Advance Research on Bacterial Biofilm

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Biofilm".

Deadline for manuscript submissions: 20 September 2024 | Viewed by 14230

Special Issue Editor


E-Mail Website
Guest Editor
LBCM EA3884, Institut Universitaire Européen de la Mer, Université de Bretagne-Sud, 56100 Lorient, France
Interests: bacterial biofilm; genetic regulation; antibiofilm metabolite
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Bacterial adhesion and subsequent biofilm formation are serious and increasing concerns in everyday life, and are responsible for significant damage in several industries, including textile, water treatment, marine transport, medicine, and food packaging. Notwithstanding the enormous efforts of academic researchers and industry, a general solution for restricting bacterial colonization remains to be found. This Special Issue plans to give an overview of the most recent advances in the comprehension of biofilm formation and how to control it in diverse applications areas. Potential topics include but are not limited to: biofilm formation, genetic regulation, antibacterial metabolites, antimicrobial nanomaterials and their applications, and mechanisms of action.

Dr. Alexis Bazire
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Microorganisms is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • bacterial biofilm
  • genetic
  • antibiofilm

Published Papers (10 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

11 pages, 553 KiB  
Article
Synergistic Effects of Combined Flavourzyme and Floating Electrode–Dielectric Barrier Discharge Plasma on Reduction of Escherichia coli Biofilms in Squid (Todarodes pacificus)
by So Hee Kim, Pantu Kumar Roy and Shin Young Park
Microorganisms 2024, 12(6), 1188; https://doi.org/10.3390/microorganisms12061188 - 12 Jun 2024
Viewed by 124
Abstract
This study investigated the synergistic effect of combining flavourzyme, a natural enzyme, and floating electrode–dielectric barrier discharge (FE-DBD) plasma (1.1 kV, 43 kHz, N2 1.5 m/s) treatment, a non-thermal decontamination technology, against Escherichia coli biofilms in squid. E. coli (ATCC 35150 and ATCC [...] Read more.
This study investigated the synergistic effect of combining flavourzyme, a natural enzyme, and floating electrode–dielectric barrier discharge (FE-DBD) plasma (1.1 kV, 43 kHz, N2 1.5 m/s) treatment, a non-thermal decontamination technology, against Escherichia coli biofilms in squid. E. coli (ATCC 35150 and ATCC 14301) biofilms were formed on the surface of squid and treated with different minimum inhibitory concentrations (MICs) of flavourzyme (1/8; 31.25 μL/mL, 1/4; 62.5 μL/mL, 2/4; 125 μL/mL, and 3/4 MIC; 250 μL/mL) and FE-DBD plasma (5, 10, 30, and 60 min). Independently, flavourzyme and FE-DBD plasma treatment decreased by 0.26–1.71 and 0.19–1.03 log CFU/cm2, respectively. The most effective synergistic combination against E. coli biofilms was observed at 3/4 MIC flavourzyme + 60 min FE-DBD plasma exposure, resulting in a reduction of 1.55 log CFU/cm2. Furthermore, the combined treatment exhibited higher efficacy in E. coli biofilm inactivation in squid compared to individual treatments. The pH values of the synergistic combinations were not significantly different from those of the untreated samples. The outcomes indicate that the combined treatment with flavourzyme and FE-DBD plasma can effectively provide effective control of E. coli biofilms without causing pH changes in squid. Therefore, our study suggests a new microbial control method for microbial safety in the seafood industry. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

