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Ayilam Ramachandran R, Baniasadi H, Robertson DM. Pseudomonas aeruginosa infection increases palmitoyl carnitine release by host-derived extracellular vesicles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.13.603378. [PMID: 39026691 PMCID: PMC11257627 DOI: 10.1101/2024.07.13.603378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Pseudomonas aeruginosa (PA), an opportunistic gram-negative pathogen, is the most common pathogen identified in all culture positive cases of infectious keratitis. Extracellular vesicles (EVs) are released by most cells in the body and function in intercellular communication. We have previously reported a change in the proteome of host-derived EVs from corneal epithelial cells during PA infection. In the present study, we investigated changes in the metabolome of host-derived EVs from PA infected (PA-C EVs) and non-infected cells (C EVs). We found that one metabolite, palmitoyl carnitine (PAMC), was significantly upregulated in PA-C EVs. To determine the significance of PAMC release, we investigated the effect of PAMC treatment on corneal epithelial cells and neutrophils. EVs were isolated from culture media using size exclusion chromatography. EVs were then characterized using nanoparticle tracking analysis, transmission electron microscopy, and western blot. Metabolomics was performed using an untargeted approach. We found that palmitoyl carnitine (PAMC) was the most abundant metabolite present in PA-C EVs and was increased more than 3 fold compared to C EVs. Treatment of corneal epithelial cells with increasing levels of PAMC increased nuclear translocation of the NF-κB subunit p65. This was associated with an increase in IL-8 production and neutrophil migration. PAMC also increased levels of mitochondrial calcium. Upon inoculation of corneal epithelial cells with PA, 50 μM PAMC completely eradicated intracellular PA, but stimulated growth of extracellular PA. Taken together, these findings suggest that PA exploits EV release by host cells to deplete PAMC from the intracellular environment.
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Ayilam Ramachandran R, Lemoff A, Robertson DM. Extracellular vesicles released by host epithelial cells during Pseudomonas aeruginosa infection function as homing beacons for neutrophils. Cell Commun Signal 2024; 22:341. [PMID: 38907250 PMCID: PMC11191230 DOI: 10.1186/s12964-024-01609-7] [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: 01/23/2024] [Accepted: 04/10/2024] [Indexed: 06/23/2024] Open
Abstract
BACKGROUND Pseudomonas aeruginosa (PA) is an opportunistic pathogen that can cause sight threatening infections in the eye and fatal infections in the cystic fibrosis airway. Extracellular vesicles (EVs) are released by host cells during infection and by the bacteria themselves; however, there are no studies on the composition and functional role of host-derived EVs during PA infection of the eye or lung. Here we investigated the composition and capacity of EVs released by PA infected epithelial cells to modulate innate immune responses in host cells. METHODS Human telomerase immortalized corneal epithelial cells (hTCEpi) cells and human telomerase immortalized bronchial epithelial cells (HBECs) were treated with a standard invasive test strain of Pseudomonas aeruginosa, PAO1, for 6 h. Host derived EVs were isolated by qEV size exclusion chromatography. EV proteomic profiles during infection were compared using mass spectrometry and functional studies were carried out using hTCEpi cells, HBECs, differentiated neutrophil-like HL-60 cells, and primary human neutrophils isolated from peripheral blood. RESULTS EVs released from PA infected corneal epithelial cells increased pro-inflammatory cytokine production in naïve corneal epithelial cells and induced neutrophil chemotaxis independent of cytokine production. The EVs released from PA infected bronchial epithelial cells were also chemotactic although they failed to induce cytokine secretion from naïve HBECs. At the proteomic level, EVs derived from PA infected corneal epithelial cells exhibited lower complexity compared to bronchial epithelial cells, with the latter having reduced protein expression compared to the non-infected control. CONCLUSIONS This is the first study to comprehensively profile EVs released by corneal and bronchial epithelial cells during Pseudomonas infection. Together, these findings show that EVs released by PA infected corneal and bronchial epithelial cells function as potent mediators of neutrophil migration, contributing to the exuberant neutrophil response that occurs during infection in these tissues.
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Affiliation(s)
| | - Andrew Lemoff
- The Departments of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Danielle M Robertson
- The Departments of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA.
- The Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, 75390-9057, Dallas, TX, USA.
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Jeong GJ, Khan F, Tabassum N, Kim YM. Natural and synthetic molecules with potential to enhance biofilm formation and virulence properties in Pseudomonas aeruginosa. Crit Rev Microbiol 2023:1-29. [PMID: 37968960 DOI: 10.1080/1040841x.2023.2282459] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 11/01/2023] [Indexed: 11/17/2023]
Abstract
Pseudomonas aeruginosa can efficiently adapt to changing environmental conditions due to its ubiquitous nature, intrinsic/acquired/adaptive resistance mechanisms, high metabolic versatility, and the production of numerous virulence factors. As a result, P. aeruginosa becomes an opportunistic pathogen, causing chronic infection in the lungs and several organs of patients suffering from cystic fibrosis. Biofilm established by P. aeruginosa in host tissues and medical device surfaces has been identified as a major obstruction to antimicrobial therapy. P. aeruginosa is very likely to be closely associated with the various microorganisms in the host tissues or organs in a pathogenic or nonpathogenic behavior. Aside from host-derived molecules, other beneficial and pathogenic microorganisms produce a diverse range of secondary metabolites that either directly or indirectly favor the persistence of P. aeruginosa. Thus, it is critical to understand how P. aeruginosa interacts with different molecules and ions in the host and abiotic environment to produce extracellular polymeric substances and virulence factors. Thus, the current review discusses how various natural and synthetic molecules in the environment induce biofilm formation and the production of multiple virulence factors.
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Affiliation(s)
- Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
| | - Fazlurrahman Khan
- Institute of Fisheries Sciences, Pukyong National University, Busan, Republic of Korea
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, Republic of Korea
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, Republic of Korea
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, Republic of Korea
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, Republic of Korea
| | - Young-Mog Kim
- Department of Food Science and Technology, Pukyong National University, Busan, Republic of Korea
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, Republic of Korea
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, Republic of Korea
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Ali A, Zahra A, Kamthan M, Husain FM, Albalawi T, Zubair M, Alatawy R, Abid M, Noorani MS. Microbial Biofilms: Applications, Clinical Consequences, and Alternative Therapies. Microorganisms 2023; 11:1934. [PMID: 37630494 PMCID: PMC10459820 DOI: 10.3390/microorganisms11081934] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/05/2023] [Accepted: 07/08/2023] [Indexed: 08/27/2023] Open
Abstract
Biofilms are complex communities of microorganisms that grow on surfaces and are embedded in a matrix of extracellular polymeric substances. These are prevalent in various natural and man-made environments, ranging from industrial settings to medical devices, where they can have both positive and negative impacts. This review explores the diverse applications of microbial biofilms, their clinical consequences, and alternative therapies targeting these resilient structures. We have discussed beneficial applications of microbial biofilms, including their role in wastewater treatment, bioremediation, food industries, agriculture, and biotechnology. Additionally, we have highlighted the mechanisms of biofilm formation and clinical consequences of biofilms in the context of human health. We have also focused on the association of biofilms with antibiotic resistance, chronic infections, and medical device-related infections. To overcome these challenges, alternative therapeutic strategies are explored. The review examines the potential of various antimicrobial agents, such as antimicrobial peptides, quorum-sensing inhibitors, phytoextracts, and nanoparticles, in targeting biofilms. Furthermore, we highlight the future directions for research in this area and the potential of phytotherapy for the prevention and treatment of biofilm-related infections in clinical settings.
