Diagnostic Utility of Quantitative Polymerase Chain Reaction versus Culture in Endophthalmitis and Uveitis

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.

Use of Optical Coherence Tomography and Optical Coherence Tomography Angiography in the Diagnosis and Follow-Up of Endogenous Candida Endophthalmitis: A Case Report

Background: Endogenous Candida endophthalmitis (ECE) is a rare but sight-threatening disease. Patients with ECE present with various clinical signs and symptoms, which can complicate the diagnosis. The aim of this report was to demonstrate the outcomes of treatment and to diagnose macular complications caused by intraocular inflammation. Case presentation: A 41-year-old woman with a history of acute intermittent porphyria presented with a progressive vision loss in her left eye. Left-eye OCT revealed findings consistent with a fungal etiology, which was confirmed by the culture of swabs collected from a central vein catheter. The outcomes of intravenous fluconazole treatment were not satisfactory, and the patient developed recurrent attacks of porphyria, suggesting a porphyrogenic effect of systemic antifungal therapy. Repeated intravitreal injections with amphotericin B led to a gradual regression of inflammatory lesions. However, follow-up examinations revealed active macular neovascularization (MNV) on both OCT and OCTA scans. The patient was administered intravitreal bevacizumab. At the 11th month of follow-up, OCT and OCTA scans showed significant inflammatory lesions regression with macula scarring, and no MNV activity was detected. Conclusions: This case highlights the importance of OCT and OCTA as valuable noninvasive imaging techniques for the identification of ECE, the monitoring of its clinical course, and the diagnosis of macular complications.

Application Progress of High-Throughput Sequencing in Ocular Diseases

Ocular diseases affect multiple eye parts and can be caused by pathogenic infections, complications of systemic diseases, genetics, environment, and old age. Understanding the etiology and pathogenesis of eye diseases and improving their diagnosis and treatment are critical for preventing any adverse consequences of these diseases. Recently, the advancement of high-throughput sequencing (HTS) technology has paved wide prospects for identifying the pathogenesis, signaling pathways, and biomarkers involved in eye diseases. Due to the advantages of HTS in nucleic acid sequence recognition, HTS has not only identified several normal ocular surface microorganisms but has also discovered many pathogenic bacteria, fungi, parasites, and viruses associated with eye diseases, including rare pathogens that were previously difficult to identify. At present, HTS can directly sequence RNA, which will promote research on the occurrence, development, and underlying mechanism of eye diseases. Although HTS has certain limitations, including low effectiveness, contamination, and high cost, it is still superior to traditional diagnostic methods for its efficient and comprehensive diagnosis of ocular diseases. This review summarizes the progress of the application of HTS in ocular diseases, intending to explore the pathogenesis of eye diseases and improve their diagnosis.

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.

Endophthalmitis secondary to donor to host infection in posterior lamellar keratoplasties: A systematic review

Donor to host transmission of infectious agents is a well-recognized entity, more commonly related to Endothelial Keratoplasty (EK) than to Penetrating Keratoplasty (PK), that involves complications ranging from interface keratitis to endophthalmitis. A systematic review of the literature was conducted to identify the published articles until December 2020 reporting cases of endophthalmitis secondary to corneal graft contamination in posterior lamellar keratoplasties (DSAEK and DMEK) along with donor characteristics, microbiological profile, treatment and outcomes. Each identified article was assessed to meet donor to host infection criteria, defined as a post-procedural infection in which the same microbiological agent was identified in both the donor corneoscleral rim or preservation medium and receptor ocular tissue. From 23 research articles, eight reports of endophthalmitis in nine patients following DSAEK or DMEK secondary to donor to host infection fulfilled the inclusion criteria. The majority were male and the median age was 72.0 (45.0-81.0) years old. Indications of surgery were primarily pseudophakic bullous keratopathy and Fuchs dystrophy. A fungal pathogen was identified in eight of nine patients. All the cases underwent surgical management with lenticule removal or endothelial plaque aspiration. The final corrected distance visual acuity (CDVA) in all cases was 20/200 or better. Endophthalmitis after an EK procedure is a rare complication whose outcome depends on the aggressive and precocious treatment. Identification of early signs of interface keratitis and lenticule removal seems mandatory in patients undergoing DSAEK or DMEK to prevent further involvement of the globe.

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.

The impact of polymerase chain reaction (PCR) on diagnosis and management of infectious uveitis at a tertiary care facility

BACKGROUND

Polymerase Chain Reaction (PCR) is a well-accepted adjunct in the management of infectious uveitis. In turn, few reports in the literature have evaluated how PCR then impacts patient care. This study aims to evaluate the impact of PCR sampling on diagnosis and treatment of infectious uveitidies at a large tertiary care facility.

