251
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Roberts AE, Kragh KN, Bjarnsholt T, Diggle SP. The Limitations of In Vitro Experimentation in Understanding Biofilms and Chronic Infection. J Mol Biol 2015; 427:3646-61. [DOI: 10.1016/j.jmb.2015.09.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/12/2015] [Accepted: 09/01/2015] [Indexed: 11/28/2022]
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252
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Qvist T, Eickhardt S, Kragh KN, Andersen CB, Iversen M, Høiby N, Bjarnsholt T. Chronic pulmonary disease with Mycobacterium abscessus complex is a biofilm infection. Eur Respir J 2015; 46:1823-6. [DOI: 10.1183/13993003.01102-2015] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/19/2015] [Indexed: 11/05/2022]
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253
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Visaggio D, Pasqua M, Bonchi C, Kaever V, Visca P, Imperi F. Cell aggregation promotes pyoverdine-dependent iron uptake and virulence in Pseudomonas aeruginosa. Front Microbiol 2015; 6:902. [PMID: 26379660 PMCID: PMC4552172 DOI: 10.3389/fmicb.2015.00902] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/17/2015] [Indexed: 11/13/2022] Open
Abstract
In Pseudomonas aeruginosa the Gac signaling system and the second messenger cyclic diguanylate (c-di-GMP) participate in the control of the switch between planktonic and biofilm lifestyles, by regulating the production of the two exopolysaccharides Pel and Psl. The Gac and c-di-GMP regulatory networks also coordinately promote the production of the pyoverdine siderophore, and the extracellular polysaccharides Pel and Psl have recently been found to mediate c-di-GMP-dependent regulation of pyoverdine genes. Here we demonstrate that Pel and Psl are also essential for Gac–mediated activation of pyoverdine production. A pel psl double mutant produces very low levels of pyoverdine and shows a marked reduction in the expression of the pyoverdine-dependent virulence factors exotoxin A and PrpL protease. While the exopolysaccharide-proficient parent strain forms multicellular planktonic aggregates in liquid cultures, the Pel and Psl-deficient mutant mainly grows as dispersed cells. Notably, artificially induced cell aggregation is able to restore pyoverdine-dependent gene expression in the pel psl mutant, in a way that appears to be independent of iron diffusion or siderophore signaling, as well as of recently described contact-dependent mechanosensitive systems. This study demonstrates that cell aggregation represents an important cue triggering the expression of pyoverdine-related genes in P. aeruginosa, suggesting a novel link between virulence gene expression, cell–cell interaction and the multicellular community lifestyle.
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Affiliation(s)
- Daniela Visaggio
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome Rome, Italy ; Department of Sciences, Universita degli Studi Roma Tre Rome, Italy
| | - Martina Pasqua
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome Rome, Italy
| | - Carlo Bonchi
- Department of Sciences, Universita degli Studi Roma Tre Rome, Italy
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Institute of Pharmacology, Hannover Medical School Hannover, Germany
| | - Paolo Visca
- Department of Sciences, Universita degli Studi Roma Tre Rome, Italy
| | - Francesco Imperi
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome Rome, Italy ; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome Rome, Italy
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254
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Chang CB, Wilking JN, Kim SH, Shum HC, Weitz DA. Monodisperse Emulsion Drop Microenvironments for Bacterial Biofilm Growth. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3954-61. [PMID: 25959709 DOI: 10.1002/smll.201403125] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 03/13/2015] [Indexed: 05/20/2023]
Abstract
In this work, microfluidic technology is used to rapidly create hundreds of thousands of monodisperse double and triple emulsion drops that serve as 3D microenvironments for the containment and growth of bacterial biofilms. The size of these drops, with diameters from tens to hundreds of micrometers, makes them amenable to rapid manipulation and analysis. This is demonstrated by using microscopy to visualize cellular differentiation of Bacillus subtilis biofilm communities within each drop and the bacterial biofilm microstructure. Biofilm growth is explored upon specific interfaces in double and triple emulsions and upon negative and positive radii of curvature. Biofilm attachment of matrix and flagella mutants is studied as well as biofilms of Pseudomonas aeruginosa. This is the first demonstration of biofilms grown in microscale emulsion drops, which serve as both templates and containers for biofilm growth and attachment. These microenvironments have the potential to transform existing high-throughput screening methods for bacterial biofilms.
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Affiliation(s)
- Connie B Chang
- School of Engineering and Applied Science, Department of Physics Harvard University, Cambridge, MA, 02138, USA
- Chemical and Biological Engineering Department, Montana State University, Bozeman, MT, 59717, USA
| | - James N Wilking
- School of Engineering and Applied Science, Department of Physics Harvard University, Cambridge, MA, 02138, USA
- Chemical and Biological Engineering Department, Montana State University, Bozeman, MT, 59717, USA
| | - Shin-Hyun Kim
- School of Engineering and Applied Science, Department of Physics Harvard University, Cambridge, MA, 02138, USA
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Korea
| | - Ho Cheung Shum
- School of Engineering and Applied Science, Department of Physics Harvard University, Cambridge, MA, 02138, USA
- Department of Mechanical Engineering, The University of Hong Kong, China
| | - David A Weitz
- School of Engineering and Applied Science, Department of Physics Harvard University, Cambridge, MA, 02138, USA
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Deepa I, Kumar SN, Sreerag RS, Nath VS, Mohandas C. Purification and synergistic antibacterial activity of arginine derived cyclic dipeptides, from Achromobacter sp. associated with a rhabditid entomopathogenic nematode against major clinically relevant biofilm forming wound bacteria. Front Microbiol 2015; 6:876. [PMID: 26379651 PMCID: PMC4548193 DOI: 10.3389/fmicb.2015.00876] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 08/10/2015] [Indexed: 01/01/2023] Open
Abstract
Skin and chronic wound infections caused by various pathogenic bacteria are an increasing and urgent health problem worldwide. In the present investigation ethyl acetate extract of an Achromobacter sp. associated with a Rhabditis entomopathogenic nematode (EPN), displayed promising antibacterial property and was further purified by silica gel column chromatography to get three different cyclic dipeptides (CDPs). Based on the spectral data and Marfey's analyses, the CDPs were identified as cyclo(D-Leu-D-Arg) (1), cyclo(L-Trp-L-Arg) (2), and cyclo(D-Trp-D-Arg) (3), respectively. Three CDPs were active against all the 10 wound associated bacteria tested. The significant antibacterial activity was recorded by CDP 3, and highest activity of 0.5 μg/ml was recorded against Staphylococcus aureus and Pseudomonas aeruginosa. The synergistic antibacterial activities of CDPs and ampicillin were assessed using the checkerboard microdilution method. The results of the current study recorded that the combined effects of CDPs and ampicillin principally recorded synergistic activity. Interestingly, the combination of CDPs and ampicillin also recorded enhanced inhibition of biofilm formation by bacteria. Moreover, CDPs significantly stimulate the production of IL-10 and IL-4 (anti-inflammatory cytokines) by human peripheral blood mononuclear cells. CDPs do not make any significant effect on the production of pro-inflammatory cytokines like TNF-α. The three CDPs have been studied for their effect on intracellular S. aureus in murine macrophages (J774) using 24 h exposure to 0.5X, 1X, and 2X MIC concentrations. Significant decrease in intracellular S. aureus burden was recorded by CDPs. CDPs also recorded no cytotoxicity toward FS normal fibroblast, VERO, and L231 normal lung epithelial cell lines. Antimicrobial activity of the arginine containing CDPs against the wound associated bacteria is reported here for the first. Moreover, this is also the first report on the production of CDPs by Achromobacter sp. Finally, we conclude that the Achromobacter sp. is an incredibly promising source of natural bioactive secondary metabolites especially against wound pathogenic bacteria that may receive significant benefit in the field of human medicine in near future as topical agents.
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Affiliation(s)
- Indira Deepa
- Division of Crop Protection, Central Tuber Crops Research Institute Thiruvananthapuram, India
| | - Sasidharan N Kumar
- Division of Crop Protection, Central Tuber Crops Research Institute Thiruvananthapuram, India
| | - Ravikumar S Sreerag
- Division of Crop Protection, Central Tuber Crops Research Institute Thiruvananthapuram, India
| | - Vishnu S Nath
- Division of Crop Protection, Central Tuber Crops Research Institute Thiruvananthapuram, India
| | - Chellapan Mohandas
- Division of Crop Protection, Central Tuber Crops Research Institute Thiruvananthapuram, India
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256
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Baumann A, Lehmann R, Beckert A, Vilcinskas A, Franta Z. Selection and Evaluation of Tissue Specific Reference Genes in Lucilia sericata during an Immune Challenge. PLoS One 2015; 10:e0135093. [PMID: 26252388 PMCID: PMC4529112 DOI: 10.1371/journal.pone.0135093] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/16/2015] [Indexed: 11/30/2022] Open
Abstract
The larvae of the common green bottle fly Lucilia sericata (Diptera: Calliphoridae) have been used for centuries to promote wound healing, but the molecular basis of their antimicrobial, debridement and healing functions remains largely unknown. The analysis of differential gene expression in specific larval tissues before and after immune challenge could be used to identify key molecular factors, but the most sensitive and reproducible method qRT-PCR requires validated reference genes. We therefore selected 10 candidate reference genes encoding products from different functional classes (18S rRNA, 28S rRNA, actin, β-tubulin, RPS3, RPLP0, EF1α, PKA, GAPDH and GST1). Two widely applied algorithms (GeNorm and Normfinder) were used to analyze reference gene candidates in different larval tissues associated with secretion, digestion, and antimicrobial activity (midgut, hindgut, salivary glands, crop and fat body). The Gram-negative bacterium Pseudomonas aeruginosa was then used to boost the larval immune system and the stability of reference gene expression was tested in comparison to three immune genes (lucimycin, defensin-1 and attacin-2), which target different pathogen classes. We observed no differential expression of the antifungal peptide lucimycin, whereas the representative targeting Gram-positive bacteria (defensin-1) was upregulated in salivary glands, crop, nerve ganglion and reached its maximum in fat body (up to 300-fold). The strongest upregulation in all immune challenged tissues (over 50,000-fold induction in the fat body) was monitored for attacin-2, the representative targeting Gram-negative bacteria. Here we identified and validated a set of reference genes that allows the accurate normalization of gene expression in specific tissues of L. sericata after immune challenge.
