Trends in microbiological spectrum of endophthalmitis at a single tertiary care ophthalmic hospital in India: a review of 25 years

Pathobiology of Fungal Endophthalmitis: A Major Review

Fungal endophthalmitis is a chronic inflammatory condition of the eye's posterior segment that can lead to irreversible vision loss. While relatively rare in western countries, its incidence is notably higher in Asia, particularly India. The condition's prevalence is exacerbated by factors such as intravenous drug use, antibiotics, and ocular surgeries. Fungal endophthalmitis can be categorized as endogenous, arising from systemic infection, or exogenous, linked to external sources such as trauma or surgery. The fungal agents responsible vary by region, with Candida species common in the West and Aspergillus and Fusarium species more prevalent in India. Management typically involves vitrectomy and intravitreal antifungal drugs such as amphotericin B and voriconazole, though treatment is often complicated by multidrug resistance and culture-negative cases. Recent proteomic and transcriptomic analyses have highlighted the early and sustained activation of the host immune response during infection involving key inflammatory and oxidative stress-related proteins. Given the potential for excessive inflammation to cause retinal damage, targeted immunotherapies are crucial. Immunomodulation, which aims to balance the immune response, shows promise in preserving vision while effectively combating the infection. Key targets for immunomodulation include pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-17), chemokines (CCL2, CXCL8), Toll-like receptors (TLR2, TLR4), and the complement system. Additionally, modulating the activity of macrophages, neutrophils, regulatory T cells, and Th17 cells, as well as targeting inflammasomes, can help control inflammation. Biologic agents and small molecule inhibitors offer further avenues for precise immune response modulation. This review underscores the importance of a comprehensive understanding of host-pathogen interactions in the development of effective therapies for fungal endophthalmitis.

EXAMINATION OF GALACTOMANNAN LEVELS IN INTRAOCULAR FLUID TO ASSIST THE DIAGNOSIS OF ASPERGILLUS ENDOPHTHALMITIS

PURPOSE

To evaluate the utility of galactomannan testing of intraocular fluid in the diagnosis of Aspergillus endophthalmitis (AE).

METHODS

This retrospective study enrolled three groups of patients, including those with 17 eyes with AE; 20 eyes with intraocular infection of bacteria, viruses, or other fungi; and 19 eyes with cataract. Intraocular fluid from all these patients was collected for galactomannan testing. In addition, the receiver operating characteristic curves and diagnostic significance were analyzed.

RESULTS

The mean optical density index (ODI) of galactomannan was 5.77 ± 1.73 in the AE group, which was significantly higher than that in the non- Aspergillus intraocular infection group (0.19 ± 0.11, P < 0.001) and the negative control group (0.29 ± 0.27, P < 0.001). The area under the receiver operating characteristic curve (area under the curve) was 1.00 (95% confidence interval, 1.00-1.00; P < 0.001) in the AE group and the other two groups. At a cutoff optical density index of 1.88, the sensitivity and specificity were 100.0% and 100.0%, respectively, and the Youden index reached its highest value of 1.00.

CONCLUSION

Galactomannan testing of intraocular fluid indicated good sensitivity and specificity for the diagnosis of AE, thereby promising a rapid diagnostic modality for AE.

Effect of Age on the Etiology and Antibiotic Susceptibility Pattern of Infectious Endophthalmitis

PURPOSE

To review the etiology and antibiotic susceptibility patterns of infectious endophthalmitis over 11 years in different age groups.

METHODS

Microbiology records of culture-positive endophthalmitis cases from January 2011 and December 2021 were reviewed for the age groups 0-30, 31-60, and >60 years. Additionally, data was also analysed for trends in antibiotic susceptibility between different age groups.

RESULTS

A total of 5590 patients were clinically diagnosed with endophthalmitis. Of these, 1316 (23.5%) patients were culture positive comprising of 1097 bacteria (83.3%) and 219 fungal (16.6%). Gram-positive bacteria predominated the culture-proven bacterial endophthalmitis group with 709 cases (62.6%). Streptococcus pneumoniae (9.3%) was the most prevalent organism in the age group between 0 and 30 years, while Staphylococcus epidermidis (6%) was the most prevalent organism in the age group of 31-60 years. In comparison, Pseudomonas aeruginosa (4.1%) was the most abundant organism in the age group >60 years. Interestingly, Aspergillus flavus (13.24%) was the predominant fungal pathogen in all age groups. There was an increasing trend in antibiotic resistance from younger to older age groups and this pattern was observed for almost all drugs tested except vancomycin and amikacin.

CONCLUSION

While infection can occur at any age, the etiology also seems to vary. This study helps us understand the demography of endophthalmitis along with choice of empirical antibiotics that would influence treatment outcomes. Although vancomycin currently holds good for the treatment for gram-positive infections, gram-negative infections calls for an immediate need for newer drugs or advanced treatment options.

Antibiotic susceptibility in Endophthalmitis Management Study and intravitreal antibiotic practice trend in India-EMS Report #5

AIM

Analyze antibiotic susceptibility in the Endophthalmitis Management Study (EMS) and compare it with the current intravitreal antibiotic practice trend of members of the Vitreoretinal Society of India (VRSI) practicing in India.

METHODS

The microbiology work-up of undiluted vitreous included microscopy, culture-susceptibility, polymerase chain reaction (PCR), and next-generation sequencing (NGS). VRSI members were invited to the survey. The EMS conventional culture-susceptibility (PCR and NGS excluded) results were compared vis-a-vis gram-positive cocci (GPC), gram-negative bacilli (GNB), and less commonly used antibiotics with the current recommended intravitreal antibiotics. p < 0.05 was considered significant.

RESULTS

Culture and positivity (culture + PCR/NGS) positivity was 28.8% and 56.1%, respectively. GPC was most susceptible to cefazolin, linezolid, and vancomycin; GNB was most susceptible to amikacin, ceftazidime, colistin, and imipenem. There was no susceptibility difference between cefazolin and vancomycin (p = 0.999) and between ceftazidime and imipenem (p = 1.0). Colistin was superior to ceftazidime (p = 0.047) against GNB. The GNB resistant to amikacin (n = 14) were equally susceptible to ceftazidime and colistin; resistant to ceftazidime (n = 16) were susceptible to colistin; and resistant to colistin (n = 7) were susceptible to ceftazidime. The preference of VRSI members (n = 231) practicing in India was a vancomycin-ceftazidime combination (82%), vancomycin for GPC (94%), ceftazidime for GNB (61%), and voriconazole for fungi (74%).

CONCLUSION

In EMS, GPC had good susceptibility to vancomycin; GNB had good susceptibility to ceftazidime and colistin. Given the lower resistance of colistin, a vancomycin-colistin combination could be an alternative empiric treatment in post-cataract endophthalmitis in India.

Complement Cascade 8 - Alpha and Calpain-2 in Extracellular Vesicles of Human Vitreous as Biomarkers of Infectious Endophthalmitis

Purpose

Extracellular vesicles (EVs) are messenger pigeons of the cells that communicate about cellular microenvironment. In this study, we evaluated the expression of C8α and calpain-2 in EVs from vitreous of patients with bacterial endophthalmitis to assess its utility as a diagnostic marker.

