Cross-Linking Assisted Infection Reduction (CLAIR): A Randomized Clinical Trial Evaluating the Effect of Adjuvant Cross-Linking on Bacterial Keratitis.

PURPOSE: To determine whether there is a benefit to adjuvant corneal cross-linking (CXL) for bacterial keratitis. METHODS: This is an outcome-masked, randomized controlled clinical trial. Consecutive patients presenting with a smear-positive bacterial ulcer at Aravind Eye Hospitals at Madurai, Pondicherry, and Coimbatore in India were enrolled. Study eyes were randomized to topical moxifloxacin 0.5% or topical moxifloxacin 0.5% plus CXL. The primary outcome of the trial was microbiological cure at 24 hours on repeat culture. Secondary outcomes included best spectacle corrected visual acuity at 3 weeks and 3 months, percentage of study participants with epithelial healing at 3 weeks and 3 months, infiltrate and/or scar size at 3 weeks and 3 months, 3-day smear and culture, and adverse events. RESULTS: Those randomized to CXL had 0.60 decreased odds of culture positivity at 24 hours (95% confidence interval [CI]: 0.10-3.50; P = 0.65), 0.9 logarithm of the minimum angle of resolution lines worse visual acuity (95% CI: -2.8 to 4.6; P = 0.63), and 0.41-mm larger scar size (95% CI: -0.48 to 1.30; P = 0.38) at 3 months. We note fewer corneal perforations or need for therapeutic penetrating keratoplasty in the CXL group. CONCLUSIONS: We were unable to confirm a benefit to adjuvant CXL in the primary treatment of moderate bacterial keratitis. However, CXL may reduce culture positivity and complication rates; therefore, a larger trial to fully evaluate this is warranted. TRIAL REGISTRATION: NCT02570321.

Drugs - Do we need them? Applications of non-pharmaceutical therapy in anterior eye disease: A review.

Natural products have been in use long before the introduction of modern drug therapies and are still used in various communities worldwide for the treatment of anterior eye disease. The aim of this review is to look at the current non-pharmaceutical modalities that have been tried and assess the body of existing evidence behind them. This includes alternative medicine, existing non-pharmaceutical therapy and more recent low and high tech solutions. A detailed search of all available databases including MEDLINE, Pubmed and Google was made to look for English-language studies for complementary and alternative treatment modalities (CAM), natural therapies and new modalities for anterior eye disease such as blepharitis, dry eye and microbial keratitis. We have included a broad discussion ranging from traditional treatments like honey and aloe vera which have been used for centuries, to the more recent technological advances like Intense Pulsed Light (IPL), LipiFlow and photoactivated chromophore for corneal cross linking in infectious keratitis (PACK-CXL). Alternative management strategies may have a role in anterior eye diseases and have a potential in changing the way we currently approach them. Some of the available CAM could play a role if incorporated in to current management practices of not only chronic diseases like blepharitis and dry eye, but also acute conditions with significant morbidity like microbial keratitis. Further large-scale randomized control trials stratified by disease severity are required to improve our understanding and to evaluate the use of non-pharmaceutical therapy against current practice.

Efficacy of Primary Collagen Cross-Linking with Photoactivated Chromophore (PACK-CXL) for the Treatment of Staphylococcus aureus-Induced Corneal Ulcers.

