Role of aqueous and vitreous cultures in diagnosing infectious endophthalmitis in rabbits

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.

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.

Diagnostic value of culture results from aqueous tap versus vitreous tap in cases of bacterial endophthalmitis

OBJECTIVE

To investigate the concordance between aqueous and vitreous tap culture results among different types of bacterial endophthalmitis.

METHODS AND ANALYSIS

This retrospective cohort analysis included all cases diagnosed with endophthalmitis at Moorfields Eye Hospital between January 2008 and March 2020. Aqueous and vitreous samples obtained simultaneously at presentation. Samples were evaluated for sensitivity, specificity, negative and positive predictive values.

RESULTS

A total of 217 patients (217 eyes) were included in the study. Postsurgical endophthalmitis was the most common type of endophthalmitis and diagnosed in 35.9% of the cases. The rate of positive culture results was 32.2% from vitreous tap and 21.7% from aqueous tap. The culture yield through vitreous sampling was 15.7% when aqueous culture results were negative, and in 5.1%, the aqueous sample was positive when the vitreous tap results were negative. Considering the vitreous tap as the gold standard, aqueous sample culture results showed a statistically significant high specificity and positive predictive values in cases of postsurgical endophthalmitis, late-onset endophthalmitis associated with glaucoma procedures, postintravitreal injection and endophthalmitis associated with bacterial keratitis. Coagulase Negative Staphylococcus was the most common organism isolated from vitreous and aqueous samples.

CONCLUSIONS

Even though the sensitivity and specificity of aqueous tap are low, our results show that in a few cases it identified important organisms, otherwise missed by vitreous sampling alone. Culture of vitreous sample remains the gold standard for isolation of pathogen in bacterial endophthalmitis, but aqueous samples should also be obtained as an adjunct for the diagnosis.

Endophthalmitis After Descemet Stripping Endothelial Keratoplasty: Microbiological Yield and Visual Outcomes

PURPOSE

To describe the clinical presentation, management, and visual outcomes of 6 eyes with endophthalmitis after Descemet stripping endothelial keratoplasty (DSEK).

DESIGN

Retrospective case series.

METHODS

Setting: Tertiary, academic eye center. StudyPopulation: Individuals developing endophthalmitis after DSEK at the Duke Eye Center from January 1, 2009, to January 1, 2018, with at least 6 months of follow-up. ObservationProcedure: Retrospective chart review. OutcomeMeasures: Diagnostic procedures, microbiological yield, and visual outcomes.

RESULTS

Six eyes of 6 patients were identified. Mean time from surgery to presentation was 51 days (range, 4-137 days). Dense vitreous opacities were present in all cases. Five of 6 cases (83%) had culture-proven infectious endophthalmitis (2 Candida glabrata, 2 coagulase-negative Staphylococcus, 1 Streptococcus pneumoniae). Aqueous tap yielded positive culture in 2 of 2 cases with adequate sample (100%); needle vitreous tap yielded positive culture in 0 of 3 cases. One eye underwent vitrectomy on presentation, and 3 eyes (50%) underwent subsequent vitrectomy for persistent endophthalmitis after a mean of 37 days. Mean pre-endophthalmitis visual acuity (VA) was 20/64; mean VA at 6 months was 20/2069 (average 15 ETDRS lines lost). VA at 6 months was light perception or no light perception in 3 of 6 cases (50%). One eye underwent enucleation at 6 months, and 1 eye became phthisical 1 year after endophthalmitis.

CONCLUSIONS

DSEK-related endophthalmitis may lead to severe vision loss, even with prompt and appropriate treatment. Aqueous tap had a higher culture yield than needle vitreous tap in our series.