14 pages, 2094 KiB  
Article
Role of Staphylococcus aureus’s Buoyant Density in the Development of Biofilm Associated Antibiotic Susceptibility
by Sarah Kispert, Madison Liguori, Cody Velikaneye, Chong Qiu, Shue Wang, Nan Zhang and Huan Gu
Microorganisms 2024, 12(4), 759; https://doi.org/10.3390/microorganisms12040759 - 9 Apr 2024
Viewed by 724
Abstract
Biofilms are clusters of microorganisms that form at various interfaces, including those between air and liquid or liquid and solid. Due to their roles in enhancing wastewater treatment processes, and their unfortunate propensity to cause persistent human infections through lowering antibiotic susceptibility, understanding [...] Read more.
Biofilms are clusters of microorganisms that form at various interfaces, including those between air and liquid or liquid and solid. Due to their roles in enhancing wastewater treatment processes, and their unfortunate propensity to cause persistent human infections through lowering antibiotic susceptibility, understanding and managing bacterial biofilms is of paramount importance. A pivotal stage in biofilm development is the initial bacterial attachment to these interfaces. However, the determinants of bacterial cell choice in colonizing an interface first and heterogeneity in bacterial adhesion remain elusive. Our research has unveiled variations in the buoyant density of free-swimming Staphylococcus aureus cells, irrespective of their growth phase. Cells with a low cell buoyant density, characterized by fewer cell contents, exhibited lower susceptibility to antibiotic treatments (100 μg/mL vancomycin) and favored biofilm formation at air–liquid interfaces. In contrast, cells with higher cell buoyant density, which have richer cell contents, were more vulnerable to antibiotics and predominantly formed biofilms on liquid–solid interfaces when contained upright. Cells with low cell buoyant density were not able to revert to a more antibiotic sensitive and high cell buoyant density phenotype. In essence, S. aureus cells with higher cell buoyant density may be more inclined to adhere to upright substrates. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

15 pages, 2843 KiB  
Article
Characterization of the Human Plasma Biofilm Model (hpBIOM) to Identify Potential Therapeutic Targets for Wound Management of Chronic Infections
by Michael Dietrich, Manuela Besser and Ewa Klara Stuermer
Microorganisms 2024, 12(2), 269; https://doi.org/10.3390/microorganisms12020269 - 26 Jan 2024
Viewed by 867
Abstract
The treatment of chronic wounds still represents a major challenge in wound management. Recent estimates suggest that 60–80% of chronic wounds are colonized by pathogenic microorganisms, which are strongly considered to have a major inhibiting influence on the healing process. By means of [...] Read more.
The treatment of chronic wounds still represents a major challenge in wound management. Recent estimates suggest that 60–80% of chronic wounds are colonized by pathogenic microorganisms, which are strongly considered to have a major inhibiting influence on the healing process. By means of an innovative biofilm model based on human plasma, the time-dependent behavior of various bacterial strains under wound-milieu-like conditions were investigated, and the growth habits of different cocci species were compared. Undescribed fusion events between colonies of MRSA as well as of Staphylococcus epidermidis were detected, which were associated with the remodeling and reorganization of the glycocalyx of the wound tissue. After reaching a maximum colony size, the spreading of individual bacteria was observed. Interestingly, the combination of different cocci species with Pseudomonas aeruginosa in the human plasma biofilm revealed partial synergistic effects in these multispecies organizations. RT-qPCR analyses gave a first impression of the relevant proteins involved in the formation and maturation of biofilms, especially the role of fibrinogen-binding proteins. Knowledge of the maturation and growth behavior of persistent biofilms investigated in a translational human biofilm model reflects a starting point for the development of novel tools for the treatment of chronic wounds. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

