Current evidence for topical azithromycin 1% ophthalmic solution in the treatment of blepharitis and blepharitis-associated ocular dryness

Composition and Diversity of the Ocular Surface Microbiota in Patients With Blepharitis in Northwestern China

Purpose: To investigate the composition and diversity of the microbiota on the ocular surface of patients with blepharitis in northwestern China via 16S rDNA amplicon sequencing.

Methods: Thirty-seven patients with blepharitis divided into groups of anterior, posterior and mixed blepharitis and twenty healthy controls from northwestern China were enrolled in the study. Samples were collected from the eyelid margin and conjunctival sac of each participant. The V3–V4 region of bacterial 16S rDNA in each sample was amplified and sequenced on the Illumina HiSeq 2500 sequencing platform, and the differences in taxonomy and diversity among different groups were compared.

Results: The composition of the ocular surface microbiota of patients with blepharitis was similar to that of healthy subjects, but there were differences in the relative abundance of each bacterium. At the phylum level, the abundances of Actinobacteria, Cyanobacteria, Verrucomicrobia, Acidobacteria, Chloroflexi, and Atribacteria were significantly higher in the blepharitis group than in the healthy control group, while the relative abundance of Firmicutes was significantly lower (p < 0.05, Mann-Whitney U). At the genus level, the abundances of Lactobacillus, Ralstonia, Bacteroides, Akkermansia, Bifidobacterium, Escherichia-Shigella, Faecalibacterium, and Brevibacterium were significantly higher in the blepharitis group than in the healthy control group, while the relative abundances of Bacillus, Staphylococcus, Streptococcus, and Acinetobacter were significantly lower in the blepharitis group (p < 0.05, Mann-Whitney U). The microbiota of anterior blepharitis was similar to that of mixed blepharitis but different from that of posterior blepharitis. Lactobacillus and Bifidobacterium are biomarkers of posterior blepharitis, and Ralstonia is a biomarker of mixed blepharitis. There was no significant difference in the ocular surface microbiota between the eyelid margin and conjunctival sac with or without blepharitis.

Conclusion: The ocular surface microbiota of patients with blepharitis varied among different study groups, according to 16S rDNA amplicon sequencing analysis. The reason might be due to the participants being from different environments and having different lifestyles. Lactobacillus, Bifidobacterium, Akkermansia, Ralstonia, and Bacteroides may play important roles in the pathogenesis of blepharitis.

[Treatment of chronic blepharitis]

The most effective method of treating chronic blepharitis - a disease with multifactorial pathogenesis requiring an individual approach - is a combination of remedial measures that addresses eyelids hygiene and includes medicated and device therapy.

Efficacy of azithromycin 1.5% eyedrops vs oral doxycycline in meibomian gland dysfunction: a randomized trial

PURPOSE

To determine the efficacy of azithromycin 1.5% eyedrops compared with oral doxycycline in patients with moderate to severe meibomian gland dysfunction (MGD).

METHODS

This prospective randomized trial included 169 participants with newly diagnosed moderate to severe MGD. Participants were randomly assigned to treatment with azithromycin 1.5% eyedrops (n = 85) twice daily for 2 days then once daily until 4 weeks or oral doxycycline (n = 84) 100 mg twice daily for 4 weeks. Signs and symptoms of MGD were evaluated at baseline and 4 weeks later. The percentages of participants with improvement in meibum quality were assessed as a primary outcome. Secondary outcomes were MGD-related symptoms, meibum expressibility, Oxford ocular surface staining score, tear film break up time (TBUT), and drug side effects.

RESULTS

Although there were significant improvements in all outcomes in both groups, there was no between-group differences in the percentages of participants with improved meibum quality (P = 0.80), MGD-related symptoms (P > 0.05), meibum expressibility (P = 0.92), Oxford ocular surface staining score (P = 0.59), and TBUT (P = 0.99). Five (5.88%) participants in azithromycin group and four (4.76%) participants in doxycycline group discontinued medications due to drug side effects (P = 0.75).

CONCLUSIONS

Both azithromycin 1.5% eyedrops and oral doxycycline significantly improved signs and symptoms in patients with moderate to severe MGD. Both azithromycin 1.5% eyedrops and oral doxycycline showed no difference in term of improved signs and symptoms of MGD as well as drug side effects that lead to discontinuation of medication.

