1
|
Shivaji S, Nagapriya B, Ranjith K. Differential Susceptibility of Mixed Polymicrobial Biofilms Involving Ocular Coccoid Bacteria ( Staphylococcus aureus and S. epidermidis) and a Filamentous Fungus ( Fusarium solani) on Ex Vivo Human Corneas. Microorganisms 2023; 11:microorganisms11020413. [PMID: 36838378 PMCID: PMC9964441 DOI: 10.3390/microorganisms11020413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
Biofilms confer several advantages to the organisms associated with them, such as increased resistances to antibacterial and antifungal compounds compared to free living cells. Compared to monomicrobial biofilms involving a single microorganism, biofilms composed of microorganisms affiliated to bacterial and fungal kingdoms are predominant in nature. Despite the predominance of polymicrobial biofilms, and more so mixed polymicrobial biofilms, they are rarely studied. The objective of the current study is to evaluate the potential of ocular bacteria and a filamentous fungus to form monomicrobial and mixed polymicrobial biofilms on synthetic and natural substrates and to monitor their response to antibiotics. In this sense, we demonstrated that the ocular pathogens Staphylococcus aureus, S. epidermidis, and Fusarium solani form monomicrobial and mixed polymicrobial biofilms both on tissue culture polystyrene plates and on ex vivo human corneas from cadavers using confocal microscopy and scanning electron microscopy. Additionally, the mixed polymicrobial biofilms involving the above ocular bacteria and a filamentous fungus were less susceptible to different antibacterials and antifungals in relation to the corresponding control planktonic cells. Further, the MICs to the screened antibacterials and antifungals in polymicrobial biofilms involving a bacterium or a fungus was either increased, decreased, or unchanged compared to the corresponding individual bacterial or fungal biofilm. The results would be useful to the ophthalmologist to plan effective treatment regimens for the eye since these are common pathogens of the eye causing keratitis, endophthalmitis, conjunctivitis, etc.
Collapse
|
2
|
Ranjith K, Nagapriya B, Shivaji S. Polymicrobial biofilms of ocular bacteria and fungi on ex vivo human corneas. Sci Rep 2022; 12:11606. [PMID: 35803992 PMCID: PMC9270462 DOI: 10.1038/s41598-022-15809-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/29/2022] [Indexed: 11/25/2022] Open
Abstract
Microbes residing in biofilms confer several fold higher antimicrobial resistances than their planktonic counterparts. Compared to monomicrobial biofilms, polymicrobial biofilms involving multiple bacteria, multiple fungi or both are more dominant in nature. Paradoxically, polymicrobial biofilms are less studied. In this study, ocular isolates of Staphylococcus aureus, S. epidermidis and Candida albicans, the etiological agents of several ocular infections, were used to demonstrate their potential to form mono- and polymicrobial biofilms both in vitro and on human cadaveric corneas. Quantitative (crystal violet and XTT methods) and qualitative (confocal and scanning electron microscopy) methods demonstrated that they form polymicrobial biofilms. The extent of biofilm formation was dependent on whether bacteria and fungi were incubated simultaneously or added to a preformed biofilm. Additionally, the polymicrobial biofilms exhibited increased resistance to different antimicrobials compared to planktonic cells. When the MBECs of different antibacterial and antifungal agents were monitored it was observed that the MBECs in the polymicrobial biofilms was either identical or decreased compared to the monomicrobial biofilms. The results are relevant in planning treatment strategies for the eye. This study demonstrates that ocular bacteria and fungi form polymicrobial biofilms and exhibit increase in antimicrobial resistance compared to the planktonic cells.
Collapse
Affiliation(s)
- Konduri Ranjith
- Jhaveri Microbiology Centre, Prof. Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, 500034, India
| | - Banka Nagapriya
- Jhaveri Microbiology Centre, Prof. Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, 500034, India
| | - Sisinthy Shivaji
- Jhaveri Microbiology Centre, Prof. Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, 500034, India.
