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Di Lodovico S, Petrini M, Di Fermo P, De Pasquale V, De Martino L, D'Ercole S, Nocera FP, Di Giulio M. Staphylococcus pseudintermedius and Pseudomonas aeruginosa Lubbock Chronic Wound Biofilm (LCWB): a suitable dual-species model for in vitro studies. Microbes Infect 2024:105384. [PMID: 38944110 DOI: 10.1016/j.micinf.2024.105384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 06/21/2024] [Accepted: 06/21/2024] [Indexed: 07/01/2024]
Abstract
Antimicrobial treatment of methicillin-resistant Staphylococcus pseudintermedius associated with canine wounds represents an important challenge. The aim of this study was to create a canine wound infection model, Lubbock Chronic Wound Biofilm (LCWB), with a focus on S. pseudintermedius, drawing inspiration from the established human model involving S. aureus. Methicillin-resistant S. pseudintermedius 115 (MRSP) and Pseudomonas aeruginosa 700 strains, isolated from dog wounds, were used to set up the LCWB at 24, 48 and 72h. The LCWBs were evaluated in terms of volume, weight, and microbial CFU/mg. The microbial spatial distribution in the LCWBs was assessed by SEM and CLSM imaging. The best incubation time for the LCWB production in terms of volume (3.38 cm3 ± 0.13), weight (0.86 gr ± 0.02) and CFU/mg (up to 7.05 x 106 CFU/mg ± 2.89 x 105) was 48h. The SEM and CLSM images showed a major viable microbial colonization at 48h with a non-mixed bacteria with a prevalence of MRSP on the surface and P. aeruginosa 700 in the depth of the wound. The obtained findings demonstrate the capability of S. pseudintermedius to grow together P. aeruginosa in the LCWB model, representing the suitable model to reproduce the animal chronic wound in vitro.
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Affiliation(s)
- Silvia Di Lodovico
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Morena Petrini
- Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio" of Chieti, Italy
| | - Paola Di Fermo
- Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio" of Chieti, Italy
| | - Valeria De Pasquale
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Luisa De Martino
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Simonetta D'Ercole
- Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio" of Chieti, Italy
| | - Francesca Paola Nocera
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy.
| | - Mara Di Giulio
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
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Tan L, Ma R, Reeves T, Katz AJ, Levi N. Repurposing Farnesol for Combating Drug-Resistant and Persistent Single and Polymicrobial Biofilms. Antibiotics (Basel) 2024; 13:350. [PMID: 38667026 PMCID: PMC11047559 DOI: 10.3390/antibiotics13040350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/29/2024] Open
Abstract
Biofilm-associated infections caused by drug-resistant and persistent bacteria remain a significant clinical challenge. Here we report that farnesol, commercially available as a cosmetic and flavoring agent, shows significant anti-biofilm properties when dissolved in ethanol using a proprietary formulation emulsion technique. Farnesol in the new formulation inhibits biofilm formation and disrupts established biofilms for Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa, including their polymicrobial biofilms, and, moreover, kills S. aureus persister cells that have developed tolerance to antibiotics. No resistance to farnesol was observed for S. aureus after twenty continuous passages. Farnesol combats biofilms by direct killing, while also facilitating biofilm detachment. Furthermore, farnesol was safe and effective for preventing and treating biofilm-associated infections of both types of bacteria in an ex vivo burned human skin model. These data suggest that farnesol in the new formulation is an effective broad-spectrum anti-biofilm agent with promising clinical potential. Due to its established safety, low-cost, versatility, and excellent efficacy-including ability to reduce persistent and resistant microbial populations-farnesol in the proprietary formulation represents a compelling transformative, translational, and commercial platform for addressing many unsolved clinical challenges.
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Affiliation(s)
- Li Tan
- Department of Plastic and Reconstructive Surgery, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; (L.T.); (A.J.K.)
| | - Rong Ma
- Department of Plastic and Reconstructive Surgery, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; (L.T.); (A.J.K.)
| | - Tony Reeves
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Adam J. Katz
- Department of Plastic and Reconstructive Surgery, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; (L.T.); (A.J.K.)
| | - Nicole Levi
- Department of Plastic and Reconstructive Surgery, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; (L.T.); (A.J.K.)
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Walsh D, Bevan J, Harrison F. How Does Airway Surface Liquid Composition Vary in Different Pulmonary Diseases, and How Can We Use This Knowledge to Model Microbial Infections? Microorganisms 2024; 12:732. [PMID: 38674677 PMCID: PMC11052052 DOI: 10.3390/microorganisms12040732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
Growth environment greatly alters many facets of pathogen physiology, including pathogenesis and antimicrobial tolerance. The importance of host-mimicking environments for attaining an accurate picture of pathogen behaviour is widely recognised. Whilst this recognition has translated into the extensive development of artificial cystic fibrosis (CF) sputum medium, attempts to mimic the growth environment in other respiratory disease states have been completely neglected. The composition of the airway surface liquid (ASL) in different pulmonary diseases is far less well characterised than CF sputum, making it very difficult for researchers to model these infection environments. In this review, we discuss the components of human ASL, how different lung pathologies affect ASL composition, and how different pathogens interact with these components. This will provide researchers interested in mimicking different respiratory environments with the information necessary to design a host-mimicking medium, allowing for better understanding of how to treat pathogens causing infection in these environments.
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Affiliation(s)
- Dean Walsh
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK (F.H.)
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Robertson SN, Romero M, Fenn S, Kohler Riedi PL, Cámara M. Development, characterization, and evaluation of a simple polymicrobial colony biofilm model for testing of antimicrobial wound dressings. J Appl Microbiol 2024; 135:lxae042. [PMID: 38366933 DOI: 10.1093/jambio/lxae042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/12/2024] [Accepted: 02/15/2024] [Indexed: 02/19/2024]
Abstract
Chronic wound infections are generally of polymicrobial nature with aerobic and anaerobic bacteria, as well as fungi frequently observed in them. Wound treatment involves a series of steps, including debridement of the wound, flushing, and often the use of multiple wound dressings many of which are antimicrobial. Yet, many wound dressings are tested versus single species of planktonic microbes, which fails to mirror the real-life presence of biofilms. AIMS Simple biofilm models are the first step to testing of any antimicrobial and wound dressing; therefore, the aim of this study was to develop and validate a simple polymicrobial colony biofilm wound model comprised of Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans on RPMI-1640 agar. The model was then used to evaluate the topical disinfectant chlorohexidine and four commercially available wound dressings using the polymicrobial model. The model used was as a starting point to mimic debridement in clinical care of wounds and the effectiveness of wound dressings evaluated afterwards. METHODS AND RESULTS Planktonic assessment using AATCC100-2004 demonstrated that all antimicrobial wound dressings reduced the planktonic microbial burden below the limit of detection; however, when challenged with polymicrobial colony biofilms, silver wound dressings showed limited effectiveness (1-2 log CFU reductions). In contrast, a single iodine releasing wound dressing showed potent antibiofilm activity reducing all species CFUs below the limit of detection (>6-10 log) depending on the species. A disrupted biofilm model challenge was performed to represent the debridement of a wound and wound silver-based wound dressings were found to be marginally more effective than in whole colony biofilm challenges while the iodine containing wound dressing reduced microbial recovery below the limit of detection. CONCLUSIONS In this model, silver dressings were ineffective versus the whole colony biofilms but showed some recovery of activity versus the disrupted colony biofilm. The iodine wound dressing reduced the viability of all species below the level of detection. This suggests that mode of action of wound dressing should be considered for the type of biofilm challenge as should the clinical use, e.g. debridement.
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Affiliation(s)
- Shaun N Robertson
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, NG7 2RD Nottingham, United Kingdom
| | - Manuel Romero
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, NG7 2RD Nottingham, United Kingdom
- Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Aquatic One Health Research Center (ARCUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Samuel Fenn
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, NG7 2RD Nottingham, United Kingdom
- Schools of Microbiology and Medicine, University College Cork, and APC Microbiome Ireland, Cork T12 TP07, Ireland
| | | | - Miguel Cámara
- National Biofilms Innovation Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, NG7 2RD Nottingham, United Kingdom
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Bastakoti S, Pesonen M, Ajayi C, Julin K, Corander J, Johannessen M, Hanssen AM. Co-culturing with Streptococcus anginosus alters Staphylococcus aureus transcriptome when exposed to tonsillar cells. Front Cell Infect Microbiol 2024; 14:1326730. [PMID: 38333035 PMCID: PMC10850355 DOI: 10.3389/fcimb.2024.1326730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/04/2024] [Indexed: 02/10/2024] Open
Abstract
Introduction Improved understanding of Staphylococcus aureus throat colonization in the presence of other co-existing microbes is important for mapping S. aureus adaptation to the human throat, and recurrence of infection. Here, we explore the responses triggered by the encounter between two common throat bacteria, S. aureus and Streptococcus anginosus, to identify genes in S. aureus that are important for colonization in the presence of human tonsillar epithelial cells and S. anginosus, and further compare this transcriptome with the genes expressed in S. aureus as only bacterium. Methods We performed an in vitro co-culture experiment followed by RNA sequencing to identify interaction-induced transcriptional alterations and differentially expressed genes (DEGs), followed by gene enrichment analysis. Results and discussion A total of 332 and 279 significantly differentially expressed genes with p-value < 0.05 and log2 FoldChange (log2FC) ≥ |2| were identified in S. aureus after 1 h and 3 h co-culturing, respectively. Alterations in expression of various S. aureus survival factors were observed when co-cultured with S. anginosus and tonsillar cells. The serine-aspartate repeat-containing protein D (sdrD) involved in adhesion, was for example highly upregulated in S. aureus during co-culturing with S. anginosus compared to S. aureus grown in the absence of S. anginosus, especially at 3 h. Several virulence genes encoding secreted proteins were also highly upregulated only when S. aureus was co-cultured with S. anginosus and tonsillar cells, and iron does not appear to be a limiting factor in this environment. These findings may be useful for the development of interventions against S. aureus throat colonization and could be further investigated to decipher the roles of the identified genes in the host immune response in context of a throat commensal landscape.
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Affiliation(s)
- Srijana Bastakoti
- Department of Medical Biology, Research group for Host-Microbe Interaction (HMI), UiT – The Arctic University of Norway, Tromsø, Norway
| | - Maiju Pesonen
- Oslo Centre of Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway
| | - Clement Ajayi
- Department of Medical Biology, Research group for Host-Microbe Interaction (HMI), UiT – The Arctic University of Norway, Tromsø, Norway
| | - Kjersti Julin
- Department of Medical Biology, Research group for Host-Microbe Interaction (HMI), UiT – The Arctic University of Norway, Tromsø, Norway
| | - Jukka Corander
- Department of Biostatistics, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridgeshire, United Kingdom
- Helsinki Institute of Information Technology, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
| | - Mona Johannessen
- Department of Medical Biology, Research group for Host-Microbe Interaction (HMI), UiT – The Arctic University of Norway, Tromsø, Norway
| | - Anne-Merethe Hanssen
- Department of Medical Biology, Research group for Host-Microbe Interaction (HMI), UiT – The Arctic University of Norway, Tromsø, Norway
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Kang Z, Martinson VG, Wang Y, Coon KL, Valzania L, Strand MR. Increased environmental microbial diversity reduces the disease risk of a mosquitocidal pathogen. mBio 2024; 15:e0272623. [PMID: 38055338 PMCID: PMC10790785 DOI: 10.1128/mbio.02726-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 10/25/2023] [Indexed: 12/08/2023] Open
Abstract
IMPORTANCE The host-specific microbiotas of animals can both reduce and increase disease risks from pathogens. In contrast, how environmental microbial communities affect pathogens is largely unexplored. Aquatic habitats are of interest because water enables environmental microbes to readily interact with animal pathogens. Here, we focused on mosquitoes, which are important disease vectors as terrestrial adults but are strictly aquatic as larvae. We identified a pathogen of mosquito larvae from the field as a strain of Chromobacterium haemolyticum. Comparative genomic analyses and functional assays indicate this strain and other Chromobacterium are mosquitocidal but are also opportunistic pathogens of other animals. We also identify a critical role for diversity of the environmental microbiota in disease risk. Our study characterizes both the virulence mechanisms of a pathogen and the role of the environmental microbiota in disease risk to an aquatic animal of significant importance to human health.
