To report the first case of Kytococcus schroeteri ocular infection manifesting as chronic post-operative endophthalmitis (CPOE) following routine phacoemulsification with intraocular lens (IOL) implantation. This gram-positive bacterium is recognised as a cause of hardware infections in immunocompetent hosts, such as prosthetic cardiac valves, ventriculoperitoneal shunts, and orthopaedic hardware, often necessitating surgical removal of the infected prostheses for cure.

Case report and literature review.

A 64-year-old male with a history of uncomplicated cataract extraction and IOL insertion had multiple presentations over 6 years, with relapsing-remitting intraocular inflammation with multiple negative vitreous cultures treated as non-infectious panuveitis. An eventual positive vitreous culture for K. schroeteri led to a diagnosis of CPOE, which was successfully treated with vitrectomy, removal of IOL, and intravitreal vancomycin injections. However, advanced vision loss occurred due to secondary glaucoma.

K. schroeteri is a novel cause of CPOE, which is typically attributed to other low virulence organisms. As with infections of non-ocular implanted hardware by K. schroeteri, surgical removal of the infected IOL-capsule complex was required for cure. The CPOE diagnosis requires a combination of high index of suspicion and culture of vitreous and capsular material. The role of IOL removal for the treatment of CPOE is discussed.

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.

The purpose of this study was to analyze the outcomes of treatment of acute postoperative endophthalmitis and verify its main causative agents.

The study included 49 patients (49 eyes) with acute postoperative endophthalmitis that developed following surgical interventions in various clinics. At the onset of endophthalmitis, 3 patients (6.1%) retained object vision with visual acuity ranging from 0.05 to 0.20, while 7 patients (14.3%) had visual acuity between 0.01 and 0.05. Visual acuity deteriorated to finger counting near face in 15 patients (30.6%), to 1/∞ pr.l.certa in 21 patients (42.9%), and to 1/∞ pr.l.incerta in 3 patients (6.1%).

All patients were treated using a new technique we developed, which involved short-term tamponade of the vitreous cavity with perfluorodecalin and intravitreal administration of antibiotics. Before treatment start, biological material was collected for bacteriological examination.

Visual function was preserved in 46 patients (93.9%). Clinically significant improvement in visual acuity (0.3-0.4) was observed in 36 patients (73.5%), while 6 patients (12.2%) achieved visual acuity greater than 0.5. No cases of recurrent inflammation were recorded; however, laser tyndallometry indicated a persistent disruption of the blood-ocular barrier for up to 6 months post-treatment, with a protein flow value of 14.6 (8.4; 19.2) ph/ms (p=0.002).

The most informative method for identifying the etiological cause of endophthalmitis was vitreous sampling (81.6% effectiveness), compared to anterior chamber sampling (38.8% effectiveness).

The best functional outcomes were achieved in patients with endophthalmitis caused by S. epidermidis and S. aureus. Endophthalmitis caused by gram-negative bacteria had a poor visual prognosis.

Endophthalmitis is an ophthalmologic emergency requiring accurate and rapid diagnosis for treatment. Currently, the diagnosis commonly relies on culture and molecular biology, which falls short of clinical rapid diagnosis. The purpose of this study was to evaluate the feasibility of a self-build Microfluidic Real-time Polymerase Chain Reaction (RT-PCR) System for rapidly identifying potential pathogens of endophthalmitis.

This study included 22 patients who presented to Shenzhen Eye Hospital and the Ophthalmology Department of the Affiliated Hospital of Guizhou Medical University in China between January 2023 and March 2024. The samples were cultured using conventional methods and underwent Microfluidic RT-PCR and metagenomic next-generation sequencing (mNGS).

The Microfluidic RT-PCR System identified pathogens in 11 of 22 cases (50.00%), compared with 40.91% for microbiology culture. 14 cases (63.64%) had concordant results, and 5 cases were positive for the microfluidic system only. The agreements between culture and microfluidic system, as well as culture and mNGS were 100.00% (6/6) and 50.00% (3/6), respectively. The average waiting time for the microfluidic system was about 30 min if excepting DNA extraction time, which was much shorter than 2.88 days for culture and 1.57 days for mNGS.

The microfluidic-based RT-PCR system was preliminarily proved to be a sensitive, easy-to-operate, and rapid in-hospital technology. It is expected to become a rapid diagnostic platform for endophthalmitis.

