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Biofilm Formation

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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Biochemistry".

Deadline for manuscript submissions: closed (5 April 2018) | Viewed by 89220

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Dr. Martin Welch

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Guest Editor

Department of Biochemistry, University of Cambridge, Hopkins Building, Downing Site, Cambridge CB2 1QW, UK
Interests: pseudomonas aeruginosa; quorum sensing; biofilms; virulence; metabolism; protein chemistry

Special Issue Information

Dear Colleagues,

Although the tendency of bacteria to attach to solid surfaces has been known about for many decades, it is fair to say that most bacteria spend most of their time in a biofilm-associated state. The last twenty years have witnessed an explosion of interest in this area. This has been largely driven by the notion that such biotic–abiotic interactions are not accidental, but instead, are governed by distinct “lifestyle decisions” driven by programmed changes in gene expression profiles. These, in turn, are now known to be underpinned by dedicated signaling pathways, which respond to environmental signals and cues. Moreover, it is becoming increasingly apparent that bacteria—once viewed as the archetypal single-celled organisms—benefit from social interactions within biofilms. Indeed, biofilms are now thought of as structured multicellular communities in which resources are shared (albeit, not always altruistically) and the response to existential threats is collective. This improved understanding of biofilm biology has become increasingly important, especially with the realization that biofilm formation is strongly-linked with greater antibiotic resistance and the onset of chronic infection. Consequently, finding new ways of suppressing biofilm formation by pathogenic bacteria has become an international priority.

Dr. Martin Welch
Guest Editor

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Keywords

Biofilm
quorum sensing
cell-cell communication
chronic infection
antibiotic resistance
microbial communities
microbiology
programmed gene expression

Published Papers (10 papers)

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Research

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16 pages, 6293 KiB

Open AccessArticle

Biofilm Inhibition by Novel Natural Product- and Biocide-Containing Coatings Using High-Throughput Screening

by Maria Salta, Simon P. Dennington and Julian A. Wharton

Int. J. Mol. Sci. 2018, 19(5), 1434; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms19051434 - 10 May 2018

Cited by 7 | Viewed by 5710

Abstract

The use of natural products (NPs) as possible alternative biocidal compounds for use in antifouling coatings has been the focus of research over the past decades. Despite the importance of this field, the efficacy of a given NP against biofilm (mainly bacteria and diatoms) formation is tested with the NP being in solution, while almost no studies test the effect of an NP once incorporated into a coating system. The development of a novel bioassay to assess the activity of NP-containing and biocide-containing coatings against marine biofilm formation has been achieved using a high-throughput microplate reader and highly sensitive confocal laser scanning microscopy (CLSM), as well as nucleic acid staining. Juglone, an isolated NP that has previously shown efficacy against bacterial attachment, was incorporated into a simple coating matrix. Biofilm formation over 48 h was assessed and compared against coatings containing the NP and the commonly used booster biocide, cuprous oxide. Leaching of the NP from the coating was quantified at two time points, 24 h and 48 h, showing evidence of both juglone and cuprous oxide being released. Results from the microplate reader showed that the NP coatings exhibited antifouling efficacy, significantly inhibiting biofilm formation when compared to the control coatings, while NP coatings and the cuprous oxide coatings performed equally well. CLSM results and COMSTAT analysis on biofilm 3D morphology showed comparable results when the NP coatings were tested against the controls, with higher biofilm biovolume and maximum thickness being found on the controls. This new method proved to be repeatable and insightful and we believe it is applicable in antifouling and other numerous applications where interactions between biofilm formation and surfaces is of interest. Full article

(This article belongs to the Special Issue Biofilm Formation)

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10 pages, 2023 KiB

Open AccessArticle

Unsaturated Fatty Acids Affect Quorum Sensing Communication System and Inhibit Motility and Biofilm Formation of Acinetobacter baumannii

by Marion Nicol, Stéphane Alexandre, Jean-Baptiste Luizet, Malena Skogman, Thierry Jouenne, Suzana P. Salcedo and Emmanuelle Dé

