Polyhexamethylene biguanide hydrochloride (PHMB)-properties and application of an antiseptic agent. A narrative review

The prevention and management of ocular surface infections is still one of the great challenges for ophthalmologists. The spread of antimicrobial resistance makes it necessary to use antiseptic substances with a broad antimicrobial spectrum. Polyhexamethylene biguanide hydrochloride (Polyhexanide, PHMB) is a broad-spectrum antiseptic with excellent tolerance and a low-risk profile. Its physicochemical action on the phospholipid membrane and DNA replication or repair mechanism, prevents or impedes the development of resistant bacterial strains. PHMB revealed its effective against numerous organisms like viruses, Gram-negative and Gram-positive bacteria, and fungi. Polyhexanide is commonly used as preservative in commercially available disinfecting solutions for contact lens care and in ophthalmic formulations at different concentrations ranging from 1 µg/ml to 50 µg/ml. The administration of 0.02% (200 µg/ml) PHMB is often the first-line therapy of Acanthamoeba keratitis. However, to date, only one close-out randomized controlled study tested the efficacy of 0.02% PHMB in Acanthamoeba keratitis and a phase III study is still ongoing. This paper reviews the antiseptic agent PHMB, focusing on biochemical mechanisms, safety profile and applications in ophthalmology.

Fungal keratitis caused by Scedosporium apiospermum: a case report

Background

We present a case of fungal keratitis caused by Scedosporium apiospermum, which is a rare agent.

Case description

A 34-year-old Caucasian male patient was admitted to our clinic with complaints of pain and blurred vision in the left eye. The patient had a history of wearing contact lenses for 3 years. According to the Snellen chart, the patient’s visual acuity was 20/20 and counting fingers at 30 cm, for right and left eyes, respectively. A 3 × 3 mm corneal abscess at the center of the cornea with hypopyon in the patient’s left eye was observed. After the patient was hospitalized, fortified gentamicin and fortified cefazolin drops were started 24 times per day. Intravenous fluconazole 1 × 800 mg loading, 1 × 400 mg maintenance dose, intravenous vancomycin 4 × 500 mg and intravenous cefoperazone + sulbactam 2 × 2 g treatments were started. We observed S. apiospermum in the corneal scraping sample, which the identification was performed by combined phenotypic characteristics and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry on the sixth day of treatment. The drops were revised as fortified vancomycin, ceftazidime, and voriconazole drops 24 times per day. Intravenous voriconazole 2 × 6 mg/kg loading and 2 × 4 mg/kg maintenance dose treatments were started. Three weeks later, left eye visual acuity increased to 20/40, and the corneal abscess regressed. On second-year follow-up, his visual acuity increased to 20/25 for the left eye and the cornea was transparent.

Conclusion

Scedosporium group is an opportunistic filamentous fungus that is very rarely seen and causes severe keratitis infections. In the literature, to the best of our knowledge, three cases of keratitis due to S. apiospermum after contact lenses were reported, and all were treated with penetrating keratoplasty. In this case, unlike the others, only medical treatment was applied. In cases with suspected fungal keratitis, medical treatment should be started without waiting for the culture result, the findings should be followed and penetrating keratoplasty should be performed in the case of no response to treatment.

Bilateral Conjunctivitis, Keratitis, and Anterior Uveitis in a Patient Co-infected with Parvovirus B19 and SARS-CoV-2

Parvovirus B-19 (B19V) is a common infection in children, occasionally complicated by ocular manifestations. In patients infected with severe acute respiratory syndrome virus (SARS-CoV-2), many cases of bacterial, fungal, and viral co-infections have been described. We report on a case of bilateral conjunctivitis, keratitis, and anterior uveitis that occurred in a patient co-infected by B19V and SARS-CoV-2. A young nurse developed, 20 days after the onset of asthenia and fever, a maculopapular rash and, in the following month, B19V-related arthritis. Shortly after a course of antibiotics and corticosteroids and the resolution of the arthritis, she began to complain of hearing loss and tinnitus. A polymerase chain reaction for SARS-CoV-2, previously negative, turned out positive; IgM for B19V decreased while IgG increased and antinuclear autoantibody and rheumatoid factor test results were positive. Ear symptoms disappeared after a course of prednisone, but eye burning and itching appeared 2 weeks after the coronavirus disease 2019 (COVID-19) positive swab. Bilateral conjunctivitis, keratitis, and anterior uveitis were diagnosed, which responded completely to a topical corticosteroid and mydriatic therapy. No relapses were observed in the following 12 months. The onset and progression of the symptoms, along with the laboratory findings, suggest a double pathogenesis of the ocular manifestations: keratitis and uveitis, along with the ear symptoms, seem to be the expression of an autoimmune reaction to B19V infection, while the conjunctivitis was likely related to direct infection of the conjunctiva by SARS-CoV-2.

