Postoperative low-grade endophthalmitis caused by biofilm-producing coccus bacteria attached to posterior surface of intraocular lens

Clinical Factors, Treatment Selection, and Outcomes in Postcataract Fungal Endophthalmitis from Contaminated Viscoelastics

PURPOSE

To investigate the factors associated with treatment outcomes of postcataract surgery fungal endophthalmitis outbreaks related to contaminated viscoelastics.

DESIGN

Retrospective analysis of clinical data from multiple institutions.

SUBJECTS

This study included 228 eyes of 210 patients who were diagnosed with postcataract surgery fungal endophthalmitis related to the use of viscoelastic material (Unial, Unimed Pharmaceutical Inc); they were followed up for 6 months after the diagnosis.

METHODS

Clinical features and causative species were identified and treatment outcomes were analyzed in patients who underwent 6 months of follow-up. Propensity score matching was conducted to elucidate the impact of vitrectomy timing and intraocular lens (IOL) removal on treatment outcomes.

MAIN OUTCOME MEASURES

Clinical factors and selection of treatment modalities associated with treatment outcomes at 6 months.

RESULTS

Baseline visual acuity (P < 0.01), age (P = 0.05), and the presence of corneal edema (P < 0.01) were closely associated with poor best-corrected visual acuity (BCVA) at 6 months. Patients who underwent immediate vitrectomy after diagnosis showed significantly better BCVA at 6 months (mean logarithm of minimum angle of resolution 0.26 ± 0.43 vs. 0.52 ± 0.52, P = 0.03) and greater degree of visual improvement (mean -0.17 ± 0.37 improvement vs. 0.10 ± 0.57 deterioration, P = 0.03) than those who underwent deferred vitrectomy. Patients who underwent IOL removal during vitrectomy required a lower number of intravitreal antifungal agent injections (mean 8.9 ± 9.1 vs. 16.7 ± 12.2, P < 0.01) and showed a lower incidence of repeated vitrectomy (20% vs. 82%, P < 0.01) than in those without IOL removal.

CONCLUSIONS

In postcataract fungal endophthalmitis, prompt vitrectomy at the time of diagnosis resulted in better treatment outcomes, and IOL removal reduced the treatment burden. Prompt and aggressive surgical intervention should be considered for postcataract fungal endophthalmitis.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

An All-in-One Highly Multiplexed Diagnostic Assay for Rapid, Sensitive, and Comprehensive Detection of Intraocular Pathogens

PURPOSE

Intraocular infections are sight-threatening conditions that can lead to vision loss. Rapid identification of the etiologies plays a key role in early initiation of effective therapy to save vision. However, current diagnostic modalities are time consuming and lack sensitivity and inclusiveness. We present here a newly developed comprehensive ocular panel designed to improve diagnostic yields and provide a tool for rapid and sensitive pathogen detection.

DESIGN

Experimental laboratory investigation.

METHODS

A panel containing 46 pathogens and 2 resistance/virulence markers that are commonly detected in intraocular infections was developed. Genomic targets were scrutinized for stretches predicted to be specific for a particular species while being conserved across different strains. A set of primers for sample enrichment, and two 50mer NanoString compatible probes were then designed for each target. Probe-target hybrids were detected and quantified using the NanoString nCounter SPRINT Profiler. Diagnostic feasibility was assessed in a pilot clinical study testing samples from infectious retinitis (n = 15) and endophthalmitis (n = 12) patients, for which the etiologies were confirmed by polymerase chain reaction (PCR) or culture.

RESULTS

Analytical studies demonstrated highly sensitive detection of a broad spectrum of pathogens, including bacteria, viruses, and parasites, with limits of detection being as low as 2.5 femtograms per reaction. We also found excellent target specificity, with minimal cross-reactivity detected. The custom-designed NanoString ocular panel correctly identified the causative agent from all clinical specimens positive for a variety of pathogens.

