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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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2
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Hazlett LD, McClellan S, Somayajulu M, Bessert D. Targeting Inflammation Driven by HMGB1 in Bacterial Keratitis-A Review. Pathogens 2021; 10:pathogens10101235. [PMID: 34684184 PMCID: PMC8538492 DOI: 10.3390/pathogens10101235] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/30/2021] [Accepted: 09/24/2021] [Indexed: 12/29/2022] Open
Abstract
Pseudomonas (P.) aeruginosa is a Gram-negative bacteria that causes human infectionsinfections. It can cause keratitis, a severe eye infection, that develops quickly and is a major cause of ulceration of the cornea and ocular complications globally. Contact lens wear is the greatest causative reason in developed countries, but in other countries, trauma and predominates. Use of non-human models of the disease are critical and may provide promising alternative argets for therapy to bolster a lack of new antibiotics and increasing antibiotic resistance. In this regard, we have shown promising data after inhibiting high mobility group box 1 (HMGB1), using small interfering RNA (siRNA). Success has also been obtained after other means to inhinit HMGB1 and include: use of HMGB1 Box A (one of three HMGB1 domains), anti-HMGB1 antibody blockage of HMGB1 and/or its receptors, Toll like receptor (TLR) 4, treatment with thrombomodulin (TM) or vasoactive intestinal peptide (VIP) and glycyrrhizin (GLY, a triterpenoid saponin) that directly binds to HMGB1. ReducingHMGB1 levels in P. aeruginosa keratitis appears a viable treatment alternative.
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3
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Ung L, Chodosh J. Foundational concepts in the biology of bacterial keratitis. Exp Eye Res 2021; 209:108647. [PMID: 34097906 PMCID: PMC8595513 DOI: 10.1016/j.exer.2021.108647] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/28/2021] [Accepted: 05/27/2021] [Indexed: 12/12/2022]
Abstract
Bacterial infections of the cornea, or bacterial keratitis (BK), are notorious for causing rapidly fulminant disease and permanent vision loss, even among treated patients. In the last sixty years, dramatic upward trajectories in the frequency of BK have been observed internationally, driven in large part by the commercialization of hydrogel contact lenses in the late 1960s. Despite this worsening burden of disease, current evidence-based therapies for BK - including broad-spectrum topical antibiotics and, if indicated, topical corticosteroids - fail to salvage vision in a substantial proportion of affected patients. Amid growing concerns of rapidly diminishing antibiotic utility, there has been renewed interest in urgently needed novel treatments that may improve clinical outcomes on an individual and public health level. Bridging the translational gap in the care of BK requires the identification of new therapeutic targets and rational treatment design, but neither of these aims can be achieved without understanding the complex biological processes that determine how bacterial corneal infections arise, progress, and resolve. In this chapter, we synthesize the current wealth of human and animal experimental data that now inform our understanding of basic BK pathophysiology, in context with modern concepts in ocular immunology and microbiology. By identifying the key molecular determinants of clinical disease, we explore how novel treatments can be developed and translated into routine patient care.
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Affiliation(s)
- Lawson Ung
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA.
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Morin CD, Déziel E, Gauthier J, Levesque RC, Lau GW. An Organ System-Based Synopsis of Pseudomonas aeruginosa Virulence. Virulence 2021; 12:1469-1507. [PMID: 34180343 PMCID: PMC8237970 DOI: 10.1080/21505594.2021.1926408] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Driven in part by its metabolic versatility, high intrinsic antibiotic resistance, and a large repertoire of virulence factors, Pseudomonas aeruginosa is expertly adapted to thrive in a wide variety of environments, and in the process, making it a notorious opportunistic pathogen. Apart from the extensively studied chronic infection in the lungs of people with cystic fibrosis (CF), P. aeruginosa also causes multiple serious infections encompassing essentially all organs of the human body, among others, lung infection in patients with chronic obstructive pulmonary disease, primary ciliary dyskinesia and ventilator-associated pneumonia; bacteremia and sepsis; soft tissue infection in burns, open wounds and postsurgery patients; urinary tract infection; diabetic foot ulcers; chronic suppurative otitis media and otitis externa; and keratitis associated with extended contact lens use. Although well characterized in the context of CF, pathogenic processes mediated by various P. aeruginosa virulence factors in other organ systems remain poorly understood. In this review, we use an organ system-based approach to provide a synopsis of disease mechanisms exerted by P. aeruginosa virulence determinants that contribute to its success as a versatile pathogen.
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Affiliation(s)
- Charles D Morin
- Centre Armand-Frappier Santé Biotechnologie, Institut National De La Recherche Scientifique (INRS), Laval, Quebec, Canada
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National De La Recherche Scientifique (INRS), Laval, Quebec, Canada
| | - Jeff Gauthier
- Département De Microbiologie-infectiologie Et Immunologie, Institut De Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec City, Quebec, Canada
| | - Roger C Levesque
- Département De Microbiologie-infectiologie Et Immunologie, Institut De Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec City, Quebec, Canada
| | - Gee W Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, US
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5
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Efron N. Putting vital stains in context. Clin Exp Optom 2021; 96:400-21. [DOI: 10.1111/j.1444-0938.2012.00802.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 06/17/2012] [Accepted: 06/19/2012] [Indexed: 11/30/2022] Open
Affiliation(s)
- Nathan Efron
- Institute of Health and Biomedical Innovation, and School of Optometry and Vision Science, Queensland University of Technology, Kelvin Grove, Queensland, Australia,
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6
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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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Sagerfors S, Ejdervik‐Lindblad B, Söderquist B. Infectious keratitis: isolated microbes and their antibiotic susceptibility pattern during 2004-2014 in Region Örebro County, Sweden. Acta Ophthalmol 2020; 98:255-260. [PMID: 31580009 PMCID: PMC7216983 DOI: 10.1111/aos.14256] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 09/06/2019] [Indexed: 01/14/2023]
Abstract
PURPOSE To describe predisposing risk factors, causative microorganisms and their antibiotic susceptibility patterns in infectious keratitis during an 11-year period in Region Örebro County, Sweden. METHODS This is a descriptive study conducted as a retrospective audit of clinical records. Patients who received treatment for infectious keratitis at any of the three ophthalmological departments within Region Örebro County, Sweden, between 2004 and 2014 were included if they fulfilled the predefined criteria for infectious keratitis. Data regarding culture results, antibiotic susceptibility pattern and risk factors for infectious keratitis were obtained from medical records and microbiological reports. RESULTS In total, 398 episodes of infectious keratitis in 392 patients were included, and 285 were culture positive. The most common predisposing risk factor was contact lens wear (45%). Coagulase-negative staphylococci (39.6%) was the most commonly isolated type of organism. Staphylococcus aureus (15.1%) followed by Moraxella spp. (7.4%) and Pseudomonas aeruginosa (6.7%) were among the most common isolated bacteria not considered to be commensal. Reduced susceptibility to fluoroquinolones was observed in five of 43 S. aureus isolates and in four of nine Streptococcus pneumoniae isolates. CONCLUSION The most common predisposing risk factor for keratitis was contact lens wear. Among the most common microbes, not considered to be exclusively commensals, isolated from the cornea in microbial keratitis were S. aureus, Moraxella spp. and P. aeruginosa. The antibiotic susceptibility patterns showed low proportion of resistance. Empiric treatment of suspected infectious keratitis with topical fluoroquinolones and chloramphenicol might be considered in a setting like ours pending culture results.