Topical cenegermin associated ocular surface and contact lens drug precipitate deposit formation

Purpose

To report for the first time drug precipitate deposit formation on both the ocular surface and bandage contact lens (BCL) of a patient treated with topical cenegermin.

Observations

A patient suffering from stage III neurotrophic keratitis developed extensive ocular surface and BCL deposits over the eight week course of her topical cenegermin therapy. The ocular surface deposits were weakly adherent, detaching and clearing from the cornea within minutes of BCL removal. They reappeared rapidly and repeatedly however after each of five BCL exchanges. Symptom wise, the patient was unaware of their presence. Of historical note, this patient: (1) developed BCL ciprofloxacin deposits while undergoing a traditional neurotrophic keratitis treatment regimen, (2) did not develop corneal drug precipitate deposits within the placebo arm of the cenegermin clinical trial (vehicle only without cenegermin or BCL), and (3) did not develop corneal deposits with a latter BCL-free cenegermin treatment course.

Conclusions and Importance

Topical cenegermin can produce extensive drug precipitate deposits on both the ocular surface and contact lens when used in conjunction with a bandage contact lens. Such deposits: (1) may represent an esthetic issue only as at least in our patient they were not symptom provoking, questionably interfered with the clinical course of the cenegermin therapy and did not require drug cessation, (2) may implicate both contact lenses and high frequency drug application as previously unidentified but formal risk factors for drug precipitate deposit formation, and (3) may act as a time-release medication reservoir enhancing drug delivery and long-term treatment efficacy.

Use of different stains for microscopic evaluation for the diagnosis of Pythium keratitis

PURPOSE

To evaluate the efficacy of various staining techniques for detection of Pythium in keratitis cases.

METHODS

Data of nineteen consecutive culture-positive cases of Pythium keratitis were retrospectively analysed. Corneal scrapings and corneal buttons (in the cases which underwent therapeutic penetrating keratoplasty [TPK]) were sent for microbiological and histopathological examination. The direct smears were stained with Potassium hydroxide and calcofluor white (KOH ​+ ​CFW), Gram and Iodine-Potassium Iodide-Sulphuric Acid (IKI-H₂SO₄) stains. The corneal buttons were stained with Gomori's Methanamine Silver (GMS), Periodic Acid-Schiff (PAS) and Iodine-Potassium Iodide-Sulphuric Acid (IKI-H₂SO₄) stains. The positivity of various stains in detecting Pythium was studied.

RESULTS

Gram and KOH ​+ ​CFW staining from smear was done in 16 out of 19 (84.2%) cases. KOH ​+ ​CFW and Gram stains were suggestive of Pythium in 10 (62.5%) and 7 (43.8%) cases, respectively. IKI-H₂SO₄ staining in scraping samples was positive for Pythium in all the 4 (100%) cases in which it was performed. Half corneal buttons were positive for Pythium with IKI-H₂SO₄ stain as well as GMS stain in all the 18 cases that underwent TPK (100%). PAS stain showed weak to faint pink staining of Pythium filaments in 7 out of 18 cases (38.9%).

CONCLUSION

IKI-H₂SO₄ stain followed by KOH ​+ ​CFW stain detects Pythium filaments most accurately in corneal scraping samples from keratitis patients, although the differences were not statistically significant. The positivity of the stains depends on astute observation by an experienced ocular microbiologist and pathologist.

Ocular emergencies visits after corneal transplantation at a tertiary eye care hospital in Saudi Arabia

PURPOSE

To evaluate the characteristics of patients with post-keratoplasty complications and their presentation at an emergency center.

DESIGN

Retrospective one-armed cohort study.