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Affiliation(s)
- Andre Baumann
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Rüdiger Lehmann
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Annika Beckert
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
| | - Andreas Vilcinskas
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- Institute of Phytopathology and Applied Zoology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Zdeněk Franta
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- * E-mail:
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Roy DC, Tomblyn S, Burmeister DM, Wrice NL, Becerra SC, Burnett LR, Saul JM, Christy RJ. Ciprofloxacin-Loaded Keratin Hydrogels Prevent Pseudomonas aeruginosa Infection and Support Healing in a Porcine Full-Thickness Excisional Wound. Adv Wound Care (New Rochelle) 2015; 4:457-468. [PMID: 26244102 DOI: 10.1089/wound.2014.0576] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 09/19/2014] [Indexed: 12/19/2022] Open
Abstract
Objective: Cutaneous wound infection can lead to impaired healing, multiple surgical procedures, and increased hospitalization time. We tested the effectiveness of keratin-based hydrogels (termed "keratose") loaded with ciprofloxacin to inhibit infection and support healing when topically administered to porcine excision wounds infected with Pseudomonas aeruginosa. Approach: Using a porcine excisional wound model, 10 mm full-thickness wounds were inoculated with 106 colony-forming units of P. aeruginosa and treated on days 1 and 3 postinoculation with ciprofloxacin-loaded keratose hydrogels. Bacteria enumeration and wound healing were assessed on days 3, 7, and 11 postinjury. Results: Ciprofloxacin-loaded keratose hydrogels reduced the amount of P. aeruginosa in the wound bed by 99.9% compared with untreated wounds on days 3, 7, and 11 postinjury. Ciprofloxacin-loaded keratose hydrogels displayed decreased wound contraction and reepithelialization at day 7 postinjury. By day 11, wounds treated with ciprofloxacin-keratose hydrogels contained collagen-rich granulation tissue and myofibroblasts. Wounds treated with ciprofloxacin-loaded keratose hydrogels exhibited a transient increase in macrophages in the wound bed at day 7 postinjury that subsided by day 11. Innovation: Current therapies for wound infection include systemic antibiotics, which could lead to antibiotic resistance, and topical antimicrobial treatments, which require multiple applications and can delay healing. Here, we show that ciprofloxacin-loaded keratose hydrogels inhibit cutaneous wound infection without interfering with key aspects of the healing process including granulation tissue deposition and remodeling. Conclusions: Ciprofloxacin-loaded keratose hydrogels have the potential to serve as a point-of-injury antibiotic therapy that prevents infection and supports healing following cutaneous injury.
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Affiliation(s)
- Daniel C. Roy
- United States Army Institute of Surgical Research, Fort Sam Houston, Texas
- KeraNetics, LLC, Winston-Salem, North Carolina
| | | | | | - Nicole L. Wrice
- United States Army Institute of Surgical Research, Fort Sam Houston, Texas
| | - Sandra C. Becerra
- United States Army Institute of Surgical Research, Fort Sam Houston, Texas
| | | | | | - Robert J. Christy
- United States Army Institute of Surgical Research, Fort Sam Houston, Texas
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Pritchard DI, Čeřovský V, Nigam Y, Pickles SF, Cazander G, Nibbering PH, Bültemann A, Jung W. TIME management by medicinal larvae. Int Wound J 2015; 13:475-84. [PMID: 26179750 DOI: 10.1111/iwj.12457] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 04/09/2015] [Accepted: 04/13/2015] [Indexed: 12/31/2022] Open
Abstract
Wound bed preparation (WBP) is an integral part of the care programme for chronic wounds. The acronym TIME is used in the context of WBP and describes four barriers to healing in chronic wounds; namely, dead Tissue, Infection and inflammation, Moisture imbalance and a non-migrating Edge. Larval debridement therapy (LDT) stems from observations that larvae of the blowfly Lucilia sericata clean wounds of debris. Subsequent clinical studies have proven debriding efficacy, which is likely to occur as a result of enzymatically active alimentary products released by the insect. The antimicrobial, anti-inflammatory and wound healing activities of LDT have also been investigated, predominantly in a pre-clinical context. This review summarises the findings of investigations into the molecular mechanisms of LDT and places these in context with the clinical concept of WBP and TIME. It is clear from these findings that biotherapy with L. sericata conforms with TIME, through the enzymatic removal of dead tissue and its associated biofilm, coupled with the secretion of defined antimicrobial peptides. This biotherapeutic impact on the wound serves to reduce inflammation, with an associated capacity for an indirect effect on moisture imbalance. Furthermore, larval serine proteinases have the capacity to alter fibroblast behaviour in a manner conducive to the formation of granulation tissue.
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Affiliation(s)
| | - Václav Čeřovský
- Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
| | - Yamni Nigam
- College of Human and Health Sciences, Swansea University, Swansea, UK
| | | | | | - Peter H Nibbering
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
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259
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Development of Spatial Distribution Patterns by Biofilm Cells. Appl Environ Microbiol 2015; 81:6120-8. [PMID: 26116674 DOI: 10.1128/aem.01614-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/19/2015] [Indexed: 01/14/2023] Open
Abstract
Confined spatial patterns of microbial distribution are prevalent in nature, such as in microbial mats, soil communities, and water stream biofilms. The symbiotic two-species consortium of Pseudomonas putida and Acinetobacter sp. strain C6, originally isolated from a creosote-polluted aquifer, has evolved a distinct spatial organization in the laboratory that is characterized by an increased fitness and productivity. In this consortium, P. putida is reliant on microcolonies formed by Acinetobacter sp. C6, to which it attaches. Here we describe the processes that lead to the microcolony pattern by Acinetobacter sp. C6. Ecological spatial pattern analyses revealed that the microcolonies were not entirely randomly distributed and instead were arranged in a uniform pattern. Detailed time-lapse confocal microscopy at the single-cell level demonstrated that the spatial pattern was the result of an intriguing self-organization: small multicellular clusters moved along the surface to fuse with one another to form microcolonies. This active distribution capability was dependent on environmental factors (carbon source and oxygen) and historical contingency (formation of phenotypic variants). The findings of this study are discussed in the context of species distribution patterns observed in macroecology, and we summarize observations about the processes involved in coadaptation between P. putida and Acinetobacter sp. C6. Our results contribute to an understanding of spatial species distribution patterns as they are observed in nature, as well as the ecology of engineered communities that have the potential for enhanced and sustainable bioprocessing capacity.
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260
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Kumar A, Ting YP. Presence ofPseudomonas aeruginosainfluences biofilm formation and surface protein expression ofStaphylococcus aureus. Environ Microbiol 2015; 17:4459-68. [DOI: 10.1111/1462-2920.12890] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 04/23/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Amit Kumar
- Department of Chemical and Biomolecular Engineering; National University of Singapore; Singapore
| | - Yen Peng Ting
- Department of Chemical and Biomolecular Engineering; National University of Singapore; Singapore
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261
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Fazli M, Bjarnsholt T, Høiby N, Givskov M, Tolker-Nielsen T. PNA-based fluorescence in situ hybridization for identification of bacteria in clinical samples. Methods Mol Biol 2015; 1211:261-71. [PMID: 25218392 DOI: 10.1007/978-1-4939-1459-3_21] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Fluorescence in situ hybridization with PNA probes (PNA-FISH) that target specific bacterial ribosomal RNA sequences is a powerful and rapid tool for identification of bacteria in clinical samples. PNA can diffuse readily through the bacterial cell wall due to its uncharged backbone, and PNA-FISH can be performed with high specificity due to the extraordinary thermal stability of RNA-PNA hybrid complexes. We describe a PNA-FISH procedure and provide examples of the application of PNA-FISH for the identification of bacteria in chronic wounds, cystic fibrosis lungs, and soft tissue fillers. In all these cases, bacteria can be identified in biofilm aggregates, which may explain their recalcitrance to antibiotic treatment.