| |
Collapse
|
3
|
Konduri R, Saiabhilash CR, Shivaji S. Biofilm-Forming Potential of Ocular Fluid Staphylococcus aureus and Staphylococcus epidermidis on Ex Vivo Human Corneas from Attachment to Dispersal Phase. Microorganisms 2021; 9:microorganisms9061124. [PMID: 34067392 PMCID: PMC8224674 DOI: 10.3390/microorganisms9061124] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/18/2021] [Accepted: 05/20/2021] [Indexed: 12/14/2022] Open
Abstract
The biofilm-forming potential of Staphylococcus aureus and Staphylococcus epidermidis, isolated from patients with Endophthalmitis, was monitored using glass cover slips and cadaveric corneas as substrata. Both the ocular fluid isolates exhibited biofilm-forming potential by the Congo red agar, Crystal violet and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-(phenylamino) carbonyl-2H-tetra-zolium hydroxide (XTT) methods. Confocal microscopy demonstrated that the thickness of the biofilm increased from 4–120 h of biofilm formation. Scanning electron microscopic studies indicated that the biofilms grown on cover slips and ex vivo corneas of both the isolates go through an adhesion phase at 4 h followed by multilayer clumping of cells with intercellular connections and copious amounts of extracellular polymeric substance. Clumps subsequently formed columns and eventually single cells were visible indicative of dispersal phase. Biofilm formation was more rapid when the cornea was used as a substratum. In the biofilms grown on corneas, clumping of cells, formation of 3D structures and final appearance of single cells indicative of dispersal phase occurred by 48 h compared to 96–120 h when biofilms were grown on cover slips. In the biofilm phase, both were several-fold more resistant to antibiotics compared to planktonic cells. This is the first study on biofilm forming potential of ocular fluid S. aureus and S. epidermidis on cadaveric cornea, from attachment to dispersal phase of biofilm formation.
Collapse
|
4
|
Ranjith K, Sharma S, Shivaji S. Microbes of the human eye: Microbiome, antimicrobial resistance and biofilm formation. Exp Eye Res 2021; 205:108476. [PMID: 33549582 DOI: 10.1016/j.exer.2021.108476] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 01/21/2023]
Abstract
BACKGROUND The review focuses on the bacteria associated with the human eye using the dual approach of detecting cultivable bacteria and the total microbiome using next generation sequencing. The purpose of this review was to highlight the connection between antimicrobial resistance and biofilm formation in ocular bacteria. METHODS Pubmed was used as the source to catalogue culturable bacteria and ocular microbiomes associated with the normal eyes and those with ocular diseases, to ascertain the emergence of anti-microbial resistance with special reference to biofilm formation. RESULTS This review highlights the genetic strategies used by microorganisms to evade the lethal effects of anti-microbial agents by tracing the connections between candidate genes and biofilm formation. CONCLUSION The eye has its own microbiome which needs to be extensively studied under different physiological conditions; data on eye microbiomes of people from different ethnicities, geographical regions etc. are also needed to understand how these microbiomes affect ocular health.
Collapse
Affiliation(s)
- Konduri Ranjith
- Jhaveri Microbiology Centre, Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India.
| | - Savitri Sharma
- Jhaveri Microbiology Centre, Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India.
| | - Sisinthy Shivaji
- Jhaveri Microbiology Centre, Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India.
| |
Collapse
|
5
|
Khosravi N, Sadeghpour Heravi F, Tabasi M, Badamchi A, Minaeian S, Javadinia S, Tabasi E, Tabatabaei A. Detection of fluoroquinolone genes and spread of antibiotic resistance profile of Enterococcus strains isolated from clinical specimens. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
6
|
Long-Term Colonization Dynamics of Enterococcus faecalis in Implanted Devices in Research Macaques. Appl Environ Microbiol 2018; 84:AEM.01336-18. [PMID: 30006402 DOI: 10.1128/aem.01336-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/10/2018] [Indexed: 12/22/2022] Open
Abstract
Enterococcus faecalis is a common opportunistic pathogen that colonizes cephalic recording chambers (CRCs) of macaques used in cognitive neuroscience research. We previously characterized 15 E. faecalis strains isolated from macaques at the Massachusetts Institute of Technology (MIT) in 2011. The goal of this study was to examine how a 2014 protocol change prohibiting the use of antimicrobials within CRCs affected colonizing E. faecalis strains. We collected 20 E. faecalis isolates from 10 macaques between 2013 and 2017 for comparison to 4 isolates previously characterized in 2011 with respect to the sequence type (ST) distribution, antimicrobial resistance, biofilm formation, and changes in genes that might confer a survival advantage. ST4 and ST55 were predominant among the isolates characterized in 2011, whereas the less antimicrobial-resistant lineage ST48 emerged to dominance after 2013. Two macaques remained colonized by ST4 and ST55 strains for 5 and 4 years, respectively. While the antimicrobial resistance and virulence factors identified in these ST4 and ST55 strains remained relatively stable, we detected an increase in biofilm formation ability over time in both isolates. We also found that ST48 strains were typically robust biofilm formers, which could explain why this ST increased in prevalence. Finally, we identified mutations in the DNA mismatch repair genes mutS and mutL in separate ST55 and ST4 strains and confirmed that strains bearing these mutations displayed a hypermutator phenotype. The presence of a hypermutator phenotype may complicate future antimicrobial treatment for clinically relevant E. faecalis infections in macaques.IMPORTANCEEnterococcus faecalis is a common cause of health care-associated infections in humans, largely due to its ability to persist in the hospital environment, colonize patients, acquire antimicrobial resistance, and form biofilms. Understanding how enterococci evolve in health care settings provides insight into factors affecting enterococcal survival and persistence. Macaques used in neuroscience research have long-term cranial implants that, despite best practices, often become colonized by E. faecalis This provides a unique opportunity to noninvasively examine the evolution of enterococci on a long-term indwelling device. We collected E. faecalis strains from cephalic implants over a 7-year period and characterized the sequence type, antimicrobial resistance, virulence factors, biofilm production, and hypermutator phenotypes. Improved antimicrobial stewardship allowed a less-antimicrobial-resistant E. faecalis strain to predominate at the implant interface, potentially improving antimicrobial treatment outcomes if future clinical infections occur. Biofilm formation appears to play an important role in the persistence of the E. faecalis strains associated with these implants.
