Prophylaxis measures for postinjection endophthalmitis

Comparing the in vitro efficacy of chlorhexidine and povidone-iodine in the prevention of post-surgical endophthalmitis

BACKGROUND

Intravitreal injections are a common ophthalmologic procedure. While infections following these injections are rare, they can lead to endophthalmitis, with potentially serious consequences. Various methods have been proposed to prevent endophthalmitis, including the use of antisepsis and antibiotics in patient preparation.

PURPOSE

To evaluate the antiseptic efficacy of aqueous chlorhexidine (CHX) and povidone-iodine (PI) when used alone and in combination with lidocaine gel (LG) in vitro.

METHODS

Two independent experimental trials were conducted. The first trial determined the minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) of CHX and PI against six bacterial strains. The second trial evaluated the bactericidal efficacy of the antiseptic agents (CHX 0.1% and PI 5%) and their combination with LG against the same bacterial strains.

RESULTS

CHX was more effective than PI in reducing the number of colonies forming units (cfus) of the tested bacteria. The order in which the antiseptic and LG were administered affected their effectiveness, with CHX administered before LG resulting in greater reduction of bacterial growth.

CONCLUSIONS

CHX 0.1% is more effective than PI 5% as an antiseptic agent. Application of CHX and PI prior to the use of lidocaine gel results in a more effective reduction of microorganisms.

Gene therapy for age-related macular degeneration: potential, feasibility, and pitfalls

PURPOSE OF REVIEW

The landscape for age-related macular degeneration (AMD) is rapidly changing with addition of biosimilars and now United States Food and Drug Administration (FDA) approved nonneovascular AMD (nnAMD) treatment options. These developments have inspired a burgeoning pipeline of gene therapy approaches focused on similar antivascular endothelial growth factors (VEGF) and complement related pathways. Historic and more recent setbacks in the gene therapy pipeline, including intraocular inflammatory reactions, have raised important concerns for adverse events related to AMD therapeutics both for gene and nongene approaches. The specific clinical profile of these therapeutics approaching later stage clinical trials are complex and under active investigation; however, these options hold promise to disrupt the current landscape and change management paradigms for one of the leading causes of vision loss worldwide.

RECENT FINDINGS

This review covers current gene therapy approaches for neovascular AMD (nAMD) and nnAMD. Intravitreal, suprachoroidal, and subretinal delivery routes are discussed with attention to technical procedure, capabilities for transgene delivery to target tissue, immunogenicity, and collateral effects. Suprachoroidal delivery is an emerging approach which may bridge some of the practical drawbacks for intravitreal and subretinal methods, though with less elaborated immunologic profile. In parallel to delivery modification, viral vectors have been cultivated to target specific cells, with promising enhancements in adeno-associated viral (AAV) vectors and persistent interest in alternate viral and nonviral delivery vectors. Ongoing questions such as steroid or immunosuppressive regimen and economic considerations from a payer and societal perspective are discussed.

SUMMARY

The present review discusses emerging gene therapy options which could foster new, more durable nAMD and nnAMD therapeutics. These options will need refinement with regards to route, vector, and dosage, and specialists must decipher the specific clinical risk benefit profile for individual patients. Ongoing concerns for immunogenicity or dosage related adverse events could stifle progress, while further vector development and refined delivery techniques have the potential to change the safety and efficacy of currently options in the pipeline.

Antimicrobials and antiseptics: Lowering effect on ocular surface bacterial flora - A systematic review

Topical antimicrobials and antiseptics are used perioperatively to reduce the ocular surface bacteria flora (OSBF) that are involved in the development of post-operative infectious complications. However, their effectiveness is still a controversial topic. This systematic review, performed according to the PRISMA guidelines and registered in PROSPERO, aims to provide an overview of the efficacy of the agents currently used in peri-cataract surgery and -intravitreal injections (IVI) in lowering the OSBF. Although effective in lowering OSBF, perioperative topical antimicrobials are associated with the risk of resistance development, with no obvious additional benefit compared with topical antisepsis. Conversely, the effectiveness of topical antiseptics before cataract surgery and IVI is strongly supported. Based on the available evidence, perioperative antimicrobials are not recommended, whereas the perioperative use of antiseptics is strongly recommended as prophylactic treatment for lowering the infection due to OSBF. Post-operative antimicrobials may be considered in eyes at higher risk for infection.

