FRIENDS Group: clinical and microbiological characteristics of post-filtering surgery endophthalmitis

Endophthalmitis: Microbiology and Organism Identification Using Current and Emerging Techniques

Endophthalmitis is an ophthalmological emergency requiring timely and appropriate diagnosis and treatment. Microbiological methods of microscopy (Gram's staining) and culture are the current gold standard for organism identification. However, a significant proportion of endophthalmitis remains culture-negative-perhaps the inflammation is non-infectious in origin, results from a novel organism are unidentifiable or because the causative organism is non-culturable often due to pre-treatment with antibiotics. This review outlines the microbiological profile of endophthalmitis, current clinically used methods for organism identification, and the newer molecular techniques of polymerase chain reaction (PCR) and next-generation sequencing (NGS) technology as diagnostic tools for endophthalmitis. They offer the potential to improve organism identification rates and clinical outcomes in infectious diseases, representing an exciting future direction for organism identification in endophthalmitis. Based on the largest ophthalmic hospital in Australia, we highlight the key practical challenges faced by Australian diagnostic laboratories for their use in a clinical setting.

A Review on Pathogens and Necessary Diagnostic Work for Bleb-Related Infections (BRIs)

At the present time, as newer techniques and minimally invasive procedures gain popularity among anterior segment surgeons for regulating intraocular pressure, trabeculectomy still has a leading role in glaucoma surgery. Trabeculectomy retains a highly successful and safe profile; however, one of the major complications includes bleb-related infections (BRIs). To date, the most common pathogens remain Gram-positive cocci, but the list of pathogens that have been identified in the literature includes more than 100 microorganisms. Because antibiotic use is more widespread than ever before and our ability to identify pathogens has improved, the pathogen spectrum will broaden in the future and more pathogens causing BRIs will be described as atypical presentations. The scope of this review was to identify all pathogens that have been described to cause bleb-related infections to date, as well as focus on the risk factors, clinical presentation, and various available diagnostic tools used for an appropriate diagnostic workup.

Acute postoperative endophthalmitis: Microbiology from the laboratory to the bedside

Postoperative endophthalmitis is a dreaded complication of intraocular surgery. Acute presentations need prompt management and good knowledge of differential diagnoses. In the last 10 years, progress in direct microbial detection and identification from intraocular samples included the use of blood culture systems and, more recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, improving the rate of bacterial identification. Whatever the method used, diagnostic sensitivity is better for vitreous samples than for aqueous humor samples. Besides, molecular biology techniques have further improved the identification rate of infectious agents in intraocular samples. They also provide faster results compared to culture-based techniques. Quantitative real-time PCR (qPCR) can also determine the bacterial load in intraocular samples. Several studies have shown that intraocular bacterial loads in endophthalmitis patients are usually high, which helps differentiating infection from contamination. The prognostic value of qPCR remains to be validated. Whole genome DNA sequencing technologies facilitate direct and sequencing of single DNA molecules. They have the potential to increase the rate of microbiological identification. Some antibiotic resistance markers (e.g., methicillin resistance in staphylococci and vancomycin resistance in enterococci) may be detected earlier using molecular techniques (usually real-time PCR tests). Early determination of the involved microorganism and their antibiotic resistances can help establishing an earlier therapeutic strategy.

Seasonal and environmental variations in endophthalmitis after intravitreal anti-vascular endothelial growth factor injection: a six-year review

PURPOSE/AIM

To evaluate seasonal and environmental variations on the incidence and outcomes of post-injection endophthalmitis.

MATERIALS AND METHODS

A single-center, retrospective cohort study was conducted including all patients diagnosed with post-injection endophthalmitis between 2013-2018. Associations between climate variables and endophthalmitis incidence were evaluated.