12 pages, 4702 KiB  
Article
A Three-Dimensional Model of Bacterial Biofilms and Its Use in Antimicrobial Susceptibility Testing
by Hala R. Ali, Pamela Collier and Roger Bayston
Microorganisms 2024, 12(1), 203; https://doi.org/10.3390/microorganisms12010203 - 19 Jan 2024
Viewed by 1222
Abstract
(1) Background: The discrepant antimicrobial susceptibility between planktonic and biofilm bacterial modes poses a problem for clinical microbiology laboratories and necessitates a relevant 3D experimental model allowing bacteria to grow in biofilm mode, in vitro, for use in anti-biofilm susceptibility testing. (2) Methods: [...] Read more.
(1) Background: The discrepant antimicrobial susceptibility between planktonic and biofilm bacterial modes poses a problem for clinical microbiology laboratories and necessitates a relevant 3D experimental model allowing bacteria to grow in biofilm mode, in vitro, for use in anti-biofilm susceptibility testing. (2) Methods: This work develops a 3D biofilm model consisting of alginate beads containing S. aureus biofilm and encased within two thick layers of alginate matrix. The constructed model was placed on a thin Boyden chamber insert suspended on a 24-well culture plate containing the culture medium. The antibacterial activity of bacitracin and chlorhexidine digluconate (CD), either combined or separately, against 2D S. aureus culture was compared to that in the 3D biofilm model. Quantitative analysis and imaging analysis were performed by assessing the bacterial load within the matrix as well as measuring the optical density of the culture medium nourishing the matrix. (3) Results: The 3D biofilm model represented the typical complex characteristics of biofilm with greater insusceptibility to the tested antimicrobials than the 2D culture. Only bacitracin and CD in combination at 100× the concentration found to be successful against 2D culture were able to completely eliminate the 3D biofilm matrix. (4) Conclusions: The 3D biofilm model, designed to be more clinically relevant, exhibits higher antimicrobial insusceptibility than the 2D culture, demonstrating that the model might be useful for testing and discovering new antimicrobial therapies. The data also support the view that combination therapy might be the optimal approach to combat biofilm infections. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

18 pages, 1516 KiB  
Article
Biofilm Formation by Escherichia coli Isolated from Urinary Tract Infections from Aguascalientes, Mexico
by Flor Yazmín Ramírez Castillo, Alma Lilian Guerrero Barrera, Josée Harel, Francisco Javier Avelar González, Philippe Vogeleer, José Manuel Arreola Guerra and Mario González Gámez
Microorganisms 2023, 11(12), 2858; https://doi.org/10.3390/microorganisms11122858 - 25 Nov 2023
Cited by 1 | Viewed by 1935
Abstract
Uropathogenic Escherichia coli (UPEC) strains are among the leading causes of urinary tract infections (UTIs) worldwide. They can colonize the urinary tract and form biofilms that allow bacteria to survive and persist, causing relapses of infections and life-threatening sequelae. Here, we analyzed biofilm [...] Read more.
Uropathogenic Escherichia coli (UPEC) strains are among the leading causes of urinary tract infections (UTIs) worldwide. They can colonize the urinary tract and form biofilms that allow bacteria to survive and persist, causing relapses of infections and life-threatening sequelae. Here, we analyzed biofilm production, antimicrobial susceptibility, virulence factors, and phylogenetic groups in 74 E. coli isolated from diagnosed patients with UTIs to describe their microbiological features and ascertain their relationship with biofilm capabilities. High levels of ceftazidime resistance are present in hospital-acquired UTIs. Isolates of multidrug resistance strains (p = 0.0017) and the yfcV gene (p = 0.0193) were higher in male patients. All the strains tested were able to form biofilms. Significant differences were found among higher optical densities (ODs) and antibiotic resistance to cefazolin (p = 0.0395), ceftazidime (p = 0.0302), and cefepime (p = 0.0420). Overall, the presence of fimH and papC coincided with strong biofilm formation by UPEC. Type 1 fimbriae (p = 0.0349), curli (p = 0.0477), and cellulose (p = 0.0253) production was significantly higher among strong biofilm formation. Our results indicated that high antibiotic resistance may be related to male infections as well as strong and moderate biofilm production. The ability of E. coli strains to produce biofilm is important for controlling urinary tract infections. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Graphical abstract