METHODS

Data were evaluated on patients who underwent corneal grafts in 2019 and presented to an emergency unit. Data were collected on patient demographics, presenting symptoms, clinical details, diagnosis at emergency visit, final diagnosis, best-corrected visual acuity (BCVA) at presentation and at the last follow-up after management. Severe visual impairment (SVI) and graft rejection were tested for correlations to other factors.

RESULTS

The study sample was comprised of 149 eyes of 124 patients with a mean age of 27.5 years. Keratoconus was the indication for keratoplasty in 94 (75.8%) patients. The main presenting symptoms were pain 57 (38.3%) and red eye in 52 (34.9%) patients. The median interval between emergency visit and keratoplasty was 1.6 years. There were 63 (42.3%) patients who had emergency visits due to suture-related problems. The rates of SVI and graft rejection at the time of discharge after managing emergencies in eyes with previous keratoplasty were 14.1% (95% CI 8.5; 19.7) and 13.4 (95% CI 7.9; 18.9), respectively. Keratoconus (OR = 22.8) and young age (P < 0.001) were negatively associated with SVI after management.

CONCLUSION

Patients with keratoplasty are at high risk for severe vision loss and should be counseled to seek urgent eye care for early detection and management of sight-threatening complications to improve graft survival and vision.

The Risk Factors and Clinical Features of Acanthamoeba Keratitis: First Time Detection of Acanthamoeba T5 Genotype from Keratitis Patients in Turkey

PURPOSE

The primary aim of this study is to investigate Acanthamoeba in clinical samples of keratitis cases (n = 60), in contact lens (CL) and lens care solutions of asymptomatic CL users (n = 41), and to identify the genotypes in positive samples. The secondary aim is to assess the risk factors and clinical features of Acanthamoeba keratitis (AK) patients.

METHODS

All samples from patients and asymptomatic CL users were examined by microscopy and inoculated in non-nutrient agar plates. PCR was performed using the DNA isolated from corneal scrapings, CL and lens care solution samples. Positive DNA samples were sequenced to determine the genotype of Acanthamoeba.

RESULTS

In none of the samples, Acanthamoeba was identified by microscopy, while Acanthamoeba was detected in a patient with keratitis by culture method. However, Acanthamoeba was detected in 11.66% (7/60) of the keratitis patients by PCR. The genotypes of these isolates detected by sequencing were T4 (4), and T5 (3). Acanthamoeba was detected in none of the samples of asymptomatic CL users by any of the three methods.

CONCLUSION

To best of our knowledge, this is the first study to detect T5 genotype in AK patients from Turkey. In addition, the CL use was found to be an important risk factor for AK.

Synergistic effect of TONS504-mediated photodynamic antimicrobial chemotherapy and additives widely contained in ophthalmic solutions: benzalkonium chloride and ethylenediaminetetraacetic acid

TONS504 (C₅₁H₅₈N₈O₅I₂), a chlorine derivative, effectively generates singlet oxygen by light activation and exhibits photodynamic antimicrobial effects (PAEs) on various pathogens. However, this photosensitizer has some limitations: a high tendency to self-aggregate and a relatively weak PAE for Gram-negative bacteria compared with Gram-positive bacteria. To overcome these limitations, the present study investigated the synergistic effects of the PAE of TONS504 and two additives commonly contained in ophthalmic solutions: benzalkonium chloride (BAC) or ethylenediaminetetraacetic acid (EDTA). Staphylococcus aureus and Pseudomonas aeruginosa were exposed to TONS504 and/or each additive. Photodynamic antimicrobial chemotherapy was performed with light irradiation centered at a wavelength of 665 nm with a total light energy of 30 J/cm². Following incubation, the number of colonies formed was counted. Additionally, we examined the inhibitory effects of the additives on TONS504 self-aggregation by observing its absorption spectrum. Consequently, the PAEs of TONS504 on S. aureus were enhanced by both additives, and BAC displayed stronger synergistic effects on the bacteria than EDTA. By contrast, only EDTA increased the PAE on P. aeruginosa. The peak of the TONS504 absorption spectrum shifted to a longer wave length and the absorbance increased in the presence of BAC, suggesting that BAC inhibited the self-aggregation of the photosensitizer. In conclusion, the combination of BAC or EDTA and TONS504-mediated photodynamic antimicrobial chemotherapy exhibits a synergistic antimicrobial effect on S. aureus and P. aeruginosa. The optimal additive to enhance the PAE may differ between bacterial strains.