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Affiliation(s)
- Asghar Ali
- Clinical Biochemistry Lab, D/O Biochemistry, School of Chemical and Lifesciences, Jamia Hamdard, New Delhi 110062, India;
| | - Andaleeb Zahra
- Department of Botany, School of Chemical and Lifesciences, Jamia Hamdard, New Delhi 110062, India;
| | - Mohan Kamthan
- Clinical Biochemistry Lab, D/O Biochemistry, School of Chemical and Lifesciences, Jamia Hamdard, New Delhi 110062, India;
| | - Fohad Mabood Husain
- Department of Food Science and Nutrition, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Thamer Albalawi
- Department of Biology, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia;
| | - Mohammad Zubair
- Department of Medical Microbiology, Faculty of Medicine, University of Tabuk, Tabuk 71491, Saudi Arabia; (M.Z.); (R.A.)
| | - Roba Alatawy
- Department of Medical Microbiology, Faculty of Medicine, University of Tabuk, Tabuk 71491, Saudi Arabia; (M.Z.); (R.A.)
| | - Mohammad Abid
- Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India;
| | - Md Salik Noorani
- Department of Botany, School of Chemical and Lifesciences, Jamia Hamdard, New Delhi 110062, India;
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Ayilam Ramachandran R, Lemoff A, Robertson DM. Pseudomonas aeruginosa-Derived Extracellular Vesicles Modulate Corneal Inflammation: Role in Microbial Keratitis? Infect Immun 2023; 91:e0003623. [PMID: 36995231 PMCID: PMC10112165 DOI: 10.1128/iai.00036-23] [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: 01/21/2023] [Accepted: 02/16/2023] [Indexed: 03/31/2023] Open
Abstract
Pseudomonas aeruginosa keratitis occurs following trauma, in immunocompromised patients, and in otherwise healthy contact lens wearers. Characterized by a light-blocking infiltrate, P. aeruginosa keratitis is the most serious complication associated with contact lens wear and, in severe cases, can lead to vision loss. Bacterial extracellular vesicles (B EVs) are membrane-enclosed nanometer-scale particles secreted from bacteria and are packed with bioactive molecules. B EVs have been shown to mediate biological functions that regulate host pathogenic responses. In the present study, we isolated P. aeruginosa-derived EVs using size exclusion chromatography and compared the proteomic compositions and functional activities of P. aeruginosa-derived EVs and P. aeruginosa-derived free protein (FP) on corneal epithelial cells and neutrophils. Importantly, P. aeruginosa-derived EVs and FP exhibited unique protein profiles, with EVs being enriched in P. aeruginosa virulence proteins. P. aeruginosa-derived EVs promoted corneal epithelial cell secretion of interleukin-6 (IL-6) and IL-8, whereas these cytokines were not upregulated following treatment with FP. In contrast, FP had a negative effect on the host inflammatory response and impaired neutrophil killing. Both P. aeruginosa-derived EVs and FP promoted intracellular bacterial survival in corneal epithelial cells. Collectively, these data suggest that P. aeruginosa-derived EVs and FP may play a critical role in the pathogenesis of corneal infection by interfering with host innate immune defense mechanisms.
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Affiliation(s)
| | - Andrew Lemoff
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, USA
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Caldara M, Belgiovine C, Secchi E, Rusconi R. Environmental, Microbiological, and Immunological Features of Bacterial Biofilms Associated with Implanted Medical Devices. Clin Microbiol Rev 2022; 35:e0022120. [PMID: 35044203 PMCID: PMC8768833 DOI: 10.1128/cmr.00221-20] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.
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Affiliation(s)
- Marina Caldara
- Interdepartmental Center on Safety, Technologies, and Agri-food Innovation (SITEIA.PARMA), University of Parma, Parma, Italy
| | - Cristina Belgiovine
- IRCCS Humanitas Research Hospital, Rozzano–Milan, Italy
- Scuola di Specializzazione in Microbiologia e Virologia, Università degli Studi di Pavia, Pavia, Italy
| | - Eleonora Secchi
- Institute of Environmental Engineering, ETH Zürich, Zürich, Switzerland
| | - Roberto Rusconi
- IRCCS Humanitas Research Hospital, Rozzano–Milan, Italy
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele–Milan, Italy
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Ejeromedoghene O, Hu YP, Oderinde O, Yao F, Akinremi C, Akinyeye R, Adewuyi S, Fu G. Transparent and photochromic poly(hydroxyethyl acrylate–acrylamide)/
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hydrogel with antibacterial properties against bacterial keratitis in contact lens. J Appl Polym Sci 2022. [DOI: 10.1002/app.51815] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | - Yi Ping Hu
- School of Chemistry and Chemical Engineering Southeast University Nanjing China
| | - Olayinka Oderinde
- Department of Chemical Sciences, Faculty of Basic Medical and Applied Sciences Lead City University Ibadan Nigeria
| | - Fang Yao
- School of Chemistry and Chemical Engineering Southeast University Nanjing China
| | - Caroline Akinremi
- Department of Chemistry College of Physical Sciences, Federal University of Agriculture Abeokuta Nigeria
| | - Richard Akinyeye
- Department of Industrial Chemistry Ekiti State University Ado‐Ekiti Nigeria
| | - Sheriff Adewuyi
- Department of Chemistry College of Physical Sciences, Federal University of Agriculture Abeokuta Nigeria
| | - Guodong Fu
- School of Chemistry and Chemical Engineering Southeast University Nanjing China
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Ito S, Nakamura J, Fukuta M, Ura T, Teshigawara T, Fukushima J, Mizuki N, Okuda K, Shimada M. Prophylactic and therapeutic vaccine against Pseudomonas aeruginosa keratitis using bacterial membrane vesicles. Vaccine 2021; 39:3152-3160. [PMID: 33934918 DOI: 10.1016/j.vaccine.2021.04.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/14/2021] [Accepted: 04/18/2021] [Indexed: 12/01/2022]
Abstract
PURPOSE Pseudomonas aeruginosa (P. aeruginosa) infection is one of the major causes of keratitis. However, effective prophylactic and therapeutic vaccines against P. aeruginosa keratitis have yet to be developed. In this study, we explored the use of P. aeruginosa membrane vesicles (MVs) as a prophylactic vaccine as well as the use of immune sera derived from P. aeruginosa MV-immunized animals as a treatment for P. aeruginosa corneal infections in C57BL/6 mice. METHODS C57BL/6 mice were intramuscularly immunized with P. aeruginosa MVs; the mouse corneas were then scarified and topically infected with several P. aeruginosa strains, followed by determination of corneal clinical score and corneal bacterial load. Next, immune sera derived from P. aeruginosa MV-immunized ICR mice were administered intraperitoneally to naïve C57BL/6 mice, followed by topical P. aeruginosa challenge. Finally, the immune sera were also used as a topical treatment in the mice with established P. aeruginosa corneal infections. RESULTS P. aeruginosa-specific IgG and IgA antibodies induced by intramuscular immunization were detected not only in the sera but also in the eye-wash solution. Both active and passive immunization significantly inhibited P. aeruginosa corneal infection. Finally, topical treatment with immune sera in the mice with established P. aeruginosa corneal infections notably decreased the corneal clinical score and corneal bacterial load. CONCLUSIONS P. aeruginosa keratitis can be attenuated by vaccination of P. aeruginosa MVs and topical application of P. aeruginosa MV-specific immune sera.