17 pages, 2454 KiB  
Article
Regulation of σB-Dependent Biofilm Formation in Staphylococcus aureus through Strain-Specific Signaling Induced by Diosgenin
by Seo-Young Kim, Minjun Kim and Tae-Jong Kim
Microorganisms 2023, 11(10), 2376; https://doi.org/10.3390/microorganisms11102376 - 23 Sep 2023
Cited by 2 | Viewed by 1184
Abstract
Staphylococcus aureus is a commensal skin bacterium and a causative agent of infectious diseases. Biofilm formation in S. aureus is a mechanism that facilitates the emergence of resistant strains. This study proposes a mechanism for the regulation of biofilm formation in S. [...] Read more.
Staphylococcus aureus is a commensal skin bacterium and a causative agent of infectious diseases. Biofilm formation in S. aureus is a mechanism that facilitates the emergence of resistant strains. This study proposes a mechanism for the regulation of biofilm formation in S. aureus through strain-specific physiological changes induced by the plant steroid diosgenin. A comparison of diosgenin-induced changes in the expression of regulatory genes associated with physiological changes revealed the intracellular regulatory mechanisms involved in biofilm formation. Diosgenin reduced biofilm formation in S. aureus ATCC 6538 and methicillin-resistant S. aureus (MRSA) CCARM 3090 by 39% and 61%, respectively. Conversely, it increased biofilm formation in S. aureus ATCC 29213 and MRSA CCARM 3820 by 186% and 582%, respectively. Cell surface hydrophobicity and extracellular protein and carbohydrate contents changed in a strain-specific manner in response to biofilm formation. An assessment of the changes in gene expression associated with biofilm formation revealed that diosgenin treatment decreased the expression of icaA and spa and increased the expression of RNAIII, agrA, sarA, and sigB in S. aureus ATCC 6538 and MRSA CCARM 3090; however, contrasting gene expression changes were noted in S. aureus ATCC 29213 and MRSA CCARM 3820. These results suggest that a regulatory mechanism of biofilm formation is that activated sigB expression sequentially increases the expression of sarA, agrA, and RNAIII. This increased RNAIII expression decreases the expression of spa, a surface-associated adhesion factor. An additional regulatory mechanism of biofilm formation is that activated sigB expression decreases the expression of an unknown regulator that increases the expression of icaA. This in turn decreases the expression of icaA, which decreases the synthesis of polysaccharide intercellular adhesins and ultimately inhibits biofilm formation. By assessing strain-specific contrasting regulatory signals induced by diosgenin in S. aureus without gene mutation, this study elucidated the signal transduction mechanisms that regulate biofilm formation based on physiological and gene expression changes. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

12 pages, 4516 KiB  
Article
A High-Throughput Microtiter Plate Screening Assay to Quantify and Differentiate Species in Dual-Species Biofilms
by Víctor Campo-Pérez, Júlia Alcàcer-Almansa, Esther Julián and Eduard Torrents
Microorganisms 2023, 11(9), 2244; https://doi.org/10.3390/microorganisms11092244 - 6 Sep 2023
Cited by 1 | Viewed by 3275
Abstract
Pathogenic bacteria form biofilms during infection, and polymicrobial biofilms are the most frequent manifestation. Biofilm attachment, maturation, and/or antibiotic sensitivity are mainly evaluated with microtiter plate assays, in which bacteria are stained to enable the quantification of the biomass by optical absorbance or [...] Read more.
Pathogenic bacteria form biofilms during infection, and polymicrobial biofilms are the most frequent manifestation. Biofilm attachment, maturation, and/or antibiotic sensitivity are mainly evaluated with microtiter plate assays, in which bacteria are stained to enable the quantification of the biomass by optical absorbance or fluorescence emission. However, using these methods to distinguish different species in dual-species or polymicrobial biofilms is currently impossible. Colony-forming unit counts from homogenized dual-species biofilms on selective agar medium allow species differentiation but are time-consuming for a high-throughput screening. Thus, reliable, feasible, and fast methods are urgently needed to study the behavior of polymicrobial and dual-species communities. This study shows that Pseudomonas aeruginosa and Burkholderia cenocepacia strains expressing specific fluorescent or bioluminescent proteins permit the more efficient study of dual-species biofilms compared to other methods that rely on measuring the total biomass. Combining fluorescence and bioluminescence measurements allows an independent analysis of the different microbial species within the biofilm, indicating the degree of presence of each one over time during a dual-species biofilm growth. The quantitative strategies developed in this work are reproducible and recommended for dual-species biofilm studies with high-throughput microtiter plate approaches using strains that can constitutively express fluorescent or bioluminescent proteins. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Graphical abstract