PURPOSE: To evaluate the efficacy of corneal collagen cross-linking (CXL) with photoactivated riboflavin (PACK-CXL) as primary therapy for Staphylococcus aureus-induced corneal ulcers in a rabbit model. METHODS: The right eye of 40 rabbits was inoculated with S. aureus to induce formation of central corneal ulcers (day 1). The ulcer was examined on day 5, and rabbits were randomly assigned to 4 groups-group A: no treatment (control); group B: topical antibiotic treatment (cefazolin 50 mg/mL, garamycin 14 mg/mL drops, chloramphenicol 5% ointment every 2 hours); group C: PACK-CXL; group D: PACK-CXL + topical antibiotics. Follow-up by biomicroscopy was performed on day 5 and then every week for 1 month. The main outcome measures included infiltrates or the scar diameter, time to healing, time to full epithelialization, and a change in corneal thickness. RESULTS: After 1 month of treatment, group C ulcers had the smallest mean scar diameter (8.8 mm), followed by groups D (11.2 mm), B (13.0 mm), and A (24.5 mm) (P = 0.011). Group C had the shortest mean healing time (15.5 days), followed by groups D (17.2 days), B (19.7 days), and A (21.8 days). Analysis of relative reduction in the infiltrate size from day 5 yielded better results for groups C (P = 0.039) and D (P = 0.034) than those of group B. CONCLUSIONS: We demonstrate a beneficial effect of PACK-CXL as primary treatment, either as stand-alone or as an adjuvant to antimicrobial therapy.

Penetration and effectiveness of prophylactic fluoroquinolones in experimental methicillin-sensitive or methicillin-resistant Staphylococcus aureus anterior chamber infections.

PURPOSE: To determine the effectiveness of moxifloxacin and besifloxacin prophylactic therapy for experimental Staphylococcus aureus infections originating in the rabbit anterior chamber. SETTING: Microbiology Department, University of Mississippi Medical Center, Jackson, Mississippi, USA. DESIGN: Experimental study. METHODS: Minimum inhibitory concentrations (MICs) of moxifloxacin 0.5% and besifloxacin 0.6% for methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) strains were determined. Eyes were treated with moxifloxacin, a moxifloxacin alternative formulation 0.5%, or besifloxacin (45 µL) 30 minutes or 60 minutes before anterior chamber infection (10(6) colony-forming units [CFUs]). Aqueous humor was removed 30 minutes after infection for quantification of antibiotic and bacteria. RESULTS: The MIC for both organisms was 0.06 µg/mL for moxifloxacin and 0.03 µg/mL for besifloxacin. In MSSA infections, the untreated eyes contained 5.18 log CFU/mL, which was similar to besifloxacin-treated eyes with either treatment (P≥.1091). Eyes treated with moxifloxacin or moxifloxacin alternative formulation contained significantly fewer CFUs than untreated controls or besifloxacin-treated eyes with either treatment (P≤.0020). The aqueous humor in eyes treated with moxifloxacin or moxifloxacin alternative formulation contained significantly more drug than besifloxacin-treated eyes at both prophylactic time points (P≤.0012). In MRSA infections, the untreated eyes contained 4.91 log CFU/mL, which was similar to besifloxacin-treated eyes with either treatment (P≥.5830). Eyes treated with moxifloxacin or moxifloxacin alternative formulation contained significantly fewer CFUs than untreated controls or besifloxacin-treated eyes at both prophylactic time points (P≤.0008). CONCLUSIONS: Moxifloxacin had greater in vivo effectiveness against MSSA and MRSA than besifloxacin. The aqueous antibiotic concentrations suggest limited penetration by besifloxacin, accounting for its lack of effectiveness.

Subconjunctival delivery of antibiotics in a controlled-release system: a novel anti-infective prophylaxis approach for cataract surgery.

