Intracameral antibiotics for prophylaxis of postoperative endophthalmitis in Australia: a review

Surface modification of commercial intraocular lens by zwitterionic and antibiotic-loaded coating for preventing postoperative endophthalmitis

After cataract surgery, to prevent possible postoperative endophthalmitis (POE) caused by attached pathogenic bacteria onto the surface of implanted intraocular lens (IOL), various antibiotic-loaded IOLs have been proposed and widely studied to inhibit bacterial infection. However, most of these developed antibiotic-loaded IOLs still suffer from shortcomings such as insufficient drug loading, short release time, poor biocompatibility, and risk of secondary infection. Herein, we propose a zwitterionic and high-drug loading coating for surface modification of commercial hydrophobic IOL with both antifouling and antibacterial properties to effectively prevent POE. In this strategy, zwitterionic poly(carboxylbetaine-co-dopamine methacrylamide) copolymers (pCBDA) and dopamine (DA) were first robustly co-deposited onto IOL surface via facile mussel-inspired chemistry, resulting in a hydrophilic coating (defined as PCB) without sacrificing the high light transmittance of the native IOL. Subsequently, amikacin (AMK), an amine-rich antibiotic was reversibly conjugated onto the coating through the acid-sensitive Schiff base bonds formed by the reaction between amino and catechol groups, with high-drug payload over ∼35.5 μg per IOL and 30 days of sustained drug release under weak acid environment. Benefiting from the antifouling property of zwitterionic pCBDA copolymers, the intraocularly implanted PCB/AMK-coated IOL could effectively resist the adhesion and proliferation of residual LECs to inhibit the development of posterior capsule opacification (PCO) without affecting the normal ocular tissues, demonstrating excellent in vivo biocompatibility. Moreover, the synergy of zwitterionic pCBDA and conjugated AMK with acidic-dependent release behavior endowed this PCB/AMK-coated IOL strong antibacterial activity against both in vitro biofilm formation and in vivo postoperative Staphylococcus aureus infection, suggesting its promising application in preventing POE.

Guideline for the treatment of no light perception eyes induced by mechanical ocular trauma

Severe mechanical ocular trauma with no light perception (NLP) predicts a poor prognosis of visual acuity and enucleation of the eyeball. Since the innovative treatment concept of exploratory vitreoretinal surgery has developed and treatment technology has advanced, the outcomes of severe ocular trauma treatment in NLP patients have greatly improved. However, there remains a lack of unified standards for the determination, surgical indication, and timing of vitrectomy in NLP eye treatment. To address these problems, we aimed to create evidence-based medical guidelines for the diagnosis, treatment, and prognosis of mechanical ocular trauma with NLP. Sixteen relevant recommendations for mechanical ocular trauma with NLP were obtained, and a consensus was reached. Each recommendation was explained in detail to guide the treatment of mechanical ocular trauma associated with NLP.

Intraoperative Cefuroxime Irrigation Prophylaxis for Acute-Onset Endophthalmitis After Phacoemulsification Surgery

Purpose

Acute-onset postoperative endophthalmitis usually compromises the visual function and anatomical integrity of the eye. The aim of this study was to evaluate the efficacy of intraoperative cefuroxime use in irrigating solution on prevention of acute-onset endophthalmitis after phacoemulsification.

Methods

This retrospective, comparative, interventional cohort study included patients who underwent phacoemulsification between January 1, 2012, and December 31, 2019. Under a uniform perioperative protocol, the patients who had surgery from January 1, 2012, to December 31, 2014, received irrigating infusion fluid containing balanced salt solution (BSS) only (group 1), and those from January 1, 2015, to December 31, 2019, received BSS with cefuroxime (1500 μg/mL) during surgery (group 2). All eyes were evaluated postoperatively, and the eyes suspected to have endophthalmitis were assessed and treated by a consultation team. The rates of postoperative endophthalmitis in these two groups were calculated.

Results

A total of 61,299 eyes were included over the eight years. Among these eyes, 11 in group 1 (0.07% of 15,948 eyes) and 5 in group 2 (0.01% of 45,351 eyes) developed endophthalmitis, and the difference was significant (P < 0.01). Five among 16 patients (31.25%) with endophthalmitis were positive in bacterial culture. The positive rate of bacterial culture was not significantly different between group 1 (4/11) and group 2 (1/5) (P > 0.05). No adverse events related to the irrigation of cefuroxime were found.

Conclusion

Intraoperative cefuroxime irrigation (1500 μg/mL) could decrease the rate of postoperative endophthalmitis after phacoemulsification by 7-fold. This study provides evidence that intraoperative irrigation with cefuroxime is effective as an antibiotic prophylaxis for endophthalmitis.

Therapeutic Effects of Intravitreously Administered Bacteriophage in a Mouse Model of Endophthalmitis Caused by Vancomycin-Sensitive or -Resistant Enterococcus faecalis

Endophthalmitis due to infection with Enterococcus spp. progresses rapidly and often results in substantial and irreversible vision loss. Given that the frequency of this condition caused by vancomycin-resistant Enterococcus faecalis has been increasing, the development of novel therapeutics is urgently required. We have demonstrated the therapeutic potential of bacteriophage ΦEF24C-P2 in a mouse model of endophthalmitis caused by vancomycin-sensitive (EF24) or vancomycin-resistant (VRE2) strains of E. faecalis Phage ΦEF24C-P2 induced rapid and pronounced bacterial lysis in turbidity reduction assays with EF24, VRE2, and clinical isolates derived from patients with E. faecalis-related postoperative endophthalmitis. Endophthalmitis was induced in mice by injection of EF24 or VRE2 (1 × 10⁴ cells) into the vitreous. The number of viable bacteria in the eye increased to >1 × 10⁷ CFU, and neutrophil infiltration into the eye was detected as an increase in myeloperoxidase activity at 24 h after infection. A clinical score based on loss of visibility of the fundus as well as the number of viable bacteria and the level of myeloperoxidase activity in the eye were all significantly decreased by intravitreous injection of ΦEF24C-P2 6 h after injection of EF24 or VRE2. Whereas histopathologic analysis revealed massive infiltration of inflammatory cells and retinal detachment in vehicle-treated eyes, the number of these cells was greatly reduced and retinal structural integrity was preserved in phage-treated eyes. Our results thus suggest that intravitreous phage therapy is a potential treatment for endophthalmitis caused by vancomycin-sensitive or -resistant strains of E. faecalis.