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Affiliation(s)
- Mustafa Fazli
- Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
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Anani K, Adjrah Y, Ameyapoh Y, Karou SD, Agbonon A, de Souza C, Gbeassor M. Effects of hydroethanolic extracts of Balanites aegyptiaca (L.) Delile (Balanitaceae) on some resistant pathogens bacteria isolated from wounds. JOURNAL OF ETHNOPHARMACOLOGY 2015; 164:16-21. [PMID: 25666430 DOI: 10.1016/j.jep.2015.01.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 01/27/2015] [Accepted: 01/29/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND The bark of Balanites aegyptiaca (L.) Delile (Balanitaceae) is widely used in the Togolese folk medicine for the treatment of wounds, malaria and skin diseases. This study aimed to evaluate the antioxidant properties and the activity of the bark extract of this plant against some resistant bacteria isolated from wounds. MATERIALS AND METHODS The antimicrobial activity was assayed using the NCCLS microdilution while the DPPH free radical scavenging and ferric reducing antioxidant power (FRAP) were used for the antioxidant activity. The susceptibility to conventional antibiotics of bacteria was assessed by an agar disk diffusion method using commercial disk. Phenolics were quantified using spectrophotometric methods. RESULTS The hydroethanolic extracts of the bark inhibited in vitro the growth of Pseudomonas aeruginosa and Staphylococcus aureus in a dose-dependent manner. Bacteriostatic effects were observed on 15 (33%) and 21 (47%) strains of Staphylococcus aureus and Pseudomonas aeruginosa respectively. The MICs and MBCs against Staphylococcus aureus strains ranged respectively from 2.5 to 12.5 µg/mL and 2.5 to 50 µg/mL. Concerning Pseudomonas aeruginosa, these values were equal (12.5 µg/mL). Multidrug resistance was 95% against six antibiotics for Pseudomonas aeruginosa and 91% against five antibiotics for Staphylococcus aureus. The DPPH radical scavenging and the FRAP assays yielded weak antioxidant activity, closely linked with the total phenolic contents. CONCLUSION This study indicated that the bark extract of Balanites aegyptiaca possess bioactive compounds implicated in the free radical scavenging and antibacterial activities, justifying the use of the plant in the traditional medicines.
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Affiliation(s)
- Kokou Anani
- Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires, Ecole Supérieure des Techniques Biologiques et Alimentaires - Université de Lomé, B.P. 1515 Lomé, Togo; Centre de Formation et de Recherche sur les Plantes Médicinales (CERFOPLAM), Université de Lomé, Togo; Centre de Recherche en Agriculture Biologique et Substances Naturelles (CRABISNA), Lomé,Togo
| | - Yao Adjrah
- Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires, Ecole Supérieure des Techniques Biologiques et Alimentaires - Université de Lomé, B.P. 1515 Lomé, Togo; Centre de Formation et de Recherche sur les Plantes Médicinales (CERFOPLAM), Université de Lomé, Togo; Centre de Recherche en Agriculture Biologique et Substances Naturelles (CRABISNA), Lomé,Togo.
| | - Yaovi Ameyapoh
- Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires, Ecole Supérieure des Techniques Biologiques et Alimentaires - Université de Lomé, B.P. 1515 Lomé, Togo; Centre de Formation et de Recherche sur les Plantes Médicinales (CERFOPLAM), Université de Lomé, Togo
| | - Simplice Damintoti Karou
- Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires, Ecole Supérieure des Techniques Biologiques et Alimentaires - Université de Lomé, B.P. 1515 Lomé, Togo; Centre de Formation et de Recherche sur les Plantes Médicinales (CERFOPLAM), Université de Lomé, Togo; Centre de Recherche en Agriculture Biologique et Substances Naturelles (CRABISNA), Lomé,Togo
| | - Amegnona Agbonon
- Laboratoire de Physiologie et de Pharmacologie, Faculté des Sciences - Université de Lomé, BP. 1515 Lomé, Togo; Centre de Formation et de Recherche sur les Plantes Médicinales (CERFOPLAM), Université de Lomé, Togo
| | - Comlan de Souza
- Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires, Ecole Supérieure des Techniques Biologiques et Alimentaires - Université de Lomé, B.P. 1515 Lomé, Togo; Centre de Formation et de Recherche sur les Plantes Médicinales (CERFOPLAM), Université de Lomé, Togo
| | - Messanvi Gbeassor
- Laboratoire de Physiologie et de Pharmacologie, Faculté des Sciences - Université de Lomé, BP. 1515 Lomé, Togo; Centre de Formation et de Recherche sur les Plantes Médicinales (CERFOPLAM), Université de Lomé, Togo
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Ward CL, Sanchez CJ, Pollot BE, Romano DR, Hardy SK, Becerra SC, Rathbone CR, Wenke JC. Soluble factors from biofilms of wound pathogens modulate human bone marrow-derived stromal cell differentiation, migration, angiogenesis, and cytokine secretion. BMC Microbiol 2015; 15:75. [PMID: 25886581 PMCID: PMC4381664 DOI: 10.1186/s12866-015-0412-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/12/2015] [Indexed: 01/08/2023] Open
Abstract
Background Chronic, non-healing wounds are often characterized by the persistence of bacteria within biofilms - aggregations of cells encased within a self-produced polysaccharide matrix. Biofilm bacteria exhibit unique characteristics from planktonic, or culture-grown, bacterial phenotype, including diminished responses to antimicrobial therapy and persistence against host immune responses. Mesenchymal stromal cells (MSCs) are host cells characterized by their multifunctional ability to undergo differentiation into multiple cell types and modulation of host-immune responses by secreting factors that promote wound healing. While these characteristics make MSCs an attractive therapeutic for wounds, these pro-healing activities may be differentially influenced in the context of an infection (i.e., biofilm related infections) within chronic wounds. Herein, we evaluated the effect of soluble factors derived from biofilms of clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa on the viability, differentiation, and paracrine activity of human MSCs to evaluate the influence of biofilms on MSC activity in vitro. Results Exposure of MSCs to biofilm-conditioned medias of S. aureus and P. aeruginosa resulted in reductions in cell viability, in part due to activation of apoptosis. Similarly, exposure to soluble factors from biofilms was also observed to diminish the migration ability of cells and to hinder multi-lineage differentiation of MSCs. In contrast to these findings, exposure of MSCs to soluble factors from biofilms resulted in significant increases in the release of paracrine factors involved in inflammation and wound healing. Conclusions Collectively, these findings demonstrate that factors produced by biofilms can negatively impact the intrinsic properties of MSCs, in particular limiting the migratory and differentiation capacity of MSCs. Consequently, these studies suggest use/application of stem-cell therapies in the context of infection may have a limited therapeutic effect. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0412-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Catherine L Ward
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
| | - Carlos J Sanchez
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
| | - Beth E Pollot
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
| | - Desiree R Romano
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
| | - Sharanda K Hardy
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
| | - Sandra C Becerra
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
| | - Christopher R Rathbone
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
| | - Joseph C Wenke
- Department of Extremity Trauma and Regenerative Medicine, United States Army Institute of Surgical Research, Fort Sam Houston, San Antonio, TX, USA.
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265
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Petkova P, Francesko A, Tzanov T. Enzyme‐assisted formation of hybrid biopolymer hydrogels incorporating active phenolic nanospheres. Eng Life Sci 2015. [DOI: 10.1002/elsc.201400143] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Petya Petkova
- Grup de Biotecnologia Molecular i IndustrialDepartment of Chemical EngineeringUniversitat Politècnica de Catalunya Terrassa Barcelona Spain
| | - Antonio Francesko
- Grup de Biotecnologia Molecular i IndustrialDepartment of Chemical EngineeringUniversitat Politècnica de Catalunya Terrassa Barcelona Spain
| | - Tzanko Tzanov
- Grup de Biotecnologia Molecular i IndustrialDepartment of Chemical EngineeringUniversitat Politècnica de Catalunya Terrassa Barcelona Spain
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266
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Serra R, Grande R, Butrico L, Rossi A, Settimio UF, Caroleo B, Amato B, Gallelli L, de Franciscis S. Chronic wound infections: the role of Pseudomonas aeruginosa and Staphylococcus aureus. Expert Rev Anti Infect Ther 2015; 13:605-13. [PMID: 25746414 DOI: 10.1586/14787210.2015.1023291] [Citation(s) in RCA: 364] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chronic leg ulcers affect 1-2% of the general population and are related to increased morbidity and health costs. Staphylococcus aureus and Pseudomonas aeruginosa are the most common bacteria isolated from chronic wounds. They can express virulence factors and surface proteins affecting wound healing. The co-infection of S. aureus and P. aeruginosa is more virulent than single infection. In particular, S. aureus and P. aeruginosa have both intrinsic and acquired antibiotic resistance, making clinical management of infection a real challenge, particularly in patients with comorbidity. Therefore, a correct and prompt diagnosis of chronic wound infection requires a detailed knowledge of skin bacterial flora. This is a necessary prerequisite for tailored pharmacological treatment, improving symptoms, and reducing side effects and antibiotic resistance.