OBJECTIVE: To compare the efficacy of subconjunctival injection of a combination of triamcinolone and ciprofloxacin hydrochloride, 2 mg/0.1 mL, in a controlled-release system (DuoCat) with that of ciprofloxacin hydrochloride, 0.3%, eyedrops for infection prophylaxis. METHODS: Rabbit eyes were injected subconjunctivally with a combination of triamcinolone and ciprofloxacin hydrochloride, 2 mg/0.1 mL, or ciprofloxacin hydrochloride, 2 mg/0.1 mL, alone. The aqueous and vitreous humor pharmacokinetic profiles were compared with those of a single drop of ciprofloxacin hydrochloride, 0.3%, 6 times daily. In 45 rabbits, Staphylococcus aureus was injected into the anterior chamber: 15 randomly received 1 drop of ciprofloxacin hydrochloride, 0.3%, every 4 hours during 24 hours; 15 received drops of balanced salt solution; and 15 received a combination of triamcinolone and ciprofloxacin hydrochloride, 2 mg/0.1 mL. After 24 hours, endophthalmitis scores were recorded, aqueous and vitreous humors underwent culture, and histologic analysis was performed. RESULTS: The combined triamcinolone and ciprofloxacin treatment allowed higher intraocular levels of ciprofloxacin. The median endophthalmitis clinical scores for the combination of triamcinolone and ciprofloxacin and ciprofloxacin-only eyedrop groups were equivalent (P = .42) and were significantly lower than those of the balanced salt solution group (P < .001). The culture was negative for S aureus in the combined triamcinolone and ciprofloxacin and ciprofloxacin eyedrop regimens. No adverse effects were observed with either route. CONCLUSIONS: Ciprofloxacin eyedrops and combined triamcinolone and ciprofloxacin were equally tolerated and efficacious. The combined triamcinolone and ciprofloxacin treatment may eliminate noncompliance issues and may prove to be a valuable clinical tool for surgical prophylaxis. CLINICAL RELEVANCE: The combined triamcinolone and ciprofloxacin treatment may be a new useful strategy for surgical prophylaxis.

Ophthalmic infections and their anti-infective challenges.

This introduction provides an overview of the succeeding articles contained within this supplement on the new fourth-generation fluoroquinolone antibiotic product, moxifloxacin ophthalmic solution 0.5% (VIGAMOX, Alcon Laboratories, Inc., Fort Worth, TX). Moxifloxacin was developed specifically to address the increasing incidence of resistance to earlier-generation antibiotic molecules. Structural modifications to the moxifloxacin molecule have decreased the likelihood of the development of resistant organisms. This antibiotic has been shown to possess greater activity than previous-generation molecules against gram-positive bacteria while maintaining excellent potency against gram-negative organisms and nontuberculous (atypical) mycobacteria. Moxifloxacin ophthalmic solution 0.5% exhibits enhanced bioavailability due to a unique molecular structure that combines high lipophilicity for enhanced corneal penetration with high aqueous solubility at physiological pH. Numerous studies have shown that moxifloxacin ophthalmic solution 0.5% has high potency against a broad range of microbial species and a favorable profile in terms of safety and tolerability. The results presented in this supplement provide additional evidence for the potential benefits of moxifloxacin ophthalmic solution 0.5% in surgical prophylaxis and treatment of sight-threatening infections, such as bacterial conjunctivitis, endophthalmitis and keratitis.

Ocular pharmacokinetics of moxifloxacin after topical treatment of animals and humans.

The ocular penetration and pharmacokinetics of moxifloxacin in comparison to other fluoroquinolones (ofloxacin, ciprofloxacin, gatifloxacin, norfloxacin, levofloxacin, and lomefloxacin) have been determined by in vitro and ex vivo techniques, as well as in animal and human studies. This article reviews the original pharmacokinetics work performed by Alcon and other studies reported in the ocular fluoroquinolone literature. The results consistently demonstrate higher maximum concentrations for moxifloxacin relative to the other fluoroquinolones in ocular tissues with levels well above its minimum inhibitory concentrations for relevant ocular pathogens. This superior performance is due to the unique structure of moxifloxacin that combines high lipophilicity for enhanced corneal penetration with high aqueous solubility at physiological pH. The latter property creates a high concentration gradient at the tear film/corneal epithelial interface providing a driving force for better ocular penetration for moxifloxacin. In addition, the higher concentration of moxifloxacin in VIGAMOX (i.e., 0.5% vs. 0.3%) allows more antibiotic to be available to ocular tissues. It is clear from the array of studies summarized in this report that moxifloxacin penetrates ocular tissues better (two- to three-fold) than gatifloxacin, ciprofloxacin, ofloxacin, or levofloxacin. This consistent, enhanced penetration of topical moxifloxacin offers powerful advantages for ophthalmic therapy.

Heat treatment enhances healing process of experimental pseudomonas corneal ulcer.