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Affiliation(s)
- Zhiwei Kang
- Hebei University, College of Life Sciences, Baoding, Hebei, China
| | - Vincent G. Martinson
- Department of Entomology, University of Georgia, Athens, Georgia, USA
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Yin Wang
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Kerri L. Coon
- Department of Entomology, University of Georgia, Athens, Georgia, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Luca Valzania
- Department of Entomology, University of Georgia, Athens, Georgia, USA
- Institut Curie, Paris, France
| | - Michael R. Strand
- Department of Entomology, University of Georgia, Athens, Georgia, USA
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Liu Y, McQuillen EA, Rana PSJB, Gloag ES, Parsek MR, Wozniak DJ. A bacterial pigment provides cross-species protection from H 2O 2- and neutrophil-mediated killing. Proc Natl Acad Sci U S A 2024; 121:e2312334121. [PMID: 38170744 PMCID: PMC10786307 DOI: 10.1073/pnas.2312334121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 11/29/2023] [Indexed: 01/05/2024] Open
Abstract
Bacterial infections are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus cause chronic co-infections, which are more problematic than mono-species infections. Understanding the mechanisms of their interactions is crucial for treating co-infections. Staphyloxanthin (STX), a yellow pigment synthesized by the S. aureus crt operon, promotes S. aureus resistance to oxidative stress and neutrophil-mediated killing. We found that STX production by S. aureus, either as surface-grown macrocolonies or planktonic cultures, was elevated when exposed to the P. aeruginosa exoproduct, 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). This was observed with both mucoid and non-mucoid P. aeruginosa strains. The induction phenotype was found in a majority of P. aeruginosa and S. aureus clinical isolates examined. When subjected to hydrogen peroxide or human neutrophils, P. aeruginosa survival was significantly higher when mixed with wild-type (WT) S. aureus, compared to P. aeruginosa alone or with an S. aureus crt mutant deficient in STX production. In a murine wound model, co-infection with WT S. aureus, but not the STX-deficient mutant, enhanced P. aeruginosa burden and disease compared to mono-infection. In conclusion, we identified a role for P. aeruginosa HQNO mediating polymicrobial interactions with S. aureus by inducing STX production, which consequently promotes resistance to the innate immune effectors H2O2 and neutrophils. These results further our understanding of how different bacterial species cooperatively cause co-infections.
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Affiliation(s)
- Yiwei Liu
- Department of Microbiology, Ohio State University, Columbus, OH43210
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
| | - Eleanor A. McQuillen
- Department of Health and Rehabilitation Sciences, Ohio State University College of Medicine, Columbus, OH43210
| | - Pranav S. J. B. Rana
- Department of Microbiology, Ohio State University, Columbus, OH43210
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
| | - Erin S. Gloag
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
- Department of Biomedical Sciences and Pathobiology, Virginia Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA24060
| | - Matthew R. Parsek
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA98195
| | - Daniel J. Wozniak
- Department of Microbiology, Ohio State University, Columbus, OH43210
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, OH43210
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Srinivasan A, Sajeevan A, Rajaramon S, David H, Solomon AP. Solving polymicrobial puzzles: evolutionary dynamics and future directions. Front Cell Infect Microbiol 2023; 13:1295063. [PMID: 38145044 PMCID: PMC10748482 DOI: 10.3389/fcimb.2023.1295063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/03/2023] [Indexed: 12/26/2023] Open
Abstract
Polymicrobial infections include various microorganisms, often necessitating different treatment methods than a monomicrobial infection. Scientists have been puzzled by the complex interactions within these communities for generations. The presence of specific microorganisms warrants a chronic infection and impacts crucial factors such as virulence and antibiotic susceptibility. Game theory is valuable for scenarios involving multiple decision-makers, but its relevance to polymicrobial infections is limited. Eco-evolutionary dynamics introduce causation for multiple proteomic interactions like metabolic syntropy and niche segregation. The review culminates both these giants to form evolutionary dynamics (ED). There is a significant amount of literature on inter-bacterial interactions that remain unsynchronised. Such raw data can only be moulded by analysing the ED involved. The review culminates the inter-bacterial interactions in multiple clinically relevant polymicrobial infections like chronic wounds, CAUTI, otitis media and dental carries. The data is further moulded with ED to analyse the niche colonisation of two notoriously competitive bacteria: S.aureus and P.aeruginosa. The review attempts to develop a future trajectory for polymicrobial research by following recent innovative strategies incorporating ED to curb polymicrobial infections.
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Affiliation(s)
| | | | | | | | - Adline Princy Solomon
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
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Mariani F, Galvan EM. Staphylococcus aureus in Polymicrobial Skinand Soft Tissue Infections: Impact of Inter-Species Interactionsin Disease Outcome. Antibiotics (Basel) 2023; 12:1164. [PMID: 37508260 PMCID: PMC10376372 DOI: 10.3390/antibiotics12071164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
Polymicrobial biofilms provide a complex environment where co-infecting microorganisms can behave antagonistically, additively, or synergistically to alter the disease outcome compared to monomicrobial infections. Staphylococcus aureus skin and soft tissue infections (Sa-SSTIs) are frequently reported in healthcare and community settings, and they can also involve other bacterial and fungal microorganisms. This polymicrobial aetiology is usually found in chronic wounds, such as diabetic foot ulcers, pressure ulcers, and burn wounds, where the establishment of multi-species biofilms in chronic wounds has been extensively described. This review article explores the recent updates on the microorganisms commonly found together with S. aureus in SSTIs, such as Pseudomonas aeruginosa, Escherichia coli, Enterococcus spp., Acinetobacter baumannii, and Candida albicans, among others. The molecular mechanisms behind these polymicrobial interactions in the context of infected wounds and their impact on pathogenesis and antimicrobial susceptibility are also revised.
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Affiliation(s)
- Florencia Mariani
- Laboratorio de Patogénesis Bacteriana, Departamento de Investigaciones Bioquímicas y Farmacéuticas, Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Hidalgo 775, Buenos Aires C1405, Argentina;
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires A4400, Argentina
| | - Estela Maria Galvan
- Laboratorio de Patogénesis Bacteriana, Departamento de Investigaciones Bioquímicas y Farmacéuticas, Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Hidalgo 775, Buenos Aires C1405, Argentina;
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires A4400, Argentina
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Liu Y, McQuillen EA, Rana PSJB, Gloag ES, Wozniak DJ. Cross-Species Protection to Innate Immunity Mediated by A Bacterial Pigment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.15.524085. [PMID: 36711503 PMCID: PMC9882196 DOI: 10.1101/2023.01.15.524085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bacterial infections are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus cause chronic co-infections, which are more problematic than mono-species infections. We found that the production of S. aureus membrane-bound pigment staphyloxanthin (STX), was induced by the P. aeruginosa exoproduct, 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). The induction phenotype was conserved in P. aeruginosa and S. aureus clinical isolates examined. When subjected to hydrogen peroxide or human neutrophils, P. aeruginosa survival was significantly higher when mixed with wild-type (WT) S. aureus , compared to a mutant deficient in STX production or P. aeruginosa alone. In a murine wound model, co-infection with WT S. aureus , but not the STX-deficient mutant, enhanced P. aeruginosa burden and disease compared to mono-infection. In conclusion, we discovered a novel role for P. aeruginosa HQNO mediating polymicrobial interactions with S. aureus by inducing STX production, which consequently promotes resistance of both pathogens to innate immune effectors. These results further our understanding of how different bacterial species cooperatively cause co-infections.
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11
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Biofilms in Chronic Wound Infections: Innovative Antimicrobial Approaches Using the In Vitro Lubbock Chronic Wound Biofilm Model. Int J Mol Sci 2023; 24:ijms24021004. [PMID: 36674518 PMCID: PMC9862456 DOI: 10.3390/ijms24021004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/23/2022] [Accepted: 12/27/2022] [Indexed: 01/06/2023] Open
Abstract
Chronic wounds have harmful effects on both patients and healthcare systems. Wound chronicity is attributed to an impaired healing process due to several host and local factors that affect healing pathways. The resulting ulcers contain a wide variety of microorganisms that are mostly resistant to antimicrobials and possess the ability to form mono/poly-microbial biofilms. The search for new, effective and safe compounds to handle chronic wounds has come a long way throughout the history of medicine, which has included several studies and trials of conventional treatments. Treatments focus on fighting the microbial colonization that develops in the wound by multidrug resistant pathogens. The development of molecular medicine, especially in antibacterial agents, needs an in vitro model similar to the in vivo chronic wound environment to evaluate the efficacy of antimicrobial agents. The Lubbock chronic wound biofilm (LCWB) model is an in vitro model developed to mimic the pathogen colonization and the biofilm formation of a real chronic wound, and it is suitable to screen the antibacterial activity of innovative compounds. In this review, we focused on the characteristics of chronic wound biofilms and the contribution of the LCWB model both to the study of wound poly-microbial biofilms and as a model for novel treatment strategies.
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Armes AC, Walton JL, Buchan A. Quorum Sensing and Antimicrobial Production Orchestrate Biofilm Dynamics in Multispecies Bacterial Communities. Microbiol Spectr 2022; 10:e0261522. [PMID: 36255295 PMCID: PMC9769649 DOI: 10.1128/spectrum.02615-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 09/16/2022] [Indexed: 01/07/2023] Open
Abstract
Microbial interactions are often mediated by diffusible small molecules, including secondary metabolites, that play roles in cell-to-cell signaling and inhibition of competitors. Biofilms are often "hot spots" for high concentrations of bacteria and their secondary metabolites, which make them ideal systems for the study of small-molecule contributions to microbial interactions. Here, we use a five-member synthetic community consisting of Roseobacteraceae representatives to investigate the role of secondary metabolites on microbial biofilm dynamics. One synthetic community member, Rhodobacterales strain Y4I, possesses two acylated homoserine lactone (AHL)-based cell-to-cell signaling systems (pgaRI and phaRI) as well as a nonribosomal peptide synthase gene (igi) cluster that encodes the antimicrobial indigoidine. Through serial substitution of Y4I with mutants deficient in single signaling molecule pathways, the contribution of these small-molecule systems could be assessed. As secondary metabolite production is dependent upon central metabolites, the influence of growth substrate (i.e., complex medium versus defined medium with a single carbon substrate) on these dynamics was also considered. Depending on the Y4I mutant genotype included, community dynamics ranged from competitive to cooperative. The observed interactions were mostly competitive in nature. However, the community harboring a Y4I variant that was both impaired in quorum sensing (QS) pathways and unable to produce indigoidine (pgaR variant) shifted toward more cooperative interactions over time. These cooperative interactions were enhanced in the defined growth medium. The results presented provide a framework for deciphering complex, small-molecule-mediated interactions that have broad application to microbial biology. IMPORTANCE Microbial biofilms play critical roles in marine ecosystems and are hot spots for microbial interactions that play a role in the development and function of these communities. Roseobacteraceae are an abundant and active family of marine heterotrophic bacteria forming close associations with phytoplankton and carrying out key transformations in biogeochemical cycles. Group members are aggressive primary colonizers of surfaces, where they set the stage for the development of multispecies biofilm communities. Few studies have examined the impact of secondary metabolites, such as cell-to-cell signaling and antimicrobial production, on marine microbial biofilm community structure. Here, we assessed the impact of secondary metabolites on microbial interactions using a synthetic, five-member Roseobacteraceae community by measuring species composition and biomass production during biofilm growth. We present evidence that secondary metabolites influence social behaviors within these multispecies microbial biofilms, thereby improving understanding of bacterial secondary metabolite production influence on social behaviors within marine microbial biofilm communities.