Using the West Midlands CONCERT to characterise regional incidence of acute-onset post cataract surgery endophthalmitis

BACKGROUND

Whilst research and innovation is embedded within the UK's National Health Service (NHS) constitution, Doctors-in-training have little opportunity to contribute to designing, leading and recruiting into clinical trials or cohort studies. We formed the West Midlands Collaborative Ophthalmology Network for Clinical Effectiveness & Research by Trainees (The West Midlands CONCERT) and undertook a characterisation of post cataract surgery endophthalmitis as a proof-of-concept study to test the feasibility of the CONCERT model.

METHODS

Doctors-in-training formed a collaborative working group to test the concept of delivering a pan-regional clinical effectiveness study across multiple hospital sites by performing retrospective analyses of post cataract endophthalmitis over a 6-year period.

RESULTS

Overall, 157,653 cataract surgeries were performed by participating centres accredited to deliver the Royal College of Ophthalmologists training curriculum. Thirty-eight cases of post cataract endophthalmitis were identified, giving an incidence of 2.41 per 10,000 cases (0.0241%). A further 15 endophthalmitis cases presented who had surgery in non-training centres, giving a total of 53 cases. The most common organisms were S. epidermidis (14 (51.9%)) and P. aeruginosa (5 (18.5%)). Anterior-chamber and vitreous sampling yielded positive culture in 33.3% (6/18) and 50.9% (27/53), respectively. At 6 months follow-up, 19 (51.4%) patients achieved visual acuities of ≤0.5 LogMAR. Repeat intravitreal injections (11 (20.8%)) and vitrectomy (n = 22 (41.5%)) were not associated with better outcomes.

CONCLUSIONS

Using post cataract endophthalmitis as a pilot cohort, this study highlights the feasibility of using the CONCERT model for studies across multiple sites. A UK-CONCERT could provide a powerful infrastructure enabling characterisation of patient cohorts and a platform for high-quality interventional studies, improving patient care.

Sensitivity, specificity and predictive values of anterior chamber tap in cases of bacterial endophthalmitis

Background

To assess the sensitivity, specificity, positive predictive value and negative predictive value of anterior chamber tap for the diagnosis of bacterial endophthalmitis on a population with high prevalence.

Methods

Retrospective, single centre, case series study. We reviewed all medical records with clinical diagnosis of bacterial endophthalmitis in our hospital from January 1st, 2000 to December 31st 2014. From each record, we documented general demographic data, best corrected visual acuity and vitreous and aqueous tap microbiological results. All cases were further divided according to the endophthalmitis aetiology to perform individual calculations of sensitivity, specificity, positive predictive value, negative predictive value, accuracy and prevalence. We used the results of the vitreous tap as the gold standard for diagnosis of bacterial endophthalmitis. We excluded those records in which the aqueous and vitreous samples were not taken simultaneously or had an incomplete microbiological report. Significance were assessed with chi squared statistics, with an alpha value of 0.05 for statistical significance.

Results

A total of 190 cases fulfilled the inclusion/exclusion criteria. Positive culture rate from vitreous samples was 64.74%. Positive culture rate from aqueous sample was 32.11%. Bacteria isolated from aqueous samples matched those isolated from vitreous samples 78.68% of the time. The overall sensitivity was 38.21%, specificity: 75.51%, positive predictive value: 79.66%, negative predictive value: 32.74% (p = 0.08). Subgroup analysis showed that anterior chamber taps in cases of post-surgical endophthalmitis had a moderate to low sensitivity (37.73%), high specificity (93%) and high positive predictive value (95%) (p < 0.04).

Conclusion

The sensitivity and specificity of anterior chamber tap are low and should not be used for critical therapeutic decisions in patients with suspected bacterial endophthalmitis. In cases of post-surgical endophthalmitis, the result of an anterior chamber tap could be used for therapeutic guidance, but only in conjunction with clinical presentation and in the absence of a better method for diagnosis.