RESULTS

Of 423,297 injections administered, seasonal distribution in spring, summer, autumn, and winter was 26%, 27%, 25%, and 22%, respectively. Of 171 cases of endophthalmitis identified, seasonal distribution over the spring, summer, autumn, and fall was 25%, 23%, 26%, and 26%, respectively. Endophthalmitis incidence was not correlated with monthly precipitation (p = 0.45), monthly snowfall (p = 0.49), or monthly temperature (p = 0.65). Worse visual outcomes at initial endophthalmitis presentation were correlated with increased precipitation level (p = 0.025), but were not correlated with snowfall level (p = 0.228) or mean monthly temperature (p = 0.132). Although there were no seasonal variations of visual acuity at endophthalmitis presentation (p = 0.894), odds of final visual acuity returning to within two lines of pre-endophthalmitis visual acuity were worse among patients with endophthalmitis diagnosed in the spring (OR, 0.041; p = 0.016).

CONCLUSION

In contrast to previous work on post-cataract endophthalmitis, seasonal and weather factors were not associated with post-injection endophthalmitis risk or bacterial species isolated. Visual outcomes at initial endophthalmitis presentation were correlated with precipitation, and worse visual outcomes were seen in patients who developed endophthalmitis in the spring.

Endophthalmitis in Oman: A descriptive retrospective multi-center study

PURPOSE:

The aim of this study is to report the anatomical and functional outcome, microbiology profile and treatment used for endophthalmitis in Oman.

DESIGN:

The study design involves retrospective descriptive multicenter study.

METHODS:

Demographic and clinical data of patients diagnosed with endophthalmitis over a period of 9 years were collected in three tertiary hospitals in Oman.

RESULTS:

A total of 50 endophthalmitis cases were included in the study. Exogenous endophthalmitis was diagnosed in 48 cases, whereas 2 cases were endogenous endophthalmitis. Culture-positive cases constituted 16 cases (32%) out of these, 12 cases were Gram-positive, 3 cases were Gram-negative and one case had a positive fungal culture. Immediate first-line treatment was vitreous tap and inject in 33 eyes and vitrectomy in 13 eyes. In 45 eyes in which the visual acuity (VA) was recorded; VA after treatment improved in 22 eyes (49%), remained the same in 16 eyes (36%) and worsened in 7 eyes (16%).

CONCLUSION:

Although endophthalmitis is rare, it is a devastating ocular emergency. Early diagnosis and prompt intervention are crucial in management. Awareness among the patients undergoing intraocular surgeries about this rare condition is very crucial. Moreover, frontline health-care providers must be aware and critical if they encounter patients with suspicion of endophthalmitis as early recognition, prompt referral, and timely treatment are the key for better visual prognosis. Finally, establishing a National Endophthalmitis Registry is recommended as it will help analyze the incidence, treatment instituted and the outcome of this condition across Oman.

Vitrectomy for endophthalmitis: 5-year study of outcomes and complications

Background/Aims

To analyse the complications and outcomes of vitrectomy surgery for endophthalmitis.

Methods

This was a retrospective case series. All cases that underwent 23-gauge vitrectomy surgery for endophthalmitis at a tertiary centre between 1 February 2013 and 1 February 2018 were included. Main outcome measures were as follows: visual acuity (VA) at final visit and post-vitrectomy complications.

Results

33 patients were included in the study with 20 men and 13 women, average age 63 years. Main post-surgical causes for endophthalmitis included phacoemulsification (n=9), trabeculectomy (n=5), intravitreal injection (n=5), corneal graft (n=4), vitreoretinal surgery (n=3) and endogenous endophthalmitis (n=6). Average follow-up was 18 months (SD 14). 21/33 (64%) patients had baseline perception of light VA. Analysis of exogenous endophthalmitis cases only demonstrated: mean LogMAR VA improved significantly from 2.68 to 1.66 (p=0.001). At final follow-up, 12% had VA of 6/12 or better, and 28% had VA of 6/36 or better. Vitrectomy within 7 days resulted in improved final VA outcomes (1.49 vs 2.16 LogMAR, p=0.032). Complications included retinal detachment (24.2%), macular hole (3%), hypotony (6%), suprachoroidal haemorrhage (3%) and enucleation/evisceration (6%).