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Affiliation(s)
- Raffaele Serra
- Interuniversity Center of Phlebolymphology (CIFL), International Research and Educational Program in Clinical and Experimental Biotechnology, Headquarters: University Magna Græcia of Catanzaro, Viale Europa 88100 Catanzaro, Italy
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267
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Cooper RA, Bjarnsholt T, Alhede M. Biofilms in wounds: a review of present knowledge. J Wound Care 2015; 23:570, 572-4, 576-80 passim. [PMID: 25375405 DOI: 10.12968/jowc.2014.23.11.570] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Following confirmation of the presence of biofilms in chronic wounds, the term biofilm became a buzzword within the wound healing community. For more than a century pathogens have been successfully isolated and identified from wound specimens using techniques that were devised in the nineteenth century by Louis Pasteur and Robert Koch. Although this approach still provides valuable information with which to help diagnose acute infections and to select appropriate antibiotic therapies, it is evident that those organisms isolated from clinical specimens with the conditions normally used in diagnostic laboratories are mainly in a planktonic form that is unrepresentative of the way in which most microbial species exist naturally. Usually microbial species adhere to each other, as well as to living and non-living surfaces, where they form complex communities surrounded by collectively secreted extracellular polymeric substances (EPS). Cells within such aggregations (or biofilms) display varying physiological and metabolic properties that are distinct from those of planktonic cells, and which contribute to their persistence. There are many factors that influence healing in wounds and the discovery of biofilms in chronic wounds has provided new insight into the reasons why. Increased tolerance of biofilms to antimicrobial agents explains the limited efficacy of antimicrobial agents in chronic wounds and illustrates the need to develop new management strategies. This review aims to explain the nature of biofilms, with a view to explaining their impact on wounds.
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Affiliation(s)
- R A Cooper
- Professor of Microbiology, Cardiff School of Health Sciences, Cardiff Metropolitan University, Western Avenue, Cardiff, CF5 2YB, S. Wales, UK
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268
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Eickhardt S, Kragh KN, Schrøder S, Poulsen SS, Sillesen H, Givskov M, Høiby N, Bjarnsholt T, Alhede M. Autofluorescence in samples obtained from chronic biofilm infections--"all that glitters is not gold". Pathog Dis 2015; 73:ftv012. [PMID: 25663346 DOI: 10.1093/femspd/ftv012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2015] [Indexed: 01/10/2023] Open
Abstract
When looking at tissue sections of ex vivo samples, autofluorescence can be a major cause of artifacts and misinterpretations. We here reiterate evidence that autofluorescing granules, often hemosiderin but also ceroid or mucinogen granules, are severe obstacles when imaging and diagnosing biofilm infections through fluorescent imaging techniques. We used confocal laser scanning microscopy with spectral analysis for autofluorescence detection as well as standard histological stains in order to identify the culprit and show that these granules might very well be mistaken for bacterial biofilms. Furthermore, we hypothesize that the increased amount of autofluorescing granules may be a consequence of prolonged inflammation as a consequence of chronic biofilm infections.
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Affiliation(s)
- Steffen Eickhardt
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, The faculty of Health and Medical Sciences, The University of Copenhagen, Denmark The Department of Clinical Microbiology, Rigshospitalet, Denmark
| | - Kasper N Kragh
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, The faculty of Health and Medical Sciences, The University of Copenhagen, Denmark The Department of Clinical Microbiology, Rigshospitalet, Denmark
| | - Stine Schrøder
- Ear Nose Throat Department, North Zealand Hospital, Denmark
| | - Steen Seier Poulsen
- The Department of Biomedicine, The faculty of Health and Medical Sciences, The University of Copenhagen, Denmark
| | - Henrik Sillesen
- Department of Vascular Surgery, Rigshospitalet, University of Copenhagen, Denmark
| | - Michael Givskov
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore
| | - Niels Høiby
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, The faculty of Health and Medical Sciences, The University of Copenhagen, Denmark The Department of Clinical Microbiology, Rigshospitalet, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, The faculty of Health and Medical Sciences, The University of Copenhagen, Denmark The Department of Clinical Microbiology, Rigshospitalet, Denmark
| | - Morten Alhede
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, The faculty of Health and Medical Sciences, The University of Copenhagen, Denmark The Department of Clinical Microbiology, Rigshospitalet, Denmark
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269
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Crone S, Garde C, Bjarnsholt T, Alhede M. A novelin vitrowound biofilm model used to evaluate low-frequency ultrasonic-assisted wound debridement. J Wound Care 2015; 24:64, 66-9, 72. [DOI: 10.12968/jowc.2015.24.2.64] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- S. Crone
- Professor, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - C. Garde
- Technical University of Denmark. Anker Engelunds Vej 1, 2800 Kgs. Lyngby, Denmark
| | - T. Bjarnsholt
- Professor, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - M. Alhede
- Project Leader, emendo a/s, Sundkaj 7, 2100 Copenhagen, Denmark
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270
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Tolker-Nielsen T. Pseudomonas aeruginosa biofilm infections: from molecular biofilm biology to new treatment possibilities. APMIS 2015:1-51. [PMID: 25399808 DOI: 10.1111/apm.12335] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially, biofilm infections where P. aeruginosa plays an important role are described. Subsequently, current insights into the molecular mechanisms involved in P. aeruginosa biofilm formation and the associated antimicrobial tolerance are reviewed. And finally, based on our knowledge about molecular biofilm biology, a number of therapeutic strategies for combat of P. aeruginosa biofilm infections are presented.
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Affiliation(s)
- Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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271
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Kirkup BC. Bacterial Strain Diversity Within Wounds. Adv Wound Care (New Rochelle) 2015; 4:12-23. [PMID: 25566411 DOI: 10.1089/wound.2014.0560] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/23/2014] [Indexed: 12/17/2022] Open
Abstract
Significance: Rare bacterial taxa (taxa of low relative frequency) are numerous and ubiquitous in virtually any sample-including wound samples. In addition, even the high-frequency genera and species contain multiple strains. These strains, individually, are each only a small fraction of the total bacterial population. Against the view that wounds contain relatively few kinds of bacteria, this newly recognized diversity implies a relatively high rate of migration into the wound and the potential for diversification during infection. Understanding the biological and medical importance of these numerous taxa is an important new element of wound microbiology. Recent Advances: Only recently have these numerous strains been discovered; the technology to detect, identify, and characterize them is still in its infancy. Multiple strains of both gram-negative and gram-positive bacteria have been found in a single wound. In the few cases studied, the distribution of the bacteria suggests microhabitats and biological interactions. Critical Issues: The distribution of the strains, their phenotypic diversity, and their interactions are still largely uncharacterized. The technologies to investigate this level of genomic detail are still developing and have not been largely deployed to investigate wounds. Future Directions: As advanced metagenomics, single-cell genomics, and advanced microscopy develop, the study of wound microbiology will better address the complex interplay of numerous individually rare strains with both the host and each other.
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Affiliation(s)
- Benjamin C. Kirkup
- FE Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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272
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Brackman G, Coenye T. In Vitro and In Vivo Biofilm Wound Models and Their Application. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 897:15-32. [DOI: 10.1007/5584_2015_5002] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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273
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Lavigne JP, Sotto A, Dunyach-Remy C, Lipsky BA. New Molecular Techniques to Study the Skin Microbiota of Diabetic Foot Ulcers. Adv Wound Care (New Rochelle) 2015; 4:38-49. [PMID: 25566413 DOI: 10.1089/wound.2014.0532] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 05/02/2014] [Indexed: 01/04/2023] Open
Abstract
Significance: Diabetic foot ulcers (DFU) are a major and growing public health problem. They pose difficulties in clinical practice in both diagnosis and management. Bacterial interactions on the skin surface are important in the pathophysiology of DFU and may contribute to a delay in healing. Fully identifying bacteria present in these wounds is difficult with traditional culture methods. New molecular tools, however, have greatly contributed to our understanding of the role of the cutaneous microbiota in DFU. Recent Advances: Molecular technologies revealed new information concerning how bacteria are organized in DFU. This has led to the concept of "functionally equivalent pathogroups," meaning that certain bacterial species which are usually nonpathogenic (or at least incapable of maintaining a chronic infection on their own) may coaggregate symbiotically in a pathogenic biofilm and act synergistically to cause a chronic infection. The distribution of pathogens in multispecies biofilms is nonrandom. The high bacterial diversity is probably related to the development of a microbial biofilm that is irreversibly attached to the wound matrix. Critical Issues: Using molecular techniques requires a financial outlay for high-cost equipment. They are still too time-consuming to perform and reporting is too delayed for them to be used in routine practice. Finally, they do not differentiate live from dead or pathogenic from nonpathogenic microorganisms. Future Directions: Molecular tools have better documented the composition and organization of the skin flora. Further advances are required to elucidate which among the many bacteria in the DFU flora are likely to be pathogens, rather than colonizers.
