Role of steroids in the treatment of bacterial keratitis

Recurrence of perforation and overall patient survival after penetrating keratoplasty versus amniotic membrane transplantation in corneal perforation

PURPOSE

The following is a comparative analysis on the treatment outcomes of corneal perforations using amniotic membrane transplantation (AMT) or penetrating keratoplasty (PK).

METHODS

This monocentric retrospective study was performed at the Department of Ophthalmology, University Hospital Ulm, Germany. A total of 78 eyes of 78 patients were included. Thirty-nine eyes received an AMT, and 39 patients were treated with a PK. Primary outcome was recurrence of perforation. Secondary outcomes were patient mortality and visual acuity.

RESULTS

No statistically significant difference was observed with regard to a recurrence of perforation between the two groups (26% in AMT vs 23% in PK, p > 0.99). The time of recurrences was within the first two years and did not differ statistically (p = 0.97). In addition, a proportional hazards model with cox regression regarding recurrent perforation showed no significant differences (p = 0.5). After AMT, 41% and after KP, 28% of the patients died during follow-up (p = 0.2), respectively. The Charlson Comorbidity Index (p < 0.0001) and the age at the time of surgery (p = 0.0002) were statistically significantly higher in those who were deceased. A mean follow-up of 485 ± 517 days was recorded.

CONCLUSION

Both surgical methods show good results and no statistically significant difference regarding recurrent perforation rate. About a third of the patients died during the follow-up period. The decision regarding the appropriate method should therefore be based on a combination of all factors.

A Retrospective Review of the Safety and Efficacy of Low-dose Triamcinolone Mixed with Hyaluronic Acid Fillers to Reduce Post-injection Infraorbital Swelling

OBJECTIVE

This retrospective review assesses the efficacy and safety of low-dose triamcinolone (1mg/cc) added to hyaluronic acid fillers to decrease swelling after infraorbital injection.

METHODS

This retrospective analysis includes 447 patients who underwent 706 infraorbital hyaluronic acid filler treatments from April 2013 to March 2020 by a single injector. Short-term post-procedural swelling (≤2 weeks) was assessed through follow-up phone calls, which were documented in patient charts. The effect of triamcinolone, filler type, volume, and patient characteristics on the rate of post-procedure swelling were analyzed.

RESULTS

Swelling after infraorbital hyaluronic acid filler occurred in over half of the patients (51%, 103/202), but significantly decreased (23%, 29/124) when 1mg/cc of triamcinolone was mixed with the filler (x2[1, N=326]=24.296, p<0.00001). The incidence of swelling was directly correlated with the amount of hyaluronic acid filler injected (37% ≤ 0.55cc, 51% 0.56-1cc, and 60% >1cc) [x2[1, N=95]=3.9231, p=.048]. There was no significant difference in patient age, sex, Fitzpatrick skin type, or history of allergies on incidence of post-procedure swelling. Adverse events were limited to expected injection-site reactions, and there were no reports of hypopigmentation or atrophy from the addition of triamcinolone.

LIMITATIONS

This is a retrospective study that used patient reporting for short-term post procedure swelling.

CONCLUSION

This is the first retrospective study showing the safety and efficacy of a novel technique adding low-dose triamcinolone (1mg/cc) to hyaluronic acid filler to reduce post-procedure swelling within the first few weeks following infraorbital injection. Additionally, using lower volumes is also effective at reducing post-procedure swelling. Larger, randomized, controlled trials are needed to support our findings.

Suture-Related Fungal Interstitial Interface Keratitis in Deep Anterior Lamellar Keratoplasty: A Case Report

Interstitial interface keratitis (IIK) in lamellar keratoplasty is a term used to describe infectious keratitis that primarily involves the graft-host interface. It poses specific challenges due to impaired access for microbiological testing and poor penetration of antimicrobial drugs, as well as ease of deeper extension of the microorganism. A 33-year-old male with a medical history of left eye deep anterior lamellar keratoplasty (DALK) with keratoconus, subsequently complicated with steroid-induced glaucoma controlled with Xen tube insertion, presented with acute left eye pain and redness for two days due to one broken corneal graft suture at 5 o’clock position with infiltrate at the graft-host junction. He was treated for suture-related bacterial keratitis (culture-negative) with intensive single broad-spectrum topical antibiotic after suture removal. However, the condition worsened, with dense stromal infiltrate extending into the graft-host interface junction which further progressed to an endothelial plaque. Systemic and topical antifungal treatments were started with adjunctive intracameral and subconjunctival voriconazole before improvement was observed. The condition was resolved with localized scarring without the need for repeat keratoplasty. The best-corrected vision was maintained at 6/36 due to residual sutured-related astigmatism with no signs of corneal graft rejection. Lamellar keratoplasty poses an increased risk of fungal IIK even after several years if there is a predisposing factor e.g., steroid usage and broken suture. Timely diagnosis and intervention are the keys to ensure an optimal outcome.