Methods

EVs were isolated from vitreous of patients with bacterial endophthalmitis (culture positive and culture negative) and noninfectious control by exosome isolation reagent and characterized, and the levels of C8α and calpain-2 was assessed by enzyme-linked immunosorbent assay in isolated EVs and direct vitreous. The receiver operating characteristic curve was generated to assess the diagnostic performance.

Results

Scanning electron microscopy (SEM) and dynamic light scattering (DLS) confirmed the presence of EVs having a diameter (nm) of 275.2 ± 93, 92 ± 22, and 77.28 ± 12 in culture-positive (CP), culture-negative (CN), and control respectively. The expression level (ng/mL) of C8α in the EVs obtained from CP was 144 ± 22 and CN was 31.2 ± 9.8, which was significantly higher (P < 0.01) than control 3.7 ± 2.4. Interestingly, C8α is not expressed directly in the vitreous of CN and controls. Calpain-2 was significantly downregulated (P ≤ 0.0001) in CP (0.94 ± 0.16) and CN (0.70 ± 0.14) than control. The sensitivity and specificity of 1 for C8α and calpain-2 in the EVs implied that its diagnostic accuracy was significant.

Conclusions

This study showed that the EV proteins C8α and calpain-2 could be suitable diagnostic markers for endophthalmitis. However, the presence of C8α in the EVs of CN samples but not in direct vitreous promises EVs as the future of diagnostics.

Translational Relevance

Expression levels of EV-calpain-2 and EV-C8α could diagnose CN bacterial endophthalmitis.

Global Transcriptomic Profiling of Innate and Adaptive Immunity During Aspergillus flavus Endophthalmitis in a Murine Model

Purpose

Fungal endophthalmitis is characterized by chronic inflammation leading to the partial or complete vision loss. Herein, we analyzed the transcriptomic landscape of Aspergillus flavus (A. flavus) endophthalmitis in C57BL/6 mice to understand the host-pathogen interactions.

Methods

Endophthalmitis was induced by intravitreal injection of A. flavus spores in C57BL/6 mice and monitored for disease progression up to 72 hours. The enucleated eyeballs were subjected to histopathological analysis and mRNA sequencing using the Illumina Nextseq 2000. Pathway enrichment analysis was performed to further annotate the functions of differentially expressed genes (DEGs) and validation of cytokines was performed in vitreous of patients with fungal endophthalmitis using multiplex ELISA.

Results

Transcriptomic landscape of A. flavus endophthalmitis revealed upregulated T-cell receptor signaling, PI3K-AKT, MAPK, NF-κB, JAK-STAT, and NOD like receptor signaling pathways. We observed significant increase in the T-cells during infection especially at 72 hours infection along with elevated expression levels of IL-6, IL-10, IL-12, IL-18, IL-19, IL-23, CCR3, and CCR7. Furthermore, host-immune response associated genes, such as T-cell interacting activating receptor, TNF receptor-associated factor 1, TLR1, TLR9, and bradykinin receptor beta 1, were enriched. Histopathological assessment validated the significant increase in inflammatory cells, especially T-cells at 72 hours post-infection along with increased disruption in the retinal architecture. Additionally, IL-6, IL-8, IL-17, TNF-α, and IL-1β were also significantly elevated, whereas IL-10 was downregulated in vitreous of patients with Aspergillus endophthalmitis.

Conclusions

Regulating T-cell influx could be a potential strategy to modulate the excessive inflammation in the retina and potentially aid in better vision recovery in fungal endophthalmitis.

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.

Anti-fungal efficacy of combination of amphotericin B with colistin and gentamicin in McCarey-Kaufman corneal preservation medium

Purpose

To curtail the potential of donor corneal tissue disseminating fungi to the recipient's eye, we evaluated the addition of amphotericin B to McCarey-Kaufman (M-K)-corneal storage medium supplemented with colistin.

Methods

Amphotericin B was examined for its ability to inhibit the growth of Candida albicans and Aspergillus flavus using a microbroth dilution test and checkerboard assay in combination with only gentamicin and a combination of colistin, gentamicin, and amphotericin B. The safety on epithelium and endothelium was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

Results

The minimal inhibitory concentration of gentamicin was found to be >256 μg/ml against both C. albicans and A. flavus, whereas that of amphotericin B was found to be in a range of 0.25-0.5 and 1-2 μg/ml for C. albicans and A. flavus, respectively. According to the checkerboard assay, 80% (4/5) of C. albicans isolates and 100% (5/5) of A. flavus isolates responded synergistically to the combination of amphotericin B and gentamicin, but only 20% (1/5) of C. albicans isolates showed an additive effect. None of the tested isolates displayed antagonism. The combined effect of the three drugs also did not display any antagonistic effect. Additionally, the MTT assay reveals no toxic effect of the antimicrobials used on corneal epithelial and endothelial cells.

Conclusion

In vitro experiments demonstrate that amphotericin B is not toxic to either epithelium or endothelium and is a promising additive to the M-K medium supplemented with colistin.

Endophthalmitis Management Study-A Prospective Randomized Clinical Trial on Postoperative Endophthalmitis Management in India: An Interim Analysis. Endophthalmitis Management Study Report #3

PURPOSE

An interim analysis of the Endophthalmitis Management Study to examine the outcome of inflammation score (IS)-based treatment and antibiotic susceptibility.

DESIGN

A prospective randomized study.

PATIENTS AND METHODS

IS was measured on a 0-4 scale from presenting signs in 4 cardinal ocular tissues. The eyes with IS <10 received vitreous tap and intravitreal antibiotics, whereas eyes with IS ≥10 received vitrectomy and intravitreal antibiotics. These eyes were randomized to 2 intravitreal antibiotic combinations: (1) vancomycin and ceftazidime and (2) vancomycin and imipenem. Microbiology workup of undiluted vitreous included microscopy, culture-susceptibility, Sanger, and targeted next-generation sequencing. The clinical and microbiology outcomes were analyzed for advanced (IS = ≥20) and less advanced (IS = <10) endophthalmitis.

RESULTS

Interim analysis was performed after the Endophthalmitis Management Study recruited 56.85% (248/436) of patients and completed 54.6% (238/436) of microbiology workup. A 90-day follow-up was completed in 90.8% (168/185) of eligible people. In eyes with IS ≥20, the time to symptoms was shorter (5.8 ± 6.7 vs 8.5 ± 9.1 d; P = 0.015), and the need for additional treatment was higher (95.8% vs 53.1%; P = 0.0267). Good final vision was associated with good presenting vision (r = 0.30) and IS-based treatment decisions (r = 0.170). Microbiology positivity was 55.9%. Eyes with IS <10 had a higher Gram-positive cocci (33.9% vs 4.8%; P = 0.013) infection. Gram-positive cocci were most susceptible to vancomycin (95.7%), and Gram-negative bacilli to colistin (95.7%).

CONCLUSIONS

Considering both IS and presenting vision, rather than only one of them, helps in making appropriate management decisions for acute postoperative endophthalmitis.

A Novel and Low-cost Approach for Intravitreal Injection in an Experimental Model of Endophthalmitis

Purpose

Animal models are necessary in understanding the pathogenesis of endophthalmitis and are also necessary to assist the development of new therapeutics for this sight-threatening ocular inflammation. Hamilton syringes are usually preferred to inject pathogens when performing experiments on test subjects, however, this method has technical and financial disadvantages. In this study, we report the findings and assess the related benefits of applying a novel low-cost intravitreal injection technique to initiate endophthalmitis in a mouse model while using the Eppendorf tip and a 26G needle.