Spectrum and resistance in bacterial infections of the ocular surface in a German tertiary referral center 2009-2019

Purpose

Aim of this study was to evaluate the frequencies, trends, and antibiotic resistance of bacteria collected from ocular surface or contact lens material in a German tertiary referral center from 2009 to 2019.

Methods

Microbiological data from 2009 to 2019 was analyzed. Culture-dependent microbial identification and analysis of antibiotic sensitivity was completed by the Institute of Microbiology. Statistical analysis of age- and sex-specific differences as well as changes in the microbial spectrum and resistance over the study period was performed with GraphPad Prism 9.0 applying nonparametric tests (level of significance: p ≦ 0.05).

Results

A total of 6361 specimens were analyzed. Positivity rate was 18.6%. Sixty-three percent (n = 680) of the bacterial isolates were derived from ocular surface and 37% (n = 399) from contact lens material. The ratio of gram-negative bacteria was significantly higher in contact lens material. Multiresistant bacteria showed a significant increase with patient age (p < 0.0001). An overall increase in resistance to levofloxacin (p = 0.0239) was detected. Only 2.4% and 3.1% isolates were resistant to a combination of moxifloxacin and gentamicin, respectively, levofloxacin and gentamicin.

Conclusions

The reported bacterial spectrum is similar to comparable centers. Our data show that it should not be assumed that the newest classes of antibiotics have the best efficacy or lowest resistance levels. In suspected bacterial conjunctivitis, we propose using gentamicin as first-line therapy. In therapy refractive cases and in involvement of the cornea, we recommend a combination of gentamicin and ofloxacin or moxifloxacin. Overall, the evaluated organisms showed good sensitivity to the regularly used antibiotics.

Pain and Fatigue Improvements in Patients Treated with Repository Corticotropin Injection Across Five Indications: A Narrative Review

Repository corticotropin injection (RCI; Acthar^® Gel) is approved by the US Food and Drug Administration (FDA) for use in 19 indications, including for the treatment of selected patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), symptomatic sarcoidosis, uveitis, and keratitis. Despite treatment with disease-modifying antirheumatic drugs, many patients with RA, SLE, and other chronic inflammatory rheumatic diseases continue to be affected by severe pain and fatigue, indicating a need for other therapies. To examine the clinical data regarding the impact of RCI treatment on pain and fatigue in selected populations, this review included English-language peer-reviewed publications of clinical trials of any size and cohort studies with more than 10 patients that included pain and/or fatigue based on patient-reported outcomes (PROs) and/or physician-assessed measures in adults following treatment with RCI for RA, SLE, symptomatic sarcoidosis, uveitis, or keratitis. Literature searches identified eight studies that met these criteria. Four studies (reported in five publications) were in patients with RA or SLE, two in patients with sarcoidosis, one in patients with uveitis, and one in patients with noninfectious keratitis. Across the different types of studies assessed (clinical trials, chart reviews, real-world evidence), the results were consistent with respect to the impact of RCI treatment on improving pain and fatigue. As summarized in this review, data from patient- and physician-reported outcome measures in eight studies demonstrate that, in addition to improving more traditional efficacy measures, RCI may also improve pain and fatigue in patients with RA, SLE, symptomatic sarcoidosis, uveitis, and noninfectious keratitis.

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are chronic autoimmune diseases. Clinical studies of drugs for these diseases do not often ask patients how they feel after treatment. Despite treatment, many people with these diseases have pain and feel tired. Repository corticotropin injection (RCI) is a prescription drug for patients with RA, SLE, and other chronic immune diseases. We reviewed the results of published studies with data on pain and fatigue from patients treated with RCI. Four studies were in patients with RA or SLE. Two studies were in patients with symptomatic sarcoidosis. One study was in patients with uveitis. One study was in patients with noninfectious keratitis. These eight studies show that adding RCI to standard treatment lowers pain and fatigue in some patients. It would be helpful to measure pain and fatigue in future clinical studies of drugs for patients with chronic immune diseases.

MCC950 attenuates inflammation-mediated damage in canines with Staphylococcus pseudintermedius keratitis by inhibiting the NLRP3 inflammasome

BACKGROUND

Bacterial keratitis is a common eye disease in dogs and can seriously affect vision. This study investigated the anti-inflammatory effect of MCC950 in the cornea of canines infected with Staphylococcus pseudintermedius (S. pseudintermedius).