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Affiliation(s)
- Susanna Sagerfors
- Department of OphthalmologyFaculty of Medicine and HealthÖrebro UniversityÖrebroSweden,School of Medical SciencesFaculty of Medicine and HealthÖrebro UniversityÖrebroSweden
| | - Birgitta Ejdervik‐Lindblad
- Department of OphthalmologyFaculty of Medicine and HealthÖrebro UniversityÖrebroSweden,School of Medical SciencesFaculty of Medicine and HealthÖrebro UniversityÖrebroSweden
| | - Bo Söderquist
- School of Medical SciencesFaculty of Medicine and HealthÖrebro UniversityÖrebroSweden,Department of Laboratory Medicine Clinic of MicrobiologyFaculty of Medicine and HealthÖrebro UniversityÖrebroSweden
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9
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Diffuse lamellar keratitis associated with tabletop autoclave biofilms: case series and review. J Cataract Refract Surg 2020; 46:340-349. [DOI: 10.1097/j.jcrs.0000000000000070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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10
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Abstract
Pseudomonas aeruginosa, a versatile Gram-negative pathogen that can cause a wide range of infections, is the most common causative agent in cases of bacterial keratitis associated with contact-lens use. Corneal infections with P. aeruginosa often have poor clinical outcomes and can result in long and costly treatments. During the infection process, the pathogen exploits its large genome, encoding complex regulatory networks and a wide range of virulence factors, including motility and the secretion of various proteases and toxins. Although antibiotic resistance levels in the UK are low, higher levels have been seen in some other countries. In the face of increasing antibiotic resistance, alternative therapeutic approaches such as antivirulence strategies and phage therapy are being developed. There is increasing evidence to suggest that keratitis infections are associated with a phylogenetic subgroup of P. aeruginosa isolates carrying the gene encoding the potent cytotoxin exotoxin U, one of two mutually exclusive exotoxins secreted via the type III secretion system. The mechanisms behind this association are unclear, but understanding the genetic differences that predispose P. aeruginosa to cause corneal infections may allow for the development of targeted and more effective future treatments to reduce the morbidity of P. aeruginosa keratitis. In order to minimize the risk of severe P. aeruginosa eye infections, a wide range of contact-lens disinfection solutions are available. Constant exposure to biocides at a range of concentrations, from sub-inhibitory to inhibitory, could contribute to the development of resistance to both antibiotics and disinfectants.
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Affiliation(s)
- Yasmin Hilliam
- Department of Clinical Infection, Microbiology, and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Stephen Kaye
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Craig Winstanley
- Department of Clinical Infection, Microbiology, and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
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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: 67] [Impact Index Per Article: 13.4] [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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Ruffin M, Brochiero E. Repair Process Impairment by Pseudomonas aeruginosa in Epithelial Tissues: Major Features and Potential Therapeutic Avenues. Front Cell Infect Microbiol 2019; 9:182. [PMID: 31214514 PMCID: PMC6554286 DOI: 10.3389/fcimb.2019.00182] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 05/13/2019] [Indexed: 01/13/2023] Open
Abstract
Epithelial tissues protecting organs from the environment are the first-line of defense against pathogens. Therefore, efficient repair mechanisms after injury are crucial to maintain epithelial integrity. However, these healing processes can be insufficient to restore epithelial integrity, notably in infectious conditions. Pseudomonas aeruginosa infections in cutaneous, corneal, and respiratory tract epithelia are of particular concern because they are the leading causes of hospitalizations, disabilities, and deaths worldwide. Pseudomonas aeruginosa has been shown to alter repair processes, leading to chronic wounds and infections. Because of the current increase in the incidence of multi-drug resistant isolates of P. aeruginosa, complementary approaches to decrease the negative impact of these bacteria on epithelia are urgently needed. Here, we review the recent advances in the understanding of the impact of P. aeruginosa infections on the integrity and repair mechanisms of alveolar, airway, cutaneous and corneal epithelia. Potential therapeutic avenues aimed at counteracting this deleterious impact of infection are also discussed.
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Affiliation(s)
- Manon Ruffin
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada.,INSERM, Centre de Recherche Saint-Antoine, CRSA, Sorbonne Université, Paris, France
| | - Emmanuelle Brochiero
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada
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A novel murine model for contact lens wear reveals clandestine IL-1R dependent corneal parainflammation and susceptibility to microbial keratitis upon inoculation with Pseudomonas aeruginosa. Ocul Surf 2018; 17:119-133. [PMID: 30439473 DOI: 10.1016/j.jtos.2018.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 11/06/2018] [Accepted: 11/09/2018] [Indexed: 12/17/2022]
Abstract
PURPOSE Contact lens wear carries a risk of complications, including corneal infection. Solving these complications has been hindered by limitations of existing animal models. Here, we report development of a new murine model of contact lens wear. METHODS C57BL/6 mice were fitted with custom-made silicone-hydrogel contact lenses with or without prior inoculation with Pseudomonas aeruginosa (PAO1-GFP). Contralateral eyes served as controls. Corneas were monitored for pathology, and examined ex vivo using high-magnification, time-lapse imaging. Fluorescent reporter mice allowed visualization of host cell membranes and immune cells. Lens-colonizing bacteria were detected by viable counts and FISH. Direct-colony PCR was used for bacterial identification. RESULTS Without deliberate inoculation, lens-wearing corneas remained free of visible pathology, and retained a clarity similar to non-lens wearing controls. CD11c-YFP reporter mice revealed altered numbers, and distribution, of CD11c-positive cells in lens-wearing corneas after 24 h. Worn lenses showed bacterial colonization, primarily by known conjunctival or skin commensals. Corneal epithelial cells showed vacuolization during lens wear, and after 5 days, cells with phagocyte morphology appeared in the stroma that actively migrated over resident keratocytes that showed altered morphology. Immunofluorescence confirmed stromal Ly6G-positive cells after 5 days of lens wear, but not in MyD88 or IL-1R gene-knockout mice. P. aeruginosa-contaminated lenses caused infectious pathology in most mice from 1 to 13 days. CONCLUSIONS This murine model of contact lens wear appears to faithfully mimic events occurring during human lens wear, and could be valuable for experiments, not possible in humans, that help solve the pathogenesis of lens-related complications.