Methods

The 18-hr culture of clinical isolates of bacteria (Staphylococcus aureus and Pseudomonas aeruginosa) and fungus (Aspergillus flavus and Candida albicans) were resuspended to a final concentration of 10,000 colony forming units (CFU)/1 µL which were separately injected intravitreally into C57BL/6 mice (6-8 weeks) using a 0.1-2.5µL pipette attached to the modified Eppendorf tip with a 26G needle. The contralateral eye served as vehicle/uninjected control. Disease progression was determined by assessing the corneal haze, opacity, bacterial burden, and retinal histology of the eyes used in the model. Following euthanization, bacteria-infected mice were enucleated after 24 hr of the initial injection, and fungus-infected mice after 72 hr.

Results

Of the 50 mice injected, the modified technique was successful in 48 mice. Two mice were excluded due to cataract formed by accidental injury to the lens. The experimental endophthalmitis mice model successfully mimicked the natural clinical course. Clinical assessment and histopathology confirmed the influx of inflammatory cells into the posterior segment of the eye along with dissolution of retinal architecture.

Conclusion

Our novel method of injection using a modified Eppendorf tip and 26G needle yielded a cost-effective mouse model of clinical endophthalmitis, resulting in reproducible infection for understanding various aspects of its pathobiology.

The microbiological landscape and epidemiology of ocular infections in a multi-tier ophthalmology network in India: an electronic medical record driven analytics report

OBJECTIVE

To study the epidemiology and landscape of ocular infections in patients undergoing microbiological investigations across a multi-tier ophthalmology network in India.

METHODS

This cross-sectional hospital-based study included 15,822 patients in whom microbiology samples were analysed between September 2013 and December 2021. Ocular tissue of patients in whom a microbiology sample was processed in at least one eye were included. The data were collected using an indigenously developed electronic medical record system.

RESULTS

Among the 15,822 patients, bacteria (51.06%) was the most common aetiology followed by fungus (38.27%). The majority of the patients were male (68.10%) and adults (90.01%). The most common age group was during the sixth decade of life with 2,914 (18.42%) patients. The patients were more commonly from the lower socio-economic status (51.61%) and from the rural geography (46.82%). Majority of the specimens sent for microbiological analysis were corneal scrapings (68.61%) followed by vitreous (8.77%). The most common bacteria isolated was Staphylococcus aureus (14.45%) followed by Pseudomonas aeruginosa (12.53%) and among the fungus were Fusarium (30.53%) and Aspergillus species (29.86%). Acanthamoeba (1.26%) and Microsporidia (0.38%) accounted for a minority of the infections in the samples. Fungus (53.10%; p ≤ 0.00001) and virus (51.08%; p = 0.000673) aetiology was found to be significantly higher in patients presenting from the rural geography.

CONCLUSION

The most common aetiology of infection in ocular disease is bacterial but fungal infections also accounted for a significant proportion. The majority of the patients with ocular infections presented from the rural geography and from lower socio-economic status.

An All-in-One Highly Multiplexed Diagnostic Assay for Rapid, Sensitive, and Comprehensive Detection of Intraocular Pathogens

PURPOSE

Intraocular infections are sight-threatening conditions that can lead to vision loss. Rapid identification of the etiologies plays a key role in early initiation of effective therapy to save vision. However, current diagnostic modalities are time consuming and lack sensitivity and inclusiveness. We present here a newly developed comprehensive ocular panel designed to improve diagnostic yields and provide a tool for rapid and sensitive pathogen detection.

DESIGN

Experimental laboratory investigation.

METHODS

A panel containing 46 pathogens and 2 resistance/virulence markers that are commonly detected in intraocular infections was developed. Genomic targets were scrutinized for stretches predicted to be specific for a particular species while being conserved across different strains. A set of primers for sample enrichment, and two 50mer NanoString compatible probes were then designed for each target. Probe-target hybrids were detected and quantified using the NanoString nCounter SPRINT Profiler. Diagnostic feasibility was assessed in a pilot clinical study testing samples from infectious retinitis (n = 15) and endophthalmitis (n = 12) patients, for which the etiologies were confirmed by polymerase chain reaction (PCR) or culture.

RESULTS

Analytical studies demonstrated highly sensitive detection of a broad spectrum of pathogens, including bacteria, viruses, and parasites, with limits of detection being as low as 2.5 femtograms per reaction. We also found excellent target specificity, with minimal cross-reactivity detected. The custom-designed NanoString ocular panel correctly identified the causative agent from all clinical specimens positive for a variety of pathogens.

CONCLUSION

This highly multiplexed panel for pathogen detection offers a sensitive, comprehensive, and uniform assay run directly on ocular fluids that could significantly improve diagnostics of sight-threatening intraocular infections.

The Diagnostic Value of Triggering Receptor Expressed on Myeloid Cells-1 in Post-Traumatic Bacterial Endophthalmitis

Purpose

To determine whether soluble-triggering receptor expressed on myeloid cells-1 (sTREM-1) could serve as a reliable diagnostic biomarker of post-traumatic bacterial endophthalmitis (PTBE).

Methods

Thirty-two patients (32 eyes) clinically diagnosed having PTBE were further divided into a culture-positive (CP) group and a culture-negative (CN) group. Sixty-two patients (62 eyes) without traumatic endophthalmic infection were also enrolled. Twenty-one eyes from 11 donors without globe ocular injuries were included as control group. Vitreous sTREM-1 levels were detected by ELISA. The expression and tissue distribution of TREM-1 were revealed by immunohistochemistry. The diagnostic value of sTREM-1 was determined by receiver operating characteristic curve (ROC). The correlation between sTREM-1 concentration and final best-corrected visual acuity (FBCVA) and Peyman endophthalmitis score (PES) were also assessed.

Results

The vitreous sTREM-1 level in the PTBE group was higher than that in noninfected group and control group (P < 0.05). No remarkable difference was found between the CP group and the CN group in vitreous sTREM-1 levels (P > 0.05). No remarkable difference was found between the noninfected group and the control group (P > 0.05). No remarkable difference in TREM-1 level was found before and after intravitreal antibiotics (P > 0.05). TREM-1 was selectively highly expressed on the surface of cell membrane of neutrophils and monocytes/macrophages infiltrated in vitreous and uveal of the PTBE group. The area under the ROC curve (AUC) was 0.79 (>0.75), with a medium diagnostic efficiency. The sensitivity and specificity of sTREM-1 to differentiate PTBE from the noninfected intraocular condition were 62.50% and 86.25% separately. A cutoff value >524.50 pg/mL for sTREM-1 was predicted to be PTBE. Vitreous sTREM-1 levels in PTBE group were positively correlated with PES (r = 0.428, P < 0.05). However, sTREM-1 levels and FBCVA did not significantly correlate with one another (P > 0.05).

Conclusions

The sTREM-1 was a promising diagnostic biomarker of PTBE, especially CN-PTBE. Vitreous sTREM-1 levels were linked with intraocular inflammation levels and severity of PTBE.