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Affiliation(s)
- Jean-Philippe Lavigne
- INSERM, U1047, Université Montpellier, UFR de Médecine, Nîmes Cedex, France
- Service de Microbiologie, CHU Carémeau, Nîmes Cedex, France
| | - Albert Sotto
- INSERM, U1047, Université Montpellier, UFR de Médecine, Nîmes Cedex, France
- Service des Maladies Infectieuses et Tropicales, CHU Carémeau, Nîmes Cedex, France
| | - Catherine Dunyach-Remy
- INSERM, U1047, Université Montpellier, UFR de Médecine, Nîmes Cedex, France
- Service de Microbiologie, CHU Carémeau, Nîmes Cedex, France
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274
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Williams C, Ramage G. Fungal biofilms in human disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 831:11-27. [PMID: 25384660 DOI: 10.1007/978-3-319-09782-4_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Craig Williams
- Institute of Healthcare Associated Infection, University of the West of Scotland, Paisley, UK,
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275
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Tuttle MS. Association Between Microbial Bioburden and Healing Outcomes in Venous Leg Ulcers: A Review of the Evidence. Adv Wound Care (New Rochelle) 2015; 4:1-11. [PMID: 25566410 DOI: 10.1089/wound.2014.0535] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 04/15/2014] [Indexed: 12/29/2022] Open
Abstract
Significance: Venous leg ulcers (VLUs) are susceptible to microbial invasion, and serious complications can result without the timely control of infection. Diagnosis of wound infection is primarily based on subjective clinical characteristics and patient-reported symptoms, and the treatment with antimicrobials has not consistently shown improvement in healing outcomes. This is a review of studies using bacterial cultures and/or new molecular-based methods associating microbial bioburden with healing outcomes in VLU patients, with the goal of guiding future studies to better determine significant patterns of microbial involvement in chronic wounds. Recent Advances: Studies reviewed here use cultivation-based identification of bacteria and next-generation sequencing of the bacterial 16S rRNA gene to gain insight into microbial bioburden in VLUs. Further application of sophisticated DNA sequencing and bioinformatic analyses has the potential to revolutionize our ability to further discern, with high resolution, complex microbial communities in chronic wounds. Critical Issues: Few previous studies of microbial bioburden in VLUs have incorporated the knowledge of clinical treatments, which includes close monitoring of patients' symptoms and responses to therapy. Thus, wound care practitioners are currently without evidence-based guidance for the diagnosis and treatment of wound infections. Future Directions: Clinically relevant breakthroughs are possible by combining advanced microbial detection techniques with improved study designs that reflect clinical practices. Well-designed longitudinal studies have great potential to lead to better evidence-based diagnosis of chronic wounds. A greater understanding of microbial bioburden in chronic wounds is likely to lead to better therapies that speed healing and prevent wound infection without risking the development of antimicrobial resistance.
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Affiliation(s)
- Marie S. Tuttle
- Department of Dermatology, Case Western Reserve University, Cleveland, Ohio
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276
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Donelli G, Vuotto C. Biofilm-based infections in long-term care facilities. Future Microbiol 2014; 9:175-88. [PMID: 24571072 DOI: 10.2217/fmb.13.149] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The recent trend in the early admittance to long-term care facilities (LTCFs) of severely injured patients transferred from general hospitals has given a new dynamic to the incidence of healthcare-associated infections, including biofilm-based infections related to the implant of urinary and intravascular catheters, and the onset of pressure ulcers. Catheter-associated urinary tract infections lead in most of the surveys on LTCFs, approximately 80% of urinary tract infections in these settings being due to the short- or long-term insertion of a urinary catheter. Furthermore, the implantation of intravascular catheters is often responsible for catheter-related bloodstream infections caused by the development of an intraluminal biofilm. Pressure ulcers, frequently occurring in bedridden patients admitted to LTCFs, are also susceptible to infection by biofilm-growing aerobic and anaerobic bacteria, the biofilm formation on the wound being the main reason for its delayed healing.
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277
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Synergistic interactions of Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro wound model. Infect Immun 2014; 82:4718-28. [PMID: 25156721 DOI: 10.1128/iai.02198-14] [Citation(s) in RCA: 251] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In individuals with polymicrobial infections, microbes often display synergistic interactions that can enhance their colonization, virulence, or persistence. One of the most prevalent types of polymicrobial infection occurs in chronic wounds, where Pseudomonas aeruginosa and Staphylococcus aureus are the two most common causes. Although they are the most commonly associated microbial species in wound infections, very little is known about their interspecies relationship. Evidence suggests that P. aeruginosa-S. aureus coinfections are more virulent than monoculture infection with either species; however, difficulties in growing these two pathogens together in vitro have hampered attempts to uncover the mechanisms involved. Here we describe a simple and clinically relevant in vitro wound model that supported concomitant growth of P. aeruginosa and S. aureus. We observed that the ability of P. aeruginosa and S. aureus to survive antibiotic treatment increased when they were grown together in planktonic cocultures and that antibiotic tolerance was further enhanced when they were grown together in the wound model. We attributed this enhanced tolerance to both the "host-derived" and "bacterium-derived" matrix components. Taken together, our data indicate that P. aeruginosa and S. aureus may benefit each other by coinfecting wounds and that the host-derived matrix may serve as important a role as the bacterium-derived matrix in protecting bacteria from some antibiotics.
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278
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Ionic liquids as a class of materials for transdermal delivery and pathogen neutralization. Proc Natl Acad Sci U S A 2014; 111:13313-8. [PMID: 25157174 DOI: 10.1073/pnas.1403995111] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Biofilm-protected microbial infections in skin are a serious health risk that remains to be adequately addressed. The lack of progress in developing effective treatment strategies is largely due to the transport barriers posed by the stratum corneum of the skin and the biofilm. In this work, we report on the use of Ionic Liquids (ILs) for biofilm disruption and enhanced antibiotic delivery across skin layers. We outline the syntheses of ILs, analysis of relevant physicochemical properties, and subsequent neutralization effects on two biofilm-forming pathogens: Pseudomonas aeruginosa and Salmonella enterica. Further, the ILs were also examined for cytotoxicity, skin irritation, delivery of antibiotics through the skin, and treatment of biofilms in a wound model. Of the materials examined, choline-geranate emerged as a multipurpose IL with excellent antimicrobial activity, minimal toxicity to epithelial cells as well as skin, and effective permeation enhancement for drug delivery. Specifically, choline-geranate was comparable with, or more effective than, bleach treatment against established biofilms of S. enterica and P. aeruginosa, respectively. In addition, choline-geranate increased delivery of cefadroxil, an antibiotic, by >16-fold into the deep tissue layers of the skin without inducing skin irritation. The in vivo efficacy of choline-geranate was validated using a biofilm-infected wound model (>95% bacterial death after 2-h treatment). This work establishes the use of ILs for simultaneous enhancement of topical drug delivery and antibiotic activity.
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279
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Mulcahy LR, Isabella VM, Lewis K. Pseudomonas aeruginosa biofilms in disease. MICROBIAL ECOLOGY 2014; 68:1-12. [PMID: 24096885 PMCID: PMC3977026 DOI: 10.1007/s00248-013-0297-x] [Citation(s) in RCA: 299] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/17/2013] [Indexed: 05/19/2023]
Abstract
Pseudomonas aeruginosa is a ubiquitous organism that is the focus of intense research because of its prominent role in disease. Due to its relatively large genome and flexible metabolic capabilities, this organism exploits numerous environmental niches. It is an opportunistic pathogen that sets upon the human host when the normal immune defenses are disabled. Its deadliness is most apparent in cystic fibrosis patients, but it also is a major problem in burn wounds, chronic wounds, chronic obstructive pulmonary disorder, surface growth on implanted biomaterials, and within hospital surface and water supplies, where it poses a host of threats to vulnerable patients (Peleg and Hooper, N Engl J Med 362:1804-1813, 2010; Breathnach et al., J Hosp Infect 82:19-24, 2012). Once established in the patient, P. aeruginosa can be especially difficult to treat. The genome encodes a host of resistance genes, including multidrug efflux pumps (Poole, J Mol Microbiol Biotechnol 3:255-264, 2001) and enzymes conferring resistance to beta-lactam and aminoglycoside antibotics (Vahdani et al., Annal Burns Fire Disast 25:78-81, 2012), making therapy against this gram-negative pathogen particularly challenging due to the lack of novel antimicrobial therapeutics (Lewis, Nature 485: 439-440, 2012). This challenge is compounded by the ability of P. aeruginosa to grow in a biofilm, which may enhance its ability to cause infections by protecting bacteria from host defenses and chemotherapy. Here, we review recent studies of P. aeruginosa biofilms with a focus on how this unique mode of growth contributes to its ability to cause recalcitrant infections.
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Affiliation(s)
- Lawrence R. Mulcahy
- Antimicrobial Discovery Center, Department of Biology. Northeastern University, 306C Mugar Life Sciences, 360 Huntington Avenue, Boston, MA 02115 USA
| | - Vincent M. Isabella
- Antimicrobial Discovery Center, Department of Biology. Northeastern University, 306C Mugar Life Sciences, 360 Huntington Avenue, Boston, MA 02115 USA
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology. Northeastern University, 306C Mugar Life Sciences, 360 Huntington Avenue, Boston, MA 02115 USA
- Corresponding Author: Kim Lewis, Ph.D., 617.373.8238,
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280
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Alhede M, Bjarnsholt T, Givskov M, Alhede M. Pseudomonas aeruginosa biofilms: mechanisms of immune evasion. ADVANCES IN APPLIED MICROBIOLOGY 2014; 86:1-40. [PMID: 24377853 DOI: 10.1016/b978-0-12-800262-9.00001-9] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes (PMNs). In this chapter, the interplay between P. aeruginosa and the PMNs in chronic infections is discussed with focus on the role of rhamnolipids and extracellular DNA.