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Affiliation(s)
- Saori Ito
- Department of Ophthalmology and Visual Science, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Jutaro Nakamura
- Department of Ophthalmology and Visual Science, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Michiko Fukuta
- Department of Ophthalmology and Visual Science, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Takehiro Ura
- Department of Ophthalmology and Visual Science, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Takeshi Teshigawara
- Department of Ophthalmology, Yokosuka Chuoh Eye Clinic, Yokosuka 238-0008, Japan
| | - Jun Fukushima
- Department of Microbiology, Akita Prefectural University, Akita 010-0195, Japan
| | - Nobuhisa Mizuki
- Department of Ophthalmology and Visual Science, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Kenji Okuda
- Department of Molecular Biodefense Research, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Masaru Shimada
- Department of Molecular Biodefense Research, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan.
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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: 65] [Impact Index Per Article: 21.7] [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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Urwin L, Okurowska K, Crowther G, Roy S, Garg P, Karunakaran E, MacNeil S, Partridge LJ, Green LR, Monk PN. Corneal Infection Models: Tools to Investigate the Role of Biofilms in Bacterial Keratitis. Cells 2020; 9:E2450. [PMID: 33182687 PMCID: PMC7696224 DOI: 10.3390/cells9112450] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/06/2020] [Accepted: 11/07/2020] [Indexed: 12/15/2022] Open
Abstract
Bacterial keratitis is a corneal infection which may cause visual impairment or even loss of the infected eye. It remains a major cause of blindness in the developing world. Staphylococcus aureus and Pseudomonas aeruginosa are common causative agents and these bacterial species are known to colonise the corneal surface as biofilm populations. Biofilms are complex bacterial communities encased in an extracellular polymeric matrix and are notoriously difficult to eradicate once established. Biofilm bacteria exhibit different phenotypic characteristics from their planktonic counterparts, including an increased resistance to antibiotics and the host immune response. Therefore, understanding the role of biofilms will be essential in the development of new ophthalmic antimicrobials. A brief overview of biofilm-specific resistance mechanisms is provided, but this is a highly multifactorial and rapidly expanding field that warrants further research. Progression in this field is dependent on the development of suitable biofilm models that acknowledge the complexity of the ocular environment. Abiotic models of biofilm formation (where biofilms are studied on non-living surfaces) currently dominate the literature, but co-culture infection models are beginning to emerge. In vitro, ex vivo and in vivo corneal infection models have now been reported which use a variety of different experimental techniques and animal models. In this review, we will discuss existing corneal infection models and their application in the study of biofilms and host-pathogen interactions at the corneal surface.
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Affiliation(s)
- Lucy Urwin
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK; (L.R.G.); (P.N.M.)
| | - Katarzyna Okurowska
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; (K.O.); (G.C.); (E.K.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
| | - Grace Crowther
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; (K.O.); (G.C.); (E.K.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
| | - Sanhita Roy
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad 500034, India; (S.R.); (P.G.)
| | - Prashant Garg
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad 500034, India; (S.R.); (P.G.)
| | - Esther Karunakaran
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; (K.O.); (G.C.); (E.K.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
| | - Sheila MacNeil
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
- Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - Lynda J. Partridge
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Luke R. Green
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK; (L.R.G.); (P.N.M.)
| | - Peter N. Monk
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK; (L.R.G.); (P.N.M.)
- Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms (SCARAB), University of Sheffield, Sheffield S1 3JD, UK; (S.M.); (L.J.P.)
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Li J, Ma X, Zhao L, Li Y, Zhou Q, Du X. Extended Contact Lens Wear Promotes Corneal Norepinephrine Secretion and Pseudomonas aeruginosa Infection in Mice. Invest Ophthalmol Vis Sci 2020; 61:17. [PMID: 32298434 PMCID: PMC7401850 DOI: 10.1167/iovs.61.4.17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose Extended contact lens (CL) wear predisposes the wearer to Pseudomonas aeruginosa infection of the cornea, but the mechanism involved remains incompletely understood. The purpose of this study was to investigate the role of the stress hormone norepinephrine (NE) in the pathogenesis of CL-induced P. aeruginosa keratitis. Methods A total 195 adult C57BL/6 mice were used in this study. Corneal NE content was measured after 48 hours of sterile CL wear in mice. The effect of NE on P. aeruginosa adhesion and biofilm formation on the CL surface was examined in vitro. Moreover, mouse eyes were covered with P. aeruginosa-contaminated CLs, and either 500-µM NE was topically applied or the eyes were subconjunctivally injected with 100 µg of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) to deplete local NE. Clinical scores, neutrophil infiltration, proinflammatory cytokine levels, and bacterial load on the corneas and CLs were evaluated. Results Corneal NE content was elevated with extended CL wear in mice. In vitro, NE promoted the adhesion and biofilm formation of P. aeruginosa on the CL surface. In mice, topical application of NE aggravated P. aeruginosa infection, accompanied with increased clinical scores, neutrophil infiltration, proinflammatory cytokine expression, and bacterial burden on the corneas and CLs. However, pre-depletion of local NE with DSP-4 significantly alleviated the severity of P. aeruginosa keratitis. Conclusions Extended CL wear elevates corneal NE content, which promotes the pathogenesis of CL-induced P. aeruginosa keratitis in mice. Targeting NE may provide a potential strategy for the treatment of CL-related corneal infection caused by P. aeruginosa.
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Garza A, Diaz G, Hamdan M, Shetty A, Hong BY, Cervantes J. Homeostasis and Defense at the Surface of the Eye. The Conjunctival Microbiota. Curr Eye Res 2020; 46:1-6. [PMID: 32584612 DOI: 10.1080/02713683.2020.1788100] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The literature on ocular microbiome has grown tremendously over the past decade, and our knowledge of the different aspects and roles in homeostasis and protection is continuously growing. The development of 16 S rRNA sequencing has allowed the field to characterize communities of bacteria in health and ocular disease. Efforts should continue to further elucidate the interplay between microbiome and key players, such as age, comorbidities, and contact lens usage in order to have better control of the sight-threatening complications.
