CLINICAL UTILITY OF BETA-D-GLUCAN TESTING FOR ENDOGENOUS FUNGAL CHORIORETINITIS OR ENDOPHTHALMITIS

THE CLINICAL VALUE OF β-D-GLUCAN TESTING AND NEXT-GENERATION METAGENOMIC SEQUENCING FOR THE DIAGNOSIS OF FUNGAL ENDOPHTHALMITIS

PURPOSE

To explore the clinical value of β-D-glucan (BDG) testing and metagenomic next-generation sequencing (mNGS) for detecting the pathogens of fungal endophthalmitis (FE).

METHODS

This study included 32 cases (32 eyes) with FE and 20 cases (20 eyes) with intraocular inflammation caused by other etiologies. All patients underwent extraction of aqueous humor or vitreous fluid samples for BDG testing and mNGS. The diagnostic performance and total clinical concordance rate of BDG testing and mNGS for FE were evaluated and calculated based on the results of the clinical diagnosis.

RESULTS

Among the clinically diagnosed FE, the positivity rates of BDG testing and mNGS (90.63%) were both significantly higher ( P < 0.001) than that of microbial cultures (53.13%). There was 100% consistency in pathogen identification using mNGS and culture identification for culture-positive cases. The area under the curve was 0.927 for BDG testing and 0.853 for mNGS. When the two tests were combined, sensitivity (93.75%), specificity (100.00%), and total clinical concordance rate (96.15%) were all improved, compared with the single tests.

CONCLUSION

The positive rates of BDG test and mNGS were markedly higher than those of cultures in FE identification. The combination of these two tests showed improved performance when compared with individual tests.

UTILITY OF OCULAR β- d -GLUCAN TESTING IN PATIENTS WITH FUNGAL ENDOPHTHALMITIS

PURPOSE

To assess the diagnostic utility of (1→3)-β- d -glucan (BDG) in ocular fluid of patients with fungal endophthalmitis.

METHODS

This prospective pilot single-center study evaluated aqueous and vitreous humor BDG levels of suspected fungal endophthalmitis, bacterial endophthalmitis, and noninfectious controls with the standard Fungitell assay and the Fungitell STAT assay. β- d -Glucan levels were compared using generalized linear models followed by post hoc pairwise comparisons.

RESULTS

Seven fungal endophthalmitis, 6 bacterial endophthalmitis, and 17 noninfectious ocular samples were evaluated. Mean aqueous BDG concentrations were 204, 11.0, and 9.6 pg/mL for fungal endophthalmitis, bacterial endophthalmitis, and noninfectious controls, respectively ( P = 0.01, fungal vs. bacterial; P = 0.0005, fungal vs. noninfectious controls). Mean vitreous BDG concentrations were 165, 30.3, and 5.4 pg/mL, respectively ( P = 0.001 for fungal vs. bacterial; P < 0.0001 for fungal vs. noninfectious controls). Mean vitreous BDG index (Fungitell STAT) values were 1.7, 0.4, and 0.3, respectively ( P = 0.001, fungal vs. bacterial; P = 0.0004, fungal vs. noninfectious controls). The Pearson correlation between BDG levels and BDG index was high (correlation coefficient = 0.99, P < 0.001).

CONCLUSION

Significantly elevated ocular BDG levels were found in fungal endophthalmitis compared with bacterial endophthalmitis and noninfectious controls. Our study suggests a potential utility for BDG testing in the diagnosis of fungal endophthalmitis, and a larger study is warranted.

UNUSUAL CASE OF CLADOSPORIUM SPHAEROSPERMUM ENDOGENOUS ENDOPHTHALMITIS DURING GOLIMUMAB THERAPY: CASE REPORT AND LITERATURE REVIEW

PURPOSE

To report a case of fungal endogenous endophthalmitis from Cladosporium sphaerospermum in a patient with juvenile idiopathic arthritis receiving chronic immunosuppressive therapy with golimumab (tumor necrosis factor-α blocker).

METHODS

Case report and review of the literature.

RESULTS

A 34-year-old woman receiving chronic immunosuppressive therapy with golimumab for juvenile idiopathic arthritis was referred for unilateral visual loss and ocular pain. Worsening conditions after corticosteroid therapy and raised serum beta-D-glucan levels pointed to an infectious fungal etiology. Panfungal polymerase chain reaction-based genetic sequencing on vitreous specimens obtained during vitrectomy detected C. sphaerospermum. The patient management combined surgical treatment and systemic and intravitreal voriconazole.