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14
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Biofilm Formation on Bandage Contact Lenses Worn by Patients with the Boston Type 1 Keratoprosthesis: A Pilot Comparison Study of Prophylactic Topical Vancomycin 15 mg/mL and Linezolid 0.2%. Eye Contact Lens 2018; 44 Suppl 1:S106-S109. [DOI: 10.1097/icl.0000000000000337] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Cho CH, Lee SB. Comparison of clinical characteristics and antibiotic susceptibility between Pseudomonas aeruginosa and P. putida keratitis at a tertiary referral center: a retrospective study. BMC Ophthalmol 2018; 18:204. [PMID: 30126384 PMCID: PMC6102849 DOI: 10.1186/s12886-018-0882-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 08/10/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To compare clinical characteristics and antibiotic susceptibilities in patients with Pseudomonas aeruginosa (PA) and P. putida (PP) keratitis at a tertiary referral center in South Korea. METHODS Forty-nine cases of inpatients with culture-proven PA and PP keratitis were reviewed retrospectively between January 1998 and December 2017. We excluded cases of polymicrobial infection. Epidemiology, predisposing factors, clinical characteristics, antibiotic susceptibilities, and treatment outcomes were compared between the PA and PP groups. The risk factors for poor clinical outcome were evaluated on the basis of the total cohort and analyzed using multivariate logistic regression. RESULTS A total of 33 eyes with PA keratitis and 16 eyes with PP keratitis were included. The mean age was 47.0 years in the PA group and 59.3 years in the PP group (p = 0.060). Differences were observed between the PA and PP groups in hypopyon (45.5% vs 6.3%, p = 0.006) and symptom duration (4.3 vs 9.5 days, p = 0.022). The most common predisposing factor for PA was wearing contact lenses (36.4%) and that for PP was corneal trauma (62.5%). No significant differences were observed in sex, previous topical steroid use, systemic disease, or duration of hospitalization between the two groups. The PA and PP groups both demonstrated good efficacy of colistin (both 100%), tobramycin (93.3%, 100%), ceftazidime (93.9%, 87.5%), and ciprofloxacin (96.6%, 87.5%). Imipenem (100% vs 81.3%, p = 0.030), piperacillin (96.6% vs 75%, p = 0.047), and ticarcillin (85% vs 0%, p < 0.001) showed significantly lower efficacy in the PP group than in the PA group. A poor clinical outcome was observed in 31.2% of the PA group and 37.5% of the PP group (p = 0.665). The risk factors for poor clinical outcome were previous ocular surface disease (odds ratio 10.79, p = 0.012) and hypopyon (odds ratio 9.02, p = 0.024). CONCLUSIONS The PA group was more closely associated with younger age, wearing contact lenses, shorter symptom duration, and hypopyon, whereas the PP group was more closely associated with elderly age, corneal trauma, and decreased efficacy of the beta-lactams. Clinical outcomes were not significantly different between the two groups. Previous ocular surface disease and hypopyon were the risk factors for poor clinical outcome.
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Affiliation(s)
- Chan Ho Cho
- Department of Ophthalmology, Yeungnam University College of Medicine, 170, Hyunchung-ro, Nam-gu, Daegu, 705-717 (42415), South Korea
| | - Sang-Bumm Lee
- Department of Ophthalmology, Yeungnam University College of Medicine, 170, Hyunchung-ro, Nam-gu, Daegu, 705-717 (42415), South Korea.
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Contact Lenses and Infectious Keratitis. CURRENT OPHTHALMOLOGY REPORTS 2018. [DOI: 10.1007/s40135-018-0172-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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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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Kim DJ, Park JH, Kim M, Park CY. The Antibiofilm efficacy of nitric oxide on soft contact lenses. BMC Ophthalmol 2017; 17:206. [PMID: 29162075 PMCID: PMC5696802 DOI: 10.1186/s12886-017-0604-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/15/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND To investigate the antibiofilm efficacy of nitric oxide (NO) on soft contact lenses. METHODS Nitrite (NO precursor) release from various concentrations (0-1000 μM) of sodium nitrite (NaNO2, NO donor) was measured by Griess Assay. Cell viability assay was performed using human corneal epithelial cell under various concentration (0-1000 μM) of NaNO2. Biofilm formation on soft contact lenses was achieved by adding Staphylococcus aureus or Pseudomonas aeruginosa to the culture media. Various concentrations of NaNO2 (0-1000 μM) were added to the culture media, each containing soft contact lens. After incubation in NaNO2 containing culture media for 1, 3, or 7 days, each contact lens was transferred to a fresh, bacteria-free media without NaNO2. The bacteria in the biofilm were dispersed in the culture media for planktonic growth. After reculturing the lenses in the fresh media for 24 h, optical density (OD) of media was measured at 600 nm and colony forming unit (CFU) was counted by spreading media on tryptic soy agar plate for additional 18 h. RESULTS Nitrite release from NaNO2 showed dose-dependent suppressive effect on biofilm formation. Most nitrite release from NaNO2 tended to occur within 30 min. The viability of human corneal epithelial cells was well maintained at tested NaNO2 concentrations. The bacterial CFU and OD showed dose-dependent decrease in the NaNO2 treated samples on days 1, 3 and 7 for both Staphylococcus aureus and Pseudomonas aeruginosa. CONCLUSIONS NO successfully inhibited the biofilm formation by Staphylococcus aureus or Pseudomonas aeruginosa on soft contact lenses in dose-dependent manner.
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Affiliation(s)
- Dong Ju Kim
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, 814, Siksadong, Ilsan-dong-gu, Goyang, Gyunggido, 410-773, South Korea
| | - Joo-Hee Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, 814, Siksadong, Ilsan-dong-gu, Goyang, Gyunggido, 410-773, South Korea
| | - Marth Kim
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, 814, Siksadong, Ilsan-dong-gu, Goyang, Gyunggido, 410-773, South Korea
| | - Choul Yong Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, 814, Siksadong, Ilsan-dong-gu, Goyang, Gyunggido, 410-773, South Korea.
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Orench-Rivera N, Kuehn MJ. Environmentally controlled bacterial vesicle-mediated export. Cell Microbiol 2017; 18:1525-1536. [PMID: 27673272 DOI: 10.1111/cmi.12676] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/15/2016] [Accepted: 09/21/2016] [Indexed: 01/01/2023]
Abstract
Over the past two decades, researchers studying both microbial and host cell communities have gained an appreciation for the ability of bacteria to produce, regulate, and functionally utilize outer membrane vesicles (OMVs) as a means to survive and interact with their cellular and acellular environments. Common ground has emerged, as it appears that vesicle production is an environmentally controlled and specific secretion process; however, it has been challenging to discover the principles that govern fundamentals of vesicle-mediated transport. Namely, there does not appear to be a single mechanism modulating OMV export, nor universal "markers" for OMV cargo incorporation, nor particular host cell responses common to treatment with all OMVs. Given the diversity of species studied, their differences in envelope architecture and composition, the diversity of environmentally regulated bacterial processes, and the variety of interactions between bacteria and their abiotic and biotic environments, this is hardly surprising. Nevertheless, the ability of bacteria to control exported material in the context of a packaged insoluble particle, a vesicle, is emerging as a significant contribution to bacterial viability, biofilm communities, and bacterial-host interactions. In this review, we focus on detailing important, recent findings regarding the content and functional differences in bacterially secreted vesicles that are influenced by growth conditions.