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Affiliation(s)
- Arnulfo Garza
- Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center , El Paso, TX, USA
| | - Giancarlo Diaz
- Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center , El Paso, TX, USA
| | - Marah Hamdan
- Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center , El Paso, TX, USA
| | - Akaanksh Shetty
- Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center , El Paso, TX, USA
| | - Bo-Young Hong
- The Jackson Laboratory for Genomic Medicine , Farmington, CT, USA
| | - Jorge Cervantes
- Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center , El Paso, TX, USA
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Fleiszig SMJ, Kroken AR, Nieto V, Grosser MR, Wan SJ, Metruccio MME, Evans DJ. Contact lens-related corneal infection: Intrinsic resistance and its compromise. Prog Retin Eye Res 2019; 76:100804. [PMID: 31756497 DOI: 10.1016/j.preteyeres.2019.100804] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 12/20/2022]
Abstract
Contact lenses represent a widely utilized form of vision correction with more than 140 million wearers worldwide. Although generally well-tolerated, contact lenses can cause corneal infection (microbial keratitis), with an approximate annualized incidence ranging from ~2 to ~20 cases per 10,000 wearers, and sometimes resulting in permanent vision loss. Research suggests that the pathogenesis of contact lens-associated microbial keratitis is complex and multifactorial, likely requiring multiple conspiring factors that compromise the intrinsic resistance of a healthy cornea to infection. Here, we outline our perspective of the mechanisms by which contact lens wear sometimes renders the cornea susceptible to infection, focusing primarily on our own research efforts during the past three decades. This has included studies of host factors underlying the constitutive barrier function of the healthy cornea, its response to bacterial challenge when intrinsic resistance is not compromised, pathogen virulence mechanisms, and the effects of contact lens wear that alter the outcome of host-microbe interactions. For almost all of this work, we have utilized the bacterium Pseudomonas aeruginosa because it is the leading cause of lens-related microbial keratitis. While not yet common among corneal isolates, clinical isolates of P. aeruginosa have emerged that are resistant to virtually all currently available antibiotics, leading the United States CDC (Centers for Disease Control) to add P. aeruginosa to its list of most serious threats. Compounding this concern, the development of advanced contact lenses for biosensing and augmented reality, together with the escalating incidence of myopia, could portent an epidemic of vision-threatening corneal infections in the future. Thankfully, technological advances in genomics, proteomics, metabolomics and imaging combined with emerging models of contact lens-associated P. aeruginosa infection hold promise for solving the problem - and possibly life-threatening infections impacting other tissues.
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Affiliation(s)
- Suzanne M J Fleiszig
- School of Optometry, University of California, Berkeley, CA, USA; Graduate Group in Vision Science, University of California, Berkeley, CA, USA; Graduate Groups in Microbiology and Infectious Diseases & Immunity, University of California, Berkeley, CA, USA.
| | - Abby R Kroken
- School of Optometry, University of California, Berkeley, CA, USA
| | - Vincent Nieto
- School of Optometry, University of California, Berkeley, CA, USA
| | | | - Stephanie J Wan
- Graduate Group in Vision Science, University of California, Berkeley, CA, USA
| | | | - David J Evans
- School of Optometry, University of California, Berkeley, CA, USA; College of Pharmacy, Touro University California, Vallejo, CA, USA
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14
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Lee JK, Mereuta L, Luchian T, Park Y. Antimicrobial peptide HPA3NT3-A2 effectively inhibits biofilm formation in mice infected with drug-resistant bacteria. Biomater Sci 2019; 7:5068-5083. [PMID: 31555777 DOI: 10.1039/c9bm01051c] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bacterial biofilms formed through secretion of extracellular polymeric substances (EPS) have been implicated in many serious infections and can increase antibiotic resistance by a factor of more than 1000. Here, we examined the abilities of the antimicrobial peptide HPA3NT3-A2 to inhibit and reduce biofilm formation, eliminate EPS, and suppress inflammation in mice infected with clinical isolates of drug-resistant Pseudomonas aeruginosa strains. HPA3NT3-A2 was developed from a desirable analogue peptide, HPA3NT3, derived from residues 2-20 of the Helicobacter pylori ribosomal protein L1. HPA3NT3-A2 showed stronger activity against planktonic cells (MIC: 8 μM) compared to ciprofloxacin or tobramycin (>512 μM), and a favorable minimum biofilm inhibition and elimination concentration. This peptide also neutralized LPS; decreased levels of EPS; inhibited the production of pro-inflammatory cytokines in the lung, kidney, and spleen; decreased white blood cell counts; and increased survival among infected mice.
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Affiliation(s)
- Jong-Kook Lee
- Research Center for Proteinaceous Materials (RCPM), Chosun University, Gwangju 501-759, Korea
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15
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Patel NB, Hinojosa JA, Zhu M, Robertson DM. Acceleration of the formation of biofilms on contact lens surfaces in the presence of neutrophil-derived cellular debris is conserved across multiple genera. Mol Vis 2018; 24:94-104. [PMID: 29422767 PMCID: PMC5800429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/29/2018] [Indexed: 11/10/2022] Open
Abstract
Purpose We have previously shown that invasive strains of Pseudomonas aeruginosa exploit the robust neutrophil response to form biofilms on contact lens surfaces and invade the corneal epithelium. The present study investigated the ability of multiple bacterial genera, all commonly recovered during contact lens-related infectious events, to adhere to and form biofilms on contact lens surfaces in the presence of neutrophils. Methods Five reference strains from the American Type Culture Collection were used: P. aeruginosa, Serratia marcescens, Stenotrophomonas maltophilia, Staphylococcus aureus, and Staphylococcus epidermidis. Each bacterial strain was incubated overnight with or without stimulated human neutrophils in the presence of an unworn contact lens. Standard colony counts and laser scanning confocal microscopy of BacLight-stained contact lenses were used to assess bacterial viability. Three-dimensional modeling of lens-associated biofilms with Imaris software was used to determine the biofilm volume. Lenses were further examined using scanning electron microscopy. Results Less than 1% of the starting inoculum adhered to the contact lens surface incubated with bacteria alone. There were no differences in adhesion rates to contact lens surfaces between bacteria in the absence of neutrophils for either the Gram-negative or Gram-positive test strains. Bacterial adhesion to contact lens surfaces was accelerated in the presence of human neutrophils for all test strains. This effect was least evident with S. epidermidis. There was also an increase in the number of viable bacteria recovered from contact lens surfaces (p<0.001 for the Gram-negative and Gram-positive test strains, respectively) and in biofilm volume (p<0.001 for the Gram-negative test strains, p = 0.005 for S. aureus). Conclusions These results show that in addition to P. aeruginosa, other bacteria commonly encountered during contact lens wear possess the capacity to utilize neutrophil-derived cellular debris to facilitate colonization of the lens surface. These data suggest that this phenomenon is conserved among multiple genera. Thus, during contact lens wear, the presence of inflammation and the accumulation of neutrophil debris under the posterior lens surface likely contribute to colonization of the lens. Further studies are needed to correlate these findings with risk for infection in an animal model.
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16
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Bucki R, Durnaś B, Wątek M, Piktel E, Cruz K, Wolak P, Savage PB, Janmey PA. Targeting polyelectrolyte networks in purulent body fluids to modulate bactericidal properties of some antibiotics. Infect Drug Resist 2018; 11:77-86. [PMID: 29391814 PMCID: PMC5768182 DOI: 10.2147/idr.s145337] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The response of the human immune system to most bacterial infections results in accumulation of neutrophils at infection sites that release a significant quantity of DNA and F-actin. Both are negatively charged polyelectrolytes that can interact with positively charged host defense molecules such as cathelicidin-delivered LL-37 peptide or other cationic antibiotic agents. Evaluation of the ability of bacterial outgrowth (using luminescence measurements or counting colony-forming units) to form a biofilm (quantified by crystal violet staining) and analysis of the structure of DNA/F-actin network by optical microscopy in human pus samples treated with different antibiotics in combination with plasma gelsolin, DNAse 1, and/or poly-aspartic acid revealed that bactericidal activity of most tested antibacterial agents increases in the presence of DNA/F-actin depolymerizing factors.