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Microbiologic Trends and Biofilm Growth on Explanted Periorbital Biomaterials. Ophthalmic Plast Reconstr Surg 2013; 29:376-81. [DOI: 10.1097/iop.0b013e31829a7313] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
9
|
Sadaka A, Durand ML, Gilmore MS. Bacterial endophthalmitis in the age of outpatient intravitreal therapies and cataract surgeries: host-microbe interactions in intraocular infection. Prog Retin Eye Res 2012; 31:316-31. [PMID: 22521570 PMCID: PMC3361607 DOI: 10.1016/j.preteyeres.2012.03.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/23/2012] [Accepted: 03/27/2012] [Indexed: 02/07/2023]
Abstract
Bacterial endophthalmitis is a sight threatening infection of the interior structures of the eye. Incidence in the US has increased in recent years, which appears to be related to procedures being performed on an aging population. The advent of outpatient intravitreal therapy for management of age-related macular degeneration raises yet additional risks. Compounding the problem is the continuing progression of antibiotic resistance. Visual prognosis for endophthalmitis depends on the virulence of the causative organism, the severity of intraocular inflammation, and the timeliness of effective therapy. We review the current understanding of the pathogenesis of bacterial endophthalmitis, highlighting opportunities for the development of improved therapeutics and preventive strategies.
Collapse
Affiliation(s)
- Ama Sadaka
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | | | | |
Collapse
|
10
|
Jia Z, Chen S, Zhang J. Preparation and properties of polydimethylsiloxane-mica composites. J Appl Polym Sci 2012. [DOI: 10.1002/app.37654] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
11
|
Sommerfeld Ross S, Reinhardt JM, Fiegel J. Enhanced analysis of bacteria susceptibility in connected biofilms. J Microbiol Methods 2012; 90:9-14. [PMID: 22542520 DOI: 10.1016/j.mimet.2012.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 04/02/2012] [Accepted: 04/10/2012] [Indexed: 11/24/2022]
Abstract
A common method for visualizing bacterial biofilms is through confocal laser scanning microscopy images. Current software packages separate connected-biofilm bacteria from unconnected bacteria, such as planktonic or dispersed bacteria, but do not save both image sequences, making interpretation of the two bacterial populations difficult. Thus we report the development of an algorithm to save separate image sequences and enable qualitative and quantitative evaluation of each bacterial population. To improve bacterial viability assessment using a membrane integrity dye, a colocalization algorithm was also developed. This assigns colocalized pixels to the dead bacteria population, rather than to both the live and dead bacteria groups. Visually, this makes it clearer to distinguish a green live bacteria pixel from a yellow colocalized dead bacteria pixel. This algorithm also aids in the quantification of viability for connected-biofilm bacteria and unconnected bacteria to investigate susceptibility of each population to antimicrobials. The utility of these algorithms was demonstrated with Pseudomonas aeruginosa biofilms treated with ciprofloxacin hydrochloride. Results from this study indicate that quantification with colocalization adjustment can prevent underestimation of dead bacteria. These improvements in image processing will enable researchers to visually differentiate connected-biofilm and unconnected bacteria in a single image and to quantify these populations independently for viability without double counting the colocalized image pixels.