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Affiliation(s)
- Nichole Orench-Rivera
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Meta J Kuehn
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, 27710, USA.
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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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Metruccio MME, Evans DJ, Gabriel MM, Kadurugamuwa JL, Fleiszig SMJ. Pseudomonas aeruginosa Outer Membrane Vesicles Triggered by Human Mucosal Fluid and Lysozyme Can Prime Host Tissue Surfaces for Bacterial Adhesion. Front Microbiol 2016; 7:871. [PMID: 27375592 PMCID: PMC4891360 DOI: 10.3389/fmicb.2016.00871] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/23/2016] [Indexed: 01/24/2023] Open
Abstract
Pseudomonas aeruginosa is a leading cause of human morbidity and mortality that often targets epithelial surfaces. Host immunocompromise, or the presence of indwelling medical devices, including contact lenses, can predispose to infection. While medical devices are known to accumulate bacterial biofilms, it is not well understood why resistant epithelial surfaces become susceptible to P. aeruginosa. Many bacteria, including P. aeruginosa, release outer membrane vesicles (OMVs) in response to stress that can fuse with host cells to alter their function. Here, we tested the hypothesis that mucosal fluid can trigger OMV release to compromise an epithelial barrier. This was tested using tear fluid and corneal epithelial cells in vitro and in vivo. After 1 h both human tear fluid, and the tear component lysozyme, greatly enhanced OMV release from P. aeruginosa strain PAO1 compared to phosphate buffered saline (PBS) controls (∼100-fold). Transmission electron microscopy (TEM) and SDS-PAGE showed tear fluid and lysozyme-induced OMVs were similar in size and protein composition, but differed from biofilm-harvested OMVs, the latter smaller with fewer proteins. Lysozyme-induced OMVs were cytotoxic to human corneal epithelial cells in vitro and murine corneal epithelium in vivo. OMV exposure in vivo enhanced Ly6G/C expression at the corneal surface, suggesting myeloid cell recruitment, and primed the cornea for bacterial adhesion (∼4-fold, P < 0.01). Sonication disrupted OMVs retained cytotoxic activity, but did not promote adhesion, suggesting the latter required OMV-mediated events beyond cell killing. These data suggest that mucosal fluid induced P. aeruginosa OMVs could contribute to loss of epithelial barrier function during medical device-related infections.
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Affiliation(s)
| | - David J Evans
- School of Optometry, University of CaliforniaBerkeley, CA, USA; College of Pharmacy, Touro University CaliforniaVallejo, CA, USA
| | | | | | - Suzanne M J Fleiszig
- School of Optometry, University of CaliforniaBerkeley, CA, USA; Graduate Groups in Vision Science, Microbiology, and Infectious Diseases and Immunity, University of CaliforniaBerkeley, CA, USA
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Zimmerman AB, Nixon AD, Rueff EM. Contact lens associated microbial keratitis: practical considerations for the optometrist. CLINICAL OPTOMETRY 2016; 8:1-12. [PMID: 30214344 PMCID: PMC6095396 DOI: 10.2147/opto.s66424] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Microbial keratitis (MK) is a corneal condition that encompasses several different pathogens and etiologies. While contact lens associated MK is most often associated with bacterial infections, other pathogens (fungi, Acanthamoeba species, etc) may be responsible. This review summarizes the risk factors, microbiology, diagnostic characteristics, and treatment options for all forms of contact lens-related MK.
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Affiliation(s)
| | - Alex D Nixon
- College of Optometry, The Ohio State University, Columbus, OH, USA,
| | - Erin M Rueff
- College of Optometry, The Ohio State University, Columbus, OH, USA,
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Soumpasis I, Knapp L, Pitt T. A proof-of-concept model for the identification of the key events in the infection process with specific reference to Pseudomonas aeruginosa in corneal infections. Infect Ecol Epidemiol 2015; 5:28750. [PMID: 26546946 PMCID: PMC4636861 DOI: 10.3402/iee.v5.28750] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/16/2015] [Accepted: 10/16/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND It is a common medical practice to characterise an infection based on the causative agent and to adopt therapeutic and prevention strategies targeting the agent itself. However, from an epidemiological perspective, exposure to a microbe can be harmless to a host as a result of low-level exposure or due to host immune response, with opportunistic infection only occurring as a result of changes in the host, pathogen, or surrounding environment. METHODS We have attempted to review systematically the key host, pathogen, and environmental factors that may significantly impact clinical outcomes of exposure to a pathogen, using Pseudomonas aeruginosa eye infection as a case study. RESULTS AND DISCUSSION Extended contact lens wearing and compromised hygiene may predispose users to microbial keratitis, which can be a severe and vision-threatening infection. P. aeruginosa has a wide array of virulence-associated genes and sensing systems to initiate and maintain cell populations at the corneal surface and beyond. We have adapted the well-known concept of the epidemiological triangle in combination with the classic risk assessment framework (hazard identification, characterisation, and exposure) to develop a conceptual pathway-based model that demonstrates the overlapping relationships between the host, the pathogen, and the environment; and to illustrate the key events in P. aeruginosa eye infection. CONCLUSION This strategy differs from traditional approaches that consider potential risk factors in isolation, and hopefully will aid the identification of data and models to inform preventive and therapeutic measures in addition to risk assessment. Furthermore, this may facilitate the identification of knowledge gaps to direct research in areas of greatest impact to avert or mitigate adverse outcomes of infection.