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Affiliation(s)
- Robert Bucki
- Department of Microbiological and Nanobiomedical Engineering, Medical University of Białystok, Białystok
| | - Bonita Durnaś
- Department of Microbiology and Immunology, The Faculty of Health Sciences of the Jan Kochanowski University in Kielce
| | - Marzena Wątek
- Department of Microbiology and Immunology, The Faculty of Health Sciences of the Jan Kochanowski University in Kielce.,Holy Cross Oncology Center of Kielce, Kielce, Kielce, Poland
| | - Ewelina Piktel
- Department of Microbiological and Nanobiomedical Engineering, Medical University of Białystok, Białystok
| | - Katrina Cruz
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA
| | - Przemysław Wolak
- Department of Microbiology and Immunology, The Faculty of Health Sciences of the Jan Kochanowski University in Kielce
| | - Paul B Savage
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Paul A Janmey
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA
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17
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Hinojosa JA, Patel NB, Zhu M, Robertson DM. Antimicrobial Efficacy of Contact Lens Care Solutions Against Neutrophil-Enhanced Bacterial Biofilms. Transl Vis Sci Technol 2017; 6:11. [PMID: 28473944 PMCID: PMC5412968 DOI: 10.1167/tvst.6.2.11] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 02/21/2017] [Indexed: 12/28/2022] Open
Abstract
Purpose Neutrophil-derived extracellular debris has been shown to accelerate bacterial biofilm formation on hydrogel and silicone hydrogel contact lens surfaces compared to lenses inoculated with bacteria alone. The purpose of this study was to evaluate the disinfection efficacy of four standard commercial contact lens cleaning regimens against neutrophil-enhanced bacterial biofilms formed on silicone hydrogel contact lenses. Methods Four reference strains were used: Pseudomonas aeruginosa,Serratia marcescens,Stenotrophomonas maltophilia, and Staphylococcus aureus. Human neutrophils were isolated from peripheral blood by venipuncture. Unworn Lotrafilcon B lenses were incubated overnight in each respective strain with stimulated neutrophils. Contact lenses were then cleaned using one of four contact lens care solutions according to manufacturer instructions. Bacterial viability was assessed by colony counts and confocal microscopy. Volume of residual debris on lens surfaces after cleaning was quantified using IMARIS software. Results All four solutions tested showed effective antimicrobial activity against each bacterial strain; however, substantial amounts of nonviable bacteria and cellular debris remained on the lens surface despite concomitant digital cleaning. Conclusions Necrotic cellular debris that accumulates under the posterior lens surface during wear of an inoculated contact lens is not fully removed during routine cleaning and disinfection. Translational Relevance The accumulation of residual cellular debris on the contact lens surface may contribute to new colonization of the lens and represents a significant risk factor for a contact lens–related adverse event. Additional studies are needed to correlate these findings with risk for corneal infiltrative and/or infectious events in a standard animal model.
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Affiliation(s)
- Jorge A Hinojosa
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Naiya B Patel
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Meifang Zhu
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Danielle M Robertson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Robertson DM, Rogers NA, Petroll WM, Zhu M. Second harmonic generation imaging of corneal stroma after infection by Pseudomonas aeruginosa. Sci Rep 2017; 7:46116. [PMID: 28397809 PMCID: PMC5387403 DOI: 10.1038/srep46116] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/08/2017] [Indexed: 02/05/2023] Open
Abstract
Pseudomonas aeruginosa is a pathogenic gram-negative organism that has the ability to cause blinding corneal infections following trauma and during contact lens wear. In this study, we investigated the directional movement and orientation of an invasive corneal isolate of P. aeruginosa in the corneal stroma during infection of ex vivo and in vivo rabbit corneas using multiphoton fluorescence and second harmonic generation (SHG) imaging. Ex vivo, rabbit corneas were subject to three partial thickness wounds prior to inoculation. In vivo, New Zealand white rabbits were fit with P. aeruginosa laden contact lenses in the absence of a penetrating wound. At all time points tested, infiltration of the corneal stroma by P. aeruginosa revealed a high degree of alignment between the bacteria and collagen lamellae ex vivo (p < 0.001). In vivo, P. aeruginosa traveled throughout the stroma in discrete regions or bands. Within each region, the bacteria showed good alignment with collagen lamellae (P = 0.002). Interestingly, in both the in vitro and in vivo models, P. aeruginosa did not appear to cross the corneal limbus. Taken together, our findings suggest that P. aeruginosa exploits the precise spacing of collagen lamellae in the central cornea to facilitate spread throughout the stroma.
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Affiliation(s)
- Danielle M Robertson
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Nathan A Rogers
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - W Matthew Petroll
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Meifang Zhu
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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19
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Postnikoff C, Gorbet M. The Effect of Closed-Eye Tear Film Conditions on Blood-Isolated Neutrophils, In Vitro. Ocul Immunol Inflamm 2017; 26:706-716. [PMID: 28323491 DOI: 10.1080/09273948.2017.1281423] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE Eyelid closure results in influx of neutrophils onto the ocular surface, which are non-responsive to inflammatory stimuli. This investigation examined whether incubation of blood-isolated neutrophils in closed-eye conditions induce a tear-film neutrophil phenotype. METHODS Blood-isolated neutrophils were incubated combining various conditions: hypoxia, corneal epithelial cells (HCEC), artificial tear solution (ATS). RESULTS A hypoxic environment induced no differential effect on membrane receptor expression. Incubation in the presence of HCEC resulted in membrane receptor upregulation and increase in caspase activation. CONCLUSIONS Hypoxia, corneal epithelial cell exposure, or artificial tear fluid are insufficient to replicate a tear-film neutrophil phenotype using blood-isolated neutrophils.
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Affiliation(s)
- Cameron Postnikoff
- a Systems Design Engineering , University of Waterloo , Waterloo , Ontario , Canada
| | - Maud Gorbet
- a Systems Design Engineering , University of Waterloo , Waterloo , Ontario , Canada.,b School of Optometry and Vision Science , University of Waterloo , Waterloo , Ontario , Canada
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20
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Interactions between Neutrophils and Pseudomonas aeruginosa in Cystic Fibrosis. Pathogens 2017; 6:pathogens6010010. [PMID: 28282951 PMCID: PMC5371898 DOI: 10.3390/pathogens6010010] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/03/2017] [Indexed: 12/23/2022] Open
Abstract
Cystic fibrosis (CF) affects 70,000 patients worldwide. Morbidity and mortality in CF is largely caused by lung complications due to the triad of impaired mucociliary clearance, microbial infections and chronic inflammation. Cystic fibrosis airway inflammation is mediated by robust infiltration of polymorphonuclear neutrophil granulocytes (PMNs, neutrophils). Neutrophils are not capable of clearing lung infections and contribute to tissue damage by releasing their dangerous cargo. Pseudomonas aeruginosa is an opportunistic pathogen causing infections in immunocompromised individuals. P. aeruginosa is a main respiratory pathogen in CF infecting most patients. Although PMNs are key to attack and clear P. aeruginosa in immunocompetent individuals, PMNs fail to do so in CF. Understanding why neutrophils cannot clear P. aeruginosa in CF is essential to design novel therapies. This review provides an overview of the antimicrobial mechanisms by which PMNs attack and eliminate P. aeruginosa. It also summarizes current advances in our understanding of why PMNs are incapable of clearing P. aeruginosa and how this bacterium adapts to and resists PMN-mediated killing in the airways of CF patients chronically infected with P. aeruginosa.