Proteomic landscape of extracellular vesicles in human retinal cells infected with Staphylococcus aureus and Pseudomonas aeruginosa: Role in endophthalmitis

Extracellular Vesicles (EVs) have evolved as a promising entity for developing diagnostic and therapeutic biomarkers. We profiled global EV proteome of EVs from Human retinal cells (ARPE-19) infected with S. aureus and P. aeruginosa. EVs were isolated by ultracentrifugation and subjected to LC-MS/MS for proteome analysis. In S. aureus infection, sequest identified 864 proteins, of which 81 were differentially expressed in comparison to control. Similarly, in P. aeruginosa infection, of 516 proteins identified, 86 were differentially expressed. Additionally, 38 proteins were exclusive to infected sets. KEGG and Gene Ontology revealed crucial dysregulated pathways involving proteins such as complement cascades, annexins and calpain-2, all playing major role in the pathogenesis of the disease. This study provides insight into the global EV proteome of S. aureus and P. aeruginosa endophthalmitis with their functional correlation and distinctive pattern of expression. Calpain-2 and C8a are attractive biomarkers for bacterial endophthalmitis.

Recent Advances and Ongoing Challenges in the Diagnosis of Culture Negative Endophthalmitis

BACKGROUND

Culture negative (CN) but presumed infectious endophthalmitis poses a huge diagnostic challenge in terms of clinical management. This article outlines the current state of knowledge of infectious endophthalmitis with negative cultures and summarizes the recommendations for the work up of this condition along with providing a simple algorithm, by putting into context the recent concerns about over-diagnosing endophthalmitis.

METHODS

We searched the PubMed and Scopus databases for large hospital based studies on diagnosis of endophthalmitis, with emphasis on culture-negative infections in October 2021. Only clinical studies written in English were included. Basic science studies, letters to the editor and case reports on endophthalmitis were excluded.

RESULTS

Twenty studies were included in this study. The prevalence of CN endophthalmitis ranged from 40% to 70%. Recent advances in PCR along with high throughput sequencing have helped identify the etiological agent in most cases but these technologies are not easily available, requires advanced bioinformatic analysis and are not cost effective. Role of other inflammatory and relatively low-cost biomarkers in diagnosing a presumed infection is yet to be validated clinically but hold promise in helping ophthalmologists identify the causative agent.

CONCLUSIONS

CN endophthalmitis is a relatively frequent finding and should not be labelled as sterile endophthalmitis. Recent advances provide a new perspective for ophthalmologist in diagnosis of presumed infectious endophthalmitis and further studies are needed to confirm their utility in clinical settings.

A Rare Case of Fulminant Acute Postoperative Morganella morganii Endophthalmitis

PURPOSE

The authors present a case of a 60-year-old Indian female presented with sudden loss of vision in the right eye three days after an uneventful cataract surgery which revealed a rare organism and which was treated successfully.

METHODS

She was diagnosed with acute postoperative endophthalmitis with fulminant disease and on further work up, culture showed Morganella morganii (gram negative bacilli).

RESULTS

She was successfully treated with intravitreal imipenem, dexamethasone and vitrectomy. A review of literature was conducted to identify and discuss additional reports on similar cases. As per PubMed search with keywords "Morganella morganii endophthalmitis" this is the best achieved visual outcome to date in a case of acute post-operative Morganella morganii endophthalmitis.

CONCLUSION

Intravitreal imipenem can be considered to treat Morganella morganii endophthalmitis. Aggressive treatment in these patients can help in improving visual outcome.

Endophthalmitis in children with open eye injury: epidemiology, risk factors, treatment

The article provides an overview of endophthalmitis cases in children with open eye injury — prevalence, causes and treatment results in Great Britain, USA, China, India, Vietnam, Saudi Arabia, and other countries with different healthcare facilities, lifestyle and traditions.

The landscape of bacterial antibiotic susceptibility in a multi-tier ophthalmology network in India: an electronic medical record driven analytics report

Introduction. Injudicious use of antibiotics often leads to antibiotic resistance which contributes to significant morbidity and mortality. Knowledge of local antibiogram is important in informing appropriate empiric antimicrobial therapy.

Hypothesis / Gap. It is the first and largest study that examines bacterial isolates from multiple ocular infections across South India and provides a overview of susceptibility patterns for each individual bacteria in the detailed interactive dashboard.

Aim. To study the landscape of bacterial antibiotic susceptibility patterns of ocular infections in patients undergoing microbiological investigations across a multi-tier ophthalmology network in India.

Methodology. This cross-sectional hospital-based study included 15 822 patients in whom microbiology samples were analysed between September 2013 and December 2021. Ocular tissue of patients in whom a microbiology sample was processed in at least one eye were included as cases. The data were collected using an indigenously developed electronic medical record (EMR) system.

Results. Among the 15 822 patients, bacteria (51.06 %) was the most common aetiology, followed by fungus (38.27 %). The majority of the patients were male (68.10 %) and the majority were adults (90.01 %). The most common age group was during the sixth decade with 2914 (18.42 %) patients. The patients were more commonly from the lower socio-economic status (51.61 %) and rural geography (46.82 %). The majority of the specimens sent for microbiological analysis were corneal scraping (68.61 %). Gram-positive cocci and Gram-positive bacilli were most sensitive towards vancomycin (86.83 and 92.89% respectively) followed by cefazolin (80.88 %) and amikacin, while Gram-negative bacilli were most sensitive towards ofloxacin (65.24%).

Conclusion. The most common aetiology of infection in ocular disease is bacterial and the majority of the patients presented from the rural geography and from lower socio-economic status. While vancomycin continues to be the drug of choice for Gram-positive organisms, increasing resistance to fluoroquinolones and ceftazidime was observed. Adoption of this model will enable access to antimicrobial susceptibility data, leading to reliable decisions and better clinical outcomes.

Proteome profiling of Extracellular Vesicles in Pseudomonas aeruginosa endophthalmitis: Prognostic and therapeutic significance in a mouse model

Endophthalmitis is a sight-threatening infection and a serious consequence of complications during intraocular surgery or penetrating injury of which Pseudomonas aeruginosa is an important etiology. Extracellular vesicles (EVs) have evolved as a promising entity for developing diagnostic and therapeutic biomarkers due to their involvement in intracellular communication and pathogenesis of diseases. We aimed to characterise the protein cargo of extracellular vesicles, isolated from a murine (C57BL/6) model of P. aeruginosa endophthalmitis by LC-MS/MS at 24 h post infection (p.i). EVs were extracted by ultracentrifugation, characterized by Dynamic Light Scattering (DLS) and western blotting with tetraspannin markers, CD9 and CD81 and quantified by the ExoCet quantification kit. Multiplex ELISA was performed to estimate the levels of TNF-α, IL-6, IFN-γ and IL-1β. Proteomic analysis identified 2010 proteins (FDR ≤0.01) in EVs from infected mice eyes, of which 137 were differentially expressed (P-value ≤ 0.05). A total of 101 proteins were upregulated and 36 were downregulated. Additionally, 43 proteins were exclusive to infection set. KEGG and Gene Ontology revealed, Focal adhesion, Phagosome pathway, Complement cascade and IL-17 signalling pathway are crucial upregulated pathways involving proteins such as Tenascin, caveolin 1, caveolin 2, glutamine synthetase, microtubule-associated protein, C1, C8 and IL-17. Tenascin and caveolins are known to suppress anti-inflammatory cytokines further exacerbating the disease. The result of this study provides insight into the global extracellular vesicle proteome of P. aeruginosa endophthalmitis with their functional correlation and distinctive pattern of expression and tenascin, caveolin 1 and caveolin 2 are attractive biomarkers for P. aeruginosa endophthalmitis.