Etiological agents of fungal endophthalmitis: diagnosis and management

Endophthalmitis caused by fungi is commonly diagnosed around the world in apparently healthy and immunocompromised individuals. An accurate clinical diagnosis for endophthalmitis confirmed by laboratory techniques is essential for early treatment with antifungal drugs, such as amphotericin B, imidazoles, and other antifungals. Here, we review endophthalmitis caused by fungi according to its classification into endogenous fungal endophthalmitis (EFE) and exogenous fungal endophthalmitis (EXFE). EFE is caused by endogenously acquired fungi, whereas the traumatic implantation of opportunistic fungal pathogens is the main feature of EXFE. We highlight the most important etiologies causing endophthalmitis and the steps required for a rapid diagnosis and management.

Nosocomial acute-onset postoperative endophthalmitis at a university teaching hospital (2002-2009)

PURPOSE

To evaluate acute-onset postoperative endophthalmitis occurring at an academic medical center and to compare rates over the last 25 years at a single institution.

DESIGN

Retrospective, consecutive case series.

METHODS

Medical records were reviewed for all patients diagnosed with acute-onset postoperative nosocomial endophthalmitis from 2002 through 2009 associated with surgery at Bascom Palmer Eye Institute.

RESULTS

The 8-year frequency of acute-onset postoperative endophthalmitis was 0.025% (14 of 56 672 intraocular surgeries). The rate was 0.028% (8/28 568) for cataract surgery and 0.011% (2/18 492) for pars plana vitrectomy (PPV). Both PPV endophthalmitis cases followed 20-gauge surgery and no cases followed small-gauge, transconjunctival PPV (n = 2262). Three cases occurred following penetrating keratoplasty (3/2788, 0.108%). The most common bacterial isolate was Staphylococcus (n = 7, 50%). Initial treatment involved ocular paracentesis (n = 8, 57%) or vitrectomy (n = 5, 36%), in combination with injection of intraocular antibiotics (n = 14, 100%). Vancomycin and ceftazidime were used in 13 eyes (93%) and intraocular steroids were given initially to 9 eyes (64%). Final visual acuity was > or =20/200 in 9 eyes (64%) and 2 eyes (14%) were no light perception. At this institution since 1984, there has been a statistically significant trend for a decreasing rate of acute-onset postoperative endophthalmitis (1984-1994: 0.09%; 1995-2001: 0.05%; 2002-2009: 0.025%; P < .001).

CONCLUSION

At a university teaching hospital involving resident, fellow, and faculty surgeons, the frequency of acute-onset postoperative nosocomial endophthalmitis is low, has not increased in the era of sutureless clear corneal cataract surgery, and has steadily decreased when compared to prior time periods from the same institution.

Exogenous fungal endophthalmitis: microbiology and clinical outcomes

OBJECTIVE

To report the fungal isolates, treatment strategies, and clinical outcomes for a large series of patients with exogenous fungal endophthalmitis.

DESIGN

Retrospective, single institution, consecutive case series.

PARTICIPANTS

All patients treated at Bascom Palmer Eye Institute between January 1, 1990, and June 30, 2006, for culture-proven exogenous fungal endophthalmitis.

METHODS

Microbiologic and medical records were reviewed for all patients with intraocular cultures positive for fungal organisms and clinically diagnosed exogenous endophthalmitis.

MAIN OUTCOME MEASURES

Fungal isolates, treatment strategies, visual acuity, and rate of enucleation.

RESULTS

Culture-positive exogenous fungal endophthalmitis occurred in 41 eyes, including 18 cases (44%) associated with fungal keratitis, 10 cases (24%) occurring after penetrating ocular trauma, and 13 cases (32%) after intraocular surgery. Filamentous fungi (molds) accounted for 35 cases (85%), and Candida species (yeasts) accounted for 6 cases (15%). Although most keratitis cases were caused by Fusarium (13 of 18; 72%), Aspergillus was the most common isolate in postoperative cases (5 of 13; 38%). Open-globe cases were caused by a broader spectrum of fungi. As initial treatment, 30 (73%) patients received intraocular amphotericin B, but at least 3 antifungal agents were used in 24 (59%) cases. At least 1 pars plana vitrectomy was performed in 25 (61%) eyes, and 29 (71%) eyes underwent 3 or more procedures, including surgeries and intraocular injections. Although a final vision of 20/400 or better was achieved in 22 (54%) eyes, all but 1 of these were either in the keratitis (11 of 18) or the postoperative (10 of 13) groups. Conversely, although 10 (24%) of 41 eyes were enucleated, 7 of these were among the open-globe patients.