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21
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Wu YT, Tam C, Zhu LS, Evans DJ, Fleiszig SMJ. Human Tear Fluid Reduces Culturability of Contact Lens-Associated Pseudomonas aeruginosa Biofilms but Induces Expression of the Virulence-Associated Type III Secretion System. Ocul Surf 2016; 15:88-96. [PMID: 27670247 DOI: 10.1016/j.jtos.2016.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 09/11/2016] [Accepted: 09/11/2016] [Indexed: 01/27/2023]
Abstract
PURPOSE The type III secretion system (T3SS) is a significant virulence determinant for Pseudomonas aeruginosa. Using a rodent model, we found that contact lens (CL)-related corneal infections were associated with lens surface biofilms. Here, we studied the impact of human tear fluid on CL-associated biofilm growth and T3SS expression. METHODS P. aeruginosa biofilms were formed on contact lenses for up to 7 days with or without human tear fluid, then exposed to tear fluid for 5 or 24 h. Biofilms were imaged using confocal microscopy. Bacterial culturability was quantified by viable counts, and T3SS gene expression measured by RT-qPCR. Controls included trypticase soy broth, PBS and planktonic bacteria. RESULTS With or without tear fluid, biofilms grew to ∼108 CFU viable bacteria by 24 h. Exposing biofilms to tear fluid after they had formed without it on lenses reduced bacterial culturability ∼180-fold (P<.001). CL growth increased T3SS gene expression versus planktonic bacteria [5.46 ± 0.24-fold for T3SS transcriptional activitor exsA (P=.02), and 3.76 ± 0.36-fold for T3SS effector toxin exoS (P=.01)]. Tear fluid further enhanced exsA and exoS expression in CL-grown biofilms, but not planktonic bacteria, by 2.09 ± 0.38-fold (P=.04) and 1.89 ± 0.26-fold (P<.001), respectively. CONCLUSIONS Considering the pivitol role of the T3SS in P. aeruginosa infections, its induction in CL-grown P. aeruginosa biofilms by tear fluid might contribute to the pathogenesis of CL-related P. aeruginosa keratitis.
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Affiliation(s)
- Yvonne T Wu
- School of Optometry, University of California, Berkeley, CA, USA
| | - Connie Tam
- School of Optometry, University of California, Berkeley, CA, USA
| | - Lucia S Zhu
- School of Optometry, University of California, Berkeley, CA, USA
| | - David J Evans
- School of Optometry, University of California, Berkeley, CA, USA; College of Pharmacy, Touro University California, Vallejo, CA, USA
| | - Suzanne M J Fleiszig
- School of Optometry, University of California, Berkeley, CA, USA; Graduate Groups in Vision Science, Microbiology, and Infectious Diseases & Immunity, University of California, Berkeley, CA, USA.
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22
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Murphy MP, Caraher E. Residence in biofilms allows Burkholderia cepacia complex (Bcc) bacteria to evade the antimicrobial activities of neutrophil-like dHL60 cells. Pathog Dis 2015; 73:ftv069. [PMID: 26371179 DOI: 10.1093/femspd/ftv069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2015] [Indexed: 12/14/2022] Open
Abstract
Bacteria of the Burkholderia cepacia complex (Bcc) persist in the airways of people with cystic fibrosis (CF) despite the continuous recruitment of neutrophils. Most members of Bcc are multidrug resistant and can form biofilms. As such, we sought to investigate whether biofilm formation plays a role in protecting Bcc bacteria from neutrophils. Using the neutrophil-like, differentiated cell line, dHL60, we have shown for the first time that Bcc biofilms are enhanced in the presence of these cells. Biofilm biomass was greater following culture in the presence of dHL60 cells than in their absence, likely the result of incorporating dHL60 cellular debris into the biofilm. Moreover, we have demonstrated that mature biofilms (cultured for up to 72 h) induced necrosis in the cells. Established biofilms also acted as a barrier to the migration of the cells and masked the bacteria from being recognized by the cells; dHL60 cells expressed less IL-8 mRNA and secreted significantly less IL-8 when cultured in the presence of biofilms, with respect to planktonic bacteria. Our findings provide evidence that biofilm formation can, at least partly, enable the persistence of Bcc bacteria in the CF airway and emphasize a requirement for anti-biofilm therapeutics.
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Affiliation(s)
- Mark P Murphy
- Centre for Microbial-Host Interactions, Institute of Technology Tallaght, Dublin 24, Ireland Centre of Applied Science for Health, Institute of Technology Tallaght, Dublin 24, Ireland
| | - Emma Caraher
- Centre for Microbial-Host Interactions, Institute of Technology Tallaght, Dublin 24, Ireland Centre of Applied Science for Health, Institute of Technology Tallaght, Dublin 24, Ireland
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23
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Comparison of surface roughness and bacterial adhesion between cosmetic contact lenses and conventional contact lenses. Eye Contact Lens 2015; 41:25-33. [PMID: 25536530 DOI: 10.1097/icl.0000000000000054] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare physical characteristics of cosmetic contact lenses (Cos-CLs) and conventional contact lenses (Con-CLs) that might affect susceptibility to bacterial adhesion on the contact lens (CL) surface. METHODS Surface characteristics of Cos-CLs and Con-CLs made from the same material by the same manufacturer were measured by atomic force microscopy (AFM) and scanning electron microscopy. To determine the extent and rate of bacterial adhesion, Cos-CL and Con-CL were immersed in serum-free Roswell Park Memorial Institute media containing Staphylococcus aureus or Pseudomonas aeruginosa. Additionally, the rate of removal of adherent bacteria was evaluated using hand rubbing or immersion in multipurpose disinfecting solutions (MPDS). RESULTS The mean surface roughness (root mean square and peak-to-valley value) measured by AFM was significantly higher for Cos-CL than for Con-CL. At each time point, significantly more S. aureus and P. aeruginosa adhered to Cos-CL than to Con-CL, which correlated with the surface roughness of CL. In Cos-CL, bacteria were mainly found on the tinted surface rather than on the noncolored or convex areas. Pseudomonas aeruginosa attached earlier than S. aureus to all types of CL. However, P. aeruginosa was more easily removed from the surface of CL than S. aureus by hand rubbing or MPDS soaking. CONCLUSIONS Increased surface roughness is an important physical factor for bacterial adhesion in Cos-CL, which may explain why rates of bacterial keratitis rates are higher in Cos-CL users in CL physical characteristics.