METHODS

In vitro, canine cornea epithelial cells were pretreated with MCC950 and PDTC and then infected with S. pseudintermedius. The key proteins of the NF-κB pathway and NLRP3 inflammasome were detected by Western blotting, the levels of inflammatory factors were detected by qPCR, and the levels of MDA and LDH were detected by assay kit. In vivo, the canine keratitis model was established by injecting S. pseudintermedius into the corneal stroma layer. After treatment with MCC950, slit-lamp examinations were performed. Cornea tissue protein and RNA were extracted, and Western blotting was used to detect key proteins of the NF-κB pathway and NLRP3 inflammasome. qPCR was used to detect the inflammatory factors. Paraffin sections of corneal tissue were prepared for HE staining and immunohistochemical staining.

RESULTS

After MCC950 treatment, the expression levels of key proteins in the NF-κB pathway and NLRP3 inflammasome in canine cornea epithelial cells and corneal tissues were decreased, and the expression levels of IL-1β, IL-6, IL-8, IL-18 and TNF-α were reduced. Cellular MDA and LDH levels were decreased. In vivo, the degree of corneal opacity, edema, neovascularization and corneal injury area decreased after MCC950 treatment. Canine corneal sections showed that MCC950 attenuated neutrophil infiltration.

CONCLUSION

MCC950 alleviates the inflammatory response to canine keratitis caused by S. pseudintermedius by inhibiting the activation of the NLRP3 inflammasome.

[Atypical Cogan syndrome as a differential diagnosis of sudden sensorineural hearing loss]

Cogan I syndrome is a rare disease consisting of vestibulocochlear symptoms and non-syphilitic interstitial keratitis. Although this disease was first described in 1945, its pathogenesis is still unknown. An autoimmune vasculitis etiology is currently discussed. Atypical manifestations are characterized by delayed ocular symptoms or variability of inflammatory eye symptoms. Physical examination often reveals bilateral sensorineural hearing loss. Intratympanic corticosteroid application can be successful.

Pythium insidiosum keratitis - A review

Pythium insidiosum is an oomycete and is also called “parafungus” as it closely mimics fungal keratitis. The last decade saw an unprecedented surge in Pythium keratitis cases, especially from Asia and India, probably due to growing research on the microorganism and improved diagnostic and treatment modalities. The clinical features such as subepithelial infiltrate, cotton wool-like fluffy stromal infiltrate, satellite lesions, corneal perforation, endoexudates, and anterior chamber hypopyon closely resemble fungus. The classical clinical features of Pythium that distinguish it from other microorganisms are reticular dots, tentacular projections, peripheral furrowing, and early limbal spread, which require a high index of clinical suspicion. Pythium also exhibits morphological and microbiological resemblance to fungus on routine smearing, revealing perpendicular or obtuse septate or aseptate branching hyphae. Culture on blood agar or any other nutritional agar is the gold standard for diagnosis. It grows as cream-colored white colonies with zoospores formation, further confirmed using the leaf incarnation method. Due to limited laboratory diagnostic modalities and delayed growth on culture, there was a recent shift toward various molecular diagnostic modalities such as polymerase chain reaction, confocal microscopy, ELISA, and immunodiffusion. As corneal scraping (10% KOH, Gram) reveals fungal hyphae, antifungals are started before the culture results are available. Recent in vitro molecular studies have suggested antibacterials as the first-line drugs in the form of 0.2% linezolid and 1% azithromycin. Early therapeutic keratoplasty is warranted in nonresolving cases. This review aims to describe the epidemiology, clinical features, laboratory and molecular diagnosis, and treatment of Pythium insidiosum keratitis.

Atypical presentation of acanthamoeba keratitis resembling central toxic keratopathy

PURPOSE

To describe an atypical case of acanthamoeba keratitis with positive in vivo confocal microscopy in a non-contact lens user who presented with signs and symptoms suggestive of central toxic keratopathy.

