Effect of intravitreal triamcinolone acetonide in the treatment of experimental Staphylococcus epidermidis endophthalmitis

Clinical Profile, Antibiotic Resistance and Outcomes in Bacterial Endophthalmitis: Coagulase-Negative Staphylococcus Endophthalmitis as Compared to Other Organisms

BACKGROUND

To evaluate the clinical profile, outcomes and antibiotic resistance in bacterial endophthalmitis.

METHODS

This was a post-hoc analysis of a study conducted at a tertiary centre, where 60 consecutive cases of culture-proven bacterial endophthalmitis were included prospectively. Group 1 included coagulase-negative Staphylococcus endophthalmitis (CNSE), while group 2 included the remaining cases. Clinical features, antibiotic resistance and visual outcomes were compared. Visual acuity >3/60 at six months of follow-up was defined as a good visual outcome.

RESULTS

Group 1 had 31 cases, while group 2 had 29. Group 2 included 12 gram-positive and 17 gram-negative isolates. Among the groups, group 2 had more patients with presenting visual acuity below hand motions close to the face (25 vs. 12, p<0.001), poor visual outcomes (26 vs. 3, p<0.001) and retinal detachment (RD) (10 vs. 2, p=0.007). Pseudomonas was most commonly resistant to antibiotics, and ceftazidime (p=0.005) and cefazolin (p=0.009) resistance were higher in group 2 isolates. In group 1, five isolates were resistant to any one of the antibiotics, whereas in group 2, 13 isolates were resistant to any one of the antibiotics (p=0.024).

CONCLUSIONS

In the current study, eyes in the group of endophthalmitis caused by CNSE achieved better visual acuities at the last follow-up compared to eyes with endophthalmitis caused by other bacteria. Antibiotic resistance in isolates other than CNSE is a cause of concern.

Consensus and controversies in the science of endophthalmitis management: Basic research and clinical perspectives

Infectious endophthalmitis is a severe intraocular infection caused by bacteria, or less commonly by fungi. It can occur after penetrating eye procedures, trauma, or the spread of infection from contiguous structures or via emboli from distant organs. Because of the time-critical nature of the treatment, endophthalmitis is treated with the clinical diagnosis and modified by the microbiological report of the intraocular contents. The current strategy for managing endophthalmitis relies on pre-clinical literature, case series, and one large multi-center randomized clinical trial on post-cataract surgery endophthalmitis. Culture-susceptibility of the microorganisms from undiluted vitreous guides the definitive treatment in non-responsive cases. Strategies to reduce the incidence of endophthalmitis after penetrating eye procedures have been developed concurrently with refined means of treatment. Despite these advances, outcomes remain poor for many patients. Although consensus articles have been published on managing endophthalmitis, treatment patterns vary, and controversies remain. These include (1) the use of newer methods for early and precise microbiological diagnosis; (2) the choice of intravitreal antibiotics; (3) the need for systemic therapy; (4) early and complete vitrectomy. Here, we review the current consensus and address controversies in diagnosing and managing endophthalmitis. This review is intended to familiarize physicians and ophthalmologists with different aspects of endophthalmitis management to make informed decisions.

A Review of the Role of Intravitreal Corticosteroids as an Adjuvant to Antibiotics in Infectious Endophthalmitis

Infectious endophthalmitis is an important cause of vision loss worldwide. This entity most often occurs as a complication of intraocular surgery especially following cataract surgery or intravitreal injection. Endophthalmitis is regarded as a serious complication following ocular surgery and the final visual outcome is fundamentally contingent on timely recognition and intervention. Intravitreal and oral antibiotics in combination with pars plana vitrectomy or vitreous aspiration remain the mainstay in the management of endophthalmitis. However, significant inflammation may persist even after sterilization of the intraocular cavities with appropriate antibiotics resulting in failure of treatment. This forms the basis for the use of intravitreal corticosteroids as an adjuvant to antibiotics in the management of infectious endophthalmitis. In the index manuscript, we review the existing literature to determine the role of intravitreal corticosteroids as an adjuvant to antibiotics in treating infectious endophthalmitis, and discuss their beneficial effects and controversial concerns.

Modeling intraocular bacterial infections

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.

Macular infarction secondary to Staphylococcus epidermidis infection

PURPOSE

To describe a patient with macular infarction caused by Staphylococcus epidermidis-induced endophthalmitis.

METHODS

Case report.

RESULTS

An 88-year-old woman was referred to our clinic for endophthalmitis after cataract extraction. She was diagnosed to have an S. epidermidis infection. Her vision dropped from 20/50 to hand motions. During the course of her infection, she developed multiple multifocal branch retinal artery occlusions associated with absolute capillary nonperfusion centrally and was diagnosed with macular infarction.

CONCLUSION

Although most commonly associated with aminoglycoside toxicity, macular infarction can occur after endophthalmitis treatment without the use of aminoglycosides.

Role of Toll-like receptor (TLR) 2 in experimental Bacillus cereus endophthalmitis

Bacillus cereus causes a uniquely rapid and blinding intraocular infection, endophthalmitis. B. cereus replicates in the eye, synthesizes numerous toxins, and incites explosive intraocular inflammation. The mechanisms involved in the rapid and explosive intraocular immune response have not been addressed. Because Toll-like receptors (TLRs) are integral to the initial recognition of organisms during infection, we hypothesized that the uniquely explosive immune response observed during B. cereus endophthalmitis is directly influenced by the presence of TLR2, a known gram-positive pathogen recognition receptor. To address this hypothesis, we compared the courses of experimental B. cereus endophthalmitis in wild type C57BL/6J mice to that of age-matched homozygous TLR2(-/-) mice. Output parameters included analysis of bacterial growth, inflammatory cell (PMN) infiltration, cytokine/chemokine kinetics, retinal function testing, and histology, with N≥4 eyes/assay/time point/mouse strain. B. cereus grew at similar rates to10(8) CFU/eye by 12 h, regardless of the mouse strain. Retinal function was preserved to a greater degree in infected TLR2(-/-) eyes compared to that of infected wild type eyes, but infected eyes of both mouse strains lost significant function. Retinal architecture was preserved in infected TLR2(-/-) eyes, with limited retinal and vitreal cellular infiltration compared to that of infected wild type eyes. Ocular myeloperoxidase activities corroborated these results. In general, TNFα, IFNγ, IL6, and KC were detected in greater concentrations in infected wild type eyes than in infected TLR2(-/-) eyes. The absence of TLR2 resulted in decreased intraocular proinflammatory cytokine/chemokine levels and altered recruitment of inflammatory cells into the eye, resulting in less intraocular inflammation and preservation of retinal architecture, and a slightly greater degree of retinal function. These results demonstrate TLR2 is an important component of the initial ocular response to B. cereus endophthalmitis.