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24
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Bucki R, Niemirowicz K, Wnorowska U, Wątek M, Byfield FJ, Cruz K, Wróblewska M, Janmey PA. Polyelectrolyte-mediated increase of biofilm mass formation. BMC Microbiol 2015; 15:117. [PMID: 26048182 PMCID: PMC4458031 DOI: 10.1186/s12866-015-0457-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 05/29/2015] [Indexed: 01/08/2023] Open
Abstract
Background Biofilm formation is associated with various aspects of bacterial and fungal infection. This study was designed to assess the impact of diverse natural polyelectrolytes, such as DNA, F-actin, neurofilaments (NFs), vimentin and purified Pf1 bacteriophage on biofilm formation and swarming motility of select pathogens including Pseudomonas aeruginosa associated with lung infections in CF patients. Results The bacteriophage Pf1 (1 mg/ml) significantly increased biofilm mass produced by Pseudomonas aeruginosa P14, Escherichia coli RS218 and Bacillus subtilis ATCC6051. DNA, F-actin, NFs and Pf1 also increased biofilm mass of the fungal C. albicans 1409 strain. Addition of F-actin, DNA or Pf1 bacteriophage to 0.5% agar plates increased swarming motility of Pseudomonas aeruginosa Xen5. Conclusions The presence of polyelectrolytes at infection sites is likely to promote biofilm growth and bacterial swarming.
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Affiliation(s)
- Robert Bucki
- Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, ul. Mickiewicza 2C, Bialystok, 15-222, Poland. .,Department of Physiology, Pathophysiology and Microbiology of Infections, The Faculty of Health Sciences of the Jan Kochanowski University in Kielce, Kielce, Poland.
| | - Katarzyna Niemirowicz
- Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, ul. Mickiewicza 2C, Bialystok, 15-222, Poland.
| | - Urszula Wnorowska
- Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, ul. Mickiewicza 2C, Bialystok, 15-222, Poland.
| | - Marzena Wątek
- Department of Hematology, Holy Cross Oncology Center of Kielce, Kielce, Poland.
| | - Fitzroy J Byfield
- Department of Physiology and the Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Katrina Cruz
- Department of Physiology and the Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Marta Wróblewska
- Department of Dental Microbiology, Medical University of Warsaw, Warsaw, Poland.
| | - Paul A Janmey
- Department of Physiology and the Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
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25
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Caceres SM, Malcolm KC, Taylor-Cousar JL, Nichols DP, Saavedra MT, Bratton DL, Moskowitz SM, Burns JL, Nick JA. Enhanced in vitro formation and antibiotic resistance of nonattached Pseudomonas aeruginosa aggregates through incorporation of neutrophil products. Antimicrob Agents Chemother 2014; 58:6851-60. [PMID: 25182651 PMCID: PMC4249413 DOI: 10.1128/aac.03514-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 08/28/2014] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a major pathogen in cystic fibrosis (CF) lung disease. Children with CF are routinely exposed to P. aeruginosa from the natural environment, and by adulthood, 80% of patients are chronically infected. P. aeruginosa in the CF airway exhibits a unique biofilm-like structure, where it grows in small clusters or aggregates of bacteria in association with abundant polymers of neutrophil-derived components F-actin and DNA, among other components. These aggregates differ substantially in size and appearance compared to surface-attached in vitro biofilm models classically utilized for studies but are believed to share properties of surface-attached biofilms, including antibiotic resistance. However, little is known about the formation and function of surface-independent modes of biofilm growth, how they might be eradicated, and quorum sensing communication. To address these issues, we developed a novel in vitro model of P. aeruginosa aggregates incorporating human neutrophil-derived products. Aggregates grown in vitro and those found in CF patients' sputum samples were morphologically similar; viable bacteria were distributed in small pockets throughout the aggregate. The lasA quorum sensing gene was differentially expressed in the presence of neutrophil products. Importantly, aggregates formed in the presence of neutrophils acquired resistance to tobramycin, which was lost when the aggregates were dispersed with DNase, and antagonism of tobramycin and azithromycin was observed. This novel yet simple in vitro system advances our ability to model infection of the CF airway and will be an important tool to study virulence and test alternative eradication strategies against P. aeruginosa.
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Affiliation(s)
- Silvia M Caceres
- Department of Medicine, National Jewish Health, Denver, Colorado, USA
| | - Kenneth C Malcolm
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - Jennifer L Taylor-Cousar
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - David P Nichols
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Pediatrics, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - Milene T Saavedra
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
| | - Donna L Bratton
- Department of Pediatrics, National Jewish Health, Denver, Colorado, USA
| | - Samuel M Moskowitz
- Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jane L Burns
- Division of Pediatric Infectious Disease, Department of Pediatrics, Seattle Children's Hospital, University of Washington School of Medicine, Seattle, Washington, USA
| | - Jerry A Nick
- Department of Medicine, National Jewish Health, Denver, Colorado, USA Department of Medicine, University of Colorado, Denver, Aurora, Colorado, USA
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26
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Wei C, Zhu M, Petroll WM, Robertson DM. Pseudomonas aeruginosa infectious keratitis in a high oxygen transmissible rigid contact lens rabbit model. Invest Ophthalmol Vis Sci 2014; 55:5890-9. [PMID: 25125601 PMCID: PMC4168740 DOI: 10.1167/iovs.14-14235] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 08/02/2014] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To establish a rabbit model of infectious Pseudomonas aeruginosa keratitis using ultrahigh oxygen transmissible rigid lenses and characterize the frequency and severity of infection when compared to a non-oxygen transmissible lens material. METHODS Rabbits were fit with rigid lenses composed of ultrahigh and non-oxygen transmissible materials. Prior to wear, lenses were inoculated with an invasive corneal isolate of P. aeruginosa stably conjugated to green fluorescent protein (GFP). Corneas were examined before and after lens wear using a modified Heidelberg Rostock Tomograph in vivo confocal microscope. Viable bacteria adherent to unworn and worn lenses were assessed by standard plate counts. The presence of P. aeruginosa-GFP and myeloperoxidase-labeled neutrophils in infected corneal tissue was evaluated using laser scanning confocal microscopy. RESULTS The frequency and severity of infectious keratitis was significantly greater with inoculated ultrahigh oxygen transmissible lenses. Infection severity was associated with increasing neutrophil infiltration and in severe cases, corneal melting. In vivo confocal microscopic analysis of control corneas following lens wear confirmed that hypoxic lens wear was associated with mechanical surface damage, whereas no ocular surface damage was evident in the high-oxygen lens group. CONCLUSIONS These data indicate that in the absence of adequate tear clearance, the presence of P. aeruginosa trapped under the lens overrides the protective effects of oxygen on surface epithelial cells. These findings also suggest that alternative pathophysiological mechanisms exist whereby changes under the lens in the absence of frank hypoxic damage result in P. aeruginosa infection in the otherwise healthy corneal epithelium.
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Affiliation(s)
- Cynthia Wei
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Meifang Zhu
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - W Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Danielle M Robertson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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Abstract
Microbial keratitis is a sight-threatening complication associated with contact lenses. The introduction of silicone hydrogel lens materials with increased oxygen transmission to the ocular surface has not significantly altered the incidence of microbial keratitis. These data suggest that alternate, or additional, predisposing factors involving lens wear must be addressed to reduce or eliminate these infections. The contact lens can provide a surface for microbial growth in situ and can also influence ocular surface homeostasis through effects on the tear fluid and corneal epithelium. Thus, it is intuitive that future contact lens materials could make a significant contribution to preventing microbial keratitis. Design of the "right" material to prevent microbial keratitis requires understanding the effects of current materials on bacterial virulence in the cornea and on ocular surface innate defenses. Current knowledge in each of these areas will be presented with a discussion of future directions needed to understand the influence of lens material on the pathogenesis of microbial keratitis.