Acute allergic reaction caused by topical azithromycin eye drops: A report of two cases

Azithromycin 1.5% ophthalmic solution (Azyter®, Thea Pharmaceuticals, Newcastle, UK) is an effective and well-tolerated option for the treatment of bacterial conjunctivitis and blepharitis, and has the advantage of a shorter treatment duration than other topical antibiotics. No acute allergic reaction has yet been reported in response to topical azithromycin eye drops. Here, we report two cases with unusual acute-type allergic reaction to topical azithromycin eye drops. A 63-year-old female patient and 67-year-old male patient treated for blepharitis with topical azithromycin 1.5% eye drops presented with epiphora, eyelid edema, chemosis, conjunctival injection, hyperemia, intensive papillary reaction, and rhinitis within 30 min of instillation. Upon cessation of the topical medication and administration of antiallergic therapy, both patients immediately showed dramatic improvement. Acute-type allergic reaction to topical azithromycin eye drops may be a rare side effect, but ophthalmologists should keep this possibility in mind and inform the patients about its potential occurrence.

Reduction in bacterial load using hypochlorous acid hygiene solution on ocular skin

Purpose

To examine the magnitude of bacterial load reduction on the surface of the periocular skin 20 minutes after application of a saline hygiene solution containing 0.01% pure hypochlorous acid (HOCl).

Methods

Microbiological specimens were collected immediately prior to applying the hygiene solution and again 20 minutes later. Total microbial colonies were counted and each unique colony morphology was processed to identify the bacterial species and to determine the susceptibility profile to 15 selected antibiotics.

Results

Specimens were analyzed from the skin samples of 71 eyes from 36 patients. Prior to treatment, 194 unique bacterial isolates belonging to 33 different species were recovered. Twenty minutes after treatment, 138 unique bacterial isolates belonging to 26 different species were identified. Staphylococci accounted for 61% of all strains recovered and Staphylococcus epidermidis strains comprised 60% of the staphylococcal strains. No substantial differences in the distribution of Gram-positive, Gram-negative, or anaerobic species were noted before and after treatment. The quantitative data demonstrated a >99% reduction in the staphylococcal load on the surface of the skin 20 minutes following application of the hygiene solution. The total S. epidermidis colony-forming units were reduced by 99.5%. The HOCl hygiene solution removed staphylococcal isolates that were resistant to multiple antibiotics equally well as those isolates that were susceptible to antibiotics.

Conclusion

The application of a saline hygiene solution preserved with pure HOCl acid reduced the bacterial load significantly without altering the diversity of bacterial species remaining on the skin under the lower eyelid.

Effects of azithromycin on gene expression profiles of proinflammatory and anti-inflammatory mediators in the eyelid margin and conjunctiva of patients with meibomian gland disease

IMPORTANCE

Topical application of azithromycin suppresses expression of proinflammatory mediators while restoring transforming growth factor β1 (TGF-β1) levels as evaluated by eyelid margin and conjunctival impression cytology.

OBJECTIVE

To explore the effects of azithromycin therapy on expression of proinflammatory and anti-inflammatory mediators in meibomian gland disease (MGD).

DESIGN, SETTING, AND PARTICIPANTS

Case-control study performed in a clinic setting from August 17, 2010, to December 31, 2010. Sixteen patients with posterior blepharitis and conjunctival inflammation due to MGD were treated with azithromycin, 1%, drops for 4 weeks. Impression cytology of the lower eyelid margin and tarsal conjunctiva to measure cytokine expression by quantitative real-time polymerase chain reaction as well as tear collection to measure matrix metalloproteinase 9 (MMP-9) activity were performed once in 8 asymptomatic healthy control participants and 5 times in the 16 symptomatic patients (every 2 weeks for 8 weeks), before, during, and after azithromycin treatment.

EXPOSURE

Azithromycin, 1%, drops for 4 weeks.

MAIN OUTCOMES AND MEASURES

Cytokine expression in the eyelid margin and conjunctiva, and MMP-9 activity in tears.

RESULTS

Compared with a 1-time measurement of 8 healthy participants, among 16 symptomatic patients, the mean (SD; 95% CI) fold change of expression of proinflammatory mediators interleukin 1β (IL-1β), IL-8, and MMP-9 increased to 13.26 (4.33; 11.14-15.38; P < .001), 9.38 (3.37; 7.73-11.03; P < .001), and 13.49 (4.92; 11.08-15.90; P < .001), respectively, in conjunctival cells and to 11.75 (3.96; 9.81-13.69; P < .001), 9.31 (3.28; 7.70-10.92; P < .001), and 11.52 (3.50; 9.81-13.24; P < .001), respectively, in the eyelid margin of patients with MGD. In contrast, the mean (SD; 96% CI) fold change of expression of TGF-β1 messenger RNA (mRNA) decreased to 0.58 (0.25; 0.46-0.70; P = .02) and 0.63 (0.14; 0.56-0.70; P = .02) in conjunctival and eyelid margin cells, respectively, of patients with MGD. Azithromycin, 1%, caused a change in the expression pattern of these mediators toward normal levels during 4 weeks of treatment. Levels of IL-1β, IL-8, and MMP-9 mRNA remained suppressed, although they rebounded toward pretreatment values 4 weeks after azithromycin withdrawal. Expression of TGF-β1 increased during treatment and remained at levels similar to the healthy controls after drug withdrawal. Change in tear MMP-9 activity was similar to the pattern of MMP-9 transcripts.