Int. J. Mol. Sci. 2018, 19(1), 214; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms19010214 - 10 Jan 2018

Cited by 54 | Viewed by 9403

Abstract

The increasing threat of Acinetobacter baumannii as a nosocomial pathogen is mainly due to the occurrence of multidrug-resistant strains that are associated with the real problem of its eradication from hospital wards. The particular ability of this pathogen to form biofilms contributes to its persistence, increases antibiotic resistance, and promotes persistent/device-related infections. We previously demonstrated that virstatin, which is a small organic compound known to decrease virulence of Vibrio cholera via an inhibition of T4-pili expression, displayed very promising activity to prevent A. baumannii biofilm development. Here, we examined the antibiofilm activity of mono-unsaturated chain fatty acids, palmitoleic (PoA), and myristoleic (MoA) acids, presenting similar action on V. cholerae virulence. We demonstrated that PoA and MoA (at 0.02 mg/mL) were able to decrease A. baumannii ATCC 17978 biofilm formation up to 38% and 24%, respectively, presented a biofilm dispersing effect and drastically reduced motility. We highlighted that these fatty acids decreased the expression of the regulator abaR from the LuxIR-type quorum sensing (QS) communication system AbaIR and consequently reduced the N-acyl-homoserine lactone production (AHL). This effect can be countered by addition of exogenous AHLs. Besides, fatty acids may have additional non-targeted effects, independent from QS. Atomic force microscopy experiments probed indeed that PoA and MoA could also act on the initial adhesion process in modifying the material interface properties. Evaluation of fatty acids effect on 22 clinical isolates showed a strain-dependent antibiofilm activity, which was not correlated to hydrophobicity or pellicle formation ability of the tested strains, and suggested a real diversity in cell-to-cell communication systems involved in A. baumannii biofilm formation. Full article

(This article belongs to the Special Issue Biofilm Formation)

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3169 KiB

Open AccessArticle

The Semi-Synthetic Peptide Lin-SB056-1 in Combination with EDTA Exerts Strong Antimicrobial and Antibiofilm Activity against Pseudomonas aeruginosa in Conditions Mimicking Cystic Fibrosis Sputum

by Giuseppantonio Maisetta, Lucia Grassi, Semih Esin, Ilaria Serra, Mariano A. Scorciapino, Andrea C. Rinaldi and Giovanna Batoni

Int. J. Mol. Sci. 2017, 18(9), 1994; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18091994 - 16 Sep 2017

Cited by 23 | Viewed by 5280

Abstract

Pseudomonas aeruginosa is a major cause of chronic lung infections in cystic fibrosis (CF) patients. The ability of the bacterium to form biofilms and the presence of a thick and stagnant mucus in the airways of CF patients largely contribute to antibiotic therapy failure and demand for new antimicrobial agents able to act in the CF environment. The present study investigated the anti-P. aeruginosa activity of lin-SB056-1, a recently described semi-synthetic antimicrobial peptide, used alone and in combination with the cation chelator ethylenediaminetetraacetic acid (EDTA). Bactericidal assays were carried out in standard culture conditions and in an artificial sputum medium (ASM) closely resembling the CF environment. Peptide’s structure and interaction with large unilamellar vesicles in media with different ionic strengths were also investigated through infrared spectroscopy. Lin-SB056-1 demonstrated fast and strong bactericidal activity against both mucoid and non-mucoid strains of P. aeruginosa in planktonic form and, in combination with EDTA, caused significant reduction of the biomass of P. aeruginosa mature biofilms. In ASM, the peptide/EDTA combination exerted a strong bactericidal effect and inhibited the formation of biofilm-like structures of P. aeruginosa. Overall, the results obtained highlight the potential of the lin-SB056-1/EDTA combination for the treatment of P. aeruginosa lung infections in CF patients. Full article

(This article belongs to the Special Issue Biofilm Formation)