Conclusion

Vitrectomy for endophthalmitis leads to VA gains in some cases. Surgical outcomes may be improved with early vitrectomy performed within 7 days of the initial event for exogenous endophthalmitis. Patients should be advised of the potential risk of severe complications with/and without surgery.

The cereus matter of Bacillus endophthalmitis

Bacillus cereus (B. cereus) endophthalmitis is a devastating intraocular infection primarily associated with post-traumatic injuries. The majority of these infections result in substantial vision loss, if not loss of the eye itself, within 12-48 h. Multifactorial mechanisms that lead to the innate intraocular inflammatory response during this disease include the combination of robust bacterial replication, migration of the organism throughout the eye, and toxin production by the organism. Therefore, the window of therapeutic intervention in B. cereus endophthalmitis is quite narrow compared to that of other pathogens which cause this disease. Understanding the interaction of bacterial and host factors is critical in understanding the disease and formulating more rational therapeutics for salvaging vision. In this review, we will discuss clinical and research findings related to B. cereus endophthalmitis in terms of the organism's virulence and inflammogenic potential, and strategies for improving of current therapeutic regimens for this blinding disease.

[Modern diagnosis and treatment of endophthalmitis]

Endophthalmitis is characterized by inflammation of intraocular fluids and tissues, which can lead to irreversible loss of vision if the disease is not treated timely and properly. Endophthalmitis can be classified as exogenous or endogenous depending on the route of infectious agent transmission. Exogenous endophthalmitis occurs when pathogens enter the eye through direct inoculation, while endogenous endophthalmitis develops when pathogens get into the eye through the hematogenous route from a distant infection focus. Classification of endophthalmitis helps determine the etiology and probable causative organisms of the disease. Diagnosis of endophthalmitis is based on clinical data. Early diagnosis and treatment are keys to preserving the eye. Best results are achieved by rapid initiation of an empirical broad-spectrum antimicrobial therapy.

Choosing wisely and the use of antibiotics in ophthalmic surgery: There is more than meets the eye

BACKGROUND:

One of the directions of modern ophthalmology is toward an odontoiatric model, and new settings of eye care are becoming the standard of care: one day surgery and also office-based therapies.

METHODS:

Retrospective analysis of three tertiary-care centers in Italy and analysis of the literature.

RESULTS:

We provide readers with state-of-the-art measures of prophylaxis in ophthalmic surgery.

DISCUSSION AND CONCLUSION:

Role of antibiotics is criticized in the light of stewardship antimicrobial paradigm.

Bleb-related infection revisited: a literature review

Bleb-related infection (BRI) is one of the serious complications of glaucoma filtering surgery. This literature review is aimed at the evaluation of recent studies related to BRI. The review presented and discussed risk factors, and clinical and laboratory diagnosis emphasizing advances in diagnostic techniques to detect and distinguish the disease as well as to initiate immediate intensive antibacterial treatment. Clinical features of recognized prognostic factors of visual outcome were also presented. The studies showed that the prognosis of blebitis is usually good, unless infection has progressed to endophthalmitis that would signify a poorer prognosis. Despite prompt and intensive treatment of patients with bleb-related endophthalmitis, the outcomes remain unsatisfactory especially with virulent organisms and low initial visual acuity. It has been recommended that early detection and treatment of risk factors and thorough patient education are indispensable in ensuring best prognosis in post-trabeculectomy patients.

Group A streptococcal endophthalmitis complicating a sore throat in a 2-year-old child

A previously well 2-year-old presented to her general practitioner after 5 days of fever, lethargy, sore throat and a slightly red eye. A viral infection was diagnosed. Two days later, she re-presented with a swollen right eyelid and a moderately red eye. Oral amoxicillin and chloramphenicol eye drops were prescribed. The next day, marked periorbital swelling developed. She was admitted to hospital and parenteral ceftriaxone was started. Examination under anaesthetic showed injected globe diffuse corneal clouding and peripheral corneal opacities; ultrasound and CT suggested endophthalmitis. On transfer to a tertiary centre, intraocular vancomycin and subconjunctival cefuroxime were given. Aqueous fluid samples were positive for group A Streptococcus (GAS) by PCR, so parenteral clindamycin was added. GAS endophthalmitis was confirmed 1 day later from the positive intraocular fluid culture results. Visual evoked potentials revealed complete loss of vision. The eye was removed to limit potential spread. She made a good recovery postoperatively and was discharged on oral antibiotics.