CONCLUSIONS

This report highlights the differences between the clinical categories of exogenous fungal endophthalmitis. Although 85% of all cases were caused by molds, most commonly Fusarium and Aspergillus, the most common fungal genera varied by clinical category. Amphotericin B was the most commonly used antifungal agent, but most cases were treated with at least 3 different antifungal agents. Final visual outcomes were variable, with the open-globe-associated patients having the poorest outcomes. Overall, 44% of patients achieved a final visual acuity of 20/80 or better.

Metastatic endophthalmitis

Endophthalmitis carries a poor visual prognosis for patients and can be a potentially blinding condition that may result in loss of the eye. Early diagnosis and prompt treatment are imperative to save the eye. Delay in diagnosis affects visual prognosis and therefore doctors should be aware of the presenting features of endophthalmitis. Urgent ophthalmic referral is advised as soon as a diagnosis is suspected.

Post-traumatic fungal endophthalmitis--a prospective study

PURPOSE

To study the incidence, clinical presentation, and the response of anti-fungals in cases of fungal endophthalmitis following open globe injury.

METHODS

This is a prospective study of eight cases of post-traumatic fungal endophthalmitis among 110 patients who presented to us with open globe injury between August 2003 and January 2005. Patients with panophthalmitis were eviscerated and rest received intravitreal amphotericin B. Pars plana vitrectomy along with intravitreal miconazole was given in patients with inadequate response to intravitreal amphotericin.

RESULTS

Two patients had panophthalmitis at the time of presentation and were eviscerated. Six different organisms were isolated from the culture of intraocular specimen of eight patients. The yield of vitreous aspirate was 87.5% and that of aqueous aspirate was 66.6%. Aspergillus sp. and Fusarium sp. were isolated in 62.5% of cases. Minimum inhibitory concentration of amphotericin B and miconazole was less than 3 microg/ml for all organisms except for Paecilomyces lilacinus and Fusarium solani, respectively. In total, 37.5% of patient had final visual acuity of 20/400 or better.

CONCLUSIONS

Fungal endophthalmitis is a relatively rare complication of open globe injury. The final visual outcome after fungal endophthalmitis is dismal. Aspergillus fumigatus was found to be the most virulent organism. All organisms were found to be sensitive to amphotericin B, except P. lilacinus, which was sensitive to miconazole. Repeated intravitreal injection may be required to control the infection. The virulence of the organism and the site of injury are the main determinants of final visual outcome.

Endogenous bacterial endophthalmitis: a 17-year prospective series and review of 267 reported cases

Endogenous bacterial endophthalmitis is a rare but serious condition that occurs when bacteria cross the blood-ocular barrier and multiply within the eye. We provide an overview of endogenous bacterial endophthalmitis by reviewing 267 reported cases and integrating this with our experience of an additional 19 cases. The majority of patients with endogenous bacterial endophthalmitis are initially misdiagnosed and many have an underlying disease known to predispose to infection. This condition is often previously undiagnosed. Blood cultures are the most frequent means of establishing the diagnosis. The most common Gram positive organisms are Staphylococcus aureus, group B streptococci, Streptococcus pneumoniae,and Listeria monocytogenes. The most common Gram negative organisms are Klebsiella spp., Escherichia coli, Pseudomonas aeruginosa, and Neisseria meningitidis. Gram negative organisms are responsible for the majority of cases reported from East Asian hospitals, but Gram positive organisms are more common in North America and Europe. The visual outcome is poor with most cases leading to blindness in the affected eye. Many patients have extraocular foci of infection, with an associated mortality rate of 5%. The outcome of endogenous bacterial endophthalmitis has not improved in 55 years and clinicians need to have a high level of awareness of this commonly misdiagnosed condition.