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Affiliation(s)
- April C. Armes
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Jillian L. Walton
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Alison Buchan
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
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Durand BARN, Pouget C, Magnan C, Molle V, Lavigne JP, Dunyach-Remy C. Bacterial Interactions in the Context of Chronic Wound Biofilm: A Review. Microorganisms 2022; 10:microorganisms10081500. [PMID: 35893558 PMCID: PMC9332326 DOI: 10.3390/microorganisms10081500] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/15/2022] [Accepted: 07/21/2022] [Indexed: 02/04/2023] Open
Abstract
Chronic wounds, defined by their resistance to care after four weeks, are a major concern, affecting millions of patients every year. They can be divided into three types of lesions: diabetic foot ulcers (DFU), pressure ulcers (PU), and venous/arterial ulcers. Once established, the classical treatment for chronic wounds includes tissue debridement at regular intervals to decrease biofilm mass constituted by microorganisms physiologically colonizing the wound. This particular niche hosts a dynamic bacterial population constituting the bed of interaction between the various microorganisms. The temporal reshuffle of biofilm relies on an organized architecture. Microbial community turnover is mainly associated with debridement (allowing transitioning from one major representant to another), but also with microbial competition and/or collaboration within wounds. This complex network of species and interactions has the potential, through diversity in antagonist and/or synergistic crosstalk, to accelerate, delay, or worsen wound healing. Understanding these interactions between microorganisms encountered in this clinical situation is essential to improve the management of chronic wounds.
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Affiliation(s)
- Benjamin A. R. N. Durand
- Bacterial Virulence and Chronic Infections, UMR 1047, Université Montpellier, INSERM, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 30908 Nîmes, France; (B.A.R.N.D.); (C.P.); (C.M.); (J.-P.L.)
| | - Cassandra Pouget
- Bacterial Virulence and Chronic Infections, UMR 1047, Université Montpellier, INSERM, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 30908 Nîmes, France; (B.A.R.N.D.); (C.P.); (C.M.); (J.-P.L.)
| | - Chloé Magnan
- Bacterial Virulence and Chronic Infections, UMR 1047, Université Montpellier, INSERM, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 30908 Nîmes, France; (B.A.R.N.D.); (C.P.); (C.M.); (J.-P.L.)
| | - Virginie Molle
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, UMR 5235, 34000 Montpellier, France;
| | - Jean-Philippe Lavigne
- Bacterial Virulence and Chronic Infections, UMR 1047, Université Montpellier, INSERM, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 30908 Nîmes, France; (B.A.R.N.D.); (C.P.); (C.M.); (J.-P.L.)
| | - Catherine Dunyach-Remy
- Bacterial Virulence and Chronic Infections, UMR 1047, Université Montpellier, INSERM, Service de Microbiologie et Hygiène Hospitalière, CHU Nîmes, 30908 Nîmes, France; (B.A.R.N.D.); (C.P.); (C.M.); (J.-P.L.)
- Correspondence: ; Tel.: +33-466-683-202
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14
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Biswas L, Götz F. Molecular Mechanisms of Staphylococcus and Pseudomonas Interactions in Cystic Fibrosis. Front Cell Infect Microbiol 2022; 11:824042. [PMID: 35071057 PMCID: PMC8770549 DOI: 10.3389/fcimb.2021.824042] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 12/16/2021] [Indexed: 11/15/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive genetic disorder that is characterized by recurrent and chronic infections of the lung predominantly by the opportunistic pathogens, Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. While S. aureus is the main colonizing bacteria of the CF lungs during infancy and early childhood, its incidence declines thereafter and infections by P. aeruginosa become more prominent with increasing age. The competitive and cooperative interactions exhibited by these two pathogens influence their survival, antibiotic susceptibility, persistence and, consequently the disease progression. For instance, P. aeruginosa secretes small respiratory inhibitors like hydrogen cyanide, pyocyanin and quinoline N-oxides that block the electron transport pathway and suppress the growth of S. aureus. However, S. aureus survives this respiratory attack by adapting to respiration-defective small colony variant (SCV) phenotype. SCVs cause persistent and recurrent infections and are also resistant to antibiotics, especially aminoglycosides, antifolate antibiotics, and to host antimicrobial peptides such as LL-37, human β-defensin (HBD) 2 and HBD3; and lactoferricin B. The interaction between P. aeruginosa and S. aureus is multifaceted. In mucoid P. aeruginosa strains, siderophores and rhamnolipids are downregulated thus enhancing the survival of S. aureus. Conversely, protein A from S. aureus inhibits P. aeruginosa biofilm formation while protecting both P. aeruginosa and S. aureus from phagocytosis by neutrophils. This review attempts to summarize the current understanding of the molecular mechanisms that drive the competitive and cooperative interactions between S. aureus and P. aeruginosa in the CF lungs that could influence the disease outcome.
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Affiliation(s)
- Lalitha Biswas
- Centre for Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham, Kochi, India
| | - Friedrich Götz
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany
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15
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Mixed Populations and Co-Infection: Pseudomonas aeruginosa and Staphylococcus aureus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:397-424. [DOI: 10.1007/978-3-031-08491-1_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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16
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Miranda SW, Asfahl KL, Dandekar AA, Greenberg EP. Pseudomonas aeruginosa Quorum Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:95-115. [PMID: 36258070 PMCID: PMC9942581 DOI: 10.1007/978-3-031-08491-1_4] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Pseudomonas aeruginosa, like many bacteria, uses chemical signals to communicate between cells in a process called quorum sensing (QS). QS allows groups of bacteria to sense population density and, in response to changing cell densities, to coordinate behaviors. The P. aeruginosa QS system consists of two complete circuits that involve acyl-homoserine lactone signals and a third system that uses quinolone signals. Together, these three QS circuits regulate the expression of hundreds of genes, many of which code for virulence factors. P. aeruginosa has become a model for studying the molecular biology of QS and the ecology and evolution of group behaviors in bacteria. In this chapter, we recount the history of discovery of QS systems in P. aeruginosa, discuss how QS relates to virulence and the ecology of this bacterium, and explore strategies to inhibit QS. Finally, we discuss future directions for research in P. aeruginosa QS.
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Affiliation(s)
| | - Kyle L Asfahl
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
| | - Ajai A Dandekar
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - E P Greenberg
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA.
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17
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Kadam S, Madhusoodhanan V, Dhekane R, Bhide D, Ugale R, Tikhole U, Kaushik KS. Milieu matters: An in vitro wound milieu to recapitulate key features of, and probe new insights into, mixed-species bacterial biofilms. Biofilm 2021; 3:100047. [PMID: 33912828 PMCID: PMC8065265 DOI: 10.1016/j.bioflm.2021.100047] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/29/2021] [Accepted: 03/29/2021] [Indexed: 12/20/2022] Open
Abstract
Bacterial biofilms are a major cause of delayed wound healing. Consequently, the study of wound biofilms, particularly in host-relevant conditions, has gained importance. Most in vitro studies employ refined laboratory media to study biofilms, representing conditions that are not relevant to the infection state. To mimic the wound milieu, in vitro biofilm studies often incorporate serum or plasma in growth conditions, or employ clot or matrix-based biofilm models. While incorporating serum or plasma alone is a minimalistic approach, the more complex in vitro wound models are technically demanding, and poorly compatible with standard biofilm assays. Based on previous reports of clinical wound fluid composition, we have developed an in vitro wound milieu (IVWM) that includes, in addition to serum (to recapitulate wound fluid), matrix elements and biochemical factors. With Luria-Bertani broth and Fetal Bovine Serum (FBS) for comparison, the IVWM was used to study planktonic growth, biofilm features, and interspecies interactions, of common wound pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. We demonstrate that the IVWM recapitulates widely reported in vivo biofilm features such as biomass formation, metabolic activity, increased antibiotic tolerance, 3D structure, and interspecies interactions for monospecies and mixed-species biofilms. Further, the IVWM is simple to formulate, uses laboratory-grade components, and is compatible with standard biofilm assays. Given this, it holds potential as a tractable approach to study wound biofilms under host-relevant conditions.
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Affiliation(s)
- Snehal Kadam
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Vandana Madhusoodhanan
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Radhika Dhekane
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Devyani Bhide
- MES Abasaheb Garware College of Arts and Science, Pune, India
| | - Rutuja Ugale
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Utkarsha Tikhole
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune, India
| | - Karishma S. Kaushik
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune, India
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18
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Redman WK, Welch GS, Williams AC, Damron AJ, Northcut WO, Rumbaugh KP. Efficacy and safety of biofilm dispersal by glycoside hydrolases in wounds. Biofilm 2021; 3:100061. [PMID: 34825176 PMCID: PMC8605310 DOI: 10.1016/j.bioflm.2021.100061] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 12/20/2022] Open
Abstract
Novel anti-biofilm and dispersal agents are currently being investigated in an attempt to combat biofilm-associated wound infections. Glycoside hydrolases (GHs) are enzymes that hydrolyze the glycosidic bonds between sugars, such as those found within the exopolysaccharides of the biofilm matrix. Previous studies have shown that GHs can weaken the matrix, inducing bacterial dispersal, and improving antibiotic clearance. Yet, the number of GH enzymes that have been examined for potential therapeutic effects is limited. In this study, we screened sixteen GHs for their ability to disperse mono-microbial and polymicrobial biofilms grown in different environments. Six GHs, α-amylase (source: A. oryzae), alginate lyase (source: various algae), pectinase (source: Rhizopus sp.), amyloglucosidase (source: A. niger), inulinase (source: A. niger), and xylanase (source: A. oryzae), exhibited the highest dispersal efficacy in vitro. Two GHs, α-amylase (source: Bacillus sp.) and cellulase (source: A. niger), used in conjunction with meropenem demonstrated infection clearing ability in a mouse wound model. GHs were also effective in improving antibiotic clearance in diabetic mice. To examine their safety, we screened the GHs for toxicity in cell culture. Overall, there was an inverse relationship between enzyme exposure time and cellular toxicity, with twelve out of sixteen GHs demonstrating some level of toxicity in cell culture. However, only one GH exhibited harmful effects in mice. These results further support the ability of GHs to improve antibiotic clearance of biofilm-associated infections and help lay a foundation for establishing GHs as therapeutic agents for chronic wound infections.
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Affiliation(s)
- Whitni K Redman
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Garrett S Welch
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,TTUHSC Surgery Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Avery C Williams
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Addyson J Damron
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | | | - Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA.,TTUHSC Surgery Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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19
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Pekmezovic M, Kaune AK, Austermeier S, Hitzler SUJ, Mogavero S, Hovhannisyan H, Gabaldón T, Gresnigt MS, Hube B. Human albumin enhances the pathogenic potential of Candida glabrata on vaginal epithelial cells. PLoS Pathog 2021; 17:e1010037. [PMID: 34710198 PMCID: PMC8577789 DOI: 10.1371/journal.ppat.1010037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/09/2021] [Accepted: 10/15/2021] [Indexed: 12/15/2022] Open
Abstract
The opportunistic pathogen Candida glabrata is the second most frequent causative agent of vulvovaginal candidiasis (VVC), a disease that affects 70–75% of women at least once during their life. However, C. glabrata is almost avirulent in mice and normally incapable of inflicting damage to vaginal epithelial cells in vitro. We thus proposed that host factors present in vivo may influence C. glabrata pathogenicity. We, therefore, analyzed the impact of albumin, one of the most abundant proteins of the vaginal fluid. The presence of human, but not murine, albumin dramatically increased the potential of C. glabrata to damage vaginal epithelial cells. This effect depended on macropinocytosis-mediated epithelial uptake of albumin and subsequent proteolytic processing. The enhanced pathogenicity of C. glabrata can be explained by a combination of beneficial effects for the fungus, which includes an increased access to iron, accelerated growth, and increased adhesion. Screening of C. glabrata deletion mutants revealed that Hap5, a key regulator of iron homeostasis, is essential for the albumin-augmented damage potential. The albumin-augmented pathogenicity was reversed by the addition of iron chelators and a similar increase in pathogenicity was shown by increasing the iron availability, confirming a key role of iron. Accelerated growth not only led to higher cell numbers, but also to increased fungal metabolic activity and oxidative stress resistance. Finally, the albumin-driven enhanced damage potential was associated with the expression of distinct C. glabrata virulence genes. Transcriptional responses of the epithelial cells suggested an unfolded protein response (UPR) and ER-stress responses combined with glucose starvation induced by fast growing C. glabrata cells as potential mechanisms by which cytotoxicity is mediated.Collectively, we demonstrate that albumin augments the pathogenic potential of C. glabrata during interaction with vaginal epithelial cells. This suggests a role for albumin as a key player in the pathogenesis of VVC. Candida glabrata is the overall second causative species of candidiasis in humans, but little is known about the pathogenicity mechanisms of this yeast. C. glabrata is capable of causing lethal systemic candidiasis mostly in elderly immunocompromised patients, but is also a frequent cause of vulvovaginal candidiasis. These clinical insights suggest that C. glabrata has a high virulence potential, yet little pathogenicity is observed in both in vitro and in vivo infection models. The finding that human albumin, the most abundant protein in the human body, is boosting C. glabrata pathogenicity in vitro provides novel insights into C. glabrata pathogenicity mechanisms and shows that the presence of distinct human factors can have a significant influence on the virulence potential of a pathogenic microbe.