Treatment of Non-Infectious Corneal Injury: Review of Diagnostic Agents, Therapeutic Medications, and Future Targets

Corneal injuries can occur secondary to traumatic, chemical, inflammatory, metabolic, autoimmune, and iatrogenic causes. Ocular infection may frequently occur concurrent to corneal injury; however, antimicrobial agents are excluded from this present review. While practitioners may primarily rely on clinical examination techniques to assess these injuries, several pharmacological agents, such as fluorescein, lissamine green, and rose bengal, can be used to formulate a diagnosis and develop effective treatment strategies. Practitioners may choose from several analgesic medications to help with patient comfort without risking further injury or delaying ocular healing. Atropine, cyclopentolate, scopolamine, and homatropine are among the most frequently used medications for this purpose. Additional topical analgesic agents may be used judiciously to augment patient comfort to facilitate diagnosis. Steroidal anti-inflammatory agents are frequently used as part of the therapeutic regimen. A variety of commonly used agents, including prednisolone acetate, loteprednol, difluprednate, dexamethasone, fluorometholone, and methylprednisolone are discussed. While these medications are effective for controlling ocular inflammation, side effects, such as elevated intraocular pressure and cataract formation, must be monitored by clinicians. Non-steroidal medications, such as ketorolac, bromfenac, nepafenac, and diclofenac, are additionally used for their efficacy in controlling ocular inflammation without incurring side effects seen with steroids. However, these agents have their own respective side effects, warranting close monitoring by clinicians. Additionally, ophthalmologists routinely employ several agents in an off-label manner for supplementary control of inflammation and treatment of corneal injuries. Patients with corneal injuries not infrequently have significant ocular surface disease, either as a concurrent pathology or as an exacerbation of previously existing disease. Several agents used in the management of ocular surface disease have also been found to be useful as part of the therapeutic armamentarium for treatment of corneal injuries. For example, several antibiotics, such as doxycycline and macrolides, have been used for their anti-inflammatory effects on specific cytokines that are upregulated during acute injuries. There has been a recent wave of interest in amniotic membrane therapies (AMTs), including topical, cryopreserved and dehydrated variants. AMT is particularly effective in ocular injuries with violation of corneal surface integrity due to its ability to promote re-epithelialization of the corneal epithelium. Blood-based therapies, including autologous serum tears, plasma-enriched growth factor eyedrops and autologous blood drops, have additionally been explored in small case series for effectiveness in challenging and recalcitrant cases. Protection of the ocular surface is also a vital component in the treatment of corneal injuries. Temporary protective methods, such as bandage contact lenses and mechanical closure of the eyelids (tarsorrhaphy) can be particularly helpful in selective cases. Glue therapies, including biologic and non-biologic variants, can also be used in cases of severe injury and risk of corneal perforation. Finally, there are a variety of recently introduced and in-development agents that may be used as adjuvant therapies in challenging patient populations. Neurotrophic corneal disease may occur as a result of severe or chronic injury. In such cases, recombinant human nerve growth factor (cenegermin), topical insulin, and several other novel agents may be an alternate and effective option for clinicians to consider.

Double-masked, sham and placebo-controlled trial of corneal cross-linking and topical difluprednate in the treatment of bacterial keratitis: Steroids and Cross-linking for Ulcer Treatment Trial (SCUT II) study protocol

INTRODUCTION

Although antibiotics are successful at achieving microbiological cure in infectious keratitis, outcomes are often poor due to corneal scarring. Ideal treatment of corneal ulcers would address both the infection and the inflammation. Adjunctive topical steroid treatment may improve outcomes by reducing inflammation. Corneal cross-linking (CXL) is a novel prospective therapy that may simultaneously reduce both inflammatory cells and bacterial pathogens. The purpose of this study is to determine differences in 6-month visual acuity between standard medical therapy with antibiotics versus antibiotics with adjunctive early topical steroid therapy versus antibiotic treatment plus CXL and early topical steroids.