The antibacterial effect of topical anesthetic proparacaine on conjunctival flora

PURPOSE

To investigate the antibacterial effect of topical anesthetic proparacaine on conjunctival flora.

METHODS

One hundred and forty-four eyes of 72 patients awaiting cataract surgery were included in the study. A commercially available solution of proparacaine, preserved with benzalkonium chloride 0.01%, was instilled in one eye of all subjects while the vehicle solution, including the same concentration of preservative in aqueous solution, was administered to the other eye. Conjunctival cultures were taken from all eyes before and 15 minutes after the instillation of proparacaine and the vehicle.

RESULTS

Of the 144 eyes, 76 (52.8%) had positive-conjunctival cultures with the most commonly isolated organisms being coagulase-negative staphylococci in each group. Of the 76 culture-positive eyes, 40 (52.6%) received proparacaine and 36 (47.4%) the vehicle preparation. Fifteen minutes after the instillation of proparacaine and the vehicle eyedrops, four eyes (10%) and 12 eyes (33.3%) had culture-positive conjunctival smears, respectively. Proparacaine significantly reduced the number of culture-positive eyes (p = 0.0003), in contrast to the vehicle (p = 0.21).

CONCLUSION

A topical anesthetic, proparacaine, demonstrates antibacterial effects on the conjunctival flora.

Vitreous cultures in suspected endophthalmitis. Biopsy or vitrectomy?

BACKGROUND

Isolation of bacteria from vitreous biopsy often guides therapy in suspected endophthalmitis. Therapeutic vitrectomy provides an additional source of culture material. The authors compared the ability of these two techniques to isolate organisms from patients with acute endophthalmitis.

METHODS

In a large ophthalmic microbiology laboratory during a 4-year period, the authors analyzed 206 microbial culture results from patients with suspected endophthalmitis.

RESULTS

Two hundred six cases were evaluated. While cultures of vitreous biopsy specimens obtained using a needle and syringe were positive in 91 (53.8%) of 169 patients, culturing the contents of the vitrectomy cassettes produced positive cultures in 29 (74.8%) of 39 patients. Both techniques were performed on 23 patients. Vitreous biopsy allowed isolation of the causative organism in 43% of these patients, whereas vitrectomy was 76% successful. Both comparisons were significant at the P < 0.01 level. No positive vitreous biopsy cultures had associated negative vitrectomy cultures.

CONCLUSION

Culturing the contents of the vitrectomy cassette significantly increases the likelihood of obtaining a positive culture compared with merely culturing a vitreous biopsy.

Diagnosis and therapy of bacterial endophthalmitis, and serum levels of inflammation markers

A review of 27 cases of bacterial endophthalmitis diagnosed and treated at the Specialized Outpatient Department for Infectious Eye Diseases at the 2nd Department of Ophthalmology of the University of Vienna over a period of eight years (January 1983-April 1991) is presented. In 70% of the cases the patients had undergone surgical intervention. Conjunctival samples were routinely taken for microbiological investigations (aerobic as well as anaerobic cultures). In 19 patients (70.4%) aqueous specimens were obtained, in 22 cases (81.5%) vitreous specimens collected during vitrectomy for the removal of infected material were used for microbiological diagnosis. The results for the patient population described showed the poor reliability of conjunctival cultures from intraocular infections with only 36.84% being identical with those of the vitreous specimens. In the most recent 11 patients three serological parameters of inflammation were tested on various occasions: C-reactive protein, PMN- elastase and light immunoglobulin chain assembling (kappa/lambda). Clinical results, microbiological findings and therapeutic approaches are presented and discussed.