CONCLUSIONS AND RELEVANCE

While the study did not control for potential confounding factors over time independent of the intervention that may have contributed to the results, topical azithromycin suppressed expression of proinflammatory mediators and increased expression of TGF-β1 to normal levels. Increased TGF-β1 expression may contribute to the anti-inflammatory activity of azithromycin in MGD.

An update on dry eye disease molecular treatment: advances in drug pipelines

INTRODUCTION

Dry eye disease is a common disorder provoking changes in tear film and ocular surface. Untreated dry eye could cause ocular infections, corneal ulcer and blindness. Only a few drugs are authorized so far for the treatment of dry eye disease and the possibilities of evolution in this sector are immense. Consequently, a significant number of new potential solutions are under development or placed in the pharmaceutical pipeline, promising better results and lesser side effects.

AREAS COVERED

In this article, the corresponding literature and recent Phase III clinical trial data and the corresponding literature, for dry eye disease treatment are reviewed, revealing the new strategic movements in drug pipelines.

EXPERT OPINION

From the clinical trial results, the advancement in tear substitutes and secretagogues in addressing specific deficiencies of tear components even though not resolving the underlying conditions of the disease is evident. The vast majority of new compounds under development are anti-inflammatories, steroids, non-steroids and antibiotics; however, there are also some novel lubricating drops and mucin-tear secretagogues. A future aggressive therapy for dry eye, depending on the severity of the symptoms, would include combinations of soft steroids, anti-inflammatories, such as cyclosporine A, with the addition of the new polyvalent mucin and tear secretagogues.

Antimicrobial Agents in Ophthalmology

Many types of antimicrobial agents have been introduced for the treatment of ocular infectious diseases. Some ocular infections have been eradicated such as smallpox, while others have been controlled by public health measures such as trachoma. The resilience of viruses and the tenacity of bacteria have led to the evolution of old diseases and the emergence of new infections. Continuous search for new antimicrobial agents for the treatment of infectious diseases is, therefore, highly desirable.

New infectious agents are discovering the human race, and the ecological changes are exposing mankind to new viruses and bacteria. In addition, air travel and disruption of geographic barriers are leading to new forms of infectious diseases.

In the twentieth century, there was a widespread false optimism that infectious diseases are eradicated by antimicrobial agents. It was soon discovered that many infections require new strategies for the treatment of ocular infections.

The new antimicrobial agents that have been introduced over the past century can be classified into four major categories including (1) antibiotics that inhibit cell wall synthesis and integrity, (2) antibiotics that inhibit and suppress cell membrane functions, (3) antibiotics that interfere the protein synthesis, and (4) antibiotics that modulate nucleic acid synthesis.

The selection of antimicrobial agents for the treatment of ocular infectious diseases is based on the most frequently encountered organisms, the pharmacokinetics of the antibiotics, the dosage required, the ocular penetration, and the cost of therapy. The stumbling blocks to safe and effective antimicrobial therapy in ocular infections include the resistance of the microorganisms, toxicity of the drug, and poor ocular penetration of antimicrobial agents.

Short-term azithromycin treatment promotes cornea allograft survival in the rat

Background

Any inflammatory response following corneal transplantation may induce rejection and irreversible graft failure. The purpose of this study is to analyze the anti-inflammatory effect of azithromycin (AZM) following experimental keratoplasty in rats.

Methods

Corneal transplants were performed between Fisher-donor and Lewis-recipient rats. Recipients were postoperatively treated three times daily with AZM, miglyol, ofloxacin or dexamethasone eye drops. As an additional control, AZM was applied following syngeneic keratoplasty. Furthermore, short-term treatments with AZM for seven days perioperatively or with AZM only three days prior to the transplantation were compared to appropriate controls. All transplants were monitored clinically for opacity, edema, and vascularization. Infiltrating CD45⁺, CD4⁺, CD8⁺, CD25⁺, CD161⁺ and CD163⁺ cells were quantified via immunohistochemistry.