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Affiliation(s)
- Marina Pekmezovic
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Ann-Kristin Kaune
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Sophie Austermeier
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Sophia U. J. Hitzler
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Selene Mogavero
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Hrant Hovhannisyan
- Life Sciences Department, Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Mechanisms of Disease Department, Institute for Research in Biomedicine (IRB), Barcelona, Spain
| | - Toni Gabaldón
- Life Sciences Department, Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Mechanisms of Disease Department, Institute for Research in Biomedicine (IRB), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Mark S. Gresnigt
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
- * E-mail: (MSG); (BH)
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
- * E-mail: (MSG); (BH)
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20
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Lopez AJ, Jones LM, Reynolds L, Diaz RC, George IK, Little W, Fleming D, D'souza A, Rennie MY, Rumbaugh KP, Smith AC. Detection of bacterial fluorescence from in vivo wound biofilms using a point-of-care fluorescence imaging device. Int Wound J 2021; 18:626-638. [PMID: 33565263 PMCID: PMC8450799 DOI: 10.1111/iwj.13564] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/15/2022] Open
Abstract
Wound biofilms must be identified to target disruption and bacterial eradication but are challenging to detect with standard clinical assessment. This study tested whether bacterial fluorescence imaging could detect porphyrin-producing bacteria within a biofilm using well-established in vivo models. Mouse wounds were inoculated on Day 0 with planktonic bacteria (n = 39, porphyrin-producing and non-porphyrin-producing species, 107 colony forming units (CFU)/wound) or with polymicrobial biofilms (n = 16, 3 biofilms per mouse, each with 1:1:1 parts Staphylococcus aureus/Escherichia coli/Enterobacter cloacae, 107 CFU/biofilm) that were grown in vitro. Mouse wounds inoculated with biofilm underwent fluorescence imaging up to Day 4 or 5. Wounds were then excised and sent for microbiological analysis. Bacteria-matrix interaction was assessed with scanning electron microscopy (SEM) and histopathology. A total of 48 hours after inoculation with planktonic bacteria or biofilm, red fluorescence was readily detected in wounds; red fluorescence intensified up to Day 4. Red fluorescence from biofilms persisted in excised wound tissue post-wash. SEM and histopathology confirmed bacteria-matrix interaction. This pre-clinical study is the first to demonstrate the fluorescence detection of bacterial biofilm in vivo using a point-of-care wound imaging device. These findings have implications for clinicians targeting biofilm and may facilitate improved visualisation and removal of biofilms.
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Affiliation(s)
- Andrea J. Lopez
- Department of Honors StudiesTexas Tech UniversityLubbockTexasUSA
| | | | - Landrye Reynolds
- Department of Honors StudiesTexas Tech UniversityLubbockTexasUSA
| | - Rachel C. Diaz
- Department of Honors StudiesTexas Tech UniversityLubbockTexasUSA
| | - Isaiah K. George
- Department of Honors StudiesTexas Tech UniversityLubbockTexasUSA
| | - William Little
- Department of Honors StudiesTexas Tech UniversityLubbockTexasUSA
| | - Derek Fleming
- Department of SurgeryTexas Tech University Health Sciences CenterLubbockTexasUSA
- Division of Clinical Microbiology, Department of Laboratory Medicine and PathologyMayo ClinicRochesterMinnesotaUSA
| | | | | | - Kendra P. Rumbaugh
- Department of SurgeryTexas Tech University Health Sciences CenterLubbockTexasUSA
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21
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Tabraiz S, Petropoulos E, Shamurad B, Quintela-Baluja M, Mohapatra S, Acharya K, Charlton A, Davenport RJ, Dolfing J, Sallis PJ. Temperature and immigration effects on quorum sensing in the biofilms of anaerobic membrane bioreactors. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 293:112947. [PMID: 34289594 DOI: 10.1016/j.jenvman.2021.112947] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 04/25/2021] [Accepted: 05/10/2021] [Indexed: 06/13/2023]
Abstract
Quorum sensing (QS), a microbial communication mechanism modulated by acyl homoserine lactone (AHL) molecules impacts biofilm formation in bioreactors. This study investigated the effects of temperature and immigration on AHL levels and biofouling in anaerobic membrane bioreactors. The hypothesis was that the immigrant microbial community would increase the AHL-mediated QS, thus stimulating biofouling and that low temperatures would exacerbate this. We observed that presence of immigrants, especially when exposed to low temperatures indeed increased AHL concentrations and fouling in the biofilms on the membranes. At low temperature, the concentrations of the main AHLs observed, N-dodecanoyl-L-homoserine lactone and N-decanoyl-L-homoserine lactone, were significantly higher in the biofilms than in the sludge and correlated significantly with the abundance of immigrant bacteria. Apparently low temperature, immigration and denser community structure in the biofilm stressed the communities, triggering AHL production and excretion. These insights into the social behaviour of reactor communities responding to low temperature and influx of immigrants have implications for biofouling control in bioreactors.
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Affiliation(s)
- Shamas Tabraiz
- School of Engineering, Newcastle University, Newcastle, NE1 7RU, UK; School of Natural and Applied Sciences, Canterbury Christ Church University, CT1 1QU, UK.
| | | | - Burhan Shamurad
- School of Engineering, Newcastle University, Newcastle, NE1 7RU, UK
| | | | - Sanjeeb Mohapatra
- Environmental Research Institute, National University of Singapore, 117411, Singapore
| | - Kishor Acharya
- School of Engineering, Newcastle University, Newcastle, NE1 7RU, UK
| | - Alex Charlton
- School of Natural and Environmental Sciences, Newcastle University, UK
| | | | - Jan Dolfing
- Faculty of Engineering and Environment, Northumbria University, Newcastle, NE1 8QH, UK
| | - Paul J Sallis
- School of Engineering, Newcastle University, Newcastle, NE1 7RU, UK
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22
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Abstract
Albumin is abundant in serum but is also excreted at mucosal surfaces and enters tissues when inflammation increases vascular permeability. Host-associated opportunistic pathogens encounter albumin during commensalism and when causing infections. Considering the ubiquitous presence of albumin, we investigated its role in the pathogenesis of infections with the model human fungal pathogen, Candida albicans. Albumin was introduced in various in vitro models that mimic different stages of systemic or mucosal candidiasis, where it reduced the ability of C. albicans to damage host cells. The amphipathic toxin candidalysin mediates necrotic host cell damage induced by C. albicans. Using cellular and biophysical assays, we determined that albumin functions by neutralizing candidalysin through hydrophobic interactions. We discovered that albumin, similarly, can neutralize a variety of fungal (α-amanitin), bacterial (streptolysin O and staurosporin), and insect (melittin) hydrophobic toxins. These data suggest albumin as a defense mechanism against toxins, which can play a role in the pathogenesis of microbial infections. IMPORTANCE Albumin is the most abundant serum protein in humans. During inflammation, serum albumin levels decrease drastically, and low albumin levels are associated with poor patient outcome. Thus, albumin may have specific functions during infection. Here, we describe the ability of albumin to neutralize hydrophobic microbial toxins. We show that albumin can protect against damage induced by the pathogenic yeast C. albicans by neutralizing its cytolytic toxin candidalysin. These findings suggest that albumin is a toxin-neutralizing protein that may play a role during infections with toxin-producing microorganisms.
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23
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He YZ, Xu Y, Sun J, Gao BL, Li G, Zhou YF, Lian XL, Fang LX, Liao XP, Mediavilla JR, Chen L, Liu YH. Novel Plasmid-Borne Fimbriae-Associated Gene Cluster Participates in Biofilm Formation in Escherichia coli. Microb Drug Resist 2021; 27:1624-1632. [PMID: 34077284 DOI: 10.1089/mdr.2020.0512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study reported the involvement of a gene cluster from a conjugative plasmid in the biofilm formation of Escherichia coli. We used a novel EZ-Tn5 transposon technique to generate a transposon library and used arbitrarily primed PCR to detect the insertion sites in biofilm formation-deficient mutants. To validate the function of candidate biofilm formation genes, the genes were cloned into plasmid pBluescript II SK (+) and transformed into E. coil DH5α. Biofilm production from the transformants was then assessed by phenotypic biofilm formation using Crystal Violet staining and microscopy. A total of 3,000 transposon mutants of E. coli DH5α-p253 were screened, of which 28 were found to be deficient in biofilm formation. Further characterization revealed that 24/28 mutations were detected with their insertions in chromosome, while the remaining 4 mutations were evidenced that the functional genes for biofilm formation were harbored in the plasmid. Interestingly, the plasmid sequencing showed that these four transposon mutations were all inserted into a fimbriae-associated gene cluster (fim-cluster). This fim-cluster is a hybrid segment spanning a 7,949 bp sequence, with a terminal inverted repeat sequence and two coding regions. In summary, we performed a high-efficiency screening to a library constructed with the EZ-Tn5-based transposon approach and identified the gene clusters responsible for the biofilm production of E. coli, especially the genes harbored in the plasmid. Further studies are needed to understand the spread of this novel plasmid-mediated biofilm formation gene in clinical E. coli isolates and the clinical impacts.
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Affiliation(s)
- Yu-Zhang He
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Ying Xu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Jian Sun
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Bei-Le Gao
- CAS Key Laboratory of Tropical Marine BioResources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Gong Li
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Yu-Feng Zhou
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Xin-Lei Lian
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Liang-Xing Fang
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Xiao-Ping Liao
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
| | - Jose R Mediavilla
- Hackensack Meridian Health Center for Discovery and Innovation, Nutley, New Jersey, USA.,Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
| | - Liang Chen
- Hackensack Meridian Health Center for Discovery and Innovation, Nutley, New Jersey, USA.,Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
| | - Ya-Hong Liu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine South China Agricultural University Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
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24
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Cometta S, Bock N, Suresh S, Dargaville TR, Hutmacher DW. Antibacterial Albumin-Tannic Acid Coatings for Scaffold-Guided Breast Reconstruction. Front Bioeng Biotechnol 2021; 9:638577. [PMID: 33869154 PMCID: PMC8044405 DOI: 10.3389/fbioe.2021.638577] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
Infection is the major cause of morbidity after breast implant surgery. Biodegradable medical-grade polycaprolactone (mPCL) scaffolds designed and rooted in evidence-based research offer a promising alternative to overcome the limitations of routinely used silicone implants for breast reconstruction. Nevertheless, as with any implant, biodegradable scaffolds are susceptible to bacterial infection too, especially as bacteria can rapidly colonize the biomaterial surface and form biofilms. Biofilm-related infections are notoriously challenging to treat and can lead to chronic infection and persisting inflammation of surrounding tissue. To date, no clinical solution that allows to efficiently prevent bacterial infection while promoting correct implant integration, has been developed. In this study, we demonstrated for the first time, to our knowledge that the physical immobilization of 1 and 5% human serum albumin (HSA) onto the surface of 3D printed macro- and microporous mPCL scaffolds, resulted in a reduction of Staphylococcus aureus colonization by 71.7 ± 13.6% and 54.3 ± 12.8%, respectively. Notably, when treatment of scaffolds with HSA was followed by tannic acid (TA) crosslinking/stabilization, uniform and stable coatings with improved antibacterial activity were obtained. The HSA/TA-coated scaffolds were shown to be stable when incubated at physiological conditions in cell culture media for 7 days. Moreover, they were capable of inhibiting the growth of S. aureus and Pseudomonas aeruginosa, two most commonly found bacteria in breast implant infections. Most importantly, 1%HSA/10%TA- and 5%HSA/1%TA-coated scaffolds were able to reduce S. aureus colonization on the mPCL surface, by 99.8 ± 0.1% and 98.8 ± 0.6%, respectively, in comparison to the non-coated control specimens. This system offers a new biomaterial strategy to effectively translate the prevention of biofilm-related infections on implant surfaces without relying on the use of prophylactic antibiotic treatment.