Collapse
Affiliation(s)
- Stacy Sommerfeld Ross
- The University of Iowa, College of Pharmacy, Department of Pharmaceutical Sciences and Experimental Therapeutics, Iowa City, IA 52242, USA
| | | | | |
Collapse
|
12
|
Baillif S, Hartmann D, Freney J, Kodjikian L. [Intraocular lens and bacterial adhesion: influence of the environmental factors, the characteristics of the bacteria, and the target material surface]. J Fr Ophtalmol 2010; 33:210-21. [PMID: 20202716 DOI: 10.1016/j.jfo.2010.01.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Accepted: 12/22/2009] [Indexed: 10/19/2022]
Abstract
Adhesion of bacteria to intraocular lenses is an important step in the pathogenesis of postoperative endophthalmitis. It can be described as a two-phase process including an initial, instantaneous, and reversible phase followed by a time-dependant and irreversible molecular and cellular phase. The binding of bacteria is affected by many factors including environmental factors such as medium composition, presence of proteins and flow conditions, the bacterial cell surface characteristics, and the material's surface properties. This article reviews all these factors affecting the adhesion of bacteria to intraocular lenses. A better understanding of these mechanisms would make it possible to reduce the bacterial adhesion process and thus could help decrease the incidence of postoperative endophthalmitis.
Collapse
Affiliation(s)
- S Baillif
- Département d'Ophtalmologie, Centre hospitalo-universitaire Saint Roch, Nice, France; Laboratoire "Réparation Tissulaire, Interactions Biologiques et Biomatériaux", UPSP 2007.03.135 RTI2B, Lyon, France
| | | | | | | |
Collapse
|
13
|
Shimizu K, Kobayakawa S, Tsuji A, Tochikubo T. Biofilm Formation on Hydrophilic Intraocular Lens Material. Curr Eye Res 2009; 31:989-97. [PMID: 17169836 DOI: 10.1080/02713680601038816] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To estimate bacterial biofilm formation on the hydrophilic acrylic (hydrogel) intraocular lens (IOL) Meridian (HP60M, Baush & Lomb) and to investigate a preventive effect against biofilm formation of hydrogel IOLs presoaked in antibiotics. METHODS Two Staphylococcus epidermidis strains, ATCC 12228 and ATCC 35984 (biofilm-producer), and an Enterococcus faecalis strain (KOS1, clinical isolate from an endophthalmitis patient) were used. Biofilms were cultivated on disks of different IOL materials: hydrogel, PMMA (polymethylmethacrylate), and acrylic. Biofilms were stained with crystal violet (CV), which served as an index of biofilm formation. The bacterial population was enumerated after biofilm homogenization. Biofilms were also examined by scanning electron microscopy (SEM). IOLs were presoaked in two antibiotics, levofloxacin (LVFX) and gatifloxacin (GFLX), and then the bacterial population was enumerated. As in vivo experiment, antibiotics-treated and nontreated Meridian IOLs were implanted in rabbit eyes, which served as an endophthalmitis model, and the bacterial population was enumerated. RESULTS The amount of biofilm formed was the least on hydrogel from among the three materials tested after 48- and 72-hr incubation (p < 0.05 to 0.01). The bacterial population was the least on hydrogel from among the three materials with ATCC 12228 (p < 0.05 to 0.01), and the bacterial population was significantly different between hydrogel and acrylic after 72-hr incubation with ATCC 35984 (p < 0.05). Biofilm by the two S. epidermidis strains were recognized after 24-hr incubation. Rates of biofilm-positive SEM fields, which were defined as being occupied by biofilm over at least half of the area, were increased through 72 hr with ATCC 35984. While the E. faecalis strain showed no bacterial adherence on the antibiotics-treated hydrogel IOLs, adherence of the S. epidermidis strain, ATCC 35984 was recognized on the LVFX-treated IOLs after 48-hr incubation (103 to 104 CFU/ml). In the rabbit in vivo model, the bacterial populations in eyes with an antibiotics-treated Meridian IOL were significantly smaller than in eyes with a nontreated IOL for 72 hr after surgery (p < 0.05 to 0.01). CONCLUSIONS The biofilm formation was less on hydrogel than on other two materials tested. Hydrogel presoaked in antibiotics exhibited a preventive effect against biofilm formation at least for 24 hr in vitro and against bacterial proliferation in the rabbit in vivo endophthalmitis model.
