The Streptococcus pneumoniae Capsule Is Required for Full Virulence in Pneumococcal Endophthalmitis

Sanders, Melissa E.; Norcross, Erin W.; Robertson, Zachary; Moore, Quincy C.; Fratkin, Jonathan D.; Marquart, Mary E.

doi:10.1167/iovs.10-5513

Cited by 31 publications

(40 citation statements)

References 42 publications

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“…Clinical examination was done 24 and 48 hours after infection by an observer who was masked to the grouping of each rabbit. Clinical severity scores were assigned according to previously published methods3031. In short, 8 parameters were graded from 0 to 4 and grades were totaled, yielding an overall score with a theoretical maximum of 32.…”

Section: Methodsmentioning

confidence: 99%

Exogenous Streptococcus pneumoniae Endophthalmitis in Diabetic Rabbits

Benton

Fulton

Marquart

2017

Sci Rep

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Diabetics are at increased risk for eye infections including bacterial endophthalmitis. It is unclear whether the severity of endophthalmitis is greater in these patients due to confounding factors such as pre-existing ocular diseases in some but not others. Therefore, we tested the hypothesis that disease severity and/or bacterial loads would be significantly higher in a Type I diabetic rabbit model of Streptococcus pneumoniae endophthalmitis. Rabbits were treated with alloxan to destroy pancreatic islet cells, or mock-treated with vehicle, and maintained for 10 days before intravitreal infection with S. pneumoniae E353. Clinical scoring of the eyes was performed 24 and 48 hours after infection, followed by euthanasia and vitreous harvest to quantitate bacterial loads. There were no significant differences in clinical scores (P ≥ 0.440) or bacterial loads (P = 0.736), however, 4/12 (33%) of the diabetic rabbits became bacteremic. This finding not only indicates a breakdown in the blood-ocular barrier, but also prompts further investigation into the exploitation of the diabetic eye by the streptococci.

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Section: Methodsmentioning

confidence: 99%

Exogenous Streptococcus pneumoniae Endophthalmitis in Diabetic Rabbits

Benton

Fulton

Marquart

2017

Sci Rep

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“…Sanders et al (2011) demonstrated the virulence potential of the S. pneumoniae capsule by injecting an isogenic unencapsulated strain or its wild type parental strain into rabbit eyes. Bacterial capsules cloak organisms from the immune response and, as such, are anti-phagocytic.…”

Section: Experimental Models: Therapeutics and Virulencementioning

confidence: 99%

“…Components of the Gram-positive cell wall, such as teichoic acid and peptidoglycan, have been shown to induce an intraocular inflammatory response, to be essential for growth in vitreous humor, and to be essential to establish S. aureus endophthalmitis (Suzuki et al, 2011; Kumar and Kumar, 2015). Bacterial capsules were shown to be important in the virulence of S. pneumoniae endophthalmitis in rabbits (Sanders et al, 2011). Wiskur et al (2008a) demonstrated that the hypermucoviscous (HMV) phenotype of Klebsiella pneumoniae was important to endophthalmitis pathogenesis in mice.…”

Section: Experimental Models: Therapeutics and Virulencementioning

confidence: 99%

Modeling intraocular bacterial infections

Astley

Coburn

Parkunan

et al. 2016

Progress in Retinal and Eye Research

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Bacterial endophthalmitis is an infection and inflammation of the posterior segment of the eye which can result in significant loss of visual acuity. Even with prompt antibiotic, anti-inflammatory and surgical intervention, vision and even the eye itself may be lost. For the past century, experimental animal models have been used to examine various aspects of the pathogenesis and pathophysiology of bacterial endophthalmitis, to further the development of anti-inflammatory treatment strategies, and to evaluate the pharmacokinetics and efficacies of antibiotics. Experimental models allow independent control of many parameters of infection and facilitate systematic examination of infection outcomes. While no single animal model perfectly reproduces the human pathology of bacterial endophthalmitis, investigators have successfully used these models to understand the infectious process and the host response, and have provided new information regarding therapeutic options for the treatment of bacterial endophthalmitis. This review highlights experimental animal models of endophthalmitis and correlates this information with the clinical setting. The goal is to identify knowledge gaps that may be addressed in future experimental and clinical studies focused on improvements in the therapeutic preservation of vision during and after this disease.

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“…This model mimics the infection course after introduction of bacteria directly into the posterior segment of the eye that would occur following a surgical procedure or penetrating injury, but does not allow for the analysis of host immunological status and bacterial factors that contribute to the development of EE. This model system allows intravitreal injection across the pars plana of low inocula that allow the bacterium under study to adapt to the intraocular environment of the eye and replicate (Booth et al, 1995;Booth et al, 1997;Callegan et al, 1999a;Jett et al, 1992;Sanders et al, 2010;Sanders et al, 2011). Depending on the infecting organisms, infection symptoms in the rabbit model develop over a period ranging from 6 hours to 3 days, and a number of infection parameters can be repeatedly monitored and quantitative data obtained.…”

Section: Experimental Endophthalmitis and The Roles Of Bacterial And mentioning

confidence: 99%

“…Injection of metabolically inactive bacteria or cell wall sacculi elicited significant intraocular inflammation. The rabbit model has also been used to implicate the Streptococcus pneumoniae capsule in the pathogenesis of endopthalmitis (Sanders et al, 2011). Infection with an isogenic unencapsulated S. pneumoniae mutant strain resulted in significantly lower slit lamp examination scores, significantly greater retinal function, and significantly less neutrophil infiltration into the eye compared with the wildtype parental strain in this model.…”

Section: Experimental Endophthalmitis and The Roles Of Bacterial And mentioning

confidence: 99%