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Affiliation(s)
- Maria Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.
| | - Thomas Bjarnsholt
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Michael Givskov
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Morten Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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281
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Hutchison JB, Rodesney CA, Kaushik KS, Le HH, Hurwitz DA, Irie Y, Gordon VD. Single-cell control of initial spatial structure in biofilm development using laser trapping. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:4522-4530. [PMID: 24684606 DOI: 10.1021/la500128y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Biofilms are sessile communities of microbes that are spatially structured by an embedding matrix. Biofilm infections are notoriously intractable. This arises, in part, from changes in the bacterial phenotype that result from spatial structure. Understanding these interactions requires methods to control the spatial structure of biofilms. We present a method for growing biofilms from initiating cells whose positions are controlled with single-cell precision using laser trapping. The native growth, motility, and surface adhesion of positioned microbes are preserved, as we show for model organisms Pseudomonas aeruginosa and Staphylococcus aureus. We demonstrate that laser-trapping and placing bacteria on surfaces can reveal the effects of spatial structure on bacterial growth in early biofilm development.
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Affiliation(s)
- Jaime B Hutchison
- Center for Nonlinear Dynamics and Department of Physics and ‡School of Biological Sciences, The University of Texas at Austin , Austin, Texas 78712, United States
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282
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Valente PMD, Deva A, Ngo Q, Vickery K. The increased killing of biofilms in vitro by combining topical silver dressings with topical negative pressure in chronic wounds. Int Wound J 2014; 13:130-6. [PMID: 24712658 DOI: 10.1111/iwj.12248] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/23/2022] Open
Abstract
Chronic wounds remain a significant medical and financial burden in hospitals of today. A major factor in the transition from an acute to a chronic wound is its bacterial bioburden. Developments in molecular techniques have shown that chronic wounds remain colonised by many species of bacteria and that the bacteria within these chronic wounds exist in two forms. Treatments of chronic wounds have maintained a challenging field and significant ongoing research is being conducted. With the development of an in vitro wound model, we applied topical negative pressure (TNP) dressings to a spectrum of common bacterial biofilms found in chronic wounds and studied the synergistic efficacy between the application of TNP and silver-impregnated foam against these biofilms. This synergistic response was seen within the laboratory strains of staphylococcal biofilms over a 3-day treatment period but lost following the 5 days of treatment. However, combining topical pressure dressings and silver foam lead to a synergistic inactivation in Pseudomonas species over both 3-day and 5-day treatments.
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Affiliation(s)
| | - Anand Deva
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
| | - Quan Ngo
- Department of Plastic and Reconstructive Surgery, Liverpool Hospital, Sydney, NSW, Australia
| | - Karen Vickery
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
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283
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Catheter-associated urinary tract infection by Pseudomonas aeruginosa is mediated by exopolysaccharide-independent biofilms. Infect Immun 2014; 82:2048-58. [PMID: 24595142 DOI: 10.1128/iai.01652-14] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that is especially adept at forming surface-associated biofilms. P. aeruginosa causes catheter-associated urinary tract infections (CAUTIs) through biofilm formation on the surface of indwelling catheters. P. aeruginosa encodes three extracellular polysaccharides, PEL, PSL, and alginate, and utilizes the PEL and PSL polysaccharides to form biofilms in vitro; however, the requirement of these polysaccharides during in vivo infections is not well understood. Here we show in a murine model of CAUTI that PAO1, a strain harboring pel, psl, and alg genes, and PA14, a strain harboring pel and alg genes, form biofilms on the implanted catheters. To determine the requirement of exopolysaccharide during in vivo biofilm infections, we tested isogenic mutants lacking the pel, psl, and alg operons and showed that PA14 mutants lacking these operons can successfully form biofilms on catheters in the CAUTI model. To determine the host factor(s) that induces the ΔpelD mutant to form biofilm, we tested mouse, human, and artificial urine and show that urine can induce biofilm formation by the PA14 ΔpelD mutant. By testing the major constituents of urine, we show that urea can induce a pel-, psl-, and alg-independent biofilm. These pel-, psl-, and alg-independent biofilms are mediated by the release of extracellular DNA. Treatment of biofilms formed in urea with DNase I reduced the biofilm, indicating that extracellular DNA supports biofilm formation. Our results indicate that the opportunistic pathogen P. aeruginosa utilizes a distinct program to form biofilms that are independent of exopolysaccharides during CAUTI.
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284
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Anionic polymers and 10nm Fe3O4@UA wound dressings support human foetal stem cells normal development and exhibit great antimicrobial properties. Int J Pharm 2014; 463:146-54. [DOI: 10.1016/j.ijpharm.2013.08.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 08/21/2013] [Indexed: 11/24/2022]
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285
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Metcalf D, Bowler P, Hurlow J. A clinical algorithm for wound biofilm identification. J Wound Care 2014; 23:137-8, 140-2. [DOI: 10.12968/jowc.2014.23.3.137] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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286
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Hall MR, McGillicuddy E, Kaplan LJ. Biofilm: Basic Principles, Pathophysiology, and Implications for Clinicians. Surg Infect (Larchmt) 2014; 15:1-7. [DOI: 10.1089/sur.2012.129] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Michael R. Hall
- Department of Surgery, Yale School of Medicine, New Haven, Connecticut
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287
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Burmølle M, Ren D, Bjarnsholt T, Sørensen SJ. Interactions in multispecies biofilms: do they actually matter? Trends Microbiol 2014; 22:84-91. [PMID: 24440178 DOI: 10.1016/j.tim.2013.12.004] [Citation(s) in RCA: 301] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 12/02/2013] [Accepted: 12/11/2013] [Indexed: 01/25/2023]
Abstract
The recent focus on complex bacterial communities has led to the recognition of interactions across species boundaries. This is particularly pronounced in multispecies biofilms, where synergistic interactions impact the bacterial distribution and overall biomass produced. Importantly, in a number of settings, the interactions in a multispecies biofilm affect its overall function, physiology, or surroundings, by resulting in enhanced resistance, virulence, or degradation of pollutants, which is of significant importance to human health and activities. The underlying mechanisms causing these synergistic effects are to some extent characterized at the molecular and evolutionary levels, and further exploration is now possible due to the enhanced resolution and higher throughput of available techniques.
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Affiliation(s)
- Mette Burmølle
- Section of Microbiology, Universitetsparken 15, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen Ø, Denmark.
| | - Dawei Ren
- Section of Microbiology, Universitetsparken 15, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Thomas Bjarnsholt
- Department of International Health, Immunology, and Microbiology, Costerton Biofilm Centre, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Juliane Mariesvej 22, Rigshospitalet, 2100 Copenhagen Ø, Denmark
| | - Søren J Sørensen
- Section of Microbiology, Universitetsparken 15, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen Ø, Denmark
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288
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Oates A, Bowling FL, Boulton AJM, Bowler PG, Metcalf DG, McBain AJ. The visualization of biofilms in chronic diabetic foot wounds using routine diagnostic microscopy methods. J Diabetes Res 2014; 2014:153586. [PMID: 24839608 PMCID: PMC4009286 DOI: 10.1155/2014/153586] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 02/14/2014] [Indexed: 12/31/2022] Open
Abstract
Diabetic foot wounds are commonly colonised by taxonomically diverse microbial communities and may additionally be infected with specific pathogens. Since biofilms are demonstrably less susceptible to antimicrobial agents than are planktonic bacteria, and may be present in chronic wounds, there is increasing interest in their aetiological role. In the current investigation, the presence of structured microbial assemblages in chronic diabetic foot wounds is demonstrated using several visualization methods. Debridement samples, collected from the foot wounds of diabetic patients, were histologically sectioned and examined using bright-field, fluorescence, and environmental scanning electron microscopy and assessed by quantitative differential viable counting. All samples (n = 26) harboured bioburdens in excess of 5 log₁₀ CFU/g. Microcolonies were identified in 4/4 samples by all three microscopy methods, although bright-field and fluorescence microscopy were more effective at highlighting putative biofilm morphology than ESEM. Results in this pilot study indicate that bacterial microcolonies and putative biofilm matrix can be visualized in chronic wounds using fluorescence microscopy and ESEM, but also using the simple Gram stain.