OBSERVATIONS

The patient presented with bilateral, though sequential, decreased visual acuity with mild pain. Examination showed stromal haze with corneal flattening and thinning without epithelial defects. Optical coherence tonometry of the right eye revealed an inverse dome-shaped appearance of the opacity and in-vivo confocal imaging showed double-walled cysts consistent with acanthamoeba. Corneal haze, stromal loss, resolved and visual acuity improved over time.

CONCLUSION AND IMPORTANCE

Acanthamoeba is a rare cause of infectious keratitis that is most often associated with contact lens wear in developed countries. Typically, it presents with a unilateral decrease in visual acuity, photophobia, watering, and pain that is out of proportion to slit lamp examination findings. However, many atypical presentations have been reported in the literature. Consequently, it may be misdiagnosed, especially early in the course of the disease. This delay in diagnosis can lead to progressive ulceration and visual impairment. In addition, cyst formation can make eradication with anti-amoebic treatment especially difficult.Central toxic keratopathy is a non-inflammatory clinical syndrome of unknown etiology that is most often associated with excimer laser ablation, though other associated causes have been reported. It is characterized by a central or paracentral opacity with corneal stromal loss and resultant hyperopic shift. The opacification and stromal loss mostly resolve over the course of months with an improvement in visual acuity. This report may help physicians broaden their differential and correctly diagnose atypical presentations of amoebic infection.

Peripheral ulcerative keratitis secondary to severe hidradenitis suppurativa

Purpose

To describe a unique case of peripheral ulcerative keratitis secondary to isolated, severe hidradenitis suppurativa (HS).

Observation

A 31-year-old male with HS presented with a red painful right eye with best corrected visual acuity of count fingers at 3 feet with peripheral corneal thinning, inferior descemetocele, and adjacent infiltrate. Work-up revealed negative corneal cultures and positive ANA, ANCA, and rheumatoid factor without other autoimmune or rheumatologic history or symptomatology. He was treated with topical corticosteroids with improvement until he was lost to follow-up before tumor necrosis factor-a inhibitor therapy could be started. Upon re-presentation, he was found to have corneal perforation.

Conclusions and importance

Coexistence of inflammatory eye disease and HS is known but rare, and most commonly manifests as anterior uveitis. Here we present a unique case of peripheral ulcerative keratitis secondary to HS and demonstrate the importance of ophthalmologists’ familiarly with this systemic disease and its variety of ocular manifestations.

A Systematic Review of Multi-decade Antibiotic Resistance Data for Ocular Bacterial Pathogens in the United States

INTRODUCTION

Since 2009, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study has been assessing in vitro antibiotic resistance for bacterial isolates sourced from ocular infections in the US. The main goal of this systematic review was to compare in vitro resistance data for ocular pathogens from published US studies with the most recently published data from the ARMOR study (2009-2018) and, where possible, to evaluate trends in bacterial resistance over time over all studies.

METHODS

A literature search was conducted using MEDLINE®, BIOSIS Previews®, and EMBASE^® databases (1/1/1995-6/30/2021). Data were extracted from relevant studies and antibiotic susceptibility rates for common ocular pathogens (Staphylococcus aureus, coagulase-negative staphylococci [CoNS], Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae), longitudinal changes in susceptibility, and multidrug resistance (MDR) were compared descriptively.

RESULTS

Thirty-two relevant studies were identified. High in vitro resistance was found among S. aureus and CoNS to fluoroquinolones, macrolides, and methicillin/oxacillin across studies, with high rates of MDR noted, specifically among methicillin-resistant staphylococci. Data from studies pre-dating or overlapping the early years of ARMOR reflected increasing rates of S. aureus resistance to fluoroquinolones, macrolides, methicillin/oxacillin, and aminoglycosides, while the ARMOR data suggested slight decreases in resistance to these classes between 2009 and 2018. Overall, methicillin-resistant S. aureus (MRSA) prevalence peaked from 2005 to 2015 with a possible decreasing trend in more recent years.

DISCUSSION AND CONCLUSIONS

Data from local and regional US datasets were generally consistent with data from the national ARMOR surveillance study. Continued surveillance of ocular bacterial pathogens is needed to track trends such as methicillin resistance and MDR prevalence and any new emerging antibiotic resistance phenotypes. Susceptibility data from ARMOR can inform initial choice of therapy, especially in practice areas where local antibiograms are unavailable.

