Genetic and Phenotypic Traits of Staphylococcus Epidermidis Strains Causing Postcataract Endophthalmitis Compared to Commensal Conjunctival Flora

Risk Factors for Legal Blindness in 237 Japanese Patients with Exogenous Endophthalmitis: A Multicenter Cohort Study from J-CREST

PURPOSE

We investigated potential risk factors for visual prognosis in Japanese patients with exogenous endophthalmitis.

METHODS

In this retrospective observational multicenter cohort study, risk factors for legal blindness at 12 weeks after treatment initiation were evaluated based on patient characteristics, initial BCVA, causative events, pathogens, ocular symptoms, duration from symptom onset to initial treatment, and selected treatments.

RESULTS

Overall, 23.1% of eyes developed legal blindness. The six risk factors for legal blindness were presence of eye pain, pathogen identification, poor BCVA at the initial visit, longer duration from symptom onset to initial treatment, type of causative event, and type of causative pathogen. Regarding the type of causative pathogen, coagulase-negative staphylococci was associated with a better visual impairment outcome.

CONCLUSION

Exogenous endophthalmitis remains a severe ocular infection; however, it can be managed with rapid treatment, as well as other advances in medical knowledge and technology.

Successful antibiotic management of Staphylococcus epidermidis endophthalmitis after implantable collamer lens implantation

PURPOSE

We report a case of successful medical management of endophthalmitis post implantable collamer lens (ICL) culture-positive of Staphylococcus epidermidis.

OBSERVATIONS

A 18-year-old female presented with decreased visual acuity in the left eye 20 days after ICL implantation. A diagnosis of postoperative endophthalmitis was made based on examination and ultrasonography. A vitreous tap was taken, and intravitreal antibiotics (vancomycin 1 mg/0.1ml and ceftazidime 2 mg/0.1ml) were administered twice (every 72 h), and peribulbar injection of triamcinolone acetonide after four days of the second intravitreal injection. The vitreous culture was confirmed for Staphylococcus epidermidis. The endophthalmitis was resolved, and visual acuity improved from 6/20 to 12/20 on day 7 and 22/20 on day 38. This is the first successful medical resolution of Staphylococcus epidermidis endophthalmitis post ICL surgery without ICL explantation and vitrectomy in the V4c model.

CONCLUSIONS AND IMPORTANCE

In antibiotic therapy, the excellent compliance and close follow-up of this endophthalmitis patient enabled careful postoperative surveillance on the effect of antibiotic therapy, avoiding the removal of the ICL or the loss of the integrity of the eye. The risk of potential infectious endophthalmitis post-ICL surgery should be fully emphasized during preoperative counseling.

Molecular and Phenotypic Characterization of Ocular Methicillin-Resistant Staphylococcus epidermidis Isolates in Taiwan

Purpose

Staphylococcus epidermidis, a commensal, has emerged as an important opportunistic pathogen, particularly methicillin-resistant S. epidermidis (MRSE). The mechanism behind this transformation remains unclear. This study aimed to investigate the molecular and phenotypic characteristics of MRSE isolated from healthy conjunctiva and ocular infections.

Methods

We collected MRSE isolates from two groups: healthy conjunctiva from patients undergoing cataract surgeries and ocular infections at our hospital. Genotypic analysis included pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec), and biofilm-related genes (icaA, aap, and bhp). Additionally, phenotypic data on biofilm production and antibiotic susceptibility were recorded.

Results

A total of 86 isolates, including 42 from healthy conjunctiva and 44 from ocular infections, were analyzed. MLST identified 21 sequence types (STs), with ST59 being the most frequent (n = 33, 39.5%), followed by ST130 (n = 10, 11.6%), ST57 (n = 6, 7.0%), and ST2 (n = 6, 7.0%). All isolates were categorized in 23 PFGE types, and SCCmec IV was the most prevalent SCCmec type (n = 52, 60.5%). The two sources of isolates exhibited overlapping molecular types and phenotypic traits, although the ocular infection isolates exhibited significantly higher multidrug resistance compared to healthy conjunctiva isolates (P = 0.032). When contrasting ST59 with non-ST59, ST59 displayed a significantly higher presence of aap (100%) and bhp (69.7%) while lacking icaA (0%). ST59 also showed lower susceptibility to fluoroquinolones compared to non-ST59 (42.4%-54.5% vs. 75.5%-83.0%; P < 0.01).

Conclusions

MRSE isolates from healthy conjunctiva and ocular infections demonstrated a degree of resemblance. Specific strains, notably ST59, exhibited distinctive characterizations.

Risk Factors for Legal Blindness in 77 Japanese Patients with Endogenous Endophthalmitis: A Multicenter Cohort Study from J-CREST

PURPOSE

We investigated potential predictive factors for visual prognosis in Japanese patients with endogenous endophthalmitis.

DESIGN

Retrospective observational multicenter cohort study.

METHODS

We examined the characteristics of 77 Japanese patients with endogenous endophthalmitis and performed statistical analyses of these real-world data. The primary endpoint was the identification of factors associated with visual prognosis. We examined differences between patients in the better vision and legal blindness groups at 12 weeks after treatment initiation.

RESULTS

The five risk factors for visual impairment at 12 weeks after treatment initiation were presence of pressure injuries, severe clinical symptoms (presence of eye pain and ciliary injection), pathogen identification, and poor best-corrected visual acuity at baseline. Staphylococcus aureus and fungus were associated with a better visual impairment outcome.