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Affiliation(s)
- Angela Oates
- Manchester Pharmacy School, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Frank L. Bowling
- Department of Medicine Manchester Royal Infirmary, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Andrew J. M. Boulton
- Department of Medicine Manchester Royal Infirmary, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | | | | | - Andrew J. McBain
- Manchester Pharmacy School, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
- *Andrew J. McBain:
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289
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Walker JN, Crosby HA, Spaulding AR, Salgado-Pabón W, Malone CL, Rosenthal CB, Schlievert PM, Boyd JM, Horswill AR. The Staphylococcus aureus ArlRS two-component system is a novel regulator of agglutination and pathogenesis. PLoS Pathog 2013; 9:e1003819. [PMID: 24367264 PMCID: PMC3868527 DOI: 10.1371/journal.ppat.1003819] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 10/21/2013] [Indexed: 01/31/2023] Open
Abstract
Staphylococcus aureus is a prominent bacterial pathogen that is known to agglutinate in the presence of human plasma to form stable clumps. There is increasing evidence that agglutination aids S. aureus pathogenesis, but the mechanisms of this process remain to be fully elucidated. To better define this process, we developed both tube based and flow cytometry methods to monitor clumping in the presence of extracellular matrix proteins. We discovered that the ArlRS two-component system regulates the agglutination mechanism during exposure to human plasma or fibrinogen. Using divergent S. aureus strains, we demonstrated that arlRS mutants are unable to agglutinate, and this phenotype can be complemented. We found that the ebh gene, encoding the Giant Staphylococcal Surface Protein (GSSP), was up-regulated in an arlRS mutant. By introducing an ebh complete deletion into an arlRS mutant, agglutination was restored. To assess whether GSSP is the primary effector, a constitutive promoter was inserted upstream of the ebh gene on the chromosome in a wildtype strain, which prevented clump formation and demonstrated that GSSP has a negative impact on the agglutination mechanism. Due to the parallels of agglutination with infective endocarditis development, we assessed the phenotype of an arlRS mutant in a rabbit combined model of sepsis and endocarditis. In this model the arlRS mutant displayed a large defect in vegetation formation and pathogenesis, and this phenotype was partially restored by removing GSSP. Altogether, we have discovered that the ArlRS system controls a novel mechanism through which S. aureus regulates agglutination and pathogenesis. Staphylococcus aureus is a bacterial pathogen that is responsible for causing significant disease in humans. The development of antibiotic resistant strains has made these infections more difficult to treat, and an improved understanding of how this pathogen causes infections will facilitate the development of new tools for treatment. It has long been recognized that S. aureus can bind human matrix proteins to form stable clumps in a process called agglutination, but the importance of agglutination during infection is only just becoming understood. In this work, we developed several techniques to investigate the S. aureus agglutination mechanism. We discovered that the ArlRS two-component regulatory system controls agglutination by regulating the expression of the ebh gene, which encodes the Giant Staphylococcal Surface Protein (GSSP). When ArlRS is non-functional, S. aureus agglutination is prevented through the action of GSSP. These phenotypes were confirmed in a rabbit model of sepsis and infective endocarditis, demonstrating that ArlRS is an important regulator of virulence. Taken together, the identification of ArlRS as a regulator of S. aureus agglutination and pathogenesis may lead to innovative directions for therapeutic development.
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Affiliation(s)
- Jennifer N Walker
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Heidi A Crosby
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Adam R Spaulding
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Wilmara Salgado-Pabón
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Cheryl L Malone
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Carolyn B Rosenthal
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Patrick M Schlievert
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Alexander R Horswill
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
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290
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Yang R, Zuo T, Zhu J, Zhong H, Wu K, Hou S. Effect of Radiofrequency Ablation on Healing of Infected Full-Thickness Wounds in Minipigs. INT J LOW EXTR WOUND 2013; 12:265-70. [PMID: 24275753 DOI: 10.1177/1534734613510400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The success of debridement is critical to optimize the treatment outcomes of traumatic wounds. To investigate the impact of radiofrequency ablation on healing potential of infected wounds, minipigs with infected full-thickness skin defects on backs were divided into 4 treatment groups randomly: radiofrequency ablation debridement, electric knife debridement, sharp instrument debridement, and no treatment. The healing rate, healing time, tissue filling rate, bacterial quantitative, and histological assay were evaluated postoperatively. The results obtained provide evidence that the wounds after radiofrequency ablation treatment enhanced the skin wound-healing efficacy and had better outcomes of tissue filling compared with other debridement therapies. Furthermore, we quantified the bacterial counting level in wound samples, and the results revealed a more significant decreasing trend in radiofrequency ablation group than that of the electric knife debridement group and the sharp instrument debridement group. Postoperative histological measurements showed that there were better granulation formation and re-epithelialization and collagen deposition in radiofrequency ablation–treated wounds than those in other groups. The present findings demonstrate that radiofrequency ablation has a significantly influence on reducing the number of bacteria and improving the healing quality and is a promising candidate for treatment of infected wounds.
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Affiliation(s)
- Rungong Yang
- The First Affiliated Hospital of the General Hospital of PLA, Beijing, Peoples Republic of China
| | - Tantan Zuo
- The First Affiliated Hospital of the General Hospital of PLA, Beijing, Peoples Republic of China
- Postgraduate Medical College, General Hospital of PLA, Beijing, Peoples Republic of China
| | - Jialiang Zhu
- The First Affiliated Hospital of the General Hospital of PLA, Beijing, Peoples Republic of China
| | - Hongbin Zhong
- The First Affiliated Hospital of the General Hospital of PLA, Beijing, Peoples Republic of China
| | - Kejian Wu
- The First Affiliated Hospital of the General Hospital of PLA, Beijing, Peoples Republic of China
| | - Shuxun Hou
- The First Affiliated Hospital of the General Hospital of PLA, Beijing, Peoples Republic of China
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291
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Pritchard D, Nigam Y. Maximising the secondary beneficial effects of larval debridement therapy. J Wound Care 2013; 22:610-11, 614-6. [DOI: 10.12968/jowc.2013.22.11.610] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Y. Nigam
- College of Human and Health Sciences, Swansea University, Swansea, UK
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292
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Phillips PL, Yang Q, Davis S, Sampson EM, Azeke JI, Hamad A, Schultz GS. Antimicrobial dressing efficacy against mature Pseudomonas aeruginosa biofilm on porcine skin explants. Int Wound J 2013; 12:469-83. [PMID: 24028432 PMCID: PMC7950379 DOI: 10.1111/iwj.12142] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 07/24/2013] [Indexed: 12/11/2022] Open
Abstract
An ex vivo porcine skin explant biofilm model that preserves key properties of biofilm attached to skin at different levels of maturity (0–3 days) was used to assess the efficacy of commercially available antimicrobial dressings and topical treatments. Assays were also performed on the subpopulation of antibiotic tolerant biofilm generated by 24 hours of pre‐treatment with gentamicin (120× minimal inhibitory concentration) prior to agent exposure. Five types of antimicrobial agents (iodine, silver, polyhexamethylene biguanide, honey and ethanol) and four types of moisture dressings (cotton gauze, sodium carboxymethylcellulose fibre, calcium alginate fibre and cadexomer beads) were assessed. Time‐release silver gel and cadexomer iodine dressings were the most effective in reducing mature biofilm [between 5 and 7 logarithmic (log) of 7‐log total], whereas all other dressing formulations reduced biofilm between 0·3 and 2 log in 24 or 72 hours with a single exposure. Similar results were found after 24‐hour exposure to silver release dressings using an in vivo pig burn wound model, demonstrating correlation between the ex vivo and in vivo models. Results of this study indicate that commonly used microbicidal wound dressings vary widely in their ability to kill mature biofilm and the efficacy is influenced by time of exposure, number of applications, moisture level and agent formulation (sustained release).
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Affiliation(s)
- Priscilla L Phillips
- Institute of Wound Research, Department of Obstetrics and Gynecology, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Qingping Yang
- Institute of Wound Research, Department of Obstetrics and Gynecology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Stephen Davis
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Edith M Sampson
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - John I Azeke
- Institute of Wound Research, Department of Obstetrics and Gynecology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Afifa Hamad
- Institute of Wound Research, Department of Obstetrics and Gynecology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Gregory S Schultz
- Institute of Wound Research, Department of Obstetrics and Gynecology, College of Medicine, University of Florida, Gainesville, FL, USA
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293
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Pessi G, Braunwalder R, Grunau A, Omasits U, Ahrens CH, Eberl L. Response of Burkholderia cenocepacia H111 to micro-oxia. PLoS One 2013; 8:e72939. [PMID: 24023794 PMCID: PMC3759415 DOI: 10.1371/journal.pone.0072939] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/15/2013] [Indexed: 12/20/2022] Open
Abstract
B. cenocepacia is an opportunistic human pathogen that is particularly problematic for patients suffering from cystic fibrosis (CF). In the CF lung bacteria grow to high densities within the viscous mucus that is limited in oxygen. Pseudomonas aeruginosa, the dominant pathogen in CF patients, is known to grow and survive under oxygen-limited to anaerobic conditions by using micro-oxic respiration, denitrification and fermentative pathways. In contrast, inspection of the genome sequences of available B. cenocepacia strains suggested that B. cenocepacia is an obligate aerobic and non-fermenting bacterium. In accordance with the bioinformatics analysis we observed that B. cenocepacia H111 is able to grow with as little as 0.1% O2 but not under strictly anoxic conditions. Phenotypic analyses revealed that H111 produced larger amounts of biofilm, pellicle and proteases under micro-oxic conditions (0.5%–5% O2, i.e. conditions that mimic those encountered in CF lung infection), and was more resistant to several antibiotics. RNA-Seq and shotgun proteomics analyses of cultures of B. cenocepacia H111 grown under micro-oxic and aerobic conditions showed up-regulation of genes involved in the synthesis of the exopolysaccharide (EPS) cepacian as well as several proteases, two isocitrate lyases and other genes potentially important for life in micro-oxia. Data deposition: RNA-Seq raw data files are accessible through the GEO Series accession number GSE48585. MS data have been deposited in the ProteomeXchange database (PXD000270).