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Affiliation(s)
- Silvia Cometta
- Centre in Regenerative Medicine, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.,School of Mechanical, Medical and Process Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia
| | - Nathalie Bock
- Centre in Regenerative Medicine, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.,Translational Research Institute, Brisbane, QLD, Australia.,School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia
| | - Sinduja Suresh
- Centre in Regenerative Medicine, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.,School of Mechanical, Medical and Process Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia.,ARC Industrial Transformation Training Centre for Multiscale 3D Imaging, Modelling and Manufacturing, Queensland University of Technology, Brisbane, QLD, Australia
| | - Tim R Dargaville
- School of Chemistry and Physics, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia
| | - Dietmar W Hutmacher
- Centre in Regenerative Medicine, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia.,School of Mechanical, Medical and Process Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia.,ARC Industrial Transformation Training Centre in Additive Biomanufacturing, Queensland University of Technology, Brisbane, QLD, Australia
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25
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Cendra MDM, Torrents E. Pseudomonas aeruginosa biofilms and their partners in crime. Biotechnol Adv 2021; 49:107734. [PMID: 33785375 DOI: 10.1016/j.biotechadv.2021.107734] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 12/24/2022]
Abstract
Pseudomonas aeruginosa biofilms and the capacity of the bacterium to coexist and interact with a broad range of microorganisms have a substantial clinical impact. This review focuses on the main traits of P. aeruginosa biofilms, such as the structural composition and regulatory networks involved, placing particular emphasis on the clinical challenges they represent in terms of antimicrobial susceptibility and biofilm infection clearance. Furthermore, the ability of P. aeruginosa to grow together with other microorganisms is a significant pathogenic attribute with clinical relevance; hence, the main microbial interactions of Pseudomonas are especially highlighted and detailed throughout this review. This article also explores the infections caused by single and polymicrobial biofilms of P. aeruginosa and the current models used to recreate them under laboratory conditions. Finally, the antimicrobial and antibiofilm strategies developed against P. aeruginosa mono and multispecies biofilms are detailed at the end of this review.
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Affiliation(s)
- Maria Del Mar Cendra
- Bacterial Infections and Antimicrobial therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 15-21, 08028 Barcelona, Spain.
| | - Eduard Torrents
- Bacterial Infections and Antimicrobial therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 15-21, 08028 Barcelona, Spain; Microbiology Section, Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, 643 Diagonal Ave., 08028 Barcelona, Spain.
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26
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Yung DBY, Sircombe KJ, Pletzer D. Friends or enemies? The complicated relationship between Pseudomonas aeruginosa and Staphylococcus aureus. Mol Microbiol 2021; 116:1-15. [PMID: 33576132 DOI: 10.1111/mmi.14699] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 10/22/2022]
Abstract
Pseudomonas aeruginosa (Pa) and Staphylococcus aureus (Sa) are opportunistic pathogens that are most commonly co-isolated from chronic wounds and the sputum of cystic fibrosis patients. Over the last few years, there have been plenty of contrasting results from studies involving P. aeruginosa and S. aureus co-cultures. The general concept that P. aeruginosa outcompetes S. aureus has been challenged and there is more evidence now that they can co-exist. Nevertheless, it still remains difficult to mimic polymicrobial infections in vitro and in vivo. In this review, we discuss recent advances in regard to Pa-Sa molecular interactions, their physical responses, and in vitro and in vivo models. We believe it is important to optimize growth conditions in the laboratory, determine appropriate bacterial starting ratios, and consider environmental factors to study the co-existence of these two pathogens. Ideally, optimized growth media should reflect host-mimicking conditions with or without host cells that allow both bacteria to co-exist. To further identify mechanisms that could help to treat these complex infections, we propose to use relevant polymicrobial animal models. Ultimately, we briefly discuss how polymicrobial infections can increase antibiotic tolerance.
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Affiliation(s)
- Deborah Bow Yue Yung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | | | - Daniel Pletzer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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27
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Sodium Salicylate Influences the Pseudomonas aeruginosa Biofilm Structure and Susceptibility Towards Silver. Int J Mol Sci 2021; 22:ijms22031060. [PMID: 33494399 PMCID: PMC7865925 DOI: 10.3390/ijms22031060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/12/2021] [Accepted: 01/19/2021] [Indexed: 01/30/2023] Open
Abstract
Hard-to-heal wounds are typically infected with biofilm-producing microorganisms, such as Pseudomonas aeruginosa, which strongly contribute to delayed healing. Due to the global challenge of antimicrobial resistance, alternative treatment strategies are needed. Here, we investigated whether inhibition of quorum sensing (QS) by sodium salicylate in different P. aeruginosa strains (QS-competent, QS-mutant, and chronic wound strains) influences biofilm formation and tolerance to silver. Biofilm formation was evaluated in simulated serum-containing wound fluid in the presence or absence of sodium salicylate (NaSa). Biofilms were established using a 3D collagen-based biofilm model, collagen coated glass, and the Calgary biofilm device. Furthermore, the susceptibility of 48-h-old biofilms formed by laboratory and clinical strains in the presence or absence of NaSa towards silver was evaluated by assessing cell viability. Biofilms formed in the presence of NaSa were more susceptible to silver and contained reduced levels of virulence factors associated with biofilm development than those formed in the absence of NaSa. Biofilm aggregates formed by the wild-type but not the QS mutant strain, were smaller and less heterogenous in size when grown in cultures with NaSa compared to control. These data suggest that NaSa, via a reduction of cell aggregation in biofilms, allows the antiseptic to become more readily available to cells.
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28
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Affiliation(s)
- Olivia P. Duddy
- Department of Molecular Biology, Princeton University, Princeton, United States of America
| | - Bonnie L. Bassler
- Department of Molecular Biology, Princeton University, Princeton, United States of America
- Howard Hughes Medical Institute, Chevy Chase, United States of America
- * E-mail:
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29
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Beasley KL, Cristy SA, Elmassry MM, Dzvova N, Colmer-Hamood JA, Hamood AN. During bacteremia, Pseudomonas aeruginosa PAO1 adapts by altering the expression of numerous virulence genes including those involved in quorum sensing. PLoS One 2020; 15:e0240351. [PMID: 33057423 PMCID: PMC7561203 DOI: 10.1371/journal.pone.0240351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that produces numerous virulence factors and causes serious infections in trauma patients and patients with severe burns. We previously showed that the growth of P. aeruginosa in blood from severely burned or trauma patients altered the expression of numerous genes. However, the specific influence of whole blood from healthy volunteers on P. aeruginosa gene expression is not known. Transcriptome analysis of P. aeruginosa grown for 4 h in blood from healthy volunteers compared to that when grown in laboratory medium revealed that the expression of 1085 genes was significantly altered. Quorum sensing (QS), QS-related, and pyochelin synthesis genes were downregulated, while genes of the type III secretion system and those for pyoverdine synthesis were upregulated. The observed effect on the QS and QS-related genes was shown to reside within serum fraction: growth of PAO1 in the presence of 10% human serum from healthy volunteers significantly reduced the expression of QS and QS-regulated genes at 2 and 4 h of growth but significantly enhanced their expression at 8 h. Additionally, the production of QS-regulated virulence factors, including LasA and pyocyanin, was also influenced by the presence of human serum. Serum fractionation experiments revealed that part of the observed effect resides within the serum fraction containing <10-kDa proteins. Growth in serum reduced the production of many PAO1 outer membrane proteins but enhanced the production of others including OprF, a protein previously shown to play a role in the regulation of QS gene expression. These results suggest that factor(s) within human serum: 1) impact P. aeruginosa pathogenesis by influencing the expression of different genes; 2) differentially regulate the expression of QS and QS-related genes in a growth phase- or time-dependent mechanism; and 3) manipulate the production of P. aeruginosa outer membrane proteins.
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Affiliation(s)
- Kellsie L. Beasley
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
| | - Shane A. Cristy
- Honors College, Texas Tech University, Lubbock, Texas, Untied States of America
| | - Moamen M. Elmassry
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, Untied States of America
| | - Nyaradzo Dzvova
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
| | - Jane A. Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
| | - Abdul N. Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, Texas, Untied States of America
- * E-mail:
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30
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Buch PJ, Chai Y, Goluch ED. Bacterial chatter in chronic wound infections. Wound Repair Regen 2020; 29:106-116. [PMID: 33047459 DOI: 10.1111/wrr.12867] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 08/07/2020] [Accepted: 10/06/2020] [Indexed: 11/29/2022]
Abstract
One of the hallmark characteristics of chronic diabetic wounds is the presence of biofilm-forming bacteria. Bacteria encapsulated in a biofilm may coexist as a polymicrobial community and communicate with each other through a phenomenon termed quorum sensing (QS). Here, we describe the QS circuits of bacterial species commonly found in chronic diabetic wounds. QS relies on diffusion of signaling molecules and the local concentration changes of these molecules that bacteria experience in wounds. These biochemical signaling pathways play a role not only in biofilm formation and virulence but also in wound healing. They are, therefore, key to understanding the distinctive nature of these infections. While several in vivo and in vitro models exist to study QS in wounds, there has been limited progress in understanding the interplay between QS molecules and host factors that contribute to wound healing. Lastly, we examine the potential of targeting QS for both diagnosis and therapeutic intervention purposes.
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Affiliation(s)
- Pranali J Buch
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts, USA
| | - Yunrong Chai
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Edgar D Goluch
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts, USA.,Department of Biology, Northeastern University, Boston, Massachusetts, USA
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31
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Current Knowledge and Future Directions in Developing Strategies to Combat Pseudomonas aeruginosa Infection. J Mol Biol 2020; 432:5509-5528. [PMID: 32750389 DOI: 10.1016/j.jmb.2020.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/17/2020] [Accepted: 07/22/2020] [Indexed: 12/21/2022]
Abstract
In the face of growing antimicrobial resistance, there is an urgent need for the development of effective strategies to target Pseudomonas aeruginosa. This metabolically versatile bacterium can cause a wide range of severe opportunistic infections in patients with serious underlying medical conditions, such as those with burns, surgical wounds or people with cystic fibrosis. Many of the key adaptations that arise in this organism during infection are centered on core metabolism and virulence factor synthesis. Interfering with these processes may provide a new strategy to combat infection which could be combined with conventional antibiotics. This review will provide an overview of the most recent work that has advanced our understanding of P. aeruginosa infection. Strategies that exploit this recent knowledge to combat infection will be highlighted alongside potential alternative therapeutic options and their limitations.