CONCLUSIONS

Endogenous endophthalmitis remains a severe ocular infection; however, it can be managed with rapid treatments, as well as other advances in medical knowledge and technology.

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.

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.

Clinical Characteristics and Outcomes in 314 Japanese Patients with Bacterial Endophthalmitis: A Multicenter Cohort Study from J-CREST

Bacterial endophthalmitis is an intraocular infection that causes rapid vison loss. Pathogens can infect the intraocular space directly (exogenous endophthalmitis (ExE)) or indirectly (endogenous endophthalmitis (EnE)). To identify predictive factors for the visual prognosis of Japanese patients with bacterial endophthalmitis, we retrospectively examined the bacterial endophthalmitis characteristics of 314 Japanese patients and performed statistics using these clinical data. Older patients, with significantly more severe clinical symptoms, were prevalent in the ExE group compared with the EnE group. However, the final best-corrected visual acuity (BCVA) was not significantly different between the ExE and EnE groups. Bacteria isolated from patients were not associated with age, sex, or presence of eye symptoms. Genus Streptococcus, Streptococcus pneumoniae, and Enterococcus were more prevalent in ExE patients than EnE patients and contributed to poor final BCVA. The presence of eye pain, bacterial identification, and poor BCVA at baseline were risk factors for final visual impairment.

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.

RNA-Seq analysis of differentially expressed genes of Staphylococcus epidermidis isolated from postoperative endophthalmitis and the healthy conjunctiva

Staphylococcus epidermidis (S. epidermidis) is one of the primary pathogens in postoperative endophthalmitis, which is a devastating complication of cataract surgery and often results in irreversible visual loss and even blindness. Meanwhile, it is the most frequently isolated commensal bacterium in the healthy conjunctiva. In this study, we investigated the differentially expressed genes (DEGs) of S. epidermidis isolated from the patients with postoperative endophthalmitis and the healthy conjunctiva to predict their functions and pathways by Illumina high-throughput RNA sequencing. Using genome-wide transcriptional analysis, 281 genes (142 upregulated and 139 downregulated genes) were found to be differentially expressed (fold change ≥ 2, p ≤ 0.05) in the strains from endophthalmitis. Ten randomly selected DEGs were further validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). GO enrichment analysis suggested that more DEGs were associated with the thioredoxin system and iron ion metabolism. KEGG pathway analysis revealed that more DEGs were associated with the pathways of the two-component system and pyruvate metabolism. Moreover, the gene SE1634 code for staphylococcal toxin was significantly upregulated in S. epidermidis strains of the endophthalmitis, which might be directly responsible for the pathogenesis of endophthalmitis. In conclusion, this research is helpful for further investigations on genes or pathways related with the pathogenesis and therapeutic targets of S. epidermidis endophthalmitis.

Specific PCR and Quantitative Real-Time PCR in Ocular Samples from Acute and Delayed-Onset Postoperative Endophthalmitis

PURPOSE

Rapid identification of virulent pathogens is essential to strengthen the therapeutic strategy of acute endophthalmitis.

OBJECTIVES

This study sought to compare the contribution of a combination of polymerase chain reaction (PCR)-based tests to culture methods, in patients with postoperative endophthalmitis.

DESIGN

Prospective multicenter study diagnostic evaluation.

METHODS

Setting: university referral centers.

PARTICIPANTS

153 consecutive patients presenting with acute or delayed-onset postoperative endophthalmitis, between 2008 and 2015. There were a total of 284 aqueous humor (AH) and/or vitreous fluid (VF) samples. Outcomes and measurements: microbiological tests of intraocular samples included bacterial culturing of pediatric blood culture bottles; 16SrDNA amplification and sequencing (panbacterial PCR) for detection and identification of all bacterial species; real-time PCR (qPCR) assays targeting the femA or lytA gene for detection of Staphylococcus aureus (S. aureus) or Streptococcus pneumoniae (S. pneumoniae), respectively; and a qPCR assay targeting the tuf gene for detection and quantification of Staphylococcus epidermidis (S. epidermidis).

RESULTS

At the time of admission, the rate of detection of microorganisms by PCR-based tests was not significantly different than that by culturing (38% versus 30% in AH samples [n = 69]; 66% versus 63% in VF samples [n = 82], respectively). In contrast, after 1 intravitreal injection (IVI) of antibiotics, the identification rate by PCR-based tests was higher than that in VF by culturing (62% vs 48%, respectively; n = 94; P = 0.05). Bacteria were identified in 70% of patients, with a predominance of Gram-positive bacteria (93%). Specific qPCR tests targeting S. aureus and S. pneumoniae did not provide additional diagnoses but provided earlier results. The S. epidermidis load in vitreous at the time of patients' admission was higher in cases of final visual acuity (VA) of <20/40 (127,118 ± 125,848 DNA copies/mL) in patients with a VA of ≥20/40 (40350,000 ± 46,912 DNA copies/mL; P = 0.09). No significant changes in S. epidermidis load was found after one IVI.

CONCLUSIONS

Patients with acute or delayed-onset endophthalmitis should benefit from microbiological identification in vitreous samples by combined analysis using bacterial cultures in pediatric blood culture bottles and panbacterial PCR. The last test was more effective than cultures in vitreous samples collected after an IVI of antibiotics. The qPCR tests targeting S. aureus and S. pneumoniae gave earlier results than culture and panbacterial PCR but did not provide additional diagnoses. As for S. epidermidis infections, determination of bacterial load using the qPCR test targeting the tuf gene could help evaluation of the visual prognosis of patients. Its role in the follow-up of patients after antibiotic treatment needs further investigation.