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Affiliation(s)
- Gabriella Pessi
- Department of Microbiology, University of Zurich, Zürich, Switzerland
- * E-mail:
| | | | - Alexander Grunau
- Department of Microbiology, University of Zurich, Zürich, Switzerland
| | - Ulrich Omasits
- Institute of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Christian H. Ahrens
- Institute of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Leo Eberl
- Department of Microbiology, University of Zurich, Zürich, Switzerland
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294
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Billings N, Ramirez Millan M, Caldara M, Rusconi R, Tarasova Y, Stocker R, Ribbeck K. The extracellular matrix Component Psl provides fast-acting antibiotic defense in Pseudomonas aeruginosa biofilms. PLoS Pathog 2013; 9:e1003526. [PMID: 23950711 PMCID: PMC3738486 DOI: 10.1371/journal.ppat.1003526] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 06/14/2013] [Indexed: 02/01/2023] Open
Abstract
Bacteria within biofilms secrete and surround themselves with an extracellular matrix, which serves as a first line of defense against antibiotic attack. Polysaccharides constitute major elements of the biofilm matrix and are implied in surface adhesion and biofilm organization, but their contributions to the resistance properties of biofilms remain largely elusive. Using a combination of static and continuous-flow biofilm experiments we show that Psl, one major polysaccharide in the Pseudomonas aeruginosa biofilm matrix, provides a generic first line of defense toward antibiotics with diverse biochemical properties during the initial stages of biofilm development. Furthermore, we show with mixed-strain experiments that antibiotic-sensitive “non-producing” cells lacking Psl can gain tolerance by integrating into Psl-containing biofilms. However, non-producers dilute the protective capacity of the matrix and hence, excessive incorporation can result in the collapse of resistance of the entire community. Our data also reveal that Psl mediated protection is extendible to E. coli and S. aureus in co-culture biofilms. Together, our study shows that Psl represents a critical first bottleneck to the antibiotic attack of a biofilm community early in biofilm development. Many bacteria have the ability to form multicellular communities, termed biofilms. An important characteristic of a biofilm is the ability of cells to synthesize and secrete an extracellular matrix. This matrix offers structural support, community organization, and added protection, often making the cells impervious to desiccation, predation, and antimicrobials. In this study, we investigate the contributions of polysaccharide components found in the extracellular matrix of Pseudomonas aeruginosa at progressive stages in biofilm development. We first show that one specific polysaccharide, Psl, provides an added defense for P. aeruginosa biofilms against antimicrobials of different properties for young biofilms. Then, by cultivating biofilms that contain both Psl producing and Psl non-producing strains, we find that P. aeruginosa, E. coli, and S. aureus species that lack Psl take advantage of the protection offered by cells producing Psl. Collectively, the data indicate that Psl is likely to play a key protective role in early development of P. aeruginosa biofilm associated infections.
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Affiliation(s)
- Nicole Billings
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Maria Ramirez Millan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Ralph M. Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Marina Caldara
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Roberto Rusconi
- Ralph M. Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Yekaterina Tarasova
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Roman Stocker
- Ralph M. Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Katharina Ribbeck
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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295
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Antimicrobial efficacy of two surface barrier discharges with air plasma against in vitro biofilms. PLoS One 2013; 8:e70462. [PMID: 23894661 PMCID: PMC3722131 DOI: 10.1371/journal.pone.0070462] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 06/24/2013] [Indexed: 11/19/2022] Open
Abstract
The treatment of infected wounds is one possible therapeutic aspect of plasma medicine. Chronic wounds are often associated with microbial biofilms which limit the efficacy of antiseptics. The present study investigates two different surface barrier discharges with air plasma to compare their efficacy against microbial biofilms with chlorhexidine digluconate solution (CHX) as representative of an important antibiofilm antiseptic. Pseudomonas aeruginosa SG81 and Staphylococcus epidermidis RP62A were cultivated on polycarbonate discs. The biofilms were treated for 30, 60, 150, 300 or 600 s with plasma or for 600 s with 0.1% CHX, respectively. After treatment, biofilms were dispensed by ultrasound and the antimicrobial effects were determined as difference in the number of the colony forming units by microbial culture. A high antimicrobial efficacy on biofilms of both plasma sources in comparison to CHX treatment was shown. The efficacy differs between the used strains and plasma sources. For illustration, the biofilms were examined under a scanning electron microscope before and after treatment. Additionally, cytotoxicity was determined by the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay with L929 mouse fibroblast cell line. The cell toxicity of the used plasma limits its applicability on human tissue to maximally 150 s. The emitted UV irradiance was measured to estimate whether UV could limit the application on human tissue at the given parameters. It was found that the UV emission is negligibly low. In conclusion, the results support the assumption that air plasma could be an option for therapy of chronic wounds.
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296
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Bjarnsholt T, Alhede M, Alhede M, Eickhardt-Sørensen SR, Moser C, Kühl M, Jensen PØ, Høiby N. The in vivo biofilm. Trends Microbiol 2013; 21:466-74. [PMID: 23827084 DOI: 10.1016/j.tim.2013.06.002] [Citation(s) in RCA: 492] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/26/2013] [Accepted: 06/05/2013] [Indexed: 11/15/2022]
Abstract
Bacteria can grow and proliferate either as single, independent cells or organized in aggregates commonly referred to as biofilms. When bacteria succeed in forming a biofilm within the human host, the infection often becomes very resistant to treatment and can develop into a chronic state. Biofilms have been studied for decades using various in vitro models, but it remains debatable whether such in vitro biofilms actually resemble in vivo biofilms in chronic infections. In vivo biofilms share several structural characteristics that differ from most in vitro biofilms. Additionally, the in vivo experimental time span and presence of host defenses differ from chronic infections and the chemical microenvironment of both in vivo and in vitro biofilms is seldom taken into account. In this review, we discuss why the current in vitro models of biofilms might be limited for describing infectious biofilms, and we suggest new strategies for improving this discrepancy.
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Affiliation(s)
- Thomas Bjarnsholt
- Department of International Health, Immunology, and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology 9301, Juliane Mariesvej 22, Copenhagen University Hospital, Copenhagen, Denmark.
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297
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Jakobsen TH, Bjarnsholt T, Jensen PØ, Givskov M, Høiby N. Targeting quorum sensing in Pseudomonas aeruginosa biofilms: current and emerging inhibitors. Future Microbiol 2013; 8:901-21. [DOI: 10.2217/fmb.13.57] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bacterial resistance to conventional antibiotics combined with an increasing acknowledgement of the role of biofilms in chronic infections has led to a growing interest in new antimicrobial strategies that target the biofilm mode of growth. In the aggregated biofilm mode, cell-to-cell communication systems involved in the process known as quorum sensing regulate coordinated expression of virulence with immune shielding mechanisms and antibiotic resistance. For two decades, the potential of interference with quorum sensing by small chemical compounds has been investigated with the aim of developing alternative antibacterial strategies. Here, we review state of the art research of quorum sensing inhibitors against the opportunistic human pathogen Pseudomonas aeruginosa, which is found in a number of biofilm-associated infections and identified as the predominant organism infecting the lungs of cystic fibrosis patients.
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Affiliation(s)
- Tim Holm Jakobsen
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Michael Givskov
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, DK-2100 Copenhagen, Denmark
- Costerton Biofilm Center, Department of International Health, Immunology & Microbiology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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298
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Mendes JJ, Leandro C, Corte-Real S, Barbosa R, Cavaco-Silva P, Melo-Cristino J, Górski A, Garcia M. Wound healing potential of topical bacteriophage therapy on diabetic cutaneous wounds. Wound Repair Regen 2013; 21:595-603. [DOI: 10.1111/wrr.12056] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 03/18/2013] [Indexed: 12/17/2022]
Affiliation(s)
| | | | | | | | | | - José Melo-Cristino
- Faculty of Medicine of the University of Lisbon; Institute of Microbiology; Lisbon; Portugal
| | - Andrzej Górski
- Bacteriophage Laboratory; Ludwik Hirszfeld Institute of Immunology and Experimental Therapy; Polish Academy of Sciences; Wroclaw; Poland
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What Is New in the Understanding of Non Healing Wounds Epidemiology, Pathophysiology, and Therapies. ACTA ACUST UNITED AC 2013. [DOI: 10.1155/2013/625934] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chronic wounds are a growing socioeconomic problem in the western world. Knowledge on recalcitrant wounds relies on in vitro studies or clinical observations, and there is emerging evidence on the clinical impact of bacterial biofilm on skin healing. Chronic wounds are locked in the inflammatory state of wound healing, and there are multiple explanations for this arrest with the theory of exaggerated proteolysis as the most commonly accepted. Previously, there has not been enough focus on the different etiologies of chronic wounds compared to acute, healing wounds. There is an urgent need to group chronic wounds by its cause when searching for possible diagnostic or therapeutic targets. Good wound management should therefore consist of recognition of basic wound etiology, irrigation, and debridement in order to reduce microbial and necrotic load, frequently changed dressings, and appropriate antimicrobial and antibiofilm strategies based on precise diagnosis. Representative sampling is required for diagnosis and antimicrobial treatment of wounds. The present review aims at describing the impact of biofilm infections on wounds in relation to diagnosing, treatment strategies, including experimentally adjuvant approaches and animal models.
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