To evaluate the usefulness of metagenomic analysis in the search for causative organisms of bacterial endophthalmitis.

Twenty-one consecutive treatment-naïve patients (13 men and 8 women; mean age, 60.8±19.8 years) with suspected endophthalmitis were recruited. Vitrectomy was performed to diagnose and treat endophthalmitis. Bacterial culture and metagenomic analysis of the vitreous body were performed. Extracted DNA was analysed using 16S rRNA sequences, and libraries were sequenced on an Illumina MiSeq sequencer. To compare the bacterial composition in each case, α and β diversities were determined.

Patients were categorised into three groups: endophthalmitis cases with matching predominant organisms according to metagenomic analysis and bacterial culture, those with negative results for bacterial culture and those with negative results in both cases. In 7 of 15 culture-negative cases, results from metagenomic analysis could detect pathogens. The diversity of bacterial populations was significantly lower in the group with positive results for predominant bacteria according to culture and metagenomic analysis. All patients with uveitis were included in the group for which the causative pathogen could not be determined by culture or metagenomic analysis. The structures of bacterial populations significantly differed between the positive and negative groups by culture and metagenomic analysis.

Metagenomic analysis could be useful for prompt detection of causative pathogens, for precise diagnosis of infection, and as a marker of inflammation processes such as uveitis.

Laboratory investigations can play a significant role in the diagnosis and decision-making of infectious uveitis. Though direct demonstration of the infective organism remains the gold standard of diagnosis, it is not always possible with ocular tissues. Recent advancements in molecular techniques have made it possible to overcome these limitations and to identify the genomic DNA of pathogens associated with infectious uveitis. Techniques such as next-generation sequencing can analyze all DNA-based lifeforms, regardless of whether they are bacteria, fungi, viruses, or parasites and have been used in the laboratory diagnosis of intraocular inflammation. On the other hand, serological tests, though they dominate the diagnostic landscape of various infectious etiologies in uveitis in routine clinical practice, have varied specificities and sensitivities in different infectious uveitis. In this review, we focus on various methods of laboratory diagnosis of infectious uveitis and discuss the recent advances in molecular diagnosis and their role in various infectious clinical entities.

The main method of treatment and prevention of endophthalmitis is a combination of intravitreal and topical administration of antibiotics, such as cefuroxime moxifloxacin or vancomycin. However, this method is ineffective due to the rapid elimination of the drug. This problem can be solved with the help of intravitreal in situ injection systems, which are injected with a syringe into the vitreous body and provide prolonged action of the drug at the focus of inflammation. Under the influence of temperature, the liquid drug undergoes a phase transition and turns into a gel after injection. This ensures its prolonged action. The study aimed to develop an intravitreal in situ cefuroxime delivery system for the treatment of endophthalmitis based on a thermosensitive biodegradable composition of poloxamer 407 and hyaluronic acid. A combination of poloxamer Kolliphor® P407, Kolliphor® P188, and PrincipHYAL® hyaluronic acids of different molecular weights was used as a delivery system. The potency of cefuroxime solid dispersion with polyvinylpyrrolidone-10000, polyethylene glycol-400, and polyethylene glycol-1500 in a 1:2 ratio was studied for prolonged action compared to cefuroxime substance. The experimental formulations were studied for the parameters of gelation temperature in a long-term test (4 months), pH, and release of cefuroxime using dialysis bags. To study the distribution parameter in the vitreous body, an in vitro model (1/13) was developed, which was a hollow agar sphere filled with 1% (w/v) polyacrylate gel. For the superior formulations, a HET-CAM test (chorioallantoic membrane test) was performed to determine the absence of irritant effects. According to the study results, a formulation containing a solid dispersion of cefuroxime:PEG-400 (1:2), the matrix of which contained 18% (w/v) Kolliphor® P407 poloxamer, 3% (w/v) Kolliphor® P188 poloxamer, and 0.5% (w/v) hyaluronic acid (1400-1800), was selected. This sample had an average gelation temperature of 34.6 °C, pH 6.7 ± 0.5, and a pronounced prolonged effect. Only 7.6% was released in 3 h of the experiment, whereas about 38% of cefuroxime was released in 72 h. No irritant effect on the chorioallantoic membrane was observed for any formulations studied.