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32
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Redman WK, Welch GS, Rumbaugh KP. Differential Efficacy of Glycoside Hydrolases to Disperse Biofilms. Front Cell Infect Microbiol 2020; 10:379. [PMID: 32793516 PMCID: PMC7393775 DOI: 10.3389/fcimb.2020.00379] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 06/19/2020] [Indexed: 01/04/2023] Open
Abstract
Chronic wounds will impact 2% of the United States population at some point in their life. These wounds are often associated with a reoccurring, chronic infection caused by a community of microorganisms encased in an extracellular polymeric substance (EPS), or a biofilm. Biofilm-associated microbes can exhibit tolerance to antibiotics, which has prompted researchers to investigate therapeutics that improve antibiotic efficacy. Glycoside hydrolases (GHs), enzymes that target the polysaccharide linkages within the EPS, are one potential adjunctive therapy. In order to develop GH-based therapeutics, it is imperative that we understand whether the composition of biofilm EPS changes based on the environment and/or presence of other microbes. Here, we utilized α-amylase and cellulase to target the polysaccharides within the EPS of mono- and dual-species Pseudomonas aeruginosa and Staphylococcus aureus biofilms in three different models that vary in clinical relevancy. We show that biofilms established in an in vitro well-plate model are not strongly adhered to the polystyrene surface and do not accurately reflect the GH efficacy seen with biofilms grown in vivo. However, dispersal efficacy in an in vitro wound microcosm model was more reflective of that seen in a murine wound model. We also saw a striking loss of efficacy for cellulase to disperse S. aureus in both mono- and dual species biofilms grown in the wound models, suggesting that EPS constituents may be altered depending on the environment.
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Affiliation(s)
- Whitni K Redman
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States.,Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Garrett S Welch
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States.,TTUHSC Surgery Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States.,Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States.,TTUHSC Surgery Burn Center of Research Excellence, Texas Tech University Health Sciences Center, Lubbock, TX, United States
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33
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Yulizal OK, Lelo A, Ilyas S, Kusumawati RL. The effect of snakehead fish extract supplementation to first-line eradication regimen on macrophage migration inhibitory factor (MIF) expression in rats induced by Helicobacter pylori infection. J Adv Vet Anim Res 2020; 7:209-217. [PMID: 32607351 PMCID: PMC7320804 DOI: 10.5455/javar.2020.g411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/16/2020] [Accepted: 04/19/2020] [Indexed: 12/21/2022] Open
Abstract
Objective: This work was organized to assess macrophage migration inhibitory factor (MIF) expression in snakehead fish extract supplementation to first-line eradication regimen in rats induced by Helicobacter pylori infection. Materials and methods: A total of 28 manly rats were haphazardly isolated equally into four groups. Group-1 was the control negative, and groups-2–4 were H. pylori-infected groups. Group-2 was the control positive. Groups-3 and 4 were treated with first-line eradication regimen and first-line eradication regimen supplemented with snakehead fish extract, respectively. Immunoreactive scores (IRS) of MIF expression and eradication testing procedure were carried out. The comparison and difference between groups were analyzed by Kruskal–Wallis and post hoc Mann–Whitney U-test. A value of p < 0.05 was considered to be a limit of significance. Results: The average IRS of MIF expression in group-2 was the highest among other groups (p < 0.05). Group-4 (supplemented by snakehead fish extract) had a lower median value IRS of MIF expression compared to group-3 [1.0 (0.0–2.0) vs. 3.5 (2.0–6.0), p = 0.004]. Conclusion: MIF expression was higher in rats induced by H. pylori infection. Snakehead fish extract supplementation to first-line eradication regimen significantly reduces more MIF expression compared to a single administration of first-line eradication regimen in rats induced by H. pylori infection.
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Affiliation(s)
- O K Yulizal
- Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
| | - Aznan Lelo
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
| | - Syafruddin Ilyas
- Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara, Medan, Indonesia
| | - Raden Lia Kusumawati
- Department of Microbiology, Faculty of Medicine, H. Adam Malik General Hospital, Universitas Sumatera Utara, Medan, Indonesia
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34
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Gerner E, Almqvist S, Werthén M, Trobos M. Sodium salicylate interferes with quorum-sensing-regulated virulence in chronic wound isolates of Pseudomonas aeruginosa in simulated wound fluid. J Med Microbiol 2020; 69:767-780. [PMID: 32320374 PMCID: PMC7451038 DOI: 10.1099/jmm.0.001188] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Introduction. An important factor for delayed healing of chronic wounds is the presence of bacteria. Quorum sensing (QS), a cell density-dependent signalling system, controls the production of many virulence factors and biofilm formation in Pseudomonas aeruginosa.Aim. Inhibition by sodium salicylate (NaSa) of QS-regulated virulence expression was evaluated in QS-characterized clinical wound isolates of P. aeruginosa, cultured in serum-containing medium.Methodology. Fourteen clinical P. aeruginosa strains from chronic wounds were evaluated for the production of QS signals and virulence factors. Inhibition of QS by NaSa in P. aeruginosa clinical strains, wild-type PAO1 and QS reporter strains was evaluated using in vitro assays for the production of biofilm, pyocyanin, siderophores, alkaline protease, elastase and stapholytic protease.Results. Six clinical strains secreted several QS-associated virulence factors and signal molecules and two were negative for all factors. Sub-inhibitory concentrations of NaSa downregulated the expression of the QS-related genes lasB, rhlA and pqsA and reduced the secretion of several virulence factors in PAO1 and clinical strains cultured in serum. Compared to serum-free media, the presence of serum increased the expression of QS genes and production of siderophores and pyocyanin but decreased biofilm formation.Conclusions. Pseudomonas aeruginosa from chronic wound infections showed different virulence properties. While very few strains showed no QS activity, approximately half were highly virulent and produced QS signals, suggesting that the targeting of QS is a viable and relevant strategy for infection control. NaSa showed activity as a QS-inhibitor by lowering the virulence phenotypes and QS signals at both transcriptional and extracellular levels.
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Affiliation(s)
- Erik Gerner
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Mölnlycke Health Care AB, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
| | | | - Maria Werthén
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden.,Department of Health Sciences, University West, Trollhättan, Sweden
| | - Margarita Trobos
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
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35
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RhlR-Regulated Acyl-Homoserine Lactone Quorum Sensing in a Cystic Fibrosis Isolate of Pseudomonas aeruginosa. mBio 2020; 11:mBio.00532-20. [PMID: 32265330 PMCID: PMC7157775 DOI: 10.1128/mbio.00532-20] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa is a prominent cystic fibrosis (CF) pathogen that uses quorum sensing (QS) to regulate virulence. In laboratory strains, the key QS regulator is LasR. Many isolates from patients with chronic CF infections appear to use an alternate QS circuitry in which another transcriptional regulator, RhlR, mediates QS. We show that a LasR-null CF clinical isolate engages in QS through RhlR and remains capable of inducing cell death in an in vivo-like lung epithelium cell model. Our findings support the notion that LasR-null clinical isolates can engage in RhlR QS and highlight the centrality of RhlR in chronic P. aeruginosa infections. The opportunistic pathogen Pseudomonas aeruginosa is a leading cause of airway infection in cystic fibrosis (CF) patients. P. aeruginosa employs several hierarchically arranged and interconnected quorum sensing (QS) regulatory circuits to produce a battery of virulence factors such as elastase, phenazines, and rhamnolipids. The QS transcription factor LasR sits atop this hierarchy and activates the transcription of dozens of genes, including that encoding the QS regulator RhlR. Paradoxically, inactivating lasR mutations are frequently observed in isolates from CF patients with chronic P. aeruginosa infections. In contrast, mutations in rhlR are rare. We have recently shown that in CF isolates, the QS circuitry is often rewired such that RhlR acts in a LasR-independent manner. To begin understanding how QS activity differs in this rewired background, we characterized QS activation and RhlR-regulated gene expression in P. aeruginosa E90, a LasR-null, RhlR-active chronic infection isolate. In this isolate, RhlR activates the expression of 53 genes in response to increasing cell density. The genes regulated by RhlR include several that encode virulence factors. Some, but not all, of these genes are present in the QS regulon described in the well-studied laboratory strain PAO1. We also demonstrate that E90 produces virulence factors at similar concentrations as PAO1, and in E90, RhlR plays a significant role in mediating cytotoxicity in a three-dimensional lung epithelium cell model. These data illuminate a rewired LasR-independent RhlR regulon in chronic infection isolates and suggest further investigation of RhlR as a possible target for therapeutic development in chronic infections.
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36
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Mukherjee S, Bassler BL. Bacterial quorum sensing in complex and dynamically changing environments. Nat Rev Microbiol 2020; 17:371-382. [PMID: 30944413 DOI: 10.1038/s41579-019-0186-5] [Citation(s) in RCA: 521] [Impact Index Per Article: 130.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Quorum sensing is a process of bacterial cell-to-cell chemical communication that relies on the production, detection and response to extracellular signalling molecules called autoinducers. Quorum sensing allows groups of bacteria to synchronously alter behaviour in response to changes in the population density and species composition of the vicinal community. Quorum-sensing-mediated communication is now understood to be the norm in the bacterial world. Elegant research has defined quorum-sensing components and their interactions, for the most part, under ideal and highly controlled conditions. Indeed, these seminal studies laid the foundations for the field. In this Review, we highlight new findings concerning how bacteria deploy quorum sensing in realistic scenarios that mimic nature. We focus on how quorums are detected and how quorum sensing controls group behaviours in complex and dynamically changing environments such as multi-species bacterial communities, in the presence of flow, in 3D non-uniform biofilms and in hosts during infection.
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Affiliation(s)
- Sampriti Mukherjee
- Princeton University, Department of Molecular Biology, Princeton, NJ, USA
| | - Bonnie L Bassler
- Princeton University, Department of Molecular Biology, Princeton, NJ, USA. .,Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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37
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Bisht K, Baishya J, Wakeman CA. Pseudomonas aeruginosa polymicrobial interactions during lung infection. Curr Opin Microbiol 2020; 53:1-8. [PMID: 32062024 DOI: 10.1016/j.mib.2020.01.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/12/2020] [Accepted: 01/15/2020] [Indexed: 12/21/2022]
Abstract
Chronic infections often contain complex polymicrobial communities that are recalcitrant to antibiotic treatment. The pathogens associated with these infectious communities are often studied in pure culture for their ability to cause disease. However, recent studies have begun to focus on the role of polymicrobial interactions in disease outcomes. Pseudomonas aeruginosa can colonize patients with chronic lung diseases for years and sometimes even decades. During these prolonged infections, P. aeruginosa encounters a plethora of other microbes including bacteria, fungi, and viruses. The interactions between these microbes can vary greatly, ranging from antagonistic to synergistic depending on specific host and microbe-associated contexts. These additional layers of complexity associated with chronic P. aeruginosa infections must be considered in future studies in order to fully understand the physiology of infection. Such studies focusing on the entire infectious community rather than individual species may ultimately lead to more effective therapeutic design for persistent polymicrobial infections.
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Affiliation(s)
- Karishma Bisht
- Texas Tech University, Department of Biological Sciences, Lubbock TX, USA
| | - Jiwasmika Baishya
- Texas Tech University, Department of Biological Sciences, Lubbock TX, USA
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38
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Morrison JM, Chojnacki M, Fadrowski JJ, Bauza C, Dunman PM, Dudas RA, Goldenberg NA, Berman DM. Serum-Associated Antibiotic Tolerance in Pediatric Clinical Isolates of Pseudomonas aeruginosa. J Pediatric Infect Dis Soc 2019; 9:671-679. [PMID: 31886511 PMCID: PMC7974018 DOI: 10.1093/jpids/piz094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 12/05/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND When grown in human serum, laboratory isolates of Pseudomonas aeruginosa exhibit tolerance to antibiotics at inhibitory concentrations. This phenomenon, known as serum-associated antibiotic tolerance (SAT), could lead to clinical treatment failure of pseudomonal infections. Our purpose in this study was to determine the prevalence and clinical impact of SAT in Pseudomonas isolates in hospitalized children. METHODS The SAT phenotype was assessed in patients aged <18 years admitted with respiratory or blood cultures positive for P. aeruginosa. The SAT phenotype was a priori defined as a ≥2-log increase in colony-forming units when grown in human serum compared with Luria-Bertani medium in the presence of minocycline or tobramycin. RESULTS SAT was detected in 29 (64%) patients. Fourteen patients each (34%) had cystic fibrosis (CF) and tracheostomies. Patient demographics and comorbidities did not differ by SAT status. Among CF patients, SAT was associated with longer duration of intravenous antibiotics (10 days vs 5 days; P < .01). CONCLUSIONS This study establishes that SAT exists in P. aeruginosa from human serum and may be a novel factor that contributes to differences in clinical outcomes. Future research should investigate the mechanisms that contribute to SAT in order to identify novel targets for adjunctive antimicrobial therapies.