Intravitreal triple therapy with vancomycin, ceftazidime, and moxifloxacin for bacterial endophthalmitis: A Twelve-year experience

PURPOSE

Increasing rates of antibiotic resistance in endophthalmitis have been reported. This study examines outcomes of triple therapy with intravitreal vancomycin, ceftazidime, and moxifloxacin for endophthalmitis.

METHODS

Retrospective, consecutive series of all patients treated with abovementioned intravitreal antibiotics from January 2009 to June 2021. Percentages of eyes attaining greater than or equal to 20/200 and 20/50 Snellen visual acuities and adverse events were evaluated.

RESULTS

112 eyes met inclusion criteria. 63 of 112 eyes (56%) achieved a visual acuity of 20/200 during follow-up, with 39 (35%) returning to at least 20/50. In subgroup analysis, 23 of 24 (96%) eyes with post-cataract endophthalmitis obtained ≥ 20/200 acuity and 21 of 24 (88%) obtained ≥ 20/50 acuity during follow-up. There were no cases of macular infarction.

CONCLUSIONS

Intravitreal moxifloxacin (160 µg/0.1 mL) was well tolerated as an adjunct to vancomycin and ceftazidime for bacterial endophthalmitis. Use of this novel combination offers several theoretical advantages compared to standard therapy with two antibiotics, including expanded gram-negative coverage and potential synergy, and may be particularly valuable in geographies where the local antibiogram supports empiric use. Further study is merited to verify the safety and efficacy profile.

Topical antibiotic prophylaxis before intravitreal injections: a pilot study

PURPOSE

To explore whether topical antibiotic prophylaxis in patients scheduled for intravitreal injections achieves surface sterility in a greater proportion of subjects as compared to povidone-iodine alone.

MATERIAL AND METHODS

A randomized, triple-blind clinical trial.

POPULATION

patients scheduled for intravitreal injections for maculopathy.

INCLUSION CRITERIA

any sex and race, age 18 years and above. Subjects were randomized into 4 groups: the first group applied chloramphenicol (CHLORAM), the second netilmicin (NETILM), the third a commercial ozonized antiseptic solution (OZONE), and the fourth applied no drops (CONTROL).

OUTCOME VARIABLE

percentage of non-sterile conjunctival swabs. Specimens were collected before and after the application of 5% povidone-iodine moments before the injection.

RESULTS

Ninety-eight subjects (33.7% females, 64.3% males), mean age: 70.2 ± 9.3 years (54-91). Before povidone-iodine, both the CHLORAM and NETILM group showed a lower percentage of non-sterile swabs (61.1% and 31.3% respectively), as compared to the OZONE (83.3%) and CONTROL (86.5%) groups (p < .04). However, this statistical difference was lost after the application of povidone-iodine for 3 min. Percentage of non-sterile swabs in each group after applying 5% povidone-iodine: CHLORAM 11.1%, NETILM 12.5%, CONTROL 15.4%, OZONE 25.0%. This was not statistically significant (p > .05).

CONCLUSIONS

Topical antibiotic prophylaxis with chloramphenicol or netilmicin drops decreases the bacterial load on the conjunctiva. However, after the application of povidone-iodine, all groups showed a significant reduction in the percentage of non-sterile swabs, and this value was comparable among all groups. For this reason, authors conclude that povidone-iodine alone is sufficient and prior topical antibiotic prophylaxis is not indicated.