CONCLUSION

This highly multiplexed panel for pathogen detection offers a sensitive, comprehensive, and uniform assay run directly on ocular fluids that could significantly improve diagnostics of sight-threatening intraocular infections.

Antibiofilm and repair activity of ozonated oil in liposome

The use of medical devices, such as contact lenses, represents a substantial risk of infection, as they can act as scaffolds for formation of microbial biofilms. Recently, the increasing emergency of antibiotic resistance has prompted the development of novel and effective antimicrobial drugs for biofilm treatment, such as oxidizing agents. The purpose of this study is to investigate the effects of Ozodrop® and Ozodrop® gel, commercial names of ozonated oil in liposomes plus hypromellose, on eradication and de novo formation of biofilms on different supports, such as plastic plates and contact lens. Our results demonstrate that ozonated liposomal sunflower oil plus hypromellose have an excellent inhibitory effect on bacterial viability and on both de novo formation and eradication of biofilms produced on plates and contact lens by Pseudomonas aeruginosa and Staphylococcus aureus. Moreover, we show that Ozodrop® formulations stimulate expression of antimicrobial peptides and that Ozodrop® gel has a strong repair activity on human epithelial cells, suggesting further applications for the treatment of non‐healing infected wounds.

Evaluation of a new method of irrigation and aspiration for removal of ophthalmic viscoelastic device during cataract surgery in a porcine model

BACKGROUND

To determine if a method for irrigation and aspiration (I/A) during cataract surgery provides effective removal of ophthalmic viscoelastic device (OVD).

METHODS

Japanese porcine eyes were used to evaluate I/A performance with Technique 1 (the I/A tip placed on the center of the anterior surface of the IOL), Technique 2 (the I/A tip alternately pressed near the edge of the IOL optic anterior surface on one side and then the other to tilt the IOL back and forth), and Technique 3 (the I/A tip inserted behind the IOL optic, between it and the posterior capsule). Techniques 1 and 2 were compared using the Miyake-Apple posterior view video technique to visualize the flow of irrigation fluid containing triamcinolone acetonide particles behind the IOL. To check the efficacy of OVD removal from behind the IOL for of all three I/A techniques, OVD with fluorescein beads were inserted inside the lens capsule before implantation of the IOL. After each I/A technique, eyes were prepared for Miyake-Apple viewing and pictures of the lens capsule were taken using fluorescent microscopy. Residual fluorescein beads in the capsular bag were analyzed.

RESULTS

Technique 1 resulted in a straight flow of fluid behind the IOL, while Technique 2 resulted in a vortex flow. The average amount of OVD retained inside the capsule after using Technique 2 or 3 was significantly lower than after using Technique 1 (p <0.0001).

CONCLUSIONS

Technique 2 proved to remove more effectively fluorescein bead-labelled OVD under the IOL than Technique 1.

Safety of intracameral injection of moxifloxacin using total replacement technique (bag and chamber flushing)

PURPOSE

To assess the safety of intracameral injection of moxifloxacin (MFLX) using the total replacement technique [bag and chamber (BC) flushing].

METHODS

The anterior chamber including the area behind the intraocular lens was irrigated and replaced using BC flushing. In Group A, 36 patients received balanced salt solution irrigation in the right eye and intracameral MFLX (150 μg/mL: 33-fold dilution of 0.5% eye drops) in the left eye. In Group B, 33 patients received intracameral MFLX in the right (500 μg/mL: 10-fold dilution) and left eyes (150 μg/mL: 33-fold dilution). Visual acuity, intraocular pressure, corneal endothelial cell density, corneal thickness, and foveal thickness were recorded before and up to 3 months after surgery.

RESULTS

In either group, there were no statistically significant differences between the right and left eyes with respect to visual acuity, intraocular pressure, corneal endothelial cell count, and foveal thickness before and at 3 months after surgery. There was no difference in corneal thickness before and at 3 months after surgery. In patients who received 500 μg/mL MFLX during surgery, central corneal thickness at 1 week after surgery was significantly reduced.