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Affiliation(s)
- Ilias Soumpasis
- Safety and Environmental Assurance Centre, Unilever, Sharnbrook, UK;
| | - Laura Knapp
- Safety and Environmental Assurance Centre, Unilever, Sharnbrook, UK
| | - Tyrone Pitt
- Clinical Bacteriology Consultant, London, UK
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Extensively and pan-drug resistant Pseudomonas aeruginosa keratitis: clinical features, risk factors, and outcome. Graefes Arch Clin Exp Ophthalmol 2015; 254:315-22. [DOI: 10.1007/s00417-015-3208-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 11/26/2022] Open
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Jee JP, Kim HJ. Development of Hydrogel Lenses with Surface-immobilized PEG Layers to Reduce Protein Adsorption. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10545] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Jun-Pil Jee
- College of Pharmacy; Chosun University; Gwangju 501-759 Korea
| | - Ho-Joong Kim
- Department of Chemistry; Chosun University; Gwangju 501-759 Korea
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26
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Bispo PJM, Haas W, Gilmore MS. Biofilms in infections of the eye. Pathogens 2015; 4:111-36. [PMID: 25806622 PMCID: PMC4384075 DOI: 10.3390/pathogens4010111] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/12/2015] [Accepted: 03/13/2015] [Indexed: 12/27/2022] Open
Abstract
The ability to form biofilms in a variety of environments is a common trait of bacteria, and may represent one of the earliest defenses against predation. Biofilms are multicellular communities usually held together by a polymeric matrix, ranging from capsular material to cell lysate. In a structure that imposes diffusion limits, environmental microgradients arise to which individual bacteria adapt their physiologies, resulting in the gamut of physiological diversity. Additionally, the proximity of cells within the biofilm creates the opportunity for coordinated behaviors through cell–cell communication using diffusible signals, the most well documented being quorum sensing. Biofilms form on abiotic or biotic surfaces, and because of that are associated with a large proportion of human infections. Biofilm formation imposes a limitation on the uses and design of ocular devices, such as intraocular lenses, posterior contact lenses, scleral buckles, conjunctival plugs, lacrimal intubation devices and orbital implants. In the absence of abiotic materials, biofilms have been observed on the capsule, and in the corneal stroma. As the evidence for the involvement of microbial biofilms in many ocular infections has become compelling, developing new strategies to prevent their formation or to eradicate them at the site of infection, has become a priority.
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Affiliation(s)
- Paulo J M Bispo
- Departments of Ophthalmology, Microbiology and Immunology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, 02114 USA
| | - Wolfgang Haas
- Departments of Ophthalmology, Microbiology and Immunology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, 02114 USA
| | - Michael S Gilmore
- Departments of Ophthalmology, Microbiology and Immunology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, 02114 USA.
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Effect of Daily Contact Lens Cleaning on Ocular Adverse Events during Extended Wear. Optom Vis Sci 2015; 92:157-66. [DOI: 10.1097/opx.0000000000000479] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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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
: Clinician-scientists bridge the gap between basic research and patient care. At the 2012 Annual Meeting, a symposium highlighting the application of cutting-edge optometric research within the anterior segment was held to present and discuss some of the recent basic scientific advances that will both shape and guide the development of future clinical care practices. This article summarizes this work, bringing together four experts, all clinician-scientists in the field of cornea and ocular surface. Collectively, this work provides new insights to clinicians and researchers alike, as well as brings forth a greater appreciation of the impact of ongoing optometric bench research in advancing clinical care.
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30
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Xu L, Ma P, Yuan B, Chen Q, Lin S, Chen X, Hua Z, Shen J. Anti-biofouling contact lenses bearing surface-immobilized layers of zwitterionic polymer by one-step modification. RSC Adv 2014. [DOI: 10.1039/c3ra47119e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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31
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Stapleton F, Marfurt C, Golebiowski B, Rosenblatt M, Bereiter D, Begley C, Dartt D, Gallar J, Belmonte C, Hamrah P, Willcox M. The TFOS International Workshop on Contact Lens Discomfort: report of the subcommittee on neurobiology. Invest Ophthalmol Vis Sci 2013; 54:TFOS71-97. [PMID: 24058137 PMCID: PMC5963174 DOI: 10.1167/iovs.13-13226] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 09/10/2013] [Indexed: 12/26/2022] Open
Abstract
This report characterizes the neurobiology of the ocular surface and highlights relevant mechanisms that may underpin contact lens-related discomfort. While there is limited evidence for the mechanisms involved in contact lens-related discomfort, neurobiological mechanisms in dry eye disease, the inflammatory pathway, the effect of hyperosmolarity on ocular surface nociceptors, and subsequent sensory processing of ocular pain and discomfort have been at least partly elucidated and are presented herein to provide insight in this new arena. The stimulus to the ocular surface from a contact lens is likely to be complex and multifactorial, including components of osmolarity, solution effects, desiccation, thermal effects, inflammation, friction, and mechanical stimulation. Sensory input will arise from stimulation of the lid margin, palpebral and bulbar conjunctiva, and the cornea.
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Affiliation(s)
- Fiona Stapleton
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Carl Marfurt
- Indiana University School of Medicine–Northwest, Gary, Indiana
| | - Blanka Golebiowski
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Mark Rosenblatt
- Weill Cornell Medical College, Cornell University, Ithaca, New York
| | - David Bereiter
- University of Minnesota School of Dentistry, Minneapolis, Minnesota
| | - Carolyn Begley
- Indiana University School of Optometry, Bloomington, Indiana
| | - Darlene Dartt
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Juana Gallar
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernandez–Consejo Superior de Investigaciones Cientificas, Alicante, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernandez–Consejo Superior de Investigaciones Cientificas, Alicante, Spain
| | - Pedram Hamrah
- Massachusetts Eye and Ear Infirmary, Stoneham, Massachusetts
| | - Mark Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Pearlman E, Sun Y, Roy S, Karmakar M, Hise AG, Szczotka-Flynn L, Ghannoum M, Chinnery HR, McMenamin PG, Rietsch A. Host defense at the ocular surface. Int Rev Immunol 2013; 32:4-18. [PMID: 23360155 DOI: 10.3109/08830185.2012.749400] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Microbial infections of the cornea frequently cause painful, blinding and debilitating disease that is often difficult to treat and may require corneal transplantation. In addition, sterile corneal infiltrates that are associated with contact lens wear cause pain, visual impairment and photophobia. In this article, we review the role of Toll-Like Receptors (TLR) in bacterial keratitis and sterile corneal infiltrates, and describe the role of MD-2 regulation in LPS responsiveness by corneal epithelial cells. We conclude that both live bacteria and bacterial products activate Toll-Like Receptors in the cornea, which leads to chemokine production and neutrophil recruitment to the corneal stroma. While neutrophils are essential for bacterial killing, they also cause tissue damage that results in loss of corneal clarity. These disparate outcomes, therefore, represent a spectrum of disease severity based on this pathway, and further indicate that targeting the TLR pathway is a feasible approach to treating inflammation caused by live bacteria and microbial products. Further, as the P. aeruginosa type III secretion system (T3SS) also plays a critical role in disease pathogenesis by inducing neutrophil apoptosis and facilitating bacterial growth in the cornea, T3SS exotoxins are additional targets for therapy for P. aeruginosa keratitis.