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1005 KiB

Open AccessArticle

Biofilm is a Major Virulence Determinant in Bacterial Colonization of Chronic Skin Ulcers Independently from the Multidrug Resistant Phenotype

by Enea Gino Di Domenico, Ilaria Farulla, Grazia Prignano, Maria Teresa Gallo, Matteo Vespaziani, Ilaria Cavallo, Isabella Sperduti, Martina Pontone, Valentina Bordignon, Laura Cilli, Alessandra De Santis, Fabiola Di Salvo, Fulvia Pimpinelli, Ilaria Lesnoni La Parola, Luigi Toma and Fabrizio Ensoli

Int. J. Mol. Sci. 2017, 18(5), 1077; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18051077 - 17 May 2017

Cited by 79 | Viewed by 8357

Abstract

Bacterial biofilm is a major factor in delayed wound healing and high levels of biofilm production have been repeatedly described in multidrug resistant organisms (MDROs). Nevertheless, a quantitative correlation between biofilm production and the profile of antimicrobial drug resistance in delayed wound healing remains to be determined. Microbial identification, antibiotic susceptibility and biofilm production were assessed in 135 clinical isolates from 87 patients. Gram-negative bacteria were the most represented microorganisms (60.8%) with MDROs accounting for 31.8% of the total isolates. Assessment of biofilm production revealed that 80% of the strains were able to form biofilm. A comparable level of biofilm production was found with both MDRO and not-MDRO with no significant differences between groups. All the methicillin-resistant Staphylococcus aureus (MRSA) and 80% of Pseudomonas aeruginosa MDR strains were found as moderate/high biofilm producers. Conversely, less than 17% of Klebsiella pneumoniae extended-spectrum beta-lactamase (ESBL), Escherichia coli-ESBL and Acinetobacter baumannii were moderate/high biofilm producers. Notably, those strains classified as non-biofilm producers, were always associated with biofilm producer bacteria in polymicrobial colonization. This study shows that biofilm producers were present in all chronic skin ulcers, suggesting that biofilm represents a key virulence determinant in promoting bacterial persistence and chronicity of ulcerative lesions independently from the MDRO phenotype. Full article

(This article belongs to the Special Issue Biofilm Formation)

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5019 KiB

Open AccessArticle

Effect of the Biofilm Age and Starvation on Acid Tolerance of Biofilm Formed by Streptococcus mutans Isolated from Caries-Active and Caries-Free Adults

by Shan Jiang, Shuai Chen, Chengfei Zhang, Xingfu Zhao, Xiaojing Huang and Zhiyu Cai

Int. J. Mol. Sci. 2017, 18(4), 713; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18040713 - 30 Mar 2017

Cited by 25 | Viewed by 5356

Abstract

Streptococcus mutans (S. mutans) is considered a leading cause of dental caries. The capability of S. mutans to tolerate low pH is essential for its cariogenicity. Aciduricity of S. mutans is linked to its adaptation to environmental stress in oral cavity. This study aimed to investigate the effect of biofilm age and starvation condition on acid tolerance of biofilm formed by S. mutans clinical isolates. S. mutans clinical strains isolated from caries-active (SM593) and caries-free (SM18) adults and a reference strain (ATCC25175) were used for biofilm formation. (1) Both young and mature biofilms were formed and then exposed to pH 3.0 for 30 min with (acid-adapted group) or without (non-adapted group) pre-exposure to pH 5.5 for three hours. (2) The mature biofilms were cultured with phosphate-buffered saline (PBS) (starved group) or TPY (polypeptone-yeast extract) medium (non-starved group) at pH 7.0 for 24 h and then immersed in medium of pH 3.0 for 30 min. Biofilms were analyzed through viability staining and confocal laser scanning microscopy. In all three strains, mature, acid-adapted and starved biofilms showed significantly less destructive structure and more viable bacteria after acid shock than young, non-adapted and non-starved biofilms, respectively (all p < 0.05). Furthermore, in each condition, SM593 biofilm was denser, with a significantly larger number of viable bacteria than that of SM18 and ATCC25175 (all p < 0.05). Findings demonstrated that mature, acid-adapted and starvation might protect biofilms of all three S. mutans strains against acid shock. Additionally, SM593 exhibited greater aciduricity compared to SM18 and ATCC25175, which indicated that the colonization of high cariogenicity of clinical strains may lead to high caries risk in individuals. Full article