We investigated the effects of hyperthermia on the healing process of experimental Pseudomonas corneal ulceration (PCU). Hartley guinea pigs were used to develop animal models of PCU. As a heat source, disposable chemical pocket warmers were applied. The healing process of PCU was compared between the heat-treated corneas and the control corneas. The severity of infection and the degree of angiogenesis were classified by a clinical scoring system. The animals were euthanized 14 days after infection and the corneas were submitted for histopathological examination. The expression of vascular endothelial growth factor (VEGF) was examined immunohistochemically. Comparative reverse transcription polymerase chain reaction was performed to measure the expression level of VEGF in the cornea. Hyperthermia significantly promoted corneal epithelization and neovascularization in the PCU model. Heat treatment significantly decreased the number of viable Pseudomonas organisms present in PCU. On immunohistochemistry, the heated cornea demonstrated more intense staining for VEGF. Comparative reverse transcription polymerase chain reaction showed upregulation of the expression level of VEGF mRNA in the heat-treated cornea. Hyperthermia accelerated the healing process of PCU with increased corneal neovascularization. Angiogenesis may play an important role in the PCU healing process, which is enhanced by the heat treatment.

Treatment of experimental Staphylococcus epidermidis endophthalmitis with oral trovafloxacin.

PURPOSE: To investigate the ocular pharmacokinetics and efficacy of oral trovafloxacin, a novel fluoroquinolone antibiotic, in Staphylococcus epidermidis endophthalmitis. METHODS: Albino rabbits (n = 20) were infected with an intravitreal inoculum of S epidermidis (1.0 x 10(8) colony-forming units [CFU/0.1 ml) and 24 hours later received a single oral dose of trovafloxacin (250 mg/kg). Serum and intraocular samples from infected and control (noninfected) eyes were obtained up to 24 hours after antibiotic administration for measurement of trovafloxacin levels. A second group of rabbits (n = 72) was infected intraocularly and randomized 24 hours later to oral trovafloxacin (250 mg/kg twice a day) for 6 days or no treatment (control). Treatment efficacy was assessed by vitreous culture, clinical examination, and histopathology. RESULTS: Following a single dose of trovafloxacin, maximal vitreous levels were achieved at 8 hours in infected eyes, with a penetration ratio of 36%. Vitreous levels were greater than 15 times the minimum inhibitory concentration of the strain employed. In animals with established endophthalmitis, treated eyes were sterilized after 5 days (P = .0495) compared with control eyes, which autosterilized at 14 days. Clinical and histologic examination revealed significant amelioration of anterior segment inflammation in treated eyes, although severe destruction of posterior segment structures occurred in both groups after 6 days of therapy. CONCLUSIONS: These data support trovafloxacin as a potential oral agent for treatment or prophylaxis of S epidermidis endophthalmitis, although retinal alterations that occur over the period required for vitreous sterilization suggest that it will not replace intravitreal therapy in established endophthalmitis.

Antimicrobial pharmacokinetics in endophthalmitis treatment: studies of ceftazidime.

Ceftazidime has pharmacokinetic advantages for treatment of endophthalmitis caused by gram negative-organisms by intravenous administration. Additionally, its spectrum of coverage for these organisms and its relatively low toxicity after intraocular injection are favorable attributes. These studies demonstrate that inflammation leads to a significant reduction of the blood-ocular barriers to ceftazidime. This increased permeability shortens the half-life of the drug after intraocular injection but allows a significant penetration into the eye after a single intravenous dose so that therapeutic levels are achieved. Ceftazidime appears to be removed by both the anterior and the posterior route without active transport. The experiments demonstrate the importance of the vitreous as a barrier to achieving significant concentration of antibiotic within the eye after intravenous administration and confirm the importance of the vitreous in prolonging the half-life of drugs injected intravitreally. Finally the results emphasize that the pharmacokinetic behavior of drugs for treatment of endophthalmitis must be assessed in inflamed eyes both with and without intact vitreous, since these factors play a large role in drug availability and concentration in the vitreous cavity and are the major variables in the clinical setting.