CONCLUSION

Endogenous fungal endophthalmitis can be a rare complication in patients undergoing chronic immunosuppressive therapy (including golimumab) without other predisposing factors. Prompt diagnosis and appropriate treatment are the keys to preserve vision.

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.

VALUABLE APPLICATION OF THE β- d -GLUCAN TESTING OF INTRAOCULAR FLUID FOR THE DIAGNOSIS OF FUNGAL ENDOPHTHALMITIS

PURPOSE

To evaluate the value of the β- d -glucan (BDG) testing of intraocular fluid for the diagnosis of fungal endophthalmitis (FE).

METHODS

Twenty patients (22 eyes) with FE were diagnosed using both culture and nonculture methods. Intraocular fluid was collected for BDG testing, including 22 eyes of FE and 55 eyes of control group. Under different BDG cutoff points as the test-positives, the BDG sensitivity, specificity, positive predictive value, and negative predictive value for FE were analyzed.

RESULTS

The BDG testing value was 1,022.78 ± 1,362.40 pg/mL in the FE group, significantly higher than that of the control group (105.0 ± 180.80 pg/mL, P < 0.001). The area under the receiver operating characteristic (ROC) curve was 0.885 (95% confidence interval, 0.793-0.978; P < 0.001). With the prespecified BDG cutoff 107.83 pg/ml as the test-positive, sensitivity was 81.8%, specificity was 87.5%, and the Youden index was 0.693. When the BDG cutoff was depicted as 202.05 pg/mL, sensitivity reduced to 77.3%, specificity increased at 95.8%, and the Youden index reached the highest value of 0.731.

CONCLUSIONS

β- d -glucan testing of intraocular fluid demonstrated good sensitivity and specificity regarding the diagnosis of FE, which can provide earlier diagnosis to achieve better outcomes.

Incidence of Endogenous Fungal Endophthalmitis in Screening Dilated Exams in Patients with Elevated Beta-D-Glucan Levels versus Positive Fungal Blood Cultures

Purpose

Endogenous endophthalmitis is a severe intraocular infectious condition requiring rapid diagnosis and treatment. This study examines the incidence of fungal endophthalmitis in patients with elevated beta-D-glucan (BG) levels and those with positive blood culture and the utility of ophthalmology consultation in these patients.

Methods

Single center retrospective consecutive cohort study was conducted on patients at Beaumont Health from 2016–2021 who either had positive fungal blood cultures or an elevated BG level.

Results

A total of 147 patients were examined by the ophthalmology department where 30 patients had an elevated BG level and 100 patients had a positive fungal blood culture. Incidence of fungal endophthalmitis was 0% in the elevated BG group and 1.5% in the positive fungal culture group, corresponding to a relative risk ratio of 0.0 (p = 0.31).

Conclusion

BG testing may be useful in diagnosing isolated cases outside the standard screening paradigm, however the data within this study support the conclusion that there is no compelling evidence at this time to add or use BG as a surrogate for endophthalmitis screening. Further studies are required to further elucidate the role of BG in the care of critically ill patients.

The Diagnosis and Treatment of Fungal Endophthalmitis: An Update

In recent, large case series of fungal endophthalmitis (FE) that were published by Asian authors, the most frequent etiologic agents for all types of FE are molds (usually Aspergillus species, while Fusarium is the prevalent etiology in keratitis-related FE). Candida was the organism found in most cases of endogenous FE. However, we must keep in mind that prevalence of fungal species varies with the geographical area. Lately, polymerase chain reaction (PCR) was increasingly used for the diagnosis of FE, allowing for very high diagnostic sensitivity, while the costs become more affordable with time. The most important shortcoming of PCR—the limited number of pathogens that can be simultaneously searched for—may be overcome by newer techniques, such as next-generation sequencing. There are even hopes of searching for genetic sequences that codify resistance to antifungals. We must not forget the potential of simpler tests (such as galactomannan and β-d-glucan) in orienting towards a diagnosis of FE. There are few reports about the use of newer antifungals in FE. Echinocandins have low penetration in the vitreous cavity, and may be of use in cases of fungal chorioretinitis (without vitritis), or injected intravitreally as an off-label, salvage therapy.