Oral administration of S-nitroso-L-glutathione (GSNO) provides anti-inflammatory and cytoprotective effects during ocular bacterial infections

Bacterial endophthalmitis is a severe complication of eye surgeries that can lead to vision loss. Current treatment involves intravitreal antibiotic injections that control bacterial growth but not inflammation. To identify newer therapeutic targets to promote inflammation resolution in endophthalmitis, we recently employed an untargeted metabolomics approach. This led to the discovery that the levels of S-nitroso-L-glutathione (GSNO) were significantly reduced in an experimental murine Staphylococcus aureus (SA) endophthalmitis model. In this study, we tested the hypothesis whether GSNO supplementation via different routes (oral, intravitreal) provides protection during bacterial endophthalmitis. Our results show that prophylactic administration of GSNO via intravitreal injections ameliorated SA endophthalmitis. Therapeutically, oral administration of GSNO was found to be most effective in reducing intraocular inflammation and bacterial burden. Moreover, oral GSNO treatment synergized with intravitreal antibiotic injections in reducing the severity of endophthalmitis. Furthermore, in vitro experiments using cultured human retinal Muller glia and retinal pigment epithelial (RPE) cells showed that GSNO treatment reduced SA-induced inflammatory mediators and cell death. Notably, both in-vivo and ex-vivo data showed that GSNO strengthened the outer blood-retinal barrier during endophthalmitis. Collectively, our study demonstrates GSNO as a potential therapeutic agent for the treatment of intraocular infections due to its dual anti-inflammatory and cytoprotective properties.

Meibomian gland dysfunction and blepharitis: A common and still unsolved ophthalmic problem

Blepharitis and meibomian gland dysfunction (MGD) are very common, usually underdiagnosed and underappreciated diseases. More than 50% of patients seeking ophthalmologic consultations have symptoms and signs indicating one or both entities. We summarize the key points of diagnosis and management of both diseases, comparing the work of Dry Eye Workshop II (2017) with the dry eye blepharitis syndrome unification theory. The impact of MGD/blepharitis on ocular surgery also is described. Although MGD and blepharitis seem to be uncurable, most of the time they can be successfully controlled. Different management options are available, but the key to success remains simple-routine eyelid hygiene and moisturizing with the use of preservative-free lubricants.

Randomized Controlled Study of Cooled vs Room-Temperature Artificial Tears for Reducing Ocular Surface Irritation After Intravitreal Injection

Purpose: To evaluate the efficacy of cooled vs room-temperature artificial tears in reducing ocular discomfort after intravitreal injections (IVIs). Methods: Patients receiving a standard intravitreal injection in the retina clinic who met the eligibility criteria and provided informed consented were enrolled in the study. Patients were randomized to the cooled tears or room-temperature tears intervention group. Both groups rated their ocular discomfort following IVI after cooled or room-temperature tears were administered. Results: The cooled group comprised 48 patients and the room-temperature group, 61 patients. There was no significant difference in the reduction of ocular discomfort between the cooled vs room-temperature artificial tears groups (P = .387). In addition, there was a similar level of reduction in ocular discomfort after either intervention (P = .681) regardless of whether or not the patients routinely used artificial tears after previous IVIs. Conclusions: Cooled tears provided no additional benefit in reducing ocular discomfort post-IVI compared with room-temperature tears. Baseline tear use after an IVI may have no true benefit other than a potential placebo effect, recall bias, or both.

An Atypical Case of Exogeneous Endophthalmitis after Intravitreal Injection Presenting with Roth Spots

PURPOSE

To report an atypical case of exogeneous endophthalmitis presenting with Roth spots.

CASE

A 67-year-old man presented with decreased vision, mild pain, and discomfort in his left eye 12 days after an intravitreal aflibercept injection. Best-corrected visual acuity was 20/200, and there were +3 anterior chamber cells. On fundus examination, multiple intraretinal hemorrhages with a central white core resembling a Roth spot were observed. Intravitreal antibiotic injections were performed, and a vitreous sample was taken. Although post-intravitreal injection history was available, full systemic screening was planned to rule out endogenous endophthalmitis because of the presence of these Roth spots. Vitrectomy was performed and methicillin-sensitive coagulase-negative Staphylococcus was detected on culture.

CONCLUSION

Although the presence of Roth spots is an unexpected finding in post-injection endophthalmitis, it was nevertheless demonstrated in our case. For this reason, it should be kept in mind that Roth spots can be encountered in bacterial endophthalmitis.