Aspergillus Endophthalmitis: Epidemiology, Pathobiology, and Current Treatments

Fungal endophthalmitis is one of the leading causes of vision loss worldwide. Post-operative and traumatic injuries are major contributing factors resulting in ocular fungal infections in healthy and, more importantly, immunocompromised individuals. Among the fungal pathogens, the Aspergillus species, Aspergillus fumigatus, continues to be more prevalent in fungal endophthalmitis patients. However, due to overlapping clinical symptoms with other endophthalmitis etiology, fungal endophthalmitis pose a challenge in its diagnosis and treatment. Hence, it is critical to understand its pathobiology to develop and deploy proper therapeutic interventions for combating Aspergillus infections. This review highlights the different modes of Aspergillus transmission and the host immune response during endophthalmitis. Additionally, we discuss recent advancements in the diagnosis of fungal endophthalmitis. Finally, we comprehensively summarize various antifungal regimens and surgical options for the treatment of Aspergillus endophthalmitis.

Validation of a multi-species-specific PCR panel to diagnose patients with suspected postoperative bacterial endophthalmitis

INTRODUCTION

Currently, patients suspected of endophthalmitis are referred to a tertiary centre for a vitreous biopsy and bacterial culture, thereby causing a treatment delay for the intravitreal antibiotics injection. We developed a new diagnostic tool, multi-mono-PCR (mm-PCR), not requiring viable bacteria, allowing antibiotic injection without delay. Performance of mm-PCR was tested on biopsies from patients with suspected postoperative endophthalmitis with known bacterial culture results.

METHODS

Most frequently occurring pathogens in endophthalmitis were determined using published data and treatment logs of endophthalmitis patient of the Rotterdam Eye Hospital. Vitreous biopsies from patients with suspected endophthalmitis were aliquoted in two parts. One part was sent out for bacterial culture and another was stored at -80°C for mm-PCR analysis and, as a backup, also by panbacterial PCR. Twelve vitreous samples from patients not suspected of having endophthalmitis were added as control samples.

RESULTS

Concordancy between bacterial culture and mm-PCR was 89% (24 of 27). All twelve control samples were negative. In three nonconcordant samples, the PCR results were most likely the correct ones.

CONCLUSION

mm-PCR results are highly concordant with bacterial culture. mm-PCR with panbacterial PCR as backup could be considered a diagnostic tool in patients with endophthalmitis, which would allow us to reverse the order of diagnosis and treatment while maintaining diagnostic surveillance, thereby preventing treatment delay.

Evaluation of Vitreous Galactomannan and (1, 3) β-D-Glucan Levels in the Diagnosis of Fungal Endophthalmitis in Southern India

PURPOSE

To evaluate vitreous Galactomannan(GM) and 1,3 β-D-Glucan (BDG) levels in the diagnosis of fungal endophthalmitis, with emphasis on culture-negative cases.

METHODS

Vitreous from 31 clinically suspected fungal endophthalmitis patients and 11 controls were evaluated for GM and BDG using ELISA Kits. The Receiver Operating Characteristic (ROC) curves and diagnostic significance was calculated.

RESULTS

The median vitreous GM in culture-positive (60.83pg/ml) and culture-negative (59.9pg/ml) samples were higher than the (51.2pg/ml) control group. The median vitreous BDG in culture-positive (1.47pg/ml) and culture-negative (1.52pg/ml) samples were also similar, and higher than the control group (1.18pg/ml). ROC analysis showed that at a cut-off of 51.35pg/ml, the sensitivity and specificity for GM were 0.88 and 0.73.Similarly, for BDG at a cut-off of 1.18pg/ml, the sensitivity and specificity were 0.94 and 0.82 respectively.

CONCLUSION

Vitreous GM and BDG above the indicated threshold level could suggest a fungal infection, even when cultures are negative.

Microbiological profile and antibiotic susceptibility trends in orbital cellulitis in India: an analysis over 15 years

PURPOSE

To report the microbiologic profile and antibiotic susceptibility trends in orbital cellulitis.

METHODS

Retrospective review of microbiology records of orbital cellulitis between 2005 and 2019. Orbital pus or conjunctival swab underwent culture for bacteria and fungi and antibiotic susceptibility testing for bacterial isolates. The microbiological profile and trends in antibiotic susceptibility were analyzed over the three study periods: 2005-2009, 2010-2014, and 2015-2019.

RESULTS

Of the 203 patient samples, 189 (93%) were orbital pus samples, and 146 (72%) were culture positive. Organisms included bacteria (167/203, 82.3%), fungi (13/203, 6.4%), and mixed infection (25/203, 10.3%). Among bacteria, 79% were gram positive, with Staphylococcus aureus and Streptococcus species being commonest, and 21% were gram negative, with Pseudomonas aeruginosa and Enterobacteriaceae group being the commonest. Aspergillus flavus was the most common fungus isolated. Trend analysis revealed no change in the number of sterile cases and fungal cellulitis. Increase in gram positive bacteria was statistically significant (p = .0002) between 2005-2009 and 2015-2019. The increase in gram negative bacteria was statistically significant (p = .047) between all three time periods. Susceptibility patterns showed increasing trend of resistance to fluoroquinolones, that reached statistical significance for Ciprofloxacin, Moxifloxacin and Gatifloxacin (p < .05). Sterile sample was not found in any of the pediatric (0-16 years) cases (n = 55), compared to 28% in adults.

CONCLUSION

There was a significant rise in gram positive and negative orbital infections over the 15 year period, with increased resistance to fluoroquinolones. Fungal cellulitis and sterile samples showed a steady trend. Orbital aspirate provides accurate detection of the causative organism.

Susceptibility of bacterial endophthalmitis isolates to vancomycin, ceftazidime, and amikacin

Bacterial endophthalmitis is a rare intraocular infection, and prompt administration of intravitreal antibiotics is crucial for preventing severe vision loss. The retrospective study is to investigate the in vitro susceptibility to the antibiotics vancomycin, amikacin, and ceftazidime of bacterial endophthalmitis isolates in specimens at a tertiary referral center from January 1996 to April 2019 in Taiwan. Overall, 450 (49.9%) isolates were Gram positive, 447 (49.6%) were Gram negative, and 4 (0.4%) were Gram variable. In Gram-positive isolates, coagulase-negative staphylococci were the most commonly cultured bacteria (158, 35.1%), followed by Streptococci (100, 22.2%), Enterococci (75, 16.7%), and Staphylococcus aureus (70, 15.6%). In Gram-negative isolates, they were Klebsiella pneumoniae (166, 37.1%) and Pseudomonas aeruginosa (131, 29.3%). All Gram-positive organisms were susceptible to vancomycin, with the exception of one Enterococcus faecium isolate (1/450, 0.2%). Of the Gram-negative isolates, 96.9% and 93.7% were susceptible to ceftazidime and amikacin, respectively. Nine isolates (9/447, 2.0%) were multidrug-resistant Gram-negative bacteria, comprising K. pneumoniae (4/164, 2.4%), Acinetobacter baumannii (2/3, 67%), and Stenotrophomonas maltophilia (3/18, 17%). In conclusion, in vitro susceptibility testing revealed that vancomycin remains the suitable antibiotic treatment for Gram-positive endophthalmitis. Ceftazidime and amikacin provide approximately the same degree of Gram-negative coverage. Multidrug-resistant bacterial endophthalmitis was uncommon.