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Affiliation(s)
- Eric Pearlman
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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Surfactant protein D contributes to ocular defense against Pseudomonas aeruginosa in a murine model of dry eye disease. PLoS One 2013; 8:e65797. [PMID: 23762428 PMCID: PMC3675081 DOI: 10.1371/journal.pone.0065797] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/02/2013] [Indexed: 01/08/2023] Open
Abstract
Dry eye disease can cause ocular surface inflammation that disrupts the corneal epithelial barrier. While dry eye patients are known to have an increased risk of corneal infection, it is not known whether there is a direct causal relationship between these two conditions. Here, we tested the hypothesis that experimentally-induced dry eye (EDE) increases susceptibility to corneal infection using a mouse model. In doing so, we also examined the role of surfactant protein D (SP-D), which we have previously shown is involved in corneal defense against infection. Scopolamine injections and fan-driven air were used to cause EDE in C57BL/6 or Black Swiss mice (wild-type and SP-D gene-knockout). Controls received PBS injections and were housed normally. After 5 or 10 days, otherwise uninjured corneas were inoculated with 10(9) cfu of Pseudomonas aeruginosa strain PAO1. Anesthesia was maintained for 3 h post-inoculation. Viable bacteria were quantified in ocular surface washes and corneal homogenates 6 h post-inoculation. SP-D was measured by Western immunoblot, and corneal pathology assessed from 6 h to 4 days. EDE mice showed reduced tear volumes after 5 and 10 days (each by ∼75%, p<0.001) and showed fluorescein staining (i.e. epithelial disruption). Surprisingly, there was no significant difference in corneal pathology between EDE mice and controls (∼10-14% incidence). Before bacterial inoculation, EDE mice showed elevated SP-D in ocular washes. After inoculation, fewer bacteria were recovered from ocular washes of EDE mice (<2% of controls, p = 0.0004). Furthermore, SP-D knockout mice showed a significant increase in P. aeruginosa corneal colonization under EDE conditions. Taken together, these data suggest that SP-D contributes to corneal defense against P. aeruginosa colonization and infection in EDE despite the loss of barrier function to fluorescein.
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Evans DJ, Fleiszig SM. Why does the healthy cornea resist Pseudomonas aeruginosa infection? Am J Ophthalmol 2013; 155:961-970.e2. [PMID: 23601656 DOI: 10.1016/j.ajo.2013.03.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE To provide our perspective on why the cornea is resistant to infection based on our research results with Pseudomonas (P) aeruginosa. We focus on our current understanding of the interplay between bacteria, tear fluid, and the corneal epithelium that determines health as the usual outcome, and propose a theoretical model for how contact lens wear might change those interactions to enable susceptibility to P aeruginosa infection. METHODS Use of "null-infection" in vivo models, cultured human corneal epithelial cells, contact lens-wearing animal models, and bacterial genetics help to elucidate mechanisms by which P aeruginosa survives at the ocular surface, adheres, and traverses multilayered corneal epithelia. These models also help elucidate the molecular mechanisms of corneal epithelial innate defense. RESULTS Tear fluid and the corneal epithelium combine to make a formidable defense against P aeruginosa infection of the cornea. Part of that defense involves the expression of antimicrobials such as β-defensins, the cathelicidin LL-37, cytokeratin-derived antimicrobial peptides, and RNase7. Immunomodulators such as SP-D and ST2 also contribute. Innate defenses of the cornea depend in part on MyD88, a key adaptor protein of TLR and IL-1R signaling, but the basal lamina represents the final barrier to bacterial penetration. Overcoming these defenses involves P aeruginosa adaptation, expression of the type III secretion system, proteases, and P aeruginosa biofilm formation on contact lenses. CONCLUSION After more than 2 decades of research focused on understanding how contact lens wear predisposes to P aeruginosa infection, our working hypothesis places blame for microbial keratitis on bacterial adaptation to ocular surface defenses, combined with changes to the biochemistry of the corneal surface caused by trapping bacteria and tear fluid against the cornea under the lens.
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Abstract
PURPOSE Microbial adhesion to contact lenses is believed to be one of the initiating events in the formation of many corneal infiltrative events, including microbial keratitis, that occur during contact lens wear. The advent of silicone hydrogel lenses has not reduced the incidence of these events. This may partly be related to the ability of microbes to adhere to these lenses. The aim of this study was to review the published literature on microbial adhesion to contact lenses, focusing on adhesion to silicone hydrogel lenses. METHODS The literature on microbial adhesion to contact lenses was searched, along with associated literature on adverse events that occur during contact lens wear. Particular reference was paid to the years 1995 through 2012 because this encompasses the time when the first clinical trials of silicone hydrogel lenses were reported, and their commercial availability and the publication of epidemiology studies on adverse events were studied. RESULTS In vitro studies of bacterial adhesion to unworn silicone hydrogel lens have shown that generally, bacteria adhere to these lenses in greater numbers than to the hydroxyethyl methacrylate-based soft lenses. Lens wear has different effects on microbial adhesion, and this is dependent on the type of lens and microbial species/genera that is studied. Biofilms that can be formed on any lens type tend to protect the bacteria and fungi from the effects on disinfectants. Fungal hyphae can penetrate the surface of most types of lenses. Acanthamoeba adhere in greater numbers to first-generation silicone hydrogel lenses compared with the second-generation or hydroxyethyl methacrylate-based soft lenses. CONCLUSION Microbial adhesion to silicone hydrogel lenses occurs and is associated with the production of corneal infiltrative events during lens wear.
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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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Narayanan S, Redfern RL, Miller WL, Nichols KK, McDermott AM. Dry eye disease and microbial keratitis: is there a connection? Ocul Surf 2013; 11:75-92. [PMID: 23583043 DOI: 10.1016/j.jtos.2012.12.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 12/14/2012] [Accepted: 12/16/2012] [Indexed: 02/07/2023]
Abstract
Dry eye is a common ocular surface disease of multifactorial etiology characterized by elevated tear osmolality and inflammation leading to a disrupted ocular surface. The latter is a risk factor for ocular surface infection, yet overt infection is not commonly seen clinically in the typical dry eye patient. This suggests that important innate mechanisms operate to protect the dry eye from invading pathogens. This article reviews the current literature on epidemiology of ocular surface infection in dry eye patients and laboratory-based studies on innate immune mechanisms operating at the ocular surface and their alterations in human dry eye and animal models. The review highlights current understanding of innate immunity in dry eye and identifies gaps in our knowledge to help direct future studies to further unravel the complexities of dry eye disease and its sequelae.