Antibiotic susceptibility of bacterial pathogens isolated from the aqueous and vitreous humor in the Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) Surveillance Study: 2009-2020 update

BACKGROUND

We evaluated antibiotic resistance among intraocular isolates obtained from presumed endophthalmitis cases collected from 2009 through 2020 in the Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) study, the only ongoing nationwide surveillance study tracking in vitro resistance in ocular pathogens.

METHODS

Presumed endophthalmitis isolates obtained from the aqueous humor and vitreous humor were collected from participating centers, and minimum inhibitory concentrations were determined and interpreted per Clinical and Laboratory Standards Institute methods and available breakpoints.

RESULTS

A total of 307 presumed endophthalmitis isolates (aqueous humor, n = 88; vitreous humor, n = 219) were obtained from 43 clinical sites, including 188 coagulase-negative staphylococci (CoNS), 61 Staphylococcus aureus, 31 Streptococcus pneumoniae, 14 Pseudomonas aeruginosa, and 13 Haemophilus influenzae isolates. Of the CoNS isolates, 47.9% (90/188) were methicillin-resistant, 58.0% (109/188) were azithromycin-resistant, and 46.3% (87/188) were ciprofloxacin-resistant. Of the S. aureus isolates, 45.9% (28/61) were methicillin-resistant, 57.4% (35/61) were azithromycin-resistant, and 44.3% (27/61) were ciprofloxacin-resistant. Multidrug resistance (MDR; i.e., resistance to ≥3 antibiotic classes) was prevalent among staphylococci, particularly methicillin-resistant strains, of which >70% exhibited MDR. Resistance among S. pneumoniae isolates was notable for azithromycin and penicillin, each 38.7% (12/31), and for polymyxin B among P. aeruginosa 100.0% (14/14), while no resistance was observed for H. influenzae isolates to the antibiotics tested.

CONCLUSION

In vitro antibiotic resistance was common among presumed endophthalmitis isolates collected in the ARMOR surveillance study. These data could inform antibiotic selection for infection prophylaxis and/or treatment of intraocular infections.

The effect of punctal plugs in reducing ocular surface irritation after povidone-iodine preparation of intravitreal injection-a randomized trial

PURPOSE

To evaluate the utility of dissolvable collagen punctal plugs (CPP) in reducing ocular surface irritation after intravitreal injections (IVI).

METHODS

Sixty-four subjects in the experimental group received CPP after intravitreal injections. Sixty-two controls did not receive CPP. Reductions in the Ocular Surface Disease Index^© (OSDI) and Standardized Patient Evaluation of Eye Dryness II (SPEED II) scores were analysed.

RESULTS

Dry eye symptoms, as measured by reductions from the pre- to post-injection OSDI (p = 0.137) and SPEED II (p = 0.381) scores, did not significantly differ between the two groups. In sub-group analysis, patients with objective findings of dry eyes had significant improvement in their symptoms (p = 0.046) with CPP. The effect of CPP is not significant in those without dry eyes (p = 0.27).

CONCLUSION

CPPs were not effective in reducing post-injection ocular irritation in patients with no or only mild dry eye symptoms. CPPs improved patients' post-injection comfort levels in those who had moderate-to-severe symptoms and objective findings of dry eye. Though costly CPP could be considered in selective patients. A standardized eye rinse could be a simple, efficacious, and cost-effective way to reduce post-injection ocular irritation; however, more studies are needed.

Safety of Receiving Anti-Vascular Endothelial Growth Factor Intravitreal Injection in Office-Based vs Operating Room Settings: A Meta-analysis

Importance

Compared with the operating room (OR), office-based intravitreal injection (IVI) is considered a more cost-effective and convenient approach, yet clinical outcomes of IVIs with anti-vascular endothelial growth factor (VEGF) agents in different settings (office-based vs OR) have not been systematically evaluated.

Objective

To evaluate the safety outcomes of IVI with anti-VEGF agents in the OR vs office-based setting.

Data Sources

PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov were searched from inception to July 2020.