Differential inflammatory response to Aspergillus flavus and Candida albicans infection in human retinal pigment epithelial cells: Role in treatment of endophthalmitis

OBJECTIVE

Fungal endophthalmitis is an emerging vision-threatening complication in tropical countries and the Retinal pigment epithelial cells (RPE) are said to play a major role in the retinal pathology. The aim of this study was to compare the immune response of Retinal pigment epithelial cells (RPE) challenged with A. flavus and C. albicans strains, isolated from patients with fungal endophthalmitis.

MATERIAL AND METHODS

Retinal Pigment epithelial cells (ARPE-19) cells were infected with A. flavus and C. albicans, and gene expression were assessed for TLRs, immune-mediators, and matrix metalloproteinases (MMPs).

RESULTS

We observed a time-dependent gene expression of TLRs (TLR-2,-7 and -9); IL-8 and TNF-α in RPE cells challenged with A. flavus and C. albicans. Additonally, IL-6 (3.3 fold), IL-10 (15.2 fold), and IL-17 (5.6 fold) were significantly up-regulated only in cells infected with A. flavus. Additionally, MMP-9 gene expression was up-regulated in both A.flavus as well as C.albicans infected cells, while MMP- 2 gene expression was induced only in cells infected with C.albicans. A total of 9 upregulated differential expression of genes (DEGs) in A. flavus infected cells and 7 DEGs in C. albicans infected cells were used to construct Protein-protein interaction (PPI) network.

CONCLUSION

RPE cells induced a differential innate immune response depending on fungal species involved (A.flavus and C.albicans) and may provide clues for novel treatment targets and better prognosis.

Microbes of the human eye: Microbiome, antimicrobial resistance and biofilm formation

BACKGROUND

The review focuses on the bacteria associated with the human eye using the dual approach of detecting cultivable bacteria and the total microbiome using next generation sequencing. The purpose of this review was to highlight the connection between antimicrobial resistance and biofilm formation in ocular bacteria.

METHODS

Pubmed was used as the source to catalogue culturable bacteria and ocular microbiomes associated with the normal eyes and those with ocular diseases, to ascertain the emergence of anti-microbial resistance with special reference to biofilm formation.

RESULTS

This review highlights the genetic strategies used by microorganisms to evade the lethal effects of anti-microbial agents by tracing the connections between candidate genes and biofilm formation.

CONCLUSION

The eye has its own microbiome which needs to be extensively studied under different physiological conditions; data on eye microbiomes of people from different ethnicities, geographical regions etc. are also needed to understand how these microbiomes affect ocular health.

In Vitro Antimicrobial Activity of Quinolones Against Major Bacterial Isolates from the Ocular Surface Bacterial Flora of Tertiary Hospital Patients in Japan

Purpose: To determine the in vitro antimicrobial activity of quinolones against major bacterial isolates from the ocular surface bacterial flora of patients in a tertiary hospital for selection of optimal antibiotic eye drop during the perioperative stage. Methods: The conjunctival sac scraping of 933 patients who underwent ophthalmic surgery was cultivated and bacterial species of the isolates were identified. The minimum inhibitory concentrations (MICs) of gatifloxacin (GFLX), moxifloxacin (MFLX), levofloxacin (LVFX), and tosufloxacin (TFLX) were measured by microdilution methods. The cumulative percentages of MICs of 4 quinolones against major bacteria were calculated. The concentrations of quinolones inhibiting 50% (MIC₅₀) and 90% (MIC₉₀) of the major bacteria were compared. Results: The study mainly included 784 patients scheduled for cataract surgery, 73 for vitrectomy, 30 for corneal transplantation, 30 for conjunctival surgery, 11 for eyelid surgery. The most frequently isolated bacterium was coagulase-negative Staphylococci (CNS) (184 strains), followed by Corynebacterium (107 strains), Staphylococcus aureus (33 strains), Streptococcus (18 strains), and Enterococcus (13 strains). The percentages of methicillin-sensitive CNS isolates for which MIC of GFLX, MFLX, LVFX, and TFLX was 0.06 μg/mL or less were 8.0%, 13.4%, 5.4%, and 63.4%, respectively. Similarly, the percentage for Corynebacterium was 23.0%, 23.0%, 0%, and 35.6%, respectively. MIC₅₀ of TFLX for Streptococcus and Enterococcus showed the lowest values, 0.12 and 0.25 μg/mL, respectively. Conclusions: Among 4 quinolones, TFLX has the highest in vitro antimicrobial activity against major bacterial isolates from the ocular surface bacterial flora of patients in a tertiary hospital.

Foveal cone count reduction in resolved endophthalmitis: an adaptive optics scanning laser ophthalmoscopy (AO-SLO)-based prospective pilot study

AIM

To report the foveal cone count in eyes with resolved endophthalmitis vis-à-vis normal fellow eyes using an indigenous adaptive optics scanning laser ophthalmoscopy (AO-SLO).

METHODS

In a prospective cross-sectional comparative pilot study, we recruited patients with resolved endophthalmitis in one eye (study eye) and a normal fellow eye (control eye). Collected data included measurement of the best-corrected visual acuity (BCVA), spectral-domain optical coherence tomography (OCT) imaging and AO-SLO imaging and cone counting at the fovea in both eyes.

RESULTS

The study included 12 eyes of 6 patients. The mean age was 51.66±11.97 years (median 56 years). BCVA in all control eyes was 20/20 (logarithm of the minimum angle of resolution (LogMAR) 0), and in the study, eyes was 0.21±0.13 (median 0.19, Snellen 20/30; p=0.001; 95% CI -0.39 to -0.09). The follow-up was 18.66±12.32 (median 20 months). The cone count at the fovea in the control eye was 4356.33±1993.93 (median 4498), and in the study eye, it was 2357.16±1541.17 (median 2187.5; p=0.03; 95% CI -3556 to -1082).

CONCLUSIONS

Eyes with resolved endophthalmitis with near-normal vision have reduced number of foveal cones even in absence of OCT-detected gross structural changes.

TRANSLATIONAL RELEVANCE

The current work describes the application of cellular-level imaging technique called adaptive optics scanning laser ophthalmoscopy (AO-SLO) to the clinical condition of resolved endophthalmitis. The study of retinal cell biology at the cellular level is possible using the emerging technology of AO-SLO. This new investigative modality that has the potential to image the retina at the cellular level until the photoreceptors is more likely to unravel the pathophysiology of a variety of retinal diseases.

Microglial Response to Aspergillus flavus and Candida albicans: Implications in Endophthalmitis

Aspergillus flavus is the most common etiology of fungal endophthalmitis in India, while Candida albicans is the causative agent in the West. In this study, we determined the role of microglial cells in evoking an inflammatory response following an infection with A. flavus and C. albicans strains isolated from patients with endophthalmitis. Microglia (CHME-3) cells were infected with A. flavus and C. albicans and the expression of Toll-Like Receptors (TLRs), cytokines and Matrix metalloproteinases (MMPs) were assessed at various time intervals. A. flavus infected cells induced higher expressions of TLR-1, -2, -5, -6, -7 and -9 and cytokines such as IL-1α, IL-6, IL-8, IL-10 and IL-17. In contrast, C. albicans infected microglia induced only TLR-2 along with the downregulation of IL-10 and IL-17. The expression of MMP-9 (Matrix metalloproteinase-9) was however upregulated in both A. flavus and C. albicans infected microglia. These results indicate that microglial cells have the ability to incite an innate response towards endophthalmitis causing fungal pathogens via TLRs and inflammatory mediators. Moreover, our study highlights the differential responses of microglia towards yeast vs. filamentous fungi.