22 pages, 2364 KiB  
Article
In Vitro Biofilm-Mediated Biodegradation of Pesticides and Dye-Contaminated Effluents Using Bacterial Biofilms
by Iram Liaqat, Awais Khalid, Saima Rubab, Farzana Rashid, Asma Abdul Latif, Sajida Naseem, Asia Bibi, Bushra Nisar Khan, Waiza Ansar, Arshad Javed, Muhammad Afzaal, Muhammad Summer, Samia Majid, Sikander Ali and Muhammad Nauman Aftab
Microorganisms 2023, 11(9), 2163; https://doi.org/10.3390/microorganisms11092163 - 26 Aug 2023
Cited by 1 | Viewed by 1233
Abstract
Overuse of pesticides in agricultural soil and dye-polluted effluents severely contaminates the environment and is toxic to animals and humans making their removal from the environment essential. The present study aimed to assess the biodegradation of pesticides (cypermethrin (CYP) and imidacloprid (IMI)), and [...] Read more.
Overuse of pesticides in agricultural soil and dye-polluted effluents severely contaminates the environment and is toxic to animals and humans making their removal from the environment essential. The present study aimed to assess the biodegradation of pesticides (cypermethrin (CYP) and imidacloprid (IMI)), and dyes (malachite green (MG) and Congo red (CR)) using biofilms of bacteria isolated from pesticide-contaminated soil and dye effluents. Biofilms of indigenous bacteria, i.e., Bacillus thuringiensis 2A (OP554568), Enterobacter hormaechei 4A (OP723332), Bacillus sp. 5A (OP586601), and Bacillus cereus 6B (OP586602) individually and in mixed culture were tested against CYP and IMI. Biofilms of indigenous bacteria i.e., Lysinibacillus sphaericus AF1 (OP589134), Bacillus sp. CF3 (OP589135) and Bacillus sp. DF4 (OP589136) individually and in mixed culture were tested for their ability to degrade dyes. The biofilm of a mixed culture of B. thuringiensis + Bacillus sp. (P7) showed 46.2% degradation of CYP compared to the biofilm of a mixed culture of B. thuringiensis + E. hormaechei + Bacillus sp. + B. cereus (P11), which showed significantly high degradation (70.0%) of IMI. Regarding dye biodegradation, a mixed culture biofilm of Bacillus sp. + Bacillus sp. (D6) showed 86.76% degradation of MG, which was significantly high compared to a mixed culture biofilm of L. sphaericus + Bacillus sp. (D4) that degraded only 30.78% of CR. UV–VIS spectroscopy revealed major peaks at 224 nm, 263 nm, 581 nm and 436 nm for CYP, IMI, MG and CR, respectively, which completely disappeared after treatment with bacterial biofilms. Fourier transform infrared (FTIR) analysis showed the appearance of new peaks in degraded metabolites and disappearance of a peak in the control spectrum after biofilm treatment. Thin layer chromatography (TLC) analysis also confirmed the degradation of CYP, IMI, MG and CR into several metabolites compared to the control. The present study demonstrates the biodegradation potential of biofilm-forming bacteria isolated from pesticide-polluted soil and dye effluents against pesticides and dyes. This is the first report demonstrating biofilm-mediated bio-degradation of CYP, IMI, MG and CR utilizing soil and effluent bacterial flora from Multan and Sheikhupura, Punjab, Pakistan. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