CONCLUSIONS

In the present study, there was no adverse effect associated with intracameral injection of 150-500 μg/mL MFLX. Moreover, our results supported the safety of BC flushing. Thus, BC flushing, which can irrigate the inside of the capsular bag and attain stable antibiotic concentrations, appears to be a favorable technique for intracameral injection of MFLX.

Intravitreal injection of the chimeric phage endolysin Ply187 protects mice from Staphylococcus aureus endophthalmitis

The treatment of endophthalmitis is becoming very challenging due to the emergence of multidrug-resistant bacteria. Hence, the development of novel therapeutic alternatives for ocular use is essential. Here, we evaluated the therapeutic potential of Ply187AN-KSH3b, a chimeric phage endolysin derived from the Ply187 prophage, in a mouse model of Staphylococcus aureus endophthalmitis. Our data showed that the chimeric Ply187 endolysin exhibited strong antimicrobial activity against both methicillin-sensitive S. aureus and methicillin-resistant S. aureus (MRSA) strains, as evidenced by MIC determinations, reductions in turbidity, and disruption of biofilms. Moreover, exposure of S. aureus to Ply187 for up to 10 generations did not lead to resistance development. The intravitreal injection of chimeric Ply187 (at 6 or 12 h postinfection) significantly improved the outcome of endophthalmitis, preserved retinal structural integrity, and maintained visual function as assessed by electroretinogram analysis. Furthermore, phage lysin treatment significantly reduced the bacterial burden and the levels of inflammatory cytokines and neutrophil infiltration in the eyes. These results indicate that the intravitreal administration of a phage lytic enzyme attenuates the development of bacterial endophthalmitis in mice. To the best of our knowledge, this is the first study demonstrating the therapeutic use of phage-based antimicrobials in ocular infections.

Pathogenicity of ocular isolates of Acinetobacter baumannii in a mouse model of bacterial endophthalmitis

PURPOSE

To determine the virulence properties of ocular isolates of Acinetobacter baumannii in causing endophthalmitis in a mouse model.

METHODS

Endophthalmitis was induced by intravitreal injections of the bacteria into C57BL/6 (B6) mouse eyes. The disease progression was monitored by ophthalmoscopic, electroretinography (ERG), histologic, cell death (TUNEL labeling), and microbiological parameters. The expression of cytokines/chemokines was checked by quantitative RT-PCR (qRT-PCR) and ELISA. Flow cytometry was used to determine cellular infiltration. The role of neutrophils was determined using neutropenic mice. The virulence traits (biofilm formation, adherence, and cytotoxicity) of the ocular isolates were tested using corneal epithelial cells.

RESULTS

Among the three clinical isolates and a standard ATCC 19606 strain tested, a biofilm producing multidrug resistant (MDR) strain of A. baumannii AB12 caused severe endophthalmitis (100% destruction of the eyes) leading to the loss of retinal function as assessed by ERG analysis. Elevated levels of inflammatory mediators (TNF-α, IL-1β, CXCL2, and IL-6) were detected in AB12-infected eyes. Histologic and TUNEL staining revealed increased retinal cell death and the flow cytometry data showed the presence of inflammatory cells, primarily neutrophils (CD45(+)/Ly6G(+)). Neutropenic mice showed an increased bacterial burden, reduced inflammatory response, and severe tissue destruction.

CONCLUSIONS

These results indicate that A. baumannii causes severe intraocular inflammation and retinal damage. Furthermore, neutrophils play an important role in the pathogenesis of A. baumannii endophthalmitis.

Virulence properties of multidrug resistant ocular isolates of Acinetobacter baumannii

PURPOSE

Acinetobacter (A.) baumannii is an opportunistic pathogen and has been reported as a causative agent of ocular infections. The aim of this study is to identify virulence properties (biofilm formation, adhesion, invasion and cytotoxicity) and antibiotic resistance among A. baumannii isolates recovered from the eye.