Evaluation of Susceptibility and Innate Immune Response in C57BL/6 and BALB/c Mice During Candida albicans Endophthalmitis

Purpose

Candida remains the leading cause of fungal endophthalmitis. However, the pathobiology and innate immune responses in this disease are not well characterized. Here, we developed two murine models of candida endophthalmitis and evaluated their disease susceptibility and differential immune response.

Methods

Endophthalmitis was induced in C57BL/6 (B6) and BALB/c mice by intravitreal injection of Candida albicans (CA). Disease progression was monitored by slit-lamp examination and clinical scoring, followed by retinal function assessment using electroretinography (ERG). Enucleated eyes were used to estimate fungal burden and retinal tissue damage by hematoxylin and eosin and TUNEL staining. The level of inflammatory mediators were determined by quantitative Polymerase Chain Reaction (qPCR) and enzyme-linked immunosorbent assay, whereas neutrophil infiltration was assessed by flow cytometry and immunostaining.

Results

Intravitreal injection of CA at 6500 colony-forming units resulted in sustained (non-resolving) ocular inflammation in both B6 and BALB/c mice as evidenced by increased levels of inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, and interleukin-6) and chemokine (CXCL2/MIP-2). In both mouse strains, fungal burden peaked at 24 to 48 hours post-infection (hpi) and decreased by 72 to 96 hpi. CA-infected eyes exhibited increased polymorphonuclear neutrophils (PMN) infiltration and retinal tissue damage. Overall retinal function declined rapidly, with a significant reduction in ERG response at 12 hpi and near-total loss by 24 hpi. Differential analyses revealed increased pathology in BALB/c versus B6 mice.

Conclusions

C. albicans was able to cause endophthalmitis in mice. Although BALB/c mice were found to be more susceptible to CA endophthalmitis, both BALB/c and B6 models could be used to study fungal endophthalmitis and test therapeutic modalities.

Etiology, microbiological isolates, and antibiotic susceptibilities in culture-proven pediatric endophthalmitis: a 9-year review

Purpose

To analyze the etiology, microbiological isolates, and antibiotic susceptibilities of endophthalmitis in pediatric patients.

Methods

Patients aged < 18 years with culture-positive endophthalmitis in Zhongshan Ophthalmic Center between January 2010 and December 2018 were included retrospectively.

Results

A total of 127 patients (127 eyes) were included, and 108 (85%) had posttraumatic endophthalmitis. Streptococcus (21.4%), coagulase-negative Staphylococcus (14.5%), Aspergillus (6.9%), and Bacillus cereus (5.3%) were the common organisms. The proportion of Streptococcus decreased with age (40.0% in 0–3 years, 16.3% in 4–12 years, and 6.3% in 13–17 years), while coagulase-negative Staphylococcus increased from 5.7% to 18.8%. Overall, fluoroquinolones achieved the highest antibiotic susceptibility rate (> 95%), while the susceptibility of isolated bacteria to tobramycin and cefazolin was only 60.2% and 59.4%, respectively. The susceptibility rates of Gram-positive cocci to cephalosporins were nearly 90%. For Gram-negative bacilli, susceptibility to neomycin was 91.3%.

Conclusion

Trauma was the main etiology for pediatric endophthalmitis. Although Streptococcus was the most prevalent organism in general, the dominant pathogen varied with age, which merits clinical attention. Fluoroquinolones showed the highest antibiotic efficacy; however, commonly used antibiotics tobramycin and cefazolin showed relatively low antibiotic susceptibility. Thus, antibiotic resistance in pediatric populations merits clinical attention.

Fungal endophthalmitis: A 20-year experience at a tertiary referral centre

IMPORTANCE

Fungal endophthalmitis is an uncommon and serious intraocular infection, often with poor outcomes. This study examines the trend in this disease over 20 years, to inform clinician decision-making and optimize patient outcomes.

BACKGROUND

Due to infrequent presentation of fungal endophthalmitis, there is limited understanding to formulate a standardized approach to management.

DESIGN

A prospective case series over the period January 1, 1999 to December 31, 2018.

PARTICIPANTS

Patients with clinically diagnosed fungal endophthalmitis managed at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia.

METHODS

Review of the Victorian Endophthalmitis Registry for endophthalmitis episode of each patient.

MAIN OUTCOME MEASURES

Patient demographics, co-morbidities, visual acuity (VA) at presentation, aetiology, treatment, microbiology results and final VA outcome.

RESULTS

Eighty-four cases of fungal endophthalmitis were identified over the study period with a median age of 43.5 years [IQR 30.8-63.0]. Then, 65.5% (n = 55) of patients were male; 81.0% (n = 68) of these cases were secondary to endogenous causes, of which 55.9% were associated with intravenous drug use (IVDU). Among the exogenous causes, penetrating eye injury (56.3%) was the most common aetiological factor. Thirty-nine patients (46.4%) grew Candida species from ocular fluid specimens, all of which were sensitive to fluconazole.

CONCLUSION AND RELEVANCE

Our case series provides important insights into fungal endophthalmitis-a high degree of suspicion for fungal endophthalmitis in patients with history of IVDU, and relatively good outlook for vision when Candida is the causative organism. This should allow institutions to implement a standardized management strategy based on evidence.

Clinical Presentations and Comparative Outcomes of Delayed-Onset Low-Grade Endophthalmitis Managed with or Without Intraocular Lens Explantation

Purpose

To compare the outcomes of delayed-onset low-grade endophthalmitis managed with and without intraocular lens (IOL) explantation.

Setting

Tertiary eye-care research institute in southern India.

Design

Retrospective comparative case series.

Methods

The study included all cases of post-cataract surgery delayed-onset endophthalmitis from January 1990 to January 2019. Time to endophthalmitis, duration of symptoms, presenting visual acuity, time to IOL explantation when performed, resolution after explantation, number of intravitreal injections, and final visual acuity were compared in the IOL non-explanted and IOL explanted groups.

Results

There were 115 eyes – 61 eyes in the IOL non-explant and 54 eyes in the IOL explant group. Between the two groups there was no statistically significant difference in age (58.37 ± 14.05 and 56.04 ± 14.96 years, respectively; p=0.35), vision at presentation (>20/400 in 29.5% and 29.6% eyes, respectively; p=0.98), and the duration of follow-up (14.38 ± 16.05, median 8.5 months and 7.06 ± 3.55, median 6 months respectively; p=0.43). There was a statistically significant difference between the IOL non-explant and IOL-explant groups in the time to resolution of inflammation (92.70 ± 36.28 and 45.33±11.2 days, respectively; p <0.0001) and the number of intravitreal injections (4.57 ± 0.75, median 5 and 2.79±2.11, median 2 respectively, p=0.005). Persistent/recurrent inflammation at 6 months was recorded in 18.03% and 5.55% in the IOL non-explant and IOL explant eyes, respectively (p=0.04). Favorable functional outcome was seen in 50.81% vs 68.51% in IOL non-explant and explant eyes, respectively (p=0.05).