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Affiliation(s)
- Srihari Narayanan
- University of the Incarnate Word, Rosenberg School of Optometry, San Antonio, TX, USA
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A Preservative-and-Fluorescein Interaction Model for Benign Multipurpose Solution–Associated Transient Corneal Hyperfluorescence. Cornea 2012; 31:1480-8. [DOI: 10.1097/ico.0b013e31824a2083] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Understanding biocompatibility: the importance of study design, methods, and proper interpretation. Cornea 2012; 31:1507; author reply 1507-8. [PMID: 23010774 DOI: 10.1097/ico.0b013e31825e83de] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Effects of aqueous polymeric surfactants on silicone-hydrogel soft- contact-lens wettability and bacterial adhesion of Pseudomonas aeruginosa. Cont Lens Anterior Eye 2012; 35:155-62. [DOI: 10.1016/j.clae.2012.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/23/2012] [Accepted: 02/29/2012] [Indexed: 11/18/2022]
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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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Sun Y, Karmakar M, Taylor PR, Rietsch A, Pearlman E. ExoS and ExoT ADP ribosyltransferase activities mediate Pseudomonas aeruginosa keratitis by promoting neutrophil apoptosis and bacterial survival. THE JOURNAL OF IMMUNOLOGY 2012; 188:1884-95. [PMID: 22250085 DOI: 10.4049/jimmunol.1102148] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pseudomonas aeruginosa is a leading cause of blinding corneal ulcers worldwide. To determine the role of type III secretion in the pathogenesis of P. aeruginosa keratitis, corneas of C57BL/6 mice were infected with P. aeruginosa strain PAO1 or PAK, which expresses ExoS, ExoT, and ExoY, but not ExoU. PAO1- and PAK-infected corneas developed severe disease with pronounced opacification and rapid bacterial growth. In contrast, corneas infected with ΔpscD or ΔpscJ mutants that cannot assemble a type III secretion system, or with mutants lacking the translocator proteins, do not develop clinical disease, and bacteria are rapidly killed by infiltrating neutrophils. Furthermore, survival of PAO1 and PAK strains in the cornea and development of corneal disease was impaired in ΔexoS, ΔexoT, and ΔexoST mutants of both strains, but not in a ΔexoY mutant. ΔexoST mutants were also rapidly killed in neutrophils in vitro and were impaired in their ability to promote neutrophil apoptosis in vivo compared with PAO1. Point mutations in the ADP ribosyltransferase (ADPR) regions of ExoS or ExoT also impaired proapoptotic activity in infected neutrophils, and exoST(ADPR-) mutants replicated the ΔexoST phenotype in vitro and in vivo, whereas mutations in rho-GTPase-activating protein showed the same phenotype as PAO1. Together, these findings demonstrate that the pathogenesis of P. aeruginosa keratitis in ExoS- and ExoT-producing strains is almost entirely due to their ADPR activities, which subvert the host response by targeting the antibacterial activity of infiltrating neutrophils.
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Affiliation(s)
- Yan Sun
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
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Tran VB, Sung YS, Fleiszig SM, Evans DJ, Radke C. Dynamics of Pseudomonas aeruginosa association with anionic hydrogel surfaces in the presence of aqueous divalent-cation salts. J Colloid Interface Sci 2011; 362:58-66. [PMID: 21723562 PMCID: PMC3789522 DOI: 10.1016/j.jcis.2011.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 06/03/2011] [Accepted: 06/03/2011] [Indexed: 10/18/2022]
Abstract
Binding of bacteria to solid surfaces is complex with many aspects incompletely understood. We investigate Pseudomonas aeruginosa uptake kinetics onto hydrogel surfaces representative of soft-contact lenses made of nonionic poly(2-hydroxyethylmethacrylate) (p-HEMA), anionic poly(methacrylic acid) (p-MAA), and anionic poly(acrylic acid) (p-AA). Using a parallel-plate flow cell under phase-contrast microscopy, we document a kinetic "burst" at the anionic hydrogel surface: dilute aqueous P. aeruginosa first rapidly accumulates and then rapidly depletes. Upon continuing flow, divalent cations in the suspending solution sorb into the hydrogel network causing the previously surface-accumulated bacteria to desorb. The number of bacteria eventually bound to the surface is low compared to the nonionic p-HEMA hydrogel. We propose that the kinetic burst is due to reversible divalent-cation bridging between the anionic bacteria and the negatively charged hydrogel surface. The number of surface bridging sites diminishes as divalent cations impregnate into and collapse the gel. P. aeruginosa association with the surface then falls. Low eventual binding of P. aeruginosa to the anionic hydrogel is ascribed to increased surface hydrophilicity compared to the counterpart nonionic p-HEMA hydrogel.
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Affiliation(s)
- Victoria B. Tran
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, United States
| | - Ye Suel Sung
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, United States
| | - Suzanne M.J. Fleiszig
- School of Optometry, University of California, Berkeley, CA 94720, United States
- Graduate Group in Vision Science, University of California, Berkeley, CA 94720, United States
- Graduate Groups in Plant and Microbial Biology, and Infectious Disease and Immunity, University of California, Berkeley, CA 94720, United States
| | - David J. Evans
- School of Optometry, University of California, Berkeley, CA 94720, United States
- Touro University – California, College of Pharmacy, Vallejo, CA 94592, United States
| | - C.J. Radke
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, United States
- Graduate Group in Vision Science, University of California, Berkeley, CA 94720, United States
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Tam C, LeDue J, Mun JJ, Herzmark P, Robey EA, Evans DJ, Fleiszig SMJ. 3D quantitative imaging of unprocessed live tissue reveals epithelial defense against bacterial adhesion and subsequent traversal requires MyD88. PLoS One 2011; 6:e24008. [PMID: 21901151 PMCID: PMC3162028 DOI: 10.1371/journal.pone.0024008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 08/03/2011] [Indexed: 12/15/2022] Open
Abstract
While a plethora of in vivo models exist for studying infectious disease and its resolution, few enable factors involved in the maintenance of health to be studied in situ. This is due in part to a paucity of tools for studying subtleties of bacterial-host interactions at a cellular level within live organs or tissues, requiring investigators to rely on overt outcomes (e.g. pathology) in their research. Here, a suite of imaging technologies were combined to enable 3D and temporal subcellular localization and quantification of bacterial distribution within the murine cornea without the need for tissue processing or dissection. These methods were then used to demonstrate the importance of MyD88, a central adaptor protein for Toll-Like Receptor (TLR) mediated signaling, in protecting a multilayered epithelium against both adhesion and traversal by the opportunistic bacterial pathogen Pseudomonas aeruginosa ex vivo and in vivo.