Results

AZM significantly promoted corneal graft survival compared with miglyol or ofloxacin treatment. This effect was comparable to topical dexamethasone. No adverse AZM effect was observed. Histology confirmed a significant reduction of infiltrating leukocytes. The short-term application of AZM for three days prior to transplantation or for seven days perioperatively reduced corneal graft rejection significantly compared with the controls.

Conclusions

Along with antibiotic properties, topical AZM has a strong anti-inflammatory effect. Following keratoplasty, this effect is comparable to topical dexamethasone without the risk of steroid-induced adverse effects. Short-term treatment with AZM three days prior to the transplantation was sufficient to promote graft survival in the rat keratoplasty model. We therefore suggest further assessing the anti-inflammatory function of topical AZM following keratoplasty in humans.

New agents for treating dry eye syndrome

Dry eye syndrome (DES) is characterized by an inadequate volume and/or quality of tears resulting in chronic ocular surface irritation and inflammation. Affecting up to 30 % of adults, DES has a considerable impact on visual function and quality of life. DES may complicate allergic ocular disease and allergy medication may exacerbate DES. The pathophysiology of DES involves osmotic, mechanical and inflammatory insults to the tear film, epithelium and subepithelial nerve plexus. Various immune-related molecular targets have been the focus of research aimed at developing new therapeutic agents for treating DES. This article provides an overview of established, new and future agents for treating DES.

Emerging drugs for the treatment of dry eye disease

INTRODUCTION

Dry eye disease (DED) is a common, age-related ocular condition that in its mildest forms causes bothersome symptoms of ocular discomfort, fatigue, and visual disturbance that interfere with quality of life and in its more severe forms causes chronic pain and fluctuating vision. Though it is highly prevalent and costs billions of dollars to manage, current treatments have largely been inadequate, making it a frustrating condition, both for physicians and patients alike.

AREAS COVERED

This article will cover the recently discovered pathophysiology of DED that has prompted investigators to explore new molecules that target the core mechanisms that drive DED. These include anti-inflammatory/immune-modulatory drugs, secretagogues, lubricant, hormones, and autologous serum. Their potential mechanism of action and data from recent trials on efficacy/safety will be reviewed.

EXPERT OPINION

The emerging drugs have a vast range of putative mechanisms of action that may not only provide symptomatic relief but may potentially break the vicious cycle of DED and provide long-lasting cure. Current and future research may change our perspective on DED and redefine its treatment algorithms.

Changes in ocular flora in eyes exposed to ophthalmic antibiotics

PURPOSE

To determine changes in ocular flora in individuals repeatedly exposed to topical macrolide or fluoroquinolone antibiotics.

DESIGN

Prospective, controlled, longitudinal study with 1-year follow-up.

PARTICIPANTS

Forty-eight eyes of 24 patients undergoing serial unilateral intravitreal injection for choroidal neovascularization.

METHODS

Patients received 4 consecutive monthly unilateral intravitreal injections and were then treated as needed. Each patient was randomized to 1 of 4 antibiotics (azithromycin 1%, gatifloxacin 0.3%, moxifloxacin 0.5%, ofloxacin 0.3%) and used only their assigned antibiotic for 4 days after each injection. Conjunctival cultures of the treated eye and untreated fellow eye (control) were taken at baseline and before each injection. All bacterial isolates were tested for antibiotic susceptibility to 16 different antibiotics using the Kirby-Bauer disc diffusion technique.

MAIN OUTCOME MEASURES

Changes in bacteria composition of the conjunctiva over time.

RESULTS

In azithromycin-treated eyes, Staphylococcus epidermidis and Staphylococcus aureus accounted for 54.5% and 18.2% of cultured isolates, respectively, at baseline and 90.9% (P<0.01) and 4.5% (P<0.01), respectively, after azithromycin exposure. In fluoroquinolone-treated eyes, 45.7% and 6.5% of cultured isolates at baseline were S epidermidis and S aureus, respectively, but these percentages increased to 63.4% (P<0.03) and 13% (P = 0.24), respectively, after fluoroquinolone exposure. In contrast, the percentage of gram-negative species decreased from 8.7% at baseline to 1.6% (P<0.05) in fluoroquinolone-treated eyes. The percentage of S epidermidis isolated from azithromycin-treated eyes was significantly greater when compared with fellow control eyes (P<0.01) or fluoroquinolone-treated eyes (P<0.01).

CONCLUSIONS

The percentage of S epidermidis isolated from the conjunctival surface significantly increases after repeated exposure to azithromycin and to a lesser degree fluoroquinolone antibiotics at the expense of other commensal flora.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.