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

Long term analysis of microbiological isolates and antibiotic susceptibilities in acute-onset postoperative endophthalmitis: a UK multicentre study

OBJECTIVES

To review the trend of microbial isolates for postoperative endophthalmitis (POE) in the United Kingdom (UK) and determine the sensitivity to current empirical intravitreal antibiotic treatment.

METHODS

We conducted a long term multicentre consecutive case review of POE across 3 geographically distant tertiary eye centres in the UK: Sunderland Eye Infirmary (2000-2022), Oxford Eye Hospital (2016-2022), and Southampton General Hospital (2016-2022). Data on the microbial samples taken and results including sensitivities to antibiotics agents given were collected. Poisson regression was used to analyse microbial trends and outcomes were considered statistically significant at a level of p < 0.05.

RESULTS

179 consecutive eyes of 177 patients with POE met our inclusion criteria. The most common primary procedure was phacoemulsification and IOL insertion followed by intravitreal injections. 104 (58.1%) were culture positive and most were Gram-positive bacteria (85, 81.7%). The microbial trend consistently showed Staphylococcus epidermidis and unspecified coagulase-negative Staphylococci to be the most prevalent pathogens. Poisson regression showed no statistically significant change in any of the bacterial isolates over our study period. Antibiotic sensitivity data was available for 74% of the culture positive samples (77/104). All Gram-positive bacteria (68/68, 100%) and most (8/9, 88.9%) Gram-negative bacteria were sensitive to the empirical antibiotics (Vancomycin and Ceftazidime/Amikacin) given at presentation.

CONCLUSIONS

Most of the bacterial isolates causing POE in the UK are Gram-positive bacteria, and the trend has remained stable over more than two decades. Current empirical treatment with intravitreal Vancomycin and Ceftazidime/Amikacin provides effective broad coverage for the vast majority of cases.

Polylysine Derivatives with a Potent Antibacterial Ability for Effectively Treating Methicillin-Resistant Staphylococcus aureus-Induced Endophthalmitis

Bacterial endophthalmitis (BE) is a severe ocular infection that can lead to irreversible blinding ocular disease. When diagnosed with BE, the main treatment approach is empirically administering intravitreal antibiotic injections. However, the excessive use of antibiotics leads to increased drug resistance in pathogens, and the retinal dose-limiting toxicities greatly limit its application in clinic. In this work, we present a series of polylysine derivatives (PLL-n) for the treatment of bacterial endophthalmitis. By precisely adjusting the balance of hydrophilic/hydrophobic, the optimal polymer, PLL-2, demonstrates high efficacy against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and various clinically isolated drug-resistant bacteria. The antibacterial mechanism showed that PLL-2 could effectively destroy the bacterial membrane and lead to bacterial death. Due to its unique antibacterial mechanism, PLL-2 exhibits rapid bactericidal kinetics and does not induce bacterial resistance up to 16 generations. More importantly, PLL-2 showed a significant therapeutic effect on a methicillin-resistant S. aureus-induced rat endophthalmitis model, which presents a promising therapeutic approach for managing endophthalmitis.

Prophylaxis of topical levofloxacin against endophthalmitis after cataract surgery in Taiwan, 2001-2019: an interrupted time series analysis

BACKGROUND

Since May 2007, topical levofloxacin 0.5% ophthalmic solution for prophylaxis of postoperative endophthalmitis (POE) in cataract surgery has been reimbursable in Taiwan.

AIM

We used the National Health Insurance Research Database to estimate the practice of levofloxacin in cataract surgery from 2001 to 2019 and compared the POE rates before and after the introduction of levofloxacin using interrupted time series (ITS) analysis.

METHOD

We did propensity score-based stabilized weights (PSSW) for each quarterly cohort and used the Joinpoint Regression Program to determine the significant change time point.

RESULTS

1,456,380 patients and 2,208,126 eyes were eligible. The Joinpoint Regression Program revealed a significant change in the second quarter of 2010. Levofloxacin use started from 0% in the second quarter of 2007, and increased to 6.3% and 30.2% in the second quarter of 2010 and the last quarter of 2019. The POE rate (per 1000 eyes) was 3.7 in the first quarter of 2001, reduced to 1.9, 1.7, and 1.4 in the first, second quarters of 2010, and the last quarter of 2019, respectively. ITS reveals a significant but smaller time trend of - 0.0088‰ during 2010Q2-2019 (post-interruption). The r-square between the levofloxacin use and the POE rate was 0.305. The results of ITS and r-square after PSSW are similar to those without PSSW.

CONCLUSION

Although the POE reduction rate in cataract surgery aligns with the increased use of levofloxacin, the small r-square and low usage implied topical levofloxacin use is not the sole determinant of POE reduction.

An annular corneal microneedle patch for minimally invasive ophthalmic drug delivery

Microneedles directly penetrating into the cornea inevitably cause pain, corneal structure damage, and reduced light transmittance. In this work, a minimally invasive annular microneedle (A-MN) patch was developed avoiding direct puncture into the central cornea for ophthalmic drug delivery. The feasible mechanical strength of A-MNs was achieved by adjusting the ratio of PVP-β-CD and PVA to puncture the cornea barrier. Through effective diffusion to corneal stroma, bioavailability of hydrophilic small-molecule drugs, hydrophobic drugs, and macromolecular protein drugs through an A-MN patch was 24.36, 17.47, and 5.36 times higher than that of free drug administration. A-MNs effectively maintained light transmittance of the cornea with a light transmittance of 96.33 to 100%, which was higher than that of S-MNs. Furthermore, A-MNs effectively avoided corneal tissue and nerve damage along with the pain. The efficiency and safety of A-MNs were also examined through both an in vitro cell experiment and an in vivo animal experimental model, which showed great potential in clinical application.