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Affiliation(s)
- John M Morrison
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Department of Medicine, Division of Hospital Medicine, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida, USA,Correspondence: John M. Morrison, 601 Fifth Street South Suite 501, Saint Petersburg, FL 33701 ()
| | - Michaelle Chojnacki
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Jeffrey J Fadrowski
- Department of Pediatrics, Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Colleen Bauza
- Department of Health Informatics, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida, USA
| | - Paul M Dunman
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Robert A Dudas
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Department of Medicine, Division of Hospital Medicine, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida, USA
| | - Neil A Goldenberg
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, and All Children’s Research Institute, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida, USA
| | - David M Berman
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida, USA
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39
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Cendra MDM, Blanco-Cabra N, Pedraz L, Torrents E. Optimal environmental and culture conditions allow the in vitro coexistence of Pseudomonas aeruginosa and Staphylococcus aureus in stable biofilms. Sci Rep 2019; 9:16284. [PMID: 31705015 PMCID: PMC6841682 DOI: 10.1038/s41598-019-52726-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/22/2019] [Indexed: 12/15/2022] Open
Abstract
The coexistence between species that occurs in some infections remains hard to achieve in vitro since bacterial fitness differences eventually lead to a single organism dominating the mixed culture. Pseudomonas aeruginosa and Staphylococcus aureus are major pathogens found growing together in biofilms in disease-affected lungs or wounds. Herein, we tested and analyzed different culture media, additives and environmental conditions to support P. aeruginosa and S. aureus coexistence in vitro. We have unraveled the potential of DMEM to support the growth of these two organisms in mature cocultured biofilms (three days old) in an environment that dampens the pH rise. Our conditions use equal initial inoculation ratios of both strains and allow the stable formation of separate S. aureus microcolonies that grow embedded in a P. aeruginosa biofilm, as well as S. aureus biofilm overgrowth when bovine serum albumin is added to the system. Remarkably, we also found that S. aureus survival is strictly dependent on a well-characterized phenomenon of oxygen stratification present in the coculture biofilm. An analysis of differential tolerance to gentamicin and ciprofloxacin treatment, depending on whether P. aeruginosa and S. aureus were growing in mono- or coculture biofilms, was used to validate our in vitro coculture conditions.
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Affiliation(s)
- Maria Del Mar Cendra
- Bacterial Infections and Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 15-21, 08028, Barcelona, Spain.
| | - Núria Blanco-Cabra
- Bacterial Infections and Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 15-21, 08028, Barcelona, Spain
| | - Lucas Pedraz
- Bacterial Infections and Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 15-21, 08028, Barcelona, Spain
| | - Eduard Torrents
- Bacterial Infections and Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 15-21, 08028, Barcelona, Spain.
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40
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Nogueira F, Sharghi S, Kuchler K, Lion T. Pathogenetic Impact of Bacterial-Fungal Interactions. Microorganisms 2019; 7:microorganisms7100459. [PMID: 31623187 PMCID: PMC6843596 DOI: 10.3390/microorganisms7100459] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/20/2019] [Accepted: 10/15/2019] [Indexed: 12/17/2022] Open
Abstract
Polymicrobial infections are of paramount importance because of the potential severity of clinical manifestations, often associated with increased resistance to antimicrobial treatment. The intricate interplay with the host and the immune system, and the impact on microbiome imbalance, are of importance in this context. The equilibrium of microbiota in the human host is critical for preventing potential dysbiosis and the ensuing development of disease. Bacteria and fungi can communicate via signaling molecules, and produce metabolites and toxins capable of modulating the immune response or altering the efficacy of treatment. Most of the bacterial–fungal interactions described to date focus on the human fungal pathogen Candida albicans and different bacteria. In this review, we discuss more than twenty different bacterial–fungal interactions involving several clinically important human pathogens. The interactions, which can be synergistic or antagonistic, both in vitro and in vivo, are addressed with a focus on the quorum-sensing molecules produced, the response of the immune system, and the impact on clinical outcome.
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Affiliation(s)
- Filomena Nogueira
- CCRI-St. Anna Children's Cancer Research Institute, Vienna 1090, Austria.
- Labdia-Labordiagnostik GmbH, Vienna 1090, Austria.
- Center of Medical Biochemistry, Max Perutz Labs, Campus Vienna Biocenter, Medical University of Vienna, Vienna 1030, Austria.
| | - Shirin Sharghi
- CCRI-St. Anna Children's Cancer Research Institute, Vienna 1090, Austria.
- Labdia-Labordiagnostik GmbH, Vienna 1090, Austria.
- Center of Medical Biochemistry, Max Perutz Labs, Campus Vienna Biocenter, Medical University of Vienna, Vienna 1030, Austria.
| | - Karl Kuchler
- Center of Medical Biochemistry, Max Perutz Labs, Campus Vienna Biocenter, Medical University of Vienna, Vienna 1030, Austria.
| | - Thomas Lion
- CCRI-St. Anna Children's Cancer Research Institute, Vienna 1090, Austria.
- Labdia-Labordiagnostik GmbH, Vienna 1090, Austria.
- Department of Pediatrics, Medical University of Vienna, Vienna 1090, Austria.
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41
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Synergistic Action of Phage and Antibiotics: Parameters to Enhance the Killing Efficacy Against Mono and Dual-Species Biofilms. Antibiotics (Basel) 2019; 8:antibiotics8030103. [PMID: 31349628 PMCID: PMC6783858 DOI: 10.3390/antibiotics8030103] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 11/17/2022] Open
Abstract
Pseudomonas aeruginosa and Staphylococcus aureus are opportunistic pathogens and are commonly found in polymicrobial biofilm-associated diseases, namely chronic wounds. Their co-existence in a biofilm contributes to an increased tolerance of the biofilm to antibiotics. Combined treatments of bacteriophages and antibiotics have shown a promising antibiofilm activity, due to the profound differences in their mechanisms of action. In this study, 48 h old mono and dual-species biofilms were treated with a newly isolated P. aeruginosa infecting phage (EPA1) and seven different antibiotics (gentamicin, kanamycin, tetracycline, chloramphenicol, erythromycin, ciprofloxacin, and meropenem), alone and in simultaneous or sequential combinations. The therapeutic efficacy of the tested antimicrobials was determined. Phage or antibiotics alone had a modest effect in reducing biofilm bacteria. However, when applied simultaneously, a profound improvement in the killing effect was observed. Moreover, an impressive biofilm reduction (below the detection limit) was observed when gentamicin or ciprofloxacin were added sequentially after 6 h of phage treatment. The effect observed does not depend on the type of antibiotic but is influenced by its concentration. Moreover, in dual-species biofilms it was necessary to increase gentamicin concentration to obtain a similar killing effect as occurs in mono-species. Overall, combining phages with antibiotics can be synergistic in reducing the bacterial density in biofilms. However, the concentration of antibiotic and the time of antibiotic application are essential factors that need to be considered in the combined treatments.
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42
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Vandeplassche E, Tavernier S, Coenye T, Crabbé A. Influence of the lung microbiome on antibiotic susceptibility of cystic fibrosis pathogens. Eur Respir Rev 2019; 28:28/152/190041. [PMID: 31285289 PMCID: PMC9488708 DOI: 10.1183/16000617.0041-2019] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 06/05/2019] [Indexed: 12/22/2022] Open
Abstract
The lungs of patients with cystic fibrosis (CF) are colonised by a microbial community comprised of pathogenic species, such as Pseudomonas aeruginosa and Staphylococcus aureus, and microorganisms that are typically not associated with worse clinical outcomes (considered as commensals). Antibiotics directed at CF pathogens are often not effective and a discrepancy is observed between activity of these agents in vitro and in the patient. This review describes how interspecies interactions within the lung microbiome might influence the outcome of antibiotic treatment targeted at common CF pathogens. Protective mechanisms by members of the microbiome such as antibiotic degradation (indirect pathogenicity), alterations of the cell wall, production of matrix components decreasing antibiotic penetration, and changes in metabolism are discussed. Interspecies interactions that increase bacterial susceptibility are also addressed. Furthermore, we discuss how experimental conditions, such as culture media, oxygen levels, incorporation of host–pathogen interactions, and microbial community composition may influence the outcome of microbial interaction studies related to antibiotic activity. Hereby, the importance to create in vitro conditions reflective of the CF lung microenvironment is highlighted. Understanding the role of the CF lung microbiome in antibiotic efficacy may help find novel therapeutic and diagnostic approaches to better tackle chronic lung infections in this patient population. Interspecies interactions in the lung microbiome may influence the outcome of antibiotic treatment targeted at cystic fibrosis pathogenshttp://bit.ly/2WQp0iQ
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Affiliation(s)
- Eva Vandeplassche
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Sarah Tavernier
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Aurélie Crabbé
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
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43
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Selective pressures during chronic infection drive microbial competition and cooperation. NPJ Biofilms Microbiomes 2019; 5:16. [PMID: 31263568 PMCID: PMC6555799 DOI: 10.1038/s41522-019-0089-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/15/2019] [Indexed: 12/14/2022] Open
Abstract
Chronic infections often contain complex mixtures of pathogenic and commensal microorganisms ranging from aerobic and anaerobic bacteria to fungi and viruses. The microbial communities present in infected tissues are not passively co-existing but rather actively interacting with each other via a spectrum of competitive and/or cooperative mechanisms. Competition versus cooperation in these microbial interactions can be driven by both the composition of the microbial community as well as the presence of host defense strategies. These interactions are typically mediated via the production of secreted molecules. In this review, we will explore the possibility that microorganisms competing for nutrients at the host–pathogen interface can evolve seemingly cooperative mechanisms by controlling the production of subsets of secreted virulence factors. We will also address interspecies versus intraspecies utilization of community resources and discuss the impact that this phenomenon might have on co-evolution at the host–pathogen interface.
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44
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Kurzbaum E, Iliasafov L, Kolik L, Starosvetsky J, Bilanovic D, Butnariu M, Armon R. From the Titanic and other shipwrecks to biofilm prevention: The interesting role of polyphenol-protein complexes in biofilm inhibition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 658:1098-1105. [PMID: 30677974 DOI: 10.1016/j.scitotenv.2018.12.197] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 05/08/2023]
Abstract
Bacteria attach themselves either reversibly or irreversibly onto practically any surface in aqueous and other environments in order to reproduce, while generating extracellular polymeric substances (EPS) as a supportive structure for biofilm formation. Surfaces with a potential to prevent cellular attachment and aggregation (biofilm) would be extremely useful in environmental, biotechnological, medical and industrial applications. The scientific community is currently focusing on the design of micro- and nano-scale textured surfaces with antibacterial and/or antifouling properties (e.g., filtration membranes). Several serum and tissue proteins promote bacterial adhesion (for example, albumin, fibronectin and fibrinogen), whereas polyphenols form complexes with proteins which change their structural, functional and nutritional properties. For example, tannic acid, a compound composed of polygalloyl glucoses or polygalloyl quinic acid esters and several galloyl moieties, inhibits the growth of many bacterial strains. The present review is based on different nautical archaeology research data, and asks a simple but as yet unanswered question: What is the chemistry that prevents leather biodegradation by environmental bacteria and/or formation of biofilms? Future research should answer these questions, which are highly important for biofilm prevention.