Study Selection

Eligible studies reporting on patients who received IVIs with anti-VEGF drugs with a clearly stated injection setting of the office or OR.

Data Extraction and Synthesis

Two reviewers independently screened studies, extracted data, and assessed risk of bias. A meta-analysis was conducted to determine the rates of endophthalmitis (EO) and culture-positive EO.

Main Outcomes and Measures

Rates of EO and culture-positive EO following anti-VEGF IVIs in the OR and office-based setting.

Results

Thirty-one studies with a total of 1 275 815 injections were included. Comparative analysis suggested no difference between rates of EO after IVIs performed in the office and OR settings (odds ratio, 3.06; 95% CI, 0.07-139.75; P = .57; I2 = 80%) were identified, yet a higher rate of culture-positive EO was found in the office setting (odds ratio, 21.52; 95% CI, 2.39-193.55; P = .006; I2 = 0%). The pooled rates of EO following anti-VEGF IVIs were 0.03% (95% CI, 0.03-0.04) and 0.02% (95% CI, 0.01-0.04) in office and OR settings, respectively, and the pooled rates of culture-positive EO were 0.01% (95% CI, 0.01-0.02) and 0.01% (95% CI, 0-0.02). The pooled rates of other ocular and systemic adverse events were low.

Conclusions and Relevance

The rate of clinically suspected or culture-positive EO following anti-VEGF IVIs was low whether the procedure was performed in the office or OR setting. Bacterial spectrum could differ between the 2 settings. This meta-analysis could not determine if it is more appropriate to give treatment in the OR for safety reasons in low-income compared with higher-income regions in the world.

Integrative metabolomics and transcriptomics identifies itaconate as an adjunct therapy to treat ocular bacterial infection

The eye is highly susceptible to inflammation-mediated tissue damage evoked during bacterial infection. However, mechanisms regulating inflammation to protect the eye remain elusive. Here, we used integrated metabolomics and transcriptomics to show that the immunomodulatory metabolite itaconate and immune-responsive gene 1 (Irg1) are induced in bacterial (Staphylococcus aureus)-infected mouse eyes, bone-marrow-derived macrophages (BMDMs), and Müller glia. Itaconate levels are also elevated in the vitreous of patients with bacterial endophthalmitis. Irg1 deficiency in mice led to increased ocular pathology. Conversely, intraocular administration of itaconate protects both Irg1-/- and wild-type mice from bacterial endophthalmitis by reducing inflammation, bacterial burden, and preserving retinal architecture and visual function. Notably, itaconate exerts synergistic effects with antibiotics. The protective, anti-inflammatory effects of itaconate are mediated via activation of NRF2/HO-1 signaling and inhibition of NLRP3 inflammasome. Collectively, our study demonstrates the Irg1/itaconate axis is a regulator of intraocular inflammation and provides evidence for using itaconate, along with antibiotics, to treat bacterial infections.

Creating an Ocular Biofactory: Surgical Approaches in Gene Therapy for Acquired Retinal Diseases

ABSTRACT

Gene therapy offers the potential to treat inherited retinal disorders and deliver sustained therapy for acquired retinal diseases. In the latter case, host cells can be harnessed to produce non-native proteins that have beneficial properties, such as antivascular endothelial growth factor activity, transforming the eye into an ocular "biofactory." Several gene therapy programs have entered clinical testing for delivery to the vitreous, subretinal, and suprachoroidal space. Improved viral vectors and refined surgical techniques are critical to successful delivery of therapeutic products to the target tissue. In this review, we discuss the development of gene therapy products aimed at acquired retinal diseases and the surgical techniques utilized to achieve targeted delivery.

Treatment-Emergent Adverse Events in Gene Therapy Trials for Inherited Retinal Diseases: A Narrative Review

Patient safety is a primary priority in the conduction of retinal gene therapy trials. An understanding of risk factors and mitigation strategies for post-procedure complications is crucial for the optimization of gene therapy clinical trial protocols. In this review, we synthesize the literature on ocular delivery methods, vector platforms, and treatment-emergent adverse effects in recent gene therapy clinical trials for inherited retinal diseases.