MATERIALS AND METHODS

The Microscan Walk-Away®, an automated bacterial identification and susceptibility testing system was used to determine antibiotic resistance. Clonal relatedness was assessed by Pulsed-field gel electrophoresis (PFGE) and plasmid profile analysis. Conjugation experiments were carried out to determine the transfer of antibiotic resistance genes and PCR was used to confirm gene transfer. Virulence properties of the isolates were determined by biofilm formation using crystal violet and immunofluorescence staining, adherence and internalization using cultured corneal epithelial cells, and cytotoxicity by TUNEL-staining and LDH release assays.

RESULTS

All ocular isolates (n = 12) exhibited multidrug resistant (MDR) phenotype and one of the isolate (AB12) was resistant to 18 antibiotics (β-lactam, aminoglycosides, tetracycline, chloramphenicol and quinolones). The plasmid profile analysis showed the presence of multiple plasmids in each isolate and a total of 10 different profiles were observed. However, PFGE analysis was more discriminatory which revealed 12 distinct genotypes. Antibiotic resistance (tetracycline and quinolone) was transferable from the isolate AB12 to a recipient Escherichia coli J53. Ten isolates were strong biofilm producers and the remaining two (AB5 and AB7) were moderate producers. All isolates demonstrated adherence and invasive properties towards HCECs. A similar trend was observed in their ability to cause cell death and toxicity.

CONCLUSIONS

Our results indicate that ocular isolates of A. baumannii are biofilm producers and adherent and invasive to corneal epithelium, a first step in the pathogenesis of ocular infection. In addition, they demonstrated plasmid-mediated transfer of MDR traits making them a reservoir of resistance genes at ocular surface.

A Case of Delayed-Onset Propionibacterium acnes Endophthalmitis after Cataract Surgery with Implantation of a Preloaded Intraocular Lens

Purpose

To report a case of delayed-onset endophthalmitis after implantation of a preloaded intraocular lens (IOL) and examine the surgically removed IOL by scanning electron microscopy (SEM).

Case

A 77-year-old female underwent uneventful phacoemulsification and aspiration with preloaded silicone IOL implantation. Since intraocular inflammation unexpectedly worsened 1 month after the surgery, she was referred to our hospital. Her visual acuity was hand motion in the left eye. Hypopyon and fibrin formation were observed in the anterior chamber. A diagnosis of postoperative delayed-onset endophthalmitis was made, and vitrectomy with anterior chamber wash-out was performed. As intraocular inflammation remained unchanged postoperatively, an additional surgery with IOL removal was performed. We cultivated the surgically removed samples of aqueous humor and vitreous fluid under both aerobic and anaerobic conditions, performed 16S rDNA clone library analysis of these clinical samples, and examined the removed IOL by SEM.

Result

Inflammation subsided after the re-operation. Although cultures of aqueous and vitreous samples were negative, DNA of Propionibacterium acnes was detected in the aqueous humor. The SEM images showed that the rod bacteria and biofilm-like material formed on the tip of the IOL haptic.

Conclusion

Delayed-onset endophthalmitis may occur after uneventful implantation of a preloaded IOL. The SEM findings suggested that the tip of the preloaded IOL haptic might scratch bacteria which adhered to the tip of the injector nozzle when the IOL was inserted into the anterior chamber. In some cases with delayed-onset endophthalmitis, IOL removal is needed to eliminate the bacteria which adhere to the tip of the IOL haptic.

Detection of staphylococcus species by polymerase chain reaction in late-onset endophthalmitis after cataract surgery and posterior capsulotomy

We report a case of late-onset endophthalmitis that developed 5 years after an uneventful phacoemulsification with implantation of a posterior chamber intraocular lens. Posterior capsulotomy was performed with by Nd:YAG laser 1 month after the cataract surgery. Polymerase chain reaction with agarose gel electrophoresis identified a Staphylococcus species in a sample from the aqueous humour. The endophthalmitis was responsive to medical therapy including antibiotic agents, and it resolved without any surgical intervention.