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Affiliation(s)
- Connie Tam
- School of Optometry, University of California, Berkeley, California, United States of America
| | - Jeffrey LeDue
- School of Optometry, University of California, Berkeley, California, United States of America
| | - James J. Mun
- Program in Vision Science, University of California, Berkeley, California, United States of America
| | - Paul Herzmark
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Ellen A. Robey
- Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - David J. Evans
- School of Optometry, University of California, Berkeley, California, United States of America
- College of Pharmacy, Touro University California, Vallejo, California, United States of America
| | - Suzanne M. J. Fleiszig
- School of Optometry, University of California, Berkeley, California, United States of America
- Program in Vision Science, University of California, Berkeley, California, United States of America
- Programs in Infectious Diseases and Immunity and Microbiology, University of California, Berkeley, California, United States of America
- * E-mail:
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Robertson DM, Parks QM, Young RL, Kret J, Poch KR, Malcolm KC, Nichols DP, Nichols M, Zhu M, Cavanagh HD, Nick JA. Disruption of contact lens-associated Pseudomonas aeruginosa biofilms formed in the presence of neutrophils. Invest Ophthalmol Vis Sci 2011; 52:2844-50. [PMID: 21245396 DOI: 10.1167/iovs.10-6469] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
PURPOSE To evaluate the capacity of neutrophils to enhance biofilm formation on contact lenses by an infectious Pseudomonas aeruginosa (PA) corneal isolate. Agents that target F-actin and DNA were tested as a therapeutic strategy for disrupting biofilms formed in the setting of neutrophils in vitro and for limiting the infectious bioburden in vivo. METHODS Biofilm formation by infectious PA strain 6294 was assessed in the presence of neutrophils on a static biofilm plate and on unworn etafilcon A soft contact lenses. A d-isomer of poly(aspartic acid) was used alone and with DNase to reduce biofilm formation on test contact lenses. The gentamicin survival assay was used to determine the effectiveness of the test compound in reducing subsequent intracellular bacterial load in the corneal epithelium in a contact lens infection model in the rabbit. RESULTS In a static reactor and on hydrogel lenses, PA biofilm density was enhanced 30-fold at 24 hours in the presence of neutrophils (P < 0.0001). The combination of DNase and anionic poly(aspartic acid) reduced the PA biofilms formed in the presence of activated neutrophils by 79.2% on hydrogel contact lenses (P < 0.001). An identical treatment resulted in a 41% reduction in internalized PA in the rabbit corneal epithelium after 24 hours (P = 0.03). CONCLUSIONS These results demonstrate that PA can exploit the presence of neutrophils to form biofilm on contact lenses within a short time. Incorporation of F-actin and DNA represent a mechanism for neutrophil-induced biofilm enhancement and are targets for available agents to disrupt pathogenic biofilms formed on contact lenses and as a treatment for established corneal infections.
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Affiliation(s)
- Danielle M Robertson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9057, USA.
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Alarcon I, Tam C, Mun JJ, LeDue J, Evans DJ, Fleiszig SMJ. Factors impacting corneal epithelial barrier function against Pseudomonas aeruginosa traversal. Invest Ophthalmol Vis Sci 2011; 52:1368-77. [PMID: 21051692 DOI: 10.1167/iovs.10-6125] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
PURPOSE Mechanisms determining epithelial resistance versus susceptibility to microbial traversal in vivo remain poorly understood. Here, a novel murine model was used to explore factors influencing the corneal epithelial barrier to Pseudomonas aeruginosa penetration. METHODS Murine corneas were blotted with tissue paper before inoculation with green fluorescent protein-expressing P. aeruginosa. The impact of blotting on epithelial integrity was evaluated by susceptibility to fluorescein staining and histology. Using fluorescence imaging, blotted corneas were compared to nonblotted corneas for susceptibility to bacterial binding and epithelial penetration after 5 hours or were monitored for disease development. In some experiments, inoculation was performed ex vivo to exclude tear fluid or corneas were pretreated with EGTA to disrupt Ca(2+)-dependent factors. The role of surfactant protein D (SP-D), which inhibits P. aeruginosa cell invasion in vitro, was examined using knockout mice. RESULTS Blotting enabled fluorescein penetration through the epithelium into the underlying stroma without obvious disruption to corneal morphology. Although blotting enabled bacterial binding to the otherwise adhesion-resistant epithelial surface, adherent bacteria did not penetrate the surface or initiate pathology. In contrast, bacteria penetrated blotted corneas after EGTA treatment and in SP-D knockouts. Visible disease occurred and progressed only in aged, blotted, and EGTA-treated, SP-D knockout mice. CONCLUSIONS Neither fluorescein staining nor bacterial adhesion necessarily predict or enable corneal susceptibility to bacterial penetration or disease. Corneal epithelial defenses limiting traversal by adherent bacteria include EGTA-sensitive factors and SP-D. Understanding mechanisms modulating epithelial traversal by microbes could improve our understanding of susceptibility to infection and may indicate new strategies for preventing disease.
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Affiliation(s)
- Irania Alarcon
- Program in Microbiology, University of California, Berkeley, Berkeley, California, USA
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Nichols JJ, Sinnott LT. Tear film, contact lens, and patient factors associated with corneal staining. Invest Ophthalmol Vis Sci 2011; 52:1127-37. [PMID: 21087960 DOI: 10.1167/iovs.10-5757] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to examine ocular surface and tear film, contact lens, care solution, medical, and patient-related factors that are associated with corneal staining in contact lens wearers. METHODS In this cross-sectional/nested case-control study, in addition to the assessment of corneal staining with fluorescein, a variety of tear film and ocular surface, contact lens, and patient-related factors were examined. Poisson regression models were used to examine the relation between corneal staining and these factors. RESULTS Data from 413 patients were eligible for the analyses described. The average age was 30.6 ± 11.1 years, and 277 (67.1%) of the patients were women. Several factors were shown to be related to increased corneal staining in multivariate modeling, including increased daily wearing times (P = 0.0006), lower income (P = 0.0008), lissamine green conjunctival staining (P = 0.002), contact lens deposition (P = 0.007), increased tear meniscus height (P = 0.007), and decreased hydrogel nominal water content (P = 0.02). The wearing of silicone hydrogels (as opposed to hydrogels) was protective against corneal staining (P = 0.0004). Notably, neither contact lens care solutions nor disinfectants were associated with corneal staining. CONCLUSIONS Corneal staining in contact lens wearers continues to be a frequent, but not well understood, outcome. These data suggest that contact lens factors (water content, material, wearing time, and deposition) are more generally associated with corneal staining than are contact lens care solutions or other ocular surface and tear film, demographic, or medical factors.
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Affiliation(s)
- Jason J Nichols
- Ohio State University, College of Optometry, Columbus, Ohio, USA.
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Animal models of bacterial keratitis. J Biomed Biotechnol 2011; 2011:680642. [PMID: 21274270 PMCID: PMC3022227 DOI: 10.1155/2011/680642] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2010] [Revised: 11/29/2010] [Accepted: 12/09/2010] [Indexed: 11/20/2022] Open
Abstract
Bacterial keratitis is a disease of the cornea characterized by pain, redness, inflammation, and opacity. Common causes of this disease are Pseudomonas aeruginosa and Staphylococcus aureus. Animal models of keratitis have been used to elucidate both the bacterial factors and the host inflammatory response involved in the disease. Reviewed herein are animal models of bacterial keratitis and some of the key findings in the last several decades.
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