Value of Anti-Vascular Endothelial Growth Factor Gene Therapy for Neovascular Age-Related Macular Degeneration

PURPOSE

To use discounted cash flow (DCF) analysis to estimate the value creation associated with anti-vascular endothelial growth factor (VEGF) genetic therapy for neovascular age-related macular degeneration (nAMD).

DESIGN

Economic analysis.

PARTICIPANTS

Adults undergoing serial intravitreal anti-VEGF injections in 1 eye for nAMD.

METHODS

Discounted cash flow modeling with scenario analysis was used to derive a present value for a 1-time alternative treatment to lifelong anti-VEGF treatment for nAMD. Multiple sensitivity analyses were performed on the basis of patient age at time of first injection and frequency interval of intravitreal injection.

MAIN OUTCOME MEASURES

Present values of DCF and scenario analyses.

RESULTS

Discounted cash flow analysis of intravitreal anti-VEGF treatment for nAMD resulted in a base-case valuation of $208 420.61, $219 093.31, and $17 379.41 for a 1-time alternative treatment to aflibercept, ranibizumab, and bevacizumab, respectively. This figure covaried significantly with anti-VEGF agent according to the patient age at first injection ($78 323.19-$292 449.87) and frequency of injections ($148 422.91-$388 096.81). In addition, for bevacizumab, variability was driven by the hypothetical degree of clinical superiority of 1-time therapy to repeated intravitreal injections due to reduction in adverse events ($17 379.41-$18 250.79) or reduction in direct or indirect costs associated with age-related macular degeneration ($17 379.41-$657 406.55).

CONCLUSIONS

Anti-VEGF gene therapy approaches can create significantly different value propositions based on the agent modeled, patient age at first injection, frequency of injections, and clinical profile of the medication. Although the use of aflibercept or ranibizumab as a comparative cost metric is logical from a bioequivalence perspective, the disparity in medication costs should not be the primary value driver in applied models. Instead, bevacizumab should be the base case ($17 379.41), with additional value driven from an improvement in quality of life through clinical superiority. A reduction in direct and indirect costs can be used to approximate the value from maintained visual acuity, which is elaborated in the DCF analysis approach described in this article. This model can serve as a basis for assessing the price ceiling of myriad gene therapy approaches. Given the high present values for these therapeutics, innovative costing and reimbursement mechanisms should be further explored, with contingencies for sustained efficacy.

iPSC-derived endothelial cell response to hypoxia via SDF1a/CXCR4 axis facilitates incorporation to revascularize ischemic retina

Ischemic retinopathies are major causes of blindness worldwide. Local hypoxia created by loss of vascular supply leads to tissue injury and aberrant neovascularization in the retina. There is a great need for therapies that enhance revascularization of hypoxic neuroretinal tissue. To test the therapeutic feasibility of human-induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs) for the treatment of ischemic retinopathies, we compared the angiogenic potential of hiPSC-ECs with mature human retinal endothelial cells (HRECs) in response to hypoxia. hiPSC-ECs formed more robust and complex vascular networks in collagen gels, whereas HRECs displayed minimal sprouting. The cells were further tested in the mouse oxygen-induced retinopathy (OIR) model. Retinas with hiPSC-EC injection showed colocalization with host vessels, whereas HRECs lacked such responses. hiPSC-ECs markedly reduced vaso-obliteration and pathological neovascularization. This beneficial effect of hiPSC-ECs was explained by the stromal cell-derived factor-1a (SDF1a)/CXCR4 axis; hiPSC-ECs exhibited much higher cell-surface expression of CXCR4 than HRECs and greater chemotaxis toward SDF1a-embedded 3D collagen hydrogel. Furthermore, treatment with neutralizing antibody to CXCR4 abolished recruitment of hiPSCs in the OIR model. These findings suggest superior angiogenic potential of hiPSC-ECs under hypoxia and underscore the importance of SDF1a/CXCR4 in the reparative function of hiPSC-ECs in ischemic diseases.