Collapse
Affiliation(s)
- Kohei Shimizu
- The First Department of Ophthalmology, School of Medicine, Toho University, Tokyo, Japan
| | | | | | | |
Collapse
|
14
|
Werner L, Tetz M, Mentak K, Aldred M, Zwisler W. Detection of pyrogens adsorbed to intraocular lenses. J Cataract Refract Surg 2009; 35:1273-80. [DOI: 10.1016/j.jcrs.2009.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 02/25/2009] [Accepted: 03/03/2009] [Indexed: 11/26/2022]
|
15
|
[Intraocular lens and cataract surgery: comparison between bacterial adhesion and risk of postoperative endophthalmitis according to intraocular lens biomaterial]. J Fr Ophtalmol 2009; 32:515-28. [PMID: 19539399 DOI: 10.1016/j.jfo.2009.04.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 04/28/2009] [Indexed: 11/24/2022]
Abstract
Cataract surgery is a usually successful procedure that restores vision by replacing the natural lens with an intraocular lens (IOL). Acute postoperative endophthalmitis is still one of the most serious complications of cataract surgery. Its incidence has been reported to be between 0.04% and 0.32%. Precisely why bacteria induce endophthalmitis is not entirely understood. Indeed the risk of its development may be influenced by several factors. Among them, bacterial adhesion to the IOL has been recently emphasized in the ophthalmology literature. Indeed, the ability of an organism to adhere to the IOL surface is believed to be associated with a risk of infection at the implantation site. Several studies have demonstrated that bacterial adhesion is influenced by IOL materials. Ever since, numerous studies have investigated the interactions between bacteria and different types of IOLs to determine which biomaterial would be most permissive to bacterial adherence. This article reviews all the epidemiological and experimental data relating to the study of the relationship between bacterial adhesion, IOL material, and risk of developing postoperative endophthalmitis. Even if discrepancies between these studies exist, mainly stemming from the use of different experimental conditions and protocols, it seems that bacterial adhesion is strongly influenced by IOL material. Epidemiological studies suggest that the implantation of silicone IOLs might be associated with increased rates of endophthalmitis. Experimental studies reach similar conclusions showing that hydrophobic IOLs such as silicone or acrylic hydrophobic IOLs are more permissive to bacterial adhesion and growth than hydrophilic IOLs such as acrylic hydrophilic IOLs. Among the interactions that govern bacterial attachment to the IOLs, it seems that hydrophilic-hydrophobic interactions have the greatest influence. Nevertheless, since bacterial adhesion is a complicated process affected by many factors, the conclusions drawn by these results have to be interpreted with care. Further investigations are still needed to understand the connections between IOL material and endophthalmitis.
Collapse
|
16
|
Abstract
Enterococci are an important global cause of nosocomial infections, being increasingly associated with urinary tract infections, endocarditis, intra-abdominal and pelvic infections, catheter-related infections, surgical wound infections, and central nervous system infections. The two most common enterococci species are Enterococcus faecalis and Enterococcus faecium. Both are capable of producing biofilms, which consist of a population of cells attached irreversibly on various biotic and abiotic surfaces, encased in a hydrated matrix of exopolymeric substances. Many environmental and genetic factors are associated or have been proposed to be associated with the production of biofilm. This review discusses recent advances in knowledge about the biology and genetics of biofilm formation and the role of biofilms in enterococci pathogenesis.
Collapse
Affiliation(s)
- Jamal A Mohamed
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX 77030, USA
| | - David B Huang
- New Jersey Veterans Affairs Medical Center, East Orange, NJ 07018, USA
| |
Collapse
|
17
|
Callegan MC, Gilmore MS, Gregory M, Ramadan RT, Wiskur BJ, Moyer AL, Hunt JJ, Novosad BD. Bacterial endophthalmitis: therapeutic challenges and host-pathogen interactions. Prog Retin Eye Res 2007; 26:189-203. [PMID: 17236804 PMCID: PMC1941835 DOI: 10.1016/j.preteyeres.2006.12.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Endophthalmitis is an infection of the posterior segment of the eye that frequently results in loss of vision. This devastating result occurs despite prompt and often aggressive therapeutic and surgical intervention. Over the past decade, research has centered on determining the bacterial and host factors involved in this potentially blinding disease. The initial focus on the bacterial factors responsible for intraocular virulence has recently expanded into analysis the inflammatory response to infection, including the molecular and cellular interactions between the pathogen and host. This review discusses the epidemiology and therapeutic challenges posed by endophthalmitis, as well as recent findings from the analysis of interactions between the host and pathogen. Based on these findings, a model for the pathogenesis of endophthalmitis is presented. A more comprehensive understanding of the molecular and cellular interactions taking place between pathogen and host during endophthalmitis will expose possible therapeutic targets designed to arrest the infection and prevent vision loss.
Collapse
Affiliation(s)
- Michelle C Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | | | | | | | | | | | | | | |
Collapse
|