Treatment of recalcitrant Acanthamoeba Keratitis with Photoactivated Chromophore for Infectious Keratitis Corneal Collagen Cross-Linking (PACK-CXL)

PURPOSE

To describe a case of recalcitrant Acanthamoeba Keratitis (AK) complicated by medical non-compliance and medication intolerance that was successfully treated with photoactivated chromophore for infectious keratitis corneal collagen cross-linking (PACK-CXL).

OBSERVATIONS

A 31-year-old male presented with right eye pain and redness in the setting of fresh water exposure and scleral contact lens wear. He had lack of a response to treatment with antiviral therapy for 3 months by an outside provider. Cultures were found to be positive for Acanthamoeba and the patient was treated with an extended course of various anti-amoebic therapies with poor compliance due to pain and toxicity. He was eventually treated with intrastromal voriconazole and Miltefosine without improvement and eventually had PACK-CXL with resolution of his infection and pain.

CONCLUSION

PACK-CXL was associated with a dramatic improvement in a case of recalcitrant Acanthamoeba keratitis unresponsive to both traditional and novel therapies and may be a viable alternative or adjunctive therapy for Acanthamoeba keratitis.

Trichostatin A inhibits dendritic cell maturation through down-regulating NF-κ B (p65) pathway

BACKGROUND

Recent evidence suggested that histone deacetylase inhibitor (HDACi) could inhibit dendritic cell (DC) maturation. However, the mechanism is unclear. Here, we aimed to study whether Trichostatin A (TSA), the most widely studied HDACi, inhibits the maturation of DCs by down-regulating NF-κB (p65) pathway.

METHODS AND RESULTS

Mouse bone marrow-derived DCs were cultured. Lipopolysaccharide (LPS) was applied as stimulation for maturation. Triptolide (TTL) was applied as p65 inhibitor. Microphotography and flow cytometry showed that TSA and p65 inhibitor separately inhibited the maturation of DCs stimulated by LPS from the aspects of cell morphology and cell phenotype. Mixed lymphocyte reaction test and ELISA showed that TSA and p65 inhibitor synergistically inhibited the proliferation of T lymphocytes stimulated by DCs, reduced the secretion of pro-inflammatory cytokine IL-12 and elevated the secretion of anti-inflammatory cytokine IL-10. Western blot and RT-qPCR showed that TSA down-regulated the expression of phosphorylated IκBα, phosphorylated-p65, Ikkβ and Ikkγ, suggesting TSA down-regulates NF-κB (p65) pathway.

CONCLUSIONS

TSA inhibits DC maturation through down-regulating NF-κB (p65) pathway.

Features of the clinical picture of keratitis in horses with different forms of the course of the disease

Background

Keratitis is a common cause of eye diseases in horses, often resulting in complete loss of vision.

Aim

The purpose of this article is to study the features of the clinical picture of primary and secondary keratitis in horses, depending on the form of the course of the disease.

Methods

The study was conducted in 2019 at 22 private horse breeding farms. The study involved 80 horses with keratitis, which were divided into two equal groups depending on the diagnosis of primary or secondary keratitis.

Results

The effectiveness of the therapies was compared 1, 3, and 6 months after the start of treatment. Following a 1-month therapy, only a minority of horses with primary keratitis had their eye functions fully restored, the number of horses with macula was two times higher (p ≤ 0.05), the number of horses with nebula was seven times higher (p ≤ 0.001), and leukomas were reported in most of the cases ( p ≤ 0.0001).

Conclusion

The effectiveness of the therapy for keratitis is directly related to the peculiarities of treatment and adherence to the regimen.

A Rare Case of Atypical Cogan's Syndrome Presenting as Encephalitis

Cogan's syndrome (CS) is a rare autoimmune vasculitis of unknown aetiology characterised by non-syphilitic interstitial keratitis, audio-vestibular symptoms, sometimes systemic symptoms and multi-organ involvement. Atypical CS has other ocular features such as scleritis, episcelritis, retinitis and optic neuritis. Diagnosis of CS is purely clinical without a confirmatory test. Hereby, we report a case of atypical CS presenting with features of encephalitis who was treated successfully with intravenous pulse methylprednisolone with cyclophosphamide. It is important to consider Cogan's syndrome in the differential diagnosis of encephalitis with ocular and vestibular symptoms in young patients, as high morbidity and mortality rates are effectively lowered by early immunosuppressive treatment.