(This article belongs to the Special Issue Biofilm Formation)

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2344 KiB

Open AccessArticle

Differential Proteome Analysis of a Flor Yeast Strain under Biofilm Formation

by Jaime Moreno-García, Juan Carlos Mauricio, Juan Moreno and Teresa García-Martínez

Int. J. Mol. Sci. 2017, 18(4), 720; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18040720 - 28 Mar 2017

Cited by 18 | Viewed by 5886

Abstract

Several Saccharomyces cerevisiae strains (flor yeasts) form a biofilm (flor velum) on the surface of Sherry wines after fermentation, when glucose is depleted. This flor velum is fundamental to biological aging of these particular wines. In this study, we identify abundant proteins in the formation of the biofilm of an industrial flor yeast strain. A database search to enrich flor yeast “biological process” and “cellular component” according to Gene Ontology Terminology (GO Terms) and, “pathways” was carried out. The most abundant proteins detected were largely involved in respiration, translation, stress damage prevention and repair, amino acid metabolism (glycine, isoleucine, leucine and arginine), glycolysis/gluconeogenesis and biosynthesis of vitamin B9 (folate). These proteins were located in cellular components as in the peroxisome, mitochondria, vacuole, cell wall and extracellular region; being these two last directly related with the flor formation. Proteins like Bgl2p, Gcv3p, Hyp2p, Mdh1p, Suc2p and Ygp1p were quantified in very high levels. This study reveals some expected processes and provides new and important information for the design of conditions and genetic constructions of flor yeasts for improving the cellular survival and, thus, to optimize biological aging of Sherry wine production. Full article

(This article belongs to the Special Issue Biofilm Formation)

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Review

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2035 KiB

Open AccessReview

The Consequences of Being in an Infectious Biofilm: Microenvironmental Conditions Governing Antibiotic Tolerance

by Majken Sønderholm, Thomas Bjarnsholt, Maria Alhede, Mette Kolpen, Peter Ø. Jensen, Michael Kühl and Kasper N. Kragh

Int. J. Mol. Sci. 2017, 18(12), 2688; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18122688 - 12 Dec 2017

Cited by 56 | Viewed by 5931

Abstract

The main driver behind biofilm research is the desire to understand the mechanisms governing the antibiotic tolerance of biofilm-growing bacteria found in chronic bacterial infections. Rather than genetic traits, several physical and chemical traits of the biofilm have been shown to be attributable to antibiotic tolerance. During infection, bacteria in biofilms exhibit slow growth and a low metabolic state due to O₂ limitation imposed by intense O₂ consumption of polymorphonuclear leukocytes or metabolically active bacteria in the biofilm periphery. Due to variable O₂ availability throughout the infection, pathogen growth can involve aerobic, microaerobic and anaerobic metabolism. This has serious implications for the antibiotic treatment of infections (e.g., in chronic wounds or in the chronic lung infection of cystic fibrosis patients), as antibiotics are usually optimized for aerobic, fast-growing bacteria. This review summarizes knowledge about the links between the microenvironment of biofilms in chronic infections and their tolerance against antibiotics. Full article

(This article belongs to the Special Issue Biofilm Formation)

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4240 KiB

Open AccessReview

Bacterial Biofilm Control by Perturbation of Bacterial Signaling Processes

by Tim Holm Jakobsen, Tim Tolker-Nielsen and Michael Givskov

Int. J. Mol. Sci. 2017, 18(9), 1970; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18091970 - 13 Sep 2017