PCR detection and identification of bacterial contaminants in ocular samples from post-operative endophthalmitis

BACKGROUND

Bacterial endophthalmitis is a sight-threatening complication of ocular surgery which requires urgent medical consideration including comprehensive diagnosis. Polymerase chain reaction (PCR) as a sensitive molecular method has been extensively used for detection of microbial species in clinical specimens.

AIM

The aim of this study was to identify the causative organisms of endophthalmitis in our patient population using a procedure based on PCR.

MATERIALS AND METHODS

Vitreous samples from 32 patients with post-operative endophthalmitis were collected. Total vitreous DNA was extracted and then assessed by agarose gel electrophoresis. Bacterial 16S rRNA gene was amplified from genomic DNA using PCR with a pair of HAD2 universal primers. Library of PCR products from 16S rRNA, cloned into the pTZ57R/T vector. The ligated products were then transformed into E. coli DH5α strain and grown in the LB-ampicillin/X-Gal/IPTG plate.

RESULTS

From the total of 32 vitreous samples, 18 specimens were positive, illustrating the presence of bacterial infection (56.4 %). Twelve species including Escherichia coli, Enterobacter cloacae, Bacillus subtilis, Neisseria gonorrhoeae, Streptococcus pneumoniae, Haemophilus influenzae, Chlamydia trachomatis, Staphylococcus aureus, Neisseria meningitides, Staphylococcus epidermidis, Pseudomonas aeruginosa and Bacillus cereus were identified using BLAST for known 16S rRNA sequences.

CONCLUSION

Polymerase chain reaction (PCR) accompanied with cloning and sequencing approved to be sensitive and specific. The rapid molecular technique was useful in detection of 12 major microbial species, in infectious endophthalmitis.

Endophthalmitis: state of the art

Endophthalmitis is an uncommon diagnosis but can have devastating visual outcomes. Endophthalmitis may be endogenous or exogenous. Exogenous endophthalmitis is caused by introduction of pathogens through mechanisms such as ocular surgery, open-globe trauma, and intravitreal injections. Endogenous endophthalmitis occurs as a result of hematogenous spread of bacteria or fungi into the eye. These categories of endophthalmitis have different risk factors and causative pathogens, and thus require different diagnostic, prevention, and treatment strategies. Novel diagnostic techniques such as real-time polymerase chain reaction (RT-PCR) have been reported to provide improved diagnostic results over traditional culture techniques and may have a more expanded role in the future. While the role of povidone-iodine in prophylaxis of postoperative endophthalmitis is established, there remains controversy with regard to the effectiveness of other measures, including prophylactic antibiotics. The Endophthalmitis Vitrectomy Study (EVS) has provided us with valuable treatment guidelines. However, these guidelines cannot be directly applied to all categories of endophthalmitis, highlighting the need for continued research into attaining improved treatment outcomes.

Update on the prevention and treatment of endophthalmitis

Endophthalmitis remains a rare but serious cause of visual loss. Over time, changes have been noted in endophthalmitis in terms of predominant causes, infecting organisms, and antibiotic susceptibilities. There is controversy regarding the use of intracameral prophylactic antimicrobials during cataract surgery. Alternatively, there appears to be increasing evidence against using routine topical antibiotics for intravitreal injections. There are also increasing reports of multidrug-resistant organisms causing endophthalmitis, but the combination of vancomycin and ceftazidime appears effective for the vast majority of cases. Future trends may involve increasing utilization of polymerase chain reaction for diagnosis, and possibly office-based pars plana vitrectomy for treatment of endophthalmitis.