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Affiliation(s)
- Eyal Kurzbaum
- Shamir Research Institute, University of Haifa, P.O. Box 97, Qatzrin 12900, Israel; Department of Geography and Environmental Studies, University of Haifa, Mount Carmel, Haifa 3498838, Israel.
| | - Luba Iliasafov
- Faculty of Civil & Environmental Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel
| | - Luba Kolik
- Faculty of Civil & Environmental Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel
| | - Jeana Starosvetsky
- Faculty of Civil & Environmental Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel
| | - Dragoljub Bilanovic
- Environmental, Economics, Earth, and Space Studies, Bemidji State University, Bemidji, MN 56601, USA.
| | - Monica Butnariu
- Banat's University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania, Timisoara 300645, Romania
| | - Robert Armon
- Faculty of Civil & Environmental Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel.
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45
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Abstract
Binding of small molecules to mucus membranes in the body has an important role in human health, as it can affect the diffusivity and activity of any molecule that acts in a mucosal environment. The binding of drugs and of toxins and signaling molecules from mucosal pathogens is of particular clinical interest. Despite the importance of mucus-small molecule binding, there is a lack of data revealing the precise chemical features of small molecules that lead to mucus binding. We developed a novel equilibrium dialysis assay to measure the binding of libraries of small molecules to mucin and other mucus components, substantially increasing the throughput of small molecule binding measurements. We validated the biological relevance of our approach by quantifying binding of the antibiotic colistin to mucin, and showing that this binding was associated with inhibition of colistin's bioactivity. We next used a small molecule microarray to identify 2,4-diaminopyrimidine as a mucin binding motif and confirmed the importance of this motif for mucin binding using equilibrium dialysis. Furthermore, we showed that, for molecules with this motif, binding to mucins and the mucus-associated biopolymers DNA and alginate is modulated by differences in hydrophobicity and charge. Finally, we showed that molecules lacking the motif exhibited different binding trends from those containing the motif. These results open up the prospect of routine testing of small molecule binding to mucus and optimization of drugs for clinically relevant mucus binding properties.
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46
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Limoli DH, Hoffman LR. Help, hinder, hide and harm: what can we learn from the interactions between Pseudomonas aeruginosa and Staphylococcus aureus during respiratory infections? Thorax 2019; 74:684-692. [PMID: 30777898 PMCID: PMC6585302 DOI: 10.1136/thoraxjnl-2018-212616] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/10/2019] [Accepted: 01/14/2019] [Indexed: 12/15/2022]
Abstract
Recent studies of human respiratory secretions using culture-independent techniques have found a surprisingly diverse array of microbes. Interactions among these community members can profoundly impact microbial survival, persistence and antibiotic susceptibility and, consequently, disease progression. Studies of polymicrobial interactions in the human microbiota have shown that the taxonomic and structural compositions, and resulting behaviours, of microbial communities differ substantially from those of the individual constituent species and in ways of clinical importance. These studies primarily involved oral and gastrointestinal microbiomes. While the field of polymicrobial respiratory disease is relatively young, early findings suggest that respiratory tract microbiota members also compete and cooperate in ways that may influence disease outcomes. Ongoing efforts therefore focus on how these findings can inform more 'enlightened', rational approaches to combat respiratory infections. Among the most common respiratory diseases involving polymicrobial infections are cystic fibrosis (CF), non-CF bronchiectasis, COPD and ventilator-associated pneumonia. While respiratory microbiota can be diverse, two of the most common and best-studied members are Staphylococcus aureus and Pseudomonas aeruginosa, which exhibit a range of competitive and cooperative interactions. Here, we review the state of research on pulmonary coinfection with these pathogens, including their prevalence, combined and independent associations with patient outcomes, and mechanisms of those interactions that could influence lung health. Because P. aeruginosa-S. aureus coinfection is common and well studied in CF, this disease serves as the paradigm for our discussions on these two organisms and inform our recommendations for future studies of polymicrobial interactions in pulmonary disease.
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Affiliation(s)
- Dominique Hope Limoli
- Microbiology and Immunology, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, Iowa, USA
| | - Lucas R Hoffman
- Departments of Pediatrics and Microbiology, University of Washington, Seattle, Washington, USA
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47
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Kalamara M, Spacapan M, Mandic‐Mulec I, Stanley‐Wall NR. Social behaviours by Bacillus subtilis: quorum sensing, kin discrimination and beyond. Mol Microbiol 2018; 110:863-878. [PMID: 30218468 PMCID: PMC6334282 DOI: 10.1111/mmi.14127] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/04/2018] [Accepted: 09/09/2018] [Indexed: 12/14/2022]
Abstract
Here, we review the multiple mechanisms that the Gram‐positive bacterium Bacillus subtilis uses to allow it to communicate between cells and establish community structures. The modes of action that are used are highly varied and include routes that sense pheromone levels during quorum sensing and control gene regulation, the intimate coupling of cells via nanotubes to share cytoplasmic contents, and long‐range electrical signalling to couple metabolic processes both within and between biofilms. We explore the ability of B. subtilis to detect ‘kin’ (and ‘cheater cells’) by looking at the mechanisms used to potentially ensure beneficial sharing (or limit exploitation) of extracellular ‘public goods’. Finally, reflecting on the array of methods that a single bacterium has at its disposal to ensure maximal benefit for its progeny, we highlight that a large future challenge will be integrating how these systems interact in mixed‐species communities.
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Affiliation(s)
- Margarita Kalamara
- Division of Molecular Microbiology, School of Life SciencesUniversity of DundeeDundeeDD15EHUK
| | - Mihael Spacapan
- Department of Food Science and Technology, Biotechnical FacultyUniversity of LjubljanaLjubljana1000Slovenia
| | - Ines Mandic‐Mulec
- Department of Food Science and Technology, Biotechnical FacultyUniversity of LjubljanaLjubljana1000Slovenia
| | - Nicola R. Stanley‐Wall
- Division of Molecular Microbiology, School of Life SciencesUniversity of DundeeDundeeDD15EHUK
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48
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Hickey C, Schaible B, Nguyen S, Hurley D, Srikumar S, Fanning S, Brown E, Crifo B, Matallanas D, McClean S, Taylor CT, Schaffer K. Increased Virulence of Bloodstream Over Peripheral Isolates of P. aeruginosa Identified Through Post-transcriptional Regulation of Virulence Factors. Front Cell Infect Microbiol 2018; 8:357. [PMID: 30416988 PMCID: PMC6212473 DOI: 10.3389/fcimb.2018.00357] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 09/18/2018] [Indexed: 11/13/2022] Open
Abstract
The factors influencing the virulence of P. aeruginosa in the development of invasive infection remain poorly understood. Here, we investigated the role of the host microenvironment in shaping pathogen virulence and investigated the mechanisms involved. Comparing seven paired genetically indistinguishable clinical bloodstream and peripheral isolates of P. aeruginosa, we demonstrate that isolates derived from bloodstream infections are more virulent than their peripheral counterparts (p = 0.025). Bloodstream and peripheral isolates elicited similar NF-kB responses in a THP-1 monocyte NF-kappaB reporter cell line implicating similar immunogenicity. Proteomic analysis by mass spectrometry identified multiple virulence and virulence-related factors including LecA and RpoN in significantly greater abundance in the bacterial supernatant from the bloodstream isolate in comparison to that from the corresponding peripheral isolate. Investigation by qPCR revealed that control of expression of these virulence factors was not due to altered levels of transcription. Based on these data, we hypothesize a post-transcriptional mechanism of virulence regulation in P. aeruginosa bloodstream infections influenced by surrounding microenvironmental conditions.
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Affiliation(s)
| | | | - Scott Nguyen
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Dublin, Ireland
| | - Daniel Hurley
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Dublin, Ireland
| | - Shabarinath Srikumar
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Dublin, Ireland
| | - Séamus Fanning
- School of Public Health, Physiotherapy & Sports Science, University College Dublin, Dublin, Ireland
| | - Eric Brown
- Conway Institute, University College Dublin, Dublin, Ireland
| | - Bianca Crifo
- Conway Institute, University College Dublin, Dublin, Ireland
| | - David Matallanas
- Systems Biology Ireland, University College Dublin, Dublin, Ireland.,School of Medicine, University College Dublin, Dublin, Ireland
| | - Siobhán McClean
- Biomedical and Biomolecular Science, University College Dublin, Dublin, Ireland
| | - Cormac T Taylor
- Conway Institute, University College Dublin, Dublin, Ireland.,Systems Biology Ireland, University College Dublin, Dublin, Ireland.,School of Medicine, University College Dublin, Dublin, Ireland
| | - Kirsten Schaffer
- School of Medicine, University College Dublin, Dublin, Ireland.,Department of Clinical Microbiology, St. Vincent's University Hospital, Dublin, Ireland
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49
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Bjarnsholt T, Buhlin K, Dufrêne YF, Gomelsky M, Moroni A, Ramstedt M, Rumbaugh KP, Schulte T, Sun L, Åkerlund B, Römling U. Biofilm formation - what we can learn from recent developments. J Intern Med 2018; 284:332-345. [PMID: 29856510 PMCID: PMC6927207 DOI: 10.1111/joim.12782] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Although biofilms have been observed early in the history of microbial research, their impact has only recently been fully recognized. Biofilm infections, which contribute to up to 80% of human microbial infections, are associated with common human disorders, such as diabetes mellitus and poor dental hygiene, but also with medical implants. The associated chronic infections such as wound infections, dental caries and periodontitis significantly enhance morbidity, affect quality of life and can aid development of follow-up diseases such as cancer. Biofilm infections remain challenging to treat and antibiotic monotherapy is often insufficient, although some rediscovered traditional compounds have shown surprising efficiency. Innovative anti-biofilm strategies include application of anti-biofilm small molecules, intrinsic or external stimulation of production of reactive molecules, utilization of materials with antimicrobial properties and dispersion of biofilms by digestion of the extracellular matrix, also in combination with physical biofilm breakdown. Although basic principles of biofilm formation have been deciphered, the molecular understanding of the formation and structural organization of various types of biofilms has just begun to emerge. Basic studies of biofilm physiology have also resulted in an unexpected discovery of cyclic dinucleotide second messengers that are involved in interkingdom crosstalk via specific mammalian receptors. These findings even open up new venues for exploring novel anti-biofilm strategies.
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Affiliation(s)
- T Bjarnsholt
- Department of Immunology and Microbiology, Costerton Biofilm Centre, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark
| | - K Buhlin
- Department of Dental Medicine, Division of Oral Facial Diagnostics and Surgery, Karolinska Institutet, Huddinge, Sweden
| | - Y F Dufrêne
- Institute of Life Sciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - M Gomelsky
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | - A Moroni
- Department of Biology and CNR-Istituto di Biofisica, Università degli Studi di Milano, Milano, Italy
| | - M Ramstedt
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - K P Rumbaugh
- Departments of Surgery & Immunology & Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - T Schulte
- Department of Medicine Solna, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
- Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - L Sun
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - B Åkerlund
- Department of Medicine Huddinge, Unit of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - U Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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50
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Abstract
Many bacteria use a cell-cell communication system called quorum sensing to coordinate population density-dependent changes in behavior. Quorum sensing involves production of and response to diffusible or secreted signals, which can vary substantially across different types of bacteria. In many species, quorum sensing modulates virulence functions and is important for pathogenesis. Over the past half-century, there has been a significant accumulation of knowledge of the molecular mechanisms, signal structures, gene regulons, and behavioral responses associated with quorum-sensing systems in diverse bacteria. More recent studies have focused on understanding quorum sensing in the context of bacterial sociality. Studies of the role of quorum sensing in cooperative and competitive microbial interactions have revealed how quorum sensing coordinates interactions both within a species and between species. Such studies of quorum sensing as a social behavior have relied on the development of "synthetic ecological" models that use nonclonal bacterial populations. In this review, we discuss some of these models and recent advances in understanding how microbes might interact with one another using quorum sensing. The knowledge gained from these lines of investigation has the potential to guide studies of microbial sociality in natural settings and the design of new medicines and therapies to treat bacterial infections.
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