Clinical factors associated with positive corneal culture in suspected microbial keratitis

AIMS

Determine demographic and clinical characteristics associated with positive culture in suspected microbial keratitis.

METHODS

Retrospective audit of patients that had corneal scrapings between October 1999-September 2004 at Princess Alexandra Hospital. Clinical information was gathered from medical records, smear and culture results from the local microbiology database. Univariate and multivariate analyses of variables associated with positive cultures and calculation of population attributable risk percentage (PAR).

RESULTS

Univariate analysis showed that positive cultures were associated with patients over 60 years (81% vs 55%; p < 0.001), presenting visual acuity (VA) of 6/24 or worse (74% vs 57%; p = 0.012) or contact lens-related keratitis (CLK 77% vs 62%; p = 0.08). Analysis of patients' clinical presentation showed that positive culture was associated with a central epithelial defect (74% vs 57%; p = 0.012), anterior chamber reaction of 2 + cells or worse (73% vs 56%; p = 0.03), an epithelial defect of 2 mm or more in diameter (71% vs 50%; p = 0.006) or no prior treatment with antibiotics (68% vs 56%; p = 0.053). Multivariate analysis showed the independent variables associated with positive cultures were VA of 6/24 or worse on presentation, contact lens-related keratitis, age greater than 60 years, an anterior chamber reaction of 2 + cells or worse and no prior treatment with antibiotics. The factor with the highest attributable risk (PAR%) for a positive corneal scraping was VA of 6/24 or worse on presentation (21%).

CONCLUSIONS

In this series positive cultures were associated with poor presenting VA contact lens keratitis (CLK), older age, anterior chamber reaction and no prior treatment with antibiotics.

Raman spectroscopy may allow rapid noninvasive screening of keratitis and conjunctivitis

Keratitis and conjunctivitis are the most common ocular diseases, their symptoms are similar and easy to confuse, however infectious conjunctivitis is highly contagious. If misdiagnosed, it may worsen the disease and pose a threat to public health.This is a preclinical study to propose a method for rapid and accurate screening of keratitis and conjunctivitis by combining tear Raman spectroscopy with deep learning models that may be applied to clinical applications in the future.The tears of 16 cases of keratitis patients, 13 cases of conjunctivitis patients and 46 cases of healthy subjects were collected, and their Raman spectra were compared and analyzed. By adding different decibels of Gaussian white noise to expand the data, the performance of the tear Raman spectra with a large sample size in the deep learning model was discussed. Principal component analysis (PCA), partial least squares (PLS) and maximum correlation minimum redundancy (mRMR) were used for feature extraction. The processed data were imported into convolutional neural network (CNN) and recurrent neural network (RNN) depth models for classification. After the data were enhanced and processed by PLS, the highest classification accuracy of healthy subjects and keratitis patients, healthy subjects and conjunctivitis patients, and keratitis and conjunctivitis patients reached 94.8%, 95.4%, and 92.7%, respectively. The results of this study show that the use of large sample tear Raman spectra data combined with PLS feature extraction and depth learning algorithms may have great potential in clinical screening of keratitis and conjunctivitis.

Pythium insidiosum keratitis reported in China, raising the alertness to this fungus-like infection: a case series

Background

The objective of this study is to report typical clinical and laboratory characteristics of three cases of keratitis caused by Pythium insidiosum in China.

Case presentation

Three Chinese patients of Han nationality diagnosed with Pythium keratitis from 2017 to 2019 were included. One 45-year-old female and one 55-year-old male were exposed to river water, and one 51-year-old female was burned by ash in the eyes. All of them are of Han ethnicity. Upon slit-lamp examination, subepithelial and superficial stromal opacities were observed in a reticular pattern. After conventional treatment with antifungal agents, the clinical status worsened and therapeutic penetrating keratoplasty was performed. Unfortunately, enucleation was performed to remove all infected tissue and relieve pain. Pythium insidiosum was identified in culture and confirmed by internal transcribed spacer ribosomal RNA gene sequencing analysis. Following the systemic and local antibiotic regimens, the patients were cured ultimately and no regression of infection was observed.

Conclusions

It is significant for ophthalmologists and microbiologist to be alert to this eye-threatening infection, especially in patients who are resistant to antifungal treatments and with water-related exposure.