studied via AFM, optical microscopy and IR-ATR. The IR analysis of the biofilm allowed collecting molecular information on the biofilm behavior during long-term contact with antimicrobial surfaces. It was demonstrated that bacterial cells may re-colonize on top of dead biomass once the latter is thick enough to prevent direct interaction with the antimicrobial surface. In summary, this study represents an excellent foundation for developing an in depth understanding on the behavior of bacterial colonies and nascent biofilms in contact with surfaces decorated with nanoantimicrobials over extended periods of time. It is anticipated that an improved understanding on the stages of biofilm formation provides insight into the processes governing antimicrobial resistance phenomena. Finally, present antimicrobial material may be a useful strategy against Corona viruses. An outlook to this urging topic will be also presented.</p> <div> <p>[1] N. Billings et al., Rep. Prog. Phys., 2015, 78, 036601. [2] D.O. Serra et al., MBio., 2013, 4, e00103. [3] C. Höfler et al., Microbiology, 2016, 162, 164. [4] M.C. Sportelli et al., Sci. Rep., 2017, 7, 11870. [5] M.C. Sportelli et al., TrAC, 2016, 84, 131.</p> </div>


2021 ◽  
Vol 12 ◽  
Author(s):  
Donald C. Hall ◽  
Phillip Palmer ◽  
Hai-Feng Ji ◽  
Garth D. Ehrlich ◽  
Jarosław E. Król

Recent advances in 3D printing have led to a rise in the use of 3D printed materials in prosthetics and external medical devices. These devices, while inexpensive, have not been adequately studied for their ability to resist biofouling and biofilm buildup. Bacterial biofilms are a major cause of biofouling in the medical field and, therefore, hospital-acquired, and medical device infections. These surface-attached bacteria are highly recalcitrant to conventional antimicrobial agents and result in chronic infections. During the COVID-19 pandemic, the U.S. Food and Drug Administration and medical officials have considered 3D printed medical devices as alternatives to conventional devices, due to manufacturing shortages. This abundant use of 3D printed devices in the medical fields warrants studies to assess the ability of different microorganisms to attach and colonize to such surfaces. In this study, we describe methods to determine bacterial biofouling and biofilm formation on 3D printed materials. We explored the biofilm-forming ability of multiple opportunistic pathogens commonly found on the human body including Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus to colonize eight commonly used polylactic acid (PLA) polymers. Biofilm quantification, surface topography, digital optical microscopy, and 3D projections were employed to better understand the bacterial attachment to 3D printed surfaces. We found that biofilm formation depends on surface structure, hydrophobicity, and that there was a wide range of antimicrobial properties among the tested polymers. We compared our tested materials with commercially available antimicrobial PLA polymers.


2020 ◽  
Vol 8 (11) ◽  
pp. 1835
Author(s):  
Puja Yadav ◽  
Shalini Verma ◽  
Richard Bauer ◽  
Monika Kumari ◽  
Meenakshi Dua ◽  
...  

Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.


2009 ◽  
Vol 75 (11) ◽  
pp. 3586-3592 ◽  
Author(s):  
Phat L. Tran ◽  
Adrienne A. Hammond ◽  
Thomas Mosley ◽  
Janette Cortez ◽  
Tracy Gray ◽  
...  

ABSTRACT Among the most difficult bacterial infections encountered in treating patients are wound infections, which may occur in burn victims, patients with traumatic wounds, necrotic lesions in people with diabetes, and patients with surgical wounds. Within a wound, infecting bacteria frequently develop biofilms. Many current wound dressings are impregnated with antimicrobial agents, such as silver or antibiotics. Diffusion of the agent(s) from the dressing may damage or destroy nearby healthy tissue as well as compromise the effectiveness of the dressing. In contrast, the antimicrobial agent selenium can be covalently attached to the surfaces of a dressing, prolonging its effectiveness. We examined the effectiveness of an organoselenium coating on cellulose discs in inhibiting Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation. Colony biofilm assays revealed that cellulose discs coated with organoselenium completely inhibited P. aeruginosa and S. aureus biofilm formation. Scanning electron microscopy of the cellulose discs confirmed these results. Additionally, the coating on the cellulose discs was stable and effective after a week of incubation in phosphate-buffered saline. These results demonstrate that 0.2% selenium in a coating on cellulose discs effectively inhibits bacterial attachment and biofilm formation and that, unlike other antimicrobial agents, longer periods of exposure to an aqueous environment do not compromise the effectiveness of the coating.


Nano LIFE ◽  
2012 ◽  
Vol 02 (04) ◽  
pp. 1242004 ◽  
Author(s):  
JOHN F. LING ◽  
MARY V. GRAHAM ◽  
NATHANIEL C. CADY

Bacterial pathogens, such as Pseudomonas aeruginosa, readily form biofilms on surfaces, limiting the efficacy of antimicrobial and antibiotic treatments. To mitigate biofilm formation, surfaces are often treated with antimicrobial agents, which have limited lifetime and efficacy. Recent studies have shown that well-ordered topographic patterns can limit bacterial attachment to surfaces and limit biofilm formation. In this study, nano and microscale patterned poly(dimethylsiloxane) surfaces were evaluated for their ability to affect adhesion and biofilm formation by Pseudomonas aeruginosa. Feature size and spacing were varied from 500 nm to 2 μm and included repeating arrays of square pillars, holes, lines and biomimetc Sharklet™ patterns. Bacterial surface adhesion and biofilm formation was assessed in microfluidic flow devices and under static conditions. Attachment profiles under static and fluid flow varied within topography types, sizes and spacing. Pillar structures of all sizes yielded lower surface attachment than line-based patterns and arrays of holes. This trend was also observed for biomimetic Sharklet™ patterns, with reduced bacterial attachment to "raised" features as compared to "recessed" features. Notably, none of the topographically patterned surfaces outperformed smooth surfaces (without topography) for resisting cell adhesion. Initial surface attachment patterns were indicative of subsequent biofilm formation and coverage, suggesting a direct role of surface topography in biofilm-based biofouling.