METHODS AND ANALYSIS

This international, randomised, sham and placebo-controlled, three-arm clinical trial randomises patients with smear positive bacterial ulcers in a 1:1:1 fashion to one of three treatment arms: (1) topical 0.5% moxifloxacin plus topical placebo plus sham CXL; (2) topical 0.5% moxifloxacin plus difluprednate 0.05% plus sham CXL; or (3) the CXL group: topical 0.5% moxifloxacin plus difluprednate 0.05% plus CXL.

ETHICS AND DISSEMINATION

We anticipate that both adjunctive topical steroids and CXL will improved best spectacle corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via ClinicalTrials.gov website, meetings and journal publications. Our data will also be available on reasonable request.

TRIAL REGISTRATION NUMBER

NCT04097730.

Topical Corticosteroids for Infectious Keratitis Before Culture-Proven Diagnosis

Purpose

In clinical practice we sometimes encounter patients with severe corneal ulcers who have been treated with topical corticosteroids. This study reviewed the clinical features and visual outcomes of these patients and investigated the background of the prescription of topical corticosteroids.

Patients and Methods

The medical records of patients who visited the Cornea Service at Fujita Health University Bantane Hospital and were treated for infectious keratitis from April 2016 to March 2020 were retrospectively reviewed. Patients treated with topical corticosteroids before a culture-proven diagnosis were studied in terms of demographics, best-corrected visual acuity at arrival and at last visit, the clinical course after visit, ocular history, and combination therapy by the previous ophthalmologist.

Results

Out of the 200 eyes of 197 patients with infectious keratitis, 14 eyes of 14 patients were treated with topical corticosteroids before a culture-proven diagnosis. All 14 patients were referred, as they had severe keratitis that could not be cured with topical antibiotics and corticosteroids. Based on the culture results, we diagnosed Acanthamoeba keratitis (AK) in six patients, fungal keratitis (FK) in two patients, bacterial keratitis (including a suspected case) in two patients, and unknown cause in four patients. Two patients with AK, FK, and unknown keratitis had unfortunate clinical courses and poor visual outcomes. From the information in the referral letters, at least six of the 14 patients were treated with either acyclovir ocular ointment or valaciclovir tablets, along with topical corticosteroids.

Conclusion

Application of topical corticosteroids for keratitis that does not respond to empirical antibiotic therapy is harmful since AK or FK is likely involved in these topical antibiotic-resistant cases. Microbiological evidence, as well as a differential diagnosis of herpetic stromal keratitis, is needed when prescribing topical corticosteroid for the treatment of suspected infectious keratitis.

Analysis of differentially expressed genes in bacterial and fungal keratitis

Purpose:

This study was aimed at identifying differentially expressed genes (DEGs) in bacterial and fungal keratitis. The candidate genes can be selected and quantified to distinguish between causative agents of infectious keratitis to improve therapeutic outcomes.

Methods:

The expression profile of bacterial or fungal infection, and normal corneal tissues were downloaded from the Gene Expression Omnibus. The limma package in R was used to screen DEGs in bacterial and fungal keratitis. The Co-Express tool was used to calculate correlation coefficients of co-expressed genes. The “Advanced network merge” function of Cytoscape tool was applied to obtain a fusional co-expression network based on bacterial and fungal keratitis DEGs. Finally, functional enrichment analysis by DAVID software and KEGG analysis by KOBAS of DEGs in fusion network were performed.

Results:

In total, 451 DEGs in bacterial keratitis and 353 DEGs in fungal keratitis were screened, among which 148 DEGs were found only in bacterial keratitis and 50 DEGs only in fungal keratitis. Besides, 117 co-expressed gene pairs were identified among bacterial keratitis DEGs and 87 pairs among fungal keratitis DEGs. In total, nine biological pathways and seven KEGG pathways were screened by analyzing DEGs in the fusional co-expression network.

Conclusion:

TLR4 is the representative DEG specific to bacterial keratitis, and SOD2 is the representative DEG specific to fungal keratitis, both of which are promising candidate genes to distinguish between bacterial and fungal keratitis.