MAIN BODY

This is a retrospective, observational study of patients with aqueous and vitreous PCR samples obtained from 2014 to 2019. The study was undertaken at a single institution. At least one follow up visit following results of PCR testing was required for inclusion. If a patient had multiple PCR samples taken, only the first sample was included. The patients were divided into three categories based on pre-sampling diagnosis. A chi-square test was used to analyze the data. 108 cases were available for analysis. PCR did not change diagnosis or management in any of the cases where pre-sampling diagnosis carried a high clinical suspicion for negative PCR. Overall, the results of PCR testing had a more significant impact on diagnosis in those cases where pre-sampling diagnosis was unknown versus those where it was confirmatory in nature, thus presumed to be related to an infectious entity tested by PCR (74% vs. 29%, p = 0.00006). The rate of treatment change based on PCR was similar between those cases where there was a high clinical suspicion for positive PCR and those where pre-sampling diagnosis was unknown (32% vs. 33%, p = 0.95). Further analyzing specimens separately depending on source of sample, this pattern persisted for aqueous samples, with PCR showing a more significant impact on diagnosis in those cases where the diagnosis was unknown versus those where sampling was confirmatory (86% vs. 31%, p = 0.00004). The rate of change in treatment between the two groups was similar (35% vs. 31%, p = 0.79). Vitreous samples followed a similar pattern with a higher rate of diagnosis change for those cases where pre-sampling diagnosis was unknown and a similar rate in treatment change between the two groups, however this did not reach statistical signifigance (44% vs. 25%, p = 0.28; 27% vs. 33%, p = 0.74).

CONCLUSION

There is no well-defined algorithm as to when to employ PCR testing in uveitis. As expected, in our experience, it has the largest impact on diagnosis when the diagnosis is unknown, however even when confirmatory in nature, it continues to impact patient management.

Fungal Endophthalmitis: A Comprehensive Review

Endophthalmitis is a serious ophthalmologic condition involving purulent inflammation of the intraocular spaces. The underlying etiology of infectious endophthalmitis is typically bacterial or fungal. The mechanism of entry into the eye is either exogenous, involving seeding of an infectious source from outside the eye (e.g., trauma or surgical complications), or endogenous, involving transit of an infectious source to the eye via the bloodstream. The most common organism for fungal endophthalmitis is Candida albicans. The most common clinical manifestation of fungal endophthalmitis is vision loss, but other signs of inflammation and infection are frequently present. Fungal endophthalmitis is a clinical diagnosis, which can be supported by vitreous, aqueous, or blood cultures. Treatment involves systemic and intravitreal antifungal medications as well as possible pars plana vitrectomy. In this review, we examine these essential elements of understanding fungal endophthalmitis as a clinically relevant entity, which threatens patients’ vision.

Successful treatment of endogenous endophthalmitis with extensive subretinal abscess: a case report

Background

Endogenous endophthalmitis could lead to a devastating outcome without a prompt and appropriate management. We report a case of advanced endogenous Klebsiella pneumoniae endophthalmitis with extensive subretinal abscess that was successfully treated with a vitrectomy.

Case presentation

A systemically well 61-year-old man complained of ocular pain and visual decrease in his right eye for eighteen days. Ophthalmic examination showed dense inflammation in the anterior chamber and vitreous body. Systemic investigations discovered diabetes and no specific site of systemic infection was found after hospitalization. The inflammation continued to worsen after the intravitreal antibiotic injection. Therefore, a pars plana vitrectomy combined with phacoemulsification was performed. Intraoperatively, a white elevated, fluffy mass with the overlying retinal whitening and necrosis was revealed in superior periphery. In addition to this, extensive retinal hemorrhages and five adjacent subretinal whitish masses with exudative retinal detachment were observed in the posterior pole and inferior quadrants, which were suggestive of extensive subretinal abscess with intense overlying retinal inflammation. The excision of white fluffy mass superiorly was performed without retinotomy and aspiration of extensive subretinal abscess. The polymerase chain reaction of vitreous samples was positive for Klebsiella pneumonia. Intravitreal 2 mg/0.1 ml ceftazidime were repeated. Nine days after the surgery, the inflammation significantly subsided and the retina reattached. The patient was in a stable condition at subsequent visit eight months later.

Conclusion

The delay in an accurate diagnosis and treatment caused extensive subretinal abscess combined with endogenous endophthalmitis. The treatment modality of subretinal abscess is typically individualized to the patient’s presentation. If the retina overlying the abscess is not necrotic, the extensive subretinal abscess can quickly absorbed after vitrectomy, retinotomy with aspiration of the abscess should be avoided to decrease the risk of retinal detachment.