Conclusion

IOL explantation in delayed-onset endophthalmitis helps in earlier resolution of inflammation, need for lesser number of intravitreal injections and a trend towards better functional outcomes.

Nine-Year Analysis of Isolated Pathogens and Antibiotic Susceptibilities of Infectious Endophthalmitis from a Large Referral Eye Center in Southern China

Purpose

To analyze the pathogen spectrum of isolated pathogens and antibiotic susceptibility trends of infectious endophthalmitis over 9 years from a large referral eye center in southern China.

Methods

Data from all inpatients who were clinically diagnosed with infectious endophthalmitis and underwent microbiological evaluation at the Zhongshan Ophthalmic Center from January 2010 to December 2018 were collected retrospectively and analyzed according to different clinical etiologies.

Results

A total of 816 cases were collected in the study. Open-globe injuries had caused 473 (57.97%) cases, 70 (8.58%) cases presented endophthalmitis after infectious keratitis, 156 (19.12%) cases were postoperative, and endogenous causes accounted for 117 (14.34%) cases. Among the 309 culture-positive cases, the predominant pathogen for both postoperative and posttraumatic endophthalmitis was gram-positive cocci (59.52% and 49.72%, respectively). Regarding keratitis-related endophthalmitis, the main pathogens were filamentous fungi (57.58%) and gram-negative bacilli (30.30%). The pathogens of endogenous endophthalmitis were almost evenly distributed among gram-positive cocci, gram-negative bacilli, and fungi. Eighty-five (10.42%) cases underwent evisceration/enucleation, including 42 cases secondary to keratitis-related endophthalmitis. The incidence of evisceration/enucleation was much higher in keratitis-related endophthalmitis than the total endophthalmitis population (χ² =123.61, P<0.001). Overall bacteria showed high susceptibility to fluoroquinolones (75.36–100.00%). Gram-positive cocci showed much higher sensitivity to cephalosporins compared to gram-negative bacilli (85.11–92.59% vs 25.42–35.72%). For the five first-line antibiotics analyzed for time trend of susceptibility, four exhibited a significant decrease of susceptibility from 2010–2014 to 2015–2018.

Conclusion

Between 2010 and 2018, posttraumatic endophthalmitis was the most common form of the treated endophthalmitis in Zhongshan Ophthalmic Center. The causative pathogens varied according to different clinical settings. Even though the overall antibiotic susceptibilities were fairly high, we observed a substantial decrease of susceptibility for most first-line antibiotics.

Vitreous D-Lactate Levels as a Biomarker in the Diagnosis of Presumed Infectious Culture Negative Endophthalmitis

Purpose: Microbiological investigations of vitreous fluid have often failed to detect the causative agent in infectious endophthalmitis resulting in a clinical dilemma. D-Lactate is a byproduct of bacterial metabolism, and its accumulation in sterile body fluids indicates bacterial infection. The aim of the study was to evaluate the measurement of vitreous fluid D-lactate for the diagnosis of infectious endophthalmitis and to define an optimal D-lactate concentration for the differentiation from non-infectious samples.Methods: Vitreous samples of 41 patients clinically diagnosed as endophthalmitis and 20 patients with non-infectious disorders, as controls, between October 2018 and February 2019 were included in the study. D-lactate levels were determined by a D-lactate colorimetric assay kit (MAK058 Sigma-Aldrich) and the receiver operating characteristic curves (ROC) of D-lactate were calculated. The clinical finding of D-lactate production in bacterial endophthalmitis was also verified in a mouse model of bacterial endophthalmitis.Results: Of the 41 patients included in the infectious group, 25 had culture-positive infections of which 13/25 were gram-positive organisms and 12/25 grew gram-negative bacilli. Based on the ROC curve, the sensitivity of D-lactate was found to be 80% and specificity 100% and a cut-off value of above 47.06 ng/µl for D-lactate was defined as positive or true infectious in vitreous samples for diagnosis of endophthalmitis. In-vivo, a mouse model of bacterial endophthalmitis showed the significant production of D-lactate levels in retina and vitreous. Interestingly the levels were elevated in Gram-negative infections compared to Gram-positive bacterial endophthalmitis.Conclusion: Our clinical and in-vivo mouse model data showed that vitreous fluid D-lactate could be used as a bacterial-specific biomarker in the diagnosis of most infectious endophthalmitis and could be implemented for the evaluation of treatment success.

Pathobiology of Aspergillus Fumigatus Endophthalmitis in Immunocompetent and Immunocompromised Mice

Despite Aspergillus being the leading cause of exogenous fungal endophthalmitis following traumatic injury to the eye, its pathogenesis is not fully understood. In the current study, we developed a murine model of Aspergillus fumigatus (AF) endophthalmitis and investigated the disease pathobiology. Endophthalmitis was induced by intravitreal injection of Aspergillus spores in immunocompetent and immunocompromised (neutropenic) C57BL/6 mice, and disease severity was assessed by eye exam, fungal burden estimation, and histological examination. Our data showed that AF infection caused a time-dependent increase in corneal haze, opacity, and hypopyon beginning at two days post-infection (DPI). The fungal burden in infected eyes of immunocompetent mice peaked at 2 DPI and declined over 9 DPI. AF-infected neuroretina exhibited induction of innate immune response via upregulation of Toll-like receptors (TLRs) and inflammatory mediators (TNFα, IL-1β, and IL6), and increased polymorphonuclear neutrophil (PMN) infiltration. Histological analysis revealed heavy cellular infiltrates in the vitreous cavity as well as disruption of normal retinal architecture and increased retinal cell death. Neutropenic mice exhibited severe disease pathology with the prolonged fungal burden and increased inflammatory mediators. Our study described the first immunocompetent murine model of exogenous AF endophthalmitis and demonstrated an important role of neutrophils in innate defense against fungal endophthalmitis.

Invasive Aspergillosis by Aspergillus flavus: Epidemiology, Diagnosis, Antifungal Resistance, and Management

Aspergillus flavus is the second most common etiological agent of invasive aspergillosis (IA) after A. fumigatus. However, most literature describes IA in relation to A. fumigatus or together with other Aspergillus species. Certain differences exist in IA caused by A. flavus and A. fumigatus and studies on A. flavus infections are increasing. Hence, we performed a comprehensive updated review on IA due to A. flavus. A. flavus is the cause of a broad spectrum of human diseases predominantly in Asia, the Middle East, and Africa possibly due to its ability to survive better in hot and arid climatic conditions compared to other Aspergillus spp. Worldwide, ~10% of cases of bronchopulmonary aspergillosis are caused by A. flavus. Outbreaks have usually been associated with construction activities as invasive pulmonary aspergillosis in immunocompromised patients and cutaneous, subcutaneous, and mucosal forms in immunocompetent individuals. Multilocus microsatellite typing is well standardized to differentiate A. flavus isolates into different clades. A. flavus is intrinsically resistant to polyenes. In contrast to A. fumigatus, triazole resistance infrequently occurs in A. flavus and is associated with mutations in the cyp51C gene. Overexpression of efflux pumps in non-wildtype strains lacking mutations in the cyp51 gene can also lead to high voriconazole minimum inhibitory concentrations. Voriconazole remains the drug of choice for treatment, and amphotericin B should be avoided. Primary therapy with echinocandins is not the first choice but the combination with voriconazole or as monotherapy may be used when the azoles and amphotericin B are contraindicated.