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Mycobacterium abscessus induces a limited pattern of neutrophil activation that promotes pathogen survival. PLoS One 2013; 8:e57402. [PMID: 23451220 PMCID: PMC3581440 DOI: 10.1371/journal.pone.0057402] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 01/21/2013] [Indexed: 12/21/2022] Open
Abstract
Mycobacterium abscessus is a rapidly growing mycobacterium increasingly detected in the neutrophil-rich environment of inflamed tissues, including the cystic fibrosis airway. Studies of the immune reaction to M. abscessus have focused primarily on macrophages and epithelial cells, but little is known regarding the neutrophil response despite the predominantly neutrophillic inflammation typical of these infections. In the current study, human neutrophils released less superoxide anion in response to M. abscessus than to Staphylococcus aureus, a pathogen that shares common sites of infection. Exposure to M. abscessus induced neutrophil-specific chemokine and proinflammatory cytokine genes. Although secretion of these protein products was confirmed, the quantity of cytokines released, and both the number and level of gene induction, was reduced compared to S. aureus. Neutrophils mediated killing of M. abscessus, but phagocytosis was reduced when compared to S. aureus, and extracellular DNA was detected in response to both bacteria, consistent with extracellular trap formation. In addition, M. abscessus did not alter cell death compared to unstimulated cells, while S. aureus enhanced necrosis and inhibited apoptosis. However, neutrophils augment M. abscessus biofilm formation. The response of neutrophils to M. abscessus suggests that the mycobacterium exploits neutrophil-rich settings to promote its survival and that the overall neutrophil response was reduced compared to S. aureus. These studies add to our understanding of M. abscessus virulence and suggest potential targets of therapy.
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Nichols DP, Caceres S, Caverly L, Fratelli C, Kim SH, Malcolm K, Poch KR, Saavedra M, Solomon G, Taylor-Cousar J, Moskowitz S, Nick JA. Effects of azithromycin in Pseudomonas aeruginosa burn wound infection. J Surg Res 2013; 183:767-76. [PMID: 23478086 DOI: 10.1016/j.jss.2013.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/29/2013] [Accepted: 02/01/2013] [Indexed: 02/01/2023]
Abstract
BACKGROUND Cutaneous thermal injuries (i.e., burns) remain a common form of debilitating trauma, and outcomes are often worsened by wound infection with environmental bacteria, chiefly Pseudomonas aeruginosa. MATERIALS AND METHODS We tested the effects of early administration of a single dose of azithromycin, with or without subsequent antipseudomonal antibiotics, in a mouse model of standardized thermal injury infected with P aeruginosa via both wound site and systemic infection. We also tested the antimicrobial effects of these antibiotics alone or combined in comparative biofilm and planktonic cultures in vitro. RESULTS In our model, early azithromycin administration significantly reduced wound and systemic infection without altering wound site or circulating neutrophil activity. The antimicrobial effect of azithromycin was additive with ciprofloxacin but significantly reduced the antimicrobial effect of tobramycin. This pattern was reproduced in biofilm cultures and not observed in planktonic cultures of P aeruginosa. CONCLUSION These data suggest that early administration of azithromycin following burn-related trauma and infection may reduce P aeruginosa infection and potential interactions with other antibiotics should be considered when designing future studies.
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Affiliation(s)
- David P Nichols
- Pulmonary Medicine Division, Department of Pediatrics, National Jewish Health, Denver, CO 80206, USA.
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Robertson DM. The effects of silicone hydrogel lens wear on the corneal epithelium and risk for microbial keratitis. Eye Contact Lens 2013; 39:67-72. [PMID: 23266590 PMCID: PMC3587121 DOI: 10.1097/icl.0b013e31827c5b73] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Previous studies using animal models and human clinical trials have demonstrated that the use of low-oxygen-transmissible contact lens materials produce corneal epithelial surface damage resulting in increased Pseudomonas aeruginosa (PA) adhesion and raft-mediated internalization into surface corneal epithelial cells. These findings led to the testable clinical predictions that (1) microbial keratitis (MK) risk is expected to be the greatest during the first 6 months of wear; (2) there is no difference between 6 and 30 night extended wear; and (3) that wear of hyperoxygen-transmissible lenses would reduce the reported incidence of infection. Subsequent epidemiologic studies have confirmed the first two predictions; however, increased oxygen transmissibility with silicone hydrogel (SiHy) lens wear has not altered the overall incidence of MK. In this review, more recent clinical and basic studies that investigate epithelial alterations and bacterial adhesion to corneal epithelial cells after the wear of SiHy lenses with and without concomitant exposure to chemically preserved multipurpose solutions (MPS) will be examined. The collective results of these studies demonstrate that even in the absence of lens-related hypoxia, MPS induce ocular surface changes during SiHy lens wear that are associated with a pathophysiologic increase in PA adherence and internalization in the corneal epithelium, and therefore, predict a greater risk for PA-MK. In addition, new data supporting an interactive role for inflammation in facilitating PA adherence and internalization in the corneal epithelium will also be discussed.
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Affiliation(s)
- Danielle M Robertson
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA.
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The impact of cellular debris on Pseudomonas aeruginosa adherence to silicone hydrogel contact lenses and contact lens storage cases. Eye Contact Lens 2012; 38:7-15. [PMID: 22138709 DOI: 10.1097/icl.0b013e31823bad0e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate neutrophil-enhanced Pseudomonas aeruginosa (PA) biofilm formation on silicone hydrogel contact lenses and to determine the effect of epithelial biodebris on PA adherence in contact lens storage cases. METHODS A fully invasive PA corneal isolate stably conjugated to green fluorescent protein was used. Unworn lotrafilcon A contact lenses were incubated at various ratios of PA to polymorphonuclear neutrophil (PMN) for 24 hours at 37°C. Lens-associated PA was evaluated using laser scanning confocal microscopy and nonviable PA were visualized using propidium iodide. Viable bacteria were enumerated by colony-forming unit (CFU) analysis. For acute epithelial cell studies, PA viability was determined after coincubation with freeze-thaw epithelial cell lysates in 96-well polystyrene plates. Levels of residual cellular debris and bacterial viability were further assessed in used contact lens storage cases. RESULTS Laser scanning confocal microscopy demonstrated that cotreatment with PMA-stimulated neutrophils increased PA adherence over 24 hours to lens surfaces with a striking alteration of PA architecture. Propidium iodide staining showed that the adherent bacteria consisted of a mixture of viable and nonviable PA; a PMN-associated increase in viable PA was confirmed by CFU (PA:PMN 0.1:1, P = 0.025; PA:PMN 1:1, P = 0.005). Acute epithelial cell debris studies revealed a significant increase in viable PA in 96-well plates in the presence of epithelial freeze-thaw lysates (PA:debris 1:1, P = 0.002; PA:debris 100:1, P = 0.002). Crystal violet staining of used lens storage cases revealed residual cellular debris at all time points, which was independent of microbial contamination; all lens cases used for periods of 9 months or more were uniformly associated with high levels of viable microorganisms. CONCLUSION These results demonstrate that prolonged corneal inflammation with the presence of PMNs when confronted with simultaneous PA challenge in extended contact lens wear has the potential to stimulate biofilm formation on silicone hydrogel contact lenses. These findings further suggest that a persistent buildup of extracellular debris in lens storage cases may contribute to the heavy biofilms reported on these surfaces.
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