Tear Fluid Pharmacokinetics Following Oral Prednisone Administration in Dogs With and Without Conjunctivitis

Purpose: To describe the pharmacokinetics (PK) of prednisone and prednisolone in tear fluid of dogs receiving oral prednisone at anti-inflammatory to immunosuppressive doses and to assess the impact of induced conjunctivitis on lacrimal drug levels. Methods: Six healthy Beagle dogs were administered 4 courses of prednisone at 0.5, 1.0, 2.0, and 4.0 mg/kg given orally once a day for 5 days. At steady state, topical histamine was applied to induce mild (1 mg/mL) or severe (375 mg/mL) conjunctivitis in 1 eye of each dog and tear samples were collected from both eyes at selected times. Prednisone and prednisolone were quantified in tears by liquid chromatography-mass spectrometry. Results: Lacrimal prednisone and prednisolone concentrations ranged from 2 to 523 ng/mL and 5 to 191 ng/mL, respectively. Drug concentrations were overall greater in dogs receiving higher doses of prednisone, but were not correlated with tear flow rate. Eyes with conjunctivitis often had larger amounts of prednisone and prednisolone in tear fluid compared to control eyes (up to +64%), but differences were not statistically significant. Significantly greater, but clinically insignificant, levels of prednisolone were found in eyes with severe versus mild conjunctivitis for oral prednisone doses ≥1.0 mg/kg. Conclusions: Disruption of the blood-tear barrier with conjunctivitis did not significantly affect drug levels in tears. Based on drug PK in tears, oral prednisone is likely safe for the management of reflex uveitis and ocular surface diseases. However, further prospective trials using systemic corticotherapy in diseased animals are warranted to confirm findings from this preclinical study.

Vaccine-induced antibodies target sequestered viral antigens to prevent ocular HSV-1 pathogenesis, preserve vision, and preempt productive neuronal infection

The cornea is essential for vision yet highly sensitive to immune-mediated damage following infection. Generating vaccines that provide sterile immunity against ocular surface pathogens without evoking vision loss is therefore clinically challenging. Here, we tested a prophylactic live-attenuated vaccine against herpes simplex virus type 1 (HSV-1), a widespread human pathogen that can cause corneal blindness. Parenteral vaccination of mice resulted in sterile immunity to subsequent HSV-1 challenge in the cornea and suppressed productive infection of the nervous system. This protection was unmatched by a relevant glycoprotein subunit vaccine. Efficacy of the live-attenuated vaccine involved a T-dependent humoral immune response and complement C3 but not Fcγ-receptor 3 or interferon-α/β signaling. Proteomic analysis of viral proteins recognized by antiserum revealed an unexpected repertoire dominated by sequestered antigens rather than surface-exposed envelope glycoproteins. Ocular HSV-1 challenge in naive and subunit-vaccinated mice triggered vision loss and severe ocular pathologies including corneal opacification, scar formation, neovascularization, and sensation loss. However, corneal pathology was absent in mice receiving the live-attenuated vaccine concomitant with complete preservation of visual acuity. Collectively, this is the first comprehensive report of a prophylactic vaccine candidate that elicits resistance to ocular HSV-1 infection while fully preserving the cornea and visual acuity.

Listeria monocytogenes and ocular abscess: an atypical but yet potential association

PURPOSE

To report a farmer's corneal abscess caused by an unusual pathogen: Listeria monocytogenes fluoroquinolone resistant.

METHODS

A 78-year-old farmer presented a central corneal abscess associated with 1-mm hypopyon and decreased visual acuity evolving since 2 weeks. First an antibiotic therapy associating oral ofloxacin and topical ciprofloxacin, vancomycin and ceftazidime was started. Different samples of the abscess were performed and sent to different microbiological laboratories.

RESULT

Listeria monocytogenes was isolated after 2 days of culture. Antibiotics sensitivity showed resistance to ciprofloxacin, fosfomycin and fusidic acid. Ceftazidime was changed for gentamicin, and after 1 month of treatment the abscess decreased considerably.

CONCLUSION

This case demonstrated that even if Listeria is rarely involved in ocular abscess, it must be evocated for people with risk factors as farmers. This suspicion should lead to an extended incubation to identify the pathogen. The analysis of Listeria resistance is essential to start an efficient therapy.