21 pages, 3730 KiB  
Article
Physiological and Transcriptomic Analyses of Escherichia coli Serotype O157:H7 in Response to Rhamnolipid Treatment
by Shuo Yang, Lan Ma, Xiaoqing Xu, Qing Peng, Huiying Zhong, Yuxin Gong, Linbo Shi, Mengxin He, Bo Shi and Yu Qiao
Microorganisms 2023, 11(8), 2112; https://doi.org/10.3390/microorganisms11082112 - 18 Aug 2023
Viewed by 1255
Abstract
Rhamnolipid (RL) can inhibit biofilm formation of Escherichia coli O157:H7, but the associated mechanism remains unknown. We here conducted comparative physiological and transcriptomic analyses of cultures treated with RL and untreated cultures to elucidate a potential mechanism by which RL may inhibit biofilm [...] Read more.
Rhamnolipid (RL) can inhibit biofilm formation of Escherichia coli O157:H7, but the associated mechanism remains unknown. We here conducted comparative physiological and transcriptomic analyses of cultures treated with RL and untreated cultures to elucidate a potential mechanism by which RL may inhibit biofilm formation in E. coli O157:H7. Anti-biofilm assays showed that over 70% of the E. coli O157:H7 biofilm formation capacity was inhibited by treatment with 0.25–1 mg/mL of RL. Cellular-level physiological analysis revealed that a high concentration of RL significantly reduced outer membrane hydrophobicity. E. coli cell membrane integrity and permeability were also significantly affected by RL due to an increase in the release of lipopolysaccharide (LPS) from the cell membrane. Furthermore, transcriptomic profiling showed 2601 differentially expressed genes (1344 up-regulated and 1257 down-regulated) in cells treated with RL compared to untreated cells. Functional enrichment analysis indicated that RL treatment up-regulated biosynthetic genes responsible for LPS synthesis, outer membrane protein synthesis, and flagellar assembly, and down-regulated genes required for poly-N-acetyl-glucosamine biosynthesis and genes present in the locus of enterocyte effacement pathogenicity island. In summary, RL treatment inhibited E. coli O157:H7 biofilm formation by modifying key outer membrane surface properties and expression levels of adhesion genes. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

15 pages, 3406 KiB  
Article
Extracts from Wallis Sponges Inhibit Vibrio harveyi Biofilm Formation
by Flore Caudal, Sophie Rodrigues, Alain Dufour, Sébastien Artigaud, Gwenaelle Le Blay, Sylvain Petek and Alexis Bazire
Microorganisms 2023, 11(7), 1762; https://doi.org/10.3390/microorganisms11071762 - 6 Jul 2023
Cited by 1 | Viewed by 1539
Abstract
Pathogenic bacteria and their biofilms are involved in many human and animal diseases and are a major public health problem with, among other things, the development of antibiotic resistance. These biofilms are known to induce chronic infections for which classical treatments using antibiotic [...] Read more.
Pathogenic bacteria and their biofilms are involved in many human and animal diseases and are a major public health problem with, among other things, the development of antibiotic resistance. These biofilms are known to induce chronic infections for which classical treatments using antibiotic therapy are often ineffective. Sponges are sessile filter-feeding marine organisms known for their dynamic symbiotic partnerships with diverse microorganisms and their production of numerous metabolites of interest. In this study, we investigated the antibiofilm efficacy of different extracts from sponges, isolated in Wallis, without biocidal activity. Out of the 47 tested extracts, from 28 different genera, 11 showed a strong activity against Vibrio harveyi biofilm formation. Moreover, one of these extracts also inhibited two quorum-sensing pathways of V. harveyi. Full article
(This article belongs to the Special Issue Advance Research on Bacterial Biofilm)
Show Figures

Figure 1

Back to TopTop