2020 ◽  
Vol 115 (6) ◽  
pp. 222-229
Author(s):  
Didem Berber ◽  
İpek Türkmenoğlu ◽  
Meral Birbir ◽  
Nüzhet Cenk Sesal

Bacteria forms biofilm to be resistant to antibacterial agents and other unfavorable environment as compared to planktonic bacterial cells. Due to resistance of bacterial biofilms to commonly used antimicrobial agents and adverse effects of these biofilms in different industries, potential natural compounds which can inhibit bacterial biofilms have attracted more attention in recent years. Lichens are known to have unique secondary metabolites with various biological activities including anti-biofilm properties. Therefore, Bacillus toyonensis, Bacillus mojavensis, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus cereus, and Bacillus licheniformis, isolated from soak liquor samples in the previous study, were tested for their ability to form biofilm in this study. Biofilm-forming Bacillus species were detected as B. subtilis, B. amyloliquefaciens, and B. velezensis. The anti-biofilm effect of the acetone extracts of Usnea sp. was evaluated at various concentrations against these biofilm-forming isolates. The anti-biofilm effect of acetone extracts of Usnea sp. against B. subtilis and B. amyloliquefaciens was observed at the concentration of 5 µg/mL by inhibition ratios of 62.75% and 72.72%, respectively. In addition, biofilm formation of B. velezensis was inhibited by the treatment with 1.25 µg/mL extracts at a 62.69% inhibition rate. Biofilm formations of B. amyloliquefaciens and B. velezensis were also suppressed by the extracts at varying percentages of inhibition ranging between 10.11-43.69% and 21.25-46.35%, respectively. This study may provide an alternative approach to overcome the biofilm formation and bacterial resistance to the antibacterial agents in the leather industry.


2013 ◽  
Vol 79 (8) ◽  
pp. 2703-2712 ◽  
Author(s):  
Lillian C. Hsu ◽  
Jean Fang ◽  
Diana A. Borca-Tasciuc ◽  
Randy W. Worobo ◽  
Carmen I. Moraru

ABSTRACTAttachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled topography could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, includingEscherichia coli,Listeria innocua, andPseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale topography was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface topography. These results are important for the design of novel microbe-repellant materials.


2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Jeffrey Jeffrey ◽  
Mieke H Satari ◽  
Dikdik Kurnia

The routine and long term use of chemicals to maintain oral and dental health have the potency to result in the emergence of side effects; therefore another strategy is needed as an alternative such as using antimicrobial agents extracted from plants. The purpose of this study is to review the effectiveness of lime (Citrus aurantifolia) peel extract as an antibacterial in preventing biofilm formation. Biofilm is a component consisting of bacteria in a self-produced polymeric matrix, attached to an inert surface, alive, and can survive because of its ability to capture nutrients and withstand adverse environmental conditions. Lime peel contains flavonoids which are the largest group of polyphenol compounds that can work as antioxidants and antibacterial by denaturing bacterial cell proteins and damaging bacterial cells. Flavonoids can also inhibit glucosyltransferase (GTF) activity of Streptococcus mutans to prevent biofilm formation. Lime peel extract inhibits the formation of the activity of the enzyme Streptococcus mutans. As a conclusion lime peel extract contains compounds with therapeutic potential and has the effect of inhibiting the formation of the activity of the enzyme Streptococcus mutans so that it can be used to inhibit the formation of biofilms. Keywords: antibacterial, biofilm, Citrus aurantifolia


2021 ◽  
Vol 8 ◽  
Author(s):  
Dmitrii Deev ◽  
Iaroslav Rybkin ◽  
Tomaž Rijavec ◽  
Aleš Lapanje

Bacterial attachment is crucial in many biotechnological applications, but many important bacterial strains cannot form biofilms. Biofilms can damage materials, and current strategies to manage biofilms are focused on inhibition and removal of biofilm. Biofilm formation is inevitable when materials are exposed to microbes and instead of biofilm prevention, we propose management of microbial composition by formation of biofilms with beneficial microbes. Since bacteria need to overcome a high repulsive force to attach to the surface and later to grow and multiply on it, electrostatic modification of the surfaces of cells or the material by polyelectrolytes (PE) was used in our approach, enabling efficient attachment of viable bacterial cells. Since highly positively charged PEs are known to be bactericidal, they were acetylated to reduce their toxicity, while preserving their net positive charge and ensuring cell viability. In our study bacterial strains were selected according to their intrinsic capability of biofilm formation, their shape variety and cell wall structure. These strains were tested to compare how the artificially prepared vs. natural biofilms can be used to populate the surface with beneficial bacteria. Using an artificial biofilm constructed of the potentially probiotic isolate Bacillus sp. strain 25.2. M, reduced the attachment and induced complete inhibition of E. coli growth over the biofilm. This study also revealed that the modification of the surfaces of cells or material by polyelectrolytes allows the deposition of bacterial cells, biofilm formation and attachment of biofilm non-forming cells onto surfaces. In this way, artificial biofilms with extended stability can be constructed, leading to selective pressure on further colonization of environmental bacteria.


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