Recent advances in photothermal nanomaterials for ophthalmic applications

The human eye, with its remarkable resolution of up to 576 million pixels, grants us the ability to perceive the world with astonishing accuracy. Despite this, over 2 billion people globally suffer from visual impairments or blindness, primarily because of the limitations of current ophthalmic treatment technologies. This underscores an urgent need for more advanced therapeutic approaches to effectively halt or even reverse the progression of eye diseases. The rapid advancement of nanotechnology offers promising pathways for the development of novel ophthalmic therapies. Notably, photothermal nanomaterials, particularly well-suited for the transparent tissues of the eye, have emerged as a potential game changer. These materials enable precise and controllable photothermal therapy by effectively manipulating the distribution of the thermal field. Moreover, they extend beyond the conventional boundaries of thermal therapy, achieving unparalleled therapeutic effects through their diverse composite structures and demonstrating enormous potential in promoting retinal drug delivery and photoacoustic imaging. This paper provides a comprehensive summary of the structure-activity relationship between the photothermal properties of these nanomaterials and their innovative therapeutic mechanisms. We review the latest research on photothermal nanomaterial-based treatments for various eye diseases. Additionally, we discuss the current challenges and future perspectives in this field, with a focus on enhancing global visual health.

The diagnosis and treatment progress of infectious endophthalmitis

Endophthalmitis is a blinding disease that may lead to permanent vision loss. The diagnosis of endophthalmitis relies on clinical findings. It is crucial to identify causative microorganisms in time for subsequent treatment and saving vision. For a long time, cultures of vitreous and/or aqueous humours have been the gold standard for the diagnosis of endophthalmitis. The development of modern molecular diagnostic techniques has brought new opportunities for identifying pathogens rapidly and improving sensitivity. Intravitreal antibiotic injection has the become standard treatment option for infectious endophthalmitis in clinical practice, however, the role and timing of pars plana vitrectomy remains controversial. Moreover, the development of new drugs for intravitreal injection and posterior segment drug delivery systems is expected to achieve the transition from invasive to non-invasive management. Thus, endophthalmitis is an ophthalmic emergency and timely diagnosis and treatment are crucial for preserving vision.

Endogenous endophthalmitis caused by Rothia dentocariosa

We report a case of a late adolescent female who presented to us with complaints of acute, painful loss of vision in her left eye. Her visual acuity (VA) had reduced to perception of hand movements within a week. Slit lamp examination and ultrasonography revealed that the patient had endophthalmitis. She was treated with intravitreal antibiotics, pars plana vitrectomy, lensectomy and a 5000 centistoke silicone oil injection. The vitreous biopsy showed significant growth of Rothia dentocariosa on blood and chocolate agars. An infected lower mandibular tooth was identified as the infective focus and treated. Systemic evaluation did not reveal any other infections. 1 month after the final procedure, she achieved a VA of 20/60 and IOP of 11 mm Hg. The retina was attached, and the infection had completely resolved. This case of atypical endogenous endophthalmitis was managed with timely surgery and using silicone oil injection and showed a good outcome.

Electroretinographic Evaluations of Eyes With Endophthalmitis

Purpose

To determine the physiological status of the retina of eyes with endophthalmitis by examining the electroretinograms (ERGs) recorded with a portable recording system and to determine whether the pretreatment ERG findings were correlated with the best-corrected visual acuity (BCVA) after the treatment.

Methods

We examined the medical records of 118 eyes of 108 patients who were diagnosed and treated for infectious endophthalmitis at Saitama Medical University Hospital, Japan, between January 2015 to November 2022. Of these, we studied the 25 eyes of 21 patients who had been evaluated by electroretinography. In bilateral cases, one eye was analyzed. The eyes were classified into those with postoperative endophthalmitis (group S, n = 12) and those with endogenous endophthalmitis (group E, n = 9). Photopic and flicker ERGs were recorded with the RETeval system. The pretreatment clinical factors studied were the ERG components that might be correlated with the post-treatment BCVA.

Results

Eyes in Group E with larger amplitude flicker ERGs (P = 0.0053, ρ = -0.8333) had better BCVA after treatment. In Group S, eyes with larger amplitude flicker ERGs (P = 0.0086, ρ = -0.7173), photopic a-waves (P = 0.0323, ρ = 0.6177), and photopic b-waves (P = 0.0055, ρ = -0.7443) had better BCVA after treatment.

Conclusions

Simple and rapid ERG evaluations under light-adapted condition are helpful in evaluating the pretreatment retinal function and to determine the visual prognosis in eyes with endophthalmitis.

Translational Relevance

Simple and non-time-consuming ERG evaluations are helpful in evaluating the retinal function in eyes with endophthalmitis and predicting the visual prognosis.

New Approaches to Overcoming Antimicrobial Resistance in Endophthalmitis

Endophthalmitis is a rare but vision-threatening infection characterized by marked inflammation of intraocular fluids and tissues, uncommonly seen following surgery and intravitreal injection. Antimicrobials are used worldwide in the prophylaxis and treatment of bacterial and fungal infections of the eye and are standard treatment in the preoperative and postoperative care of surgical patients. However, antimicrobials are reported to be overprescribed in many parts of the world, which contributes to antimicrobial resistance (AMR). AMR complicates the prophylaxis and treatment of endophthalmitis. This article examines the prevalence and mechanisms of AMR in ocular microorganisms, emphasizing the importance of understanding AMR patterns for tailored treatments. It also explores prophylaxis and management strategies for endophthalmitis, with a discussion on the use of intracameral antibiotic administration. The use of prophylactic intracameral antibiotics during cataract surgery is common in many parts of the world but is still controversial in some locations, especially in the US. Finally, it highlights the role of stewardship in ophthalmology and its benefits in the treatment of endophthalmitis.