Cited by 49 | Viewed by 8888

Abstract

The development of effective strategies to combat biofilm infections by means of either mechanical or chemical approaches could dramatically change today’s treatment procedures for the benefit of thousands of patients. Remarkably, considering the increased focus on biofilms in general, there has still not been invented and/or developed any simple, efficient and reliable methods with which to “chemically” eradicate biofilm infections. This underlines the resilience of infective agents present as biofilms and it further emphasizes the insufficiency of today’s approaches used to combat chronic infections. A potential method for biofilm dismantling is chemical interception of regulatory processes that are specifically involved in the biofilm mode of life. In particular, bacterial cell to cell signaling called “Quorum Sensing” together with intracellular signaling by bis-(3′-5′)-cyclic-dimeric guanosine monophosphate (cyclic-di-GMP) have gained a lot of attention over the last two decades. More recently, regulatory processes governed by two component regulatory systems and small non-coding RNAs have been increasingly investigated. Here, we review novel findings and potentials of using small molecules to target and modulate these regulatory processes in the bacterium Pseudomonas aeruginosa to decrease its pathogenic potential. Full article

(This article belongs to the Special Issue Biofilm Formation)

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1894 KiB

Open AccessReview

Biofilm Producing Salmonella Typhi: Chronic Colonization and Development of Gallbladder Cancer

by Enea Gino Di Domenico, Ilaria Cavallo, Martina Pontone, Luigi Toma and Fabrizio Ensoli

Int. J. Mol. Sci. 2017, 18(9), 1887; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18091887 - 31 Aug 2017

Cited by 100 | Viewed by 16425

Abstract

Salmonella enterica subspecies enterica serovar Typhi is the aetiological agent of typhoid or enteric fever. In a subset of individuals, S. Typhi colonizes the gallbladder causing an asymptomatic chronic infection. Nonetheless, these asymptomatic carriers provide a reservoir for further spreading of the disease. Epidemiological studies performed in regions where S. Typhi is endemic, revealed that the majority of chronically infected carriers also harbour gallstones, which in turn, have been indicated as a primary predisposing factor for the onset of gallbladder cancer (GC). It is now well recognised, that S. Typhi produces a typhoid toxin with a carcinogenic potential, that induces DNA damage and cell cycle alterations in intoxicated cells. In addition, biofilm production by S. Typhi may represent a key factor for the promotion of a persistent infection in the gallbladder, thus sustaining a chronic local inflammatory response and exposing the epithelium to repeated damage caused by carcinogenic toxins. This review aims to highlight the putative connection between the chronic colonization by highly pathogenic strains of S. Typhi capable of combining biofilm and toxin production and the onset of GC. Considering the high risk of GC associated with the asymptomatic carrier status, the rapid identification and profiling of biofilm production by S. Typhi strains would be key for effective therapeutic management and cancer prevention. Full article

(This article belongs to the Special Issue Biofilm Formation)

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7348 KiB

Open AccessReview

Biofilms in Endodontics—Current Status and Future Directions

by Prasanna Neelakantan, Monica Romero, Jorge Vera, Umer Daood, Asad U. Khan, Aixin Yan and Gary Shun Pan Cheung

Int. J. Mol. Sci. 2017, 18(8), 1748; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms18081748 - 11 Aug 2017

Cited by 132 | Viewed by 17038

Abstract

Microbiota are found in highly organized and complex entities, known as biofilms, the characteristics of which are fundamentally different from microbes in planktonic suspensions. Root canal infections are biofilm mediated. The complexity and variability of the root canal system, together with the multi-species nature of biofilms, make disinfection of this system extremely challenging. Microbial persistence appears to be the most important factor for failure of root canal treatment and this could further have an impact on pain and quality of life. Biofilm removal is accomplished by a chemo-mechanical process, using specific instruments and disinfecting chemicals in the form of irrigants and/or intracanal medicaments. Endodontic research has focused on the characterization of root canal biofilms and the clinical methods to disrupt the biofilms in addition to achieving microbial killing. In this narrative review, we discuss the role of microbial biofilms in endodontics and review the literature on the role of root canal disinfectants and disinfectant-activating methods on biofilm removal. Full article

(This article belongs to the Special Issue Biofilm Formation)

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