Super-Cationic Carbon Quantum Dots Synthesized from Spermidine as an Eye Drop Formulation for Topical Treatment of Bacterial Keratitis

We have developed a one-step method to synthesize carbon quantum dots (CQD_PAs) from biogenic polyamines (PAs) as an antibacterial agent for topical treatment of bacterial keratitis (BK). CQDs synthesized by direct pyrolysis of spermidine (Spd) powder through a simple dry heating treatment exhibit a solubility and yield much higher than those from putrescine and spermine. We demonstrate that CQDs obtained from Spds (CQD_Spds) possess effective antibacterial activities against non-multidrug-resistant Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica serovar Enteritidis bacteria and also against the multidrug-resistant bacteria, methicillin-resistant S. aureus. The minimal inhibitory concentration (MIC) of CQD_Spds is ∼2500-fold lower than that of spermidine alone, demonstrating their strong antibacterial capabilities. Investigation of the possible mechanisms behind the antibacterial activities of the as-synthesized CQD_Spds indicates that the super-cationic CQD_Spds with small size (diameter ca. 6 nm) and highly positive charge (ζ-potential ca. +45 mV) cause severe disruption of the bacterial membrane. In vitro cytotoxicity, hemolysis, hemagglutination, genotoxicity, and oxidative stress and in vivo morphologic and physiologic cornea change evaluations show the good biocompatibility of CQD_Spds. Furthermore, topical ocular administration of CQD_Spds can induce the opening of the tight junction of corneal epithelial cells, thereby leading to great antibacterial treatment of S. aureus-induced BK in rabbits. Our results suggest that CQD_Spds are a promising antibacterial candidate for clinical applications in treating eye-related bacterial infections and even persistent bacteria-induced infections.

Corticosteroids effects on LPS-induced rat inflammatory keratocyte cell model

Purpose

Corticosteroids are efficient anti-inflammation treatments. However, there are still arguments on whether it should be used in keratitis. This study was to observe the effect of corticosteroids on keratocytes both in normal condition and inflammation status in vitro.

Methods

Rat keratocytes were cultured and used for examination. 10 μg/ml lipopolysaccharide (LPS) was used to establish the inflammatory keratocyte cell model, and prednisolone acetate (PA), dexamethasone (Dex) and fluorometholone (Flu) were used as corticosteroids treatments. 5 d-growth curve and cell viabilities were assayed by CCK8, and cell morphologies and migration rate were studied. TNF-α, IL-6 and IL-1β levels were examined by ELISA. Western blotting was used to quantified type VI collagen (Col VI) and matrix metalloproteinase 9 (MMP9) expressions, and immunofluorescence staining assays of Col I and Col VI were carried out.

Results

In normal condition, proliferation and migration of keratocytes were slightly influenced in PA, Dex and Flu groups. The secretion of Col I and Col VI was suppressed and MMP9 expression increased in corticosteroids groups. But no significant difference was seen in TNF-α, IL-6 and IL-1β expression levels. In inflammatory status, TNF-α, IL-6 and MMP9 levels increased in LPS group, while they significantly decreased in corticosteroids groups. Although keratocytes viabilities and migration were slightly affected in 24 h, no significant differences were seen between LPS group and corticosteroids groups in 5-d proliferation. Col I and Col VI secretion in LPS-keratocytes was maintained with corticosteroids treatments.

Conclusions

Corticosteroids showed lightly effects on keratocytes proliferation and migration, but it successfully decreased TNF-α, IL-6 level and maintained the secretion of and Col I and Col VI, while suppressed the expression of MMP9 in LPS-induced keratocytes. PA was suggested to use in early stage of keratitis clinical treatment.

Anti-Infective and Anti-Inflammatory Pharmacotherapies

Ocular infection and inflammation are common and are associated with myriad ocular conditions ranging from mild disease to blinding conditions. There are numerous anti-invectives with spectra against inciting pathogens. Given the potential for ocular infections to rapidly progress initial broad spectrum therapy is usually required, with therapy tailored as microbiological identification and sensitivities become available. The emergence of antibiotic resistance has become a major health problem. Anti-inflammatory therapy can be institutes to prevent ocular symptoms and end-organ damage. A therapy should be selected which is potent enough to interrupt the inflammatory cascades in play, but which avoids potential side effects. Glucocorticoids, NSAIDs, and biological agents may be used singularly or in combination. New drug delivery devices may allow for better local treatment of chronic ocular inflammation.