Cyclopentenylcytosine (CPE-C): In Vitro and In Vivo Evaluation as an Antiviral against Adenoviral Ocular Infections.

Adenoviruses are the major cause of ocular viral infections worldwide. Currently, there is no approved antiviral treatment for these eye infections. Cyclopentenylcytosine (CPE-C) is an antiviral that has demonstrated activity against more than 20 viruses. The goals of the current study were to determine the in vitro and in vivo antiviral activity of CPE-C as well as its ocular toxicity. Antiviral activity was evaluated in vitro using standard plaque reduction assays to determine the 50% effective concentrations (EC50s) and in vivo in the Ad5/NZW rabbit ocular replication model. Ocular toxicity was determined in uninfected rabbit eyes following topical ocular application. The in vitro EC50s for CPE-C ranged from 0.03 to 0.059 µg/mL for nine adenovirus types that commonly infect the eye. Ocular toxicity testing determined CPE-C to be non-irritating or practically non-irritating by Draize scoring. In vivo, 3% CPE-C topically administered 4X or 2X daily for 7 days to adenovirus-infected eyes demonstrated effective antiviral activity compared with the negative control and comparable antiviral activity to the positive control, 0.5% cidofovir, topically administered twice daily for 7 days. We conclude CPE-C was relatively non-toxic to rabbit eyes and demonstrated potent anti-adenoviral activity in vitro and in vivo.

AzaSite® inhibits Staphylococcus aureus and coagulase-negative Staphylococcus biofilm formation in vitro.

PURPOSE: The aim of this study was to analyze the effect of azithromycin (AZM) 1% ophthalmic solution in DuraSite® (AzaSite®) on biofilm formation by Staphylococcus aureus and coagulase-negative staphylococci in vitro. METHODS: Susceptible and resistant clinical strains (n = 8) of S. aureus and coagulase-negative staphylococci were challenged with serial dilutions of AzaSite® and its components: AZM, benzalkonium chloride (BAK), and the DuraSite drug delivery vehicle. After 20 h of incubation, bacterial growth was quantified using a spectrophotometer (A = 600 nm). Plates were stained with crystal violet and biofilm formation was quantified spectrophotometrically at A = 590 nm. RESULTS: AzaSite® and AZM inhibited bacterial growth (P < 0.05) and biofilm formation (P < 0.05) in AZM-susceptible strains at all studied dilutions. AZM-resistant strains treated with AzaSite® exhibited a significant reduction in biofilm formation (P < 0.05) at subinhibitory concentrations (1.25%-5%). AZM had no effect on bacterial growth in resistant strains but conferred a small reduction in biofilm formation at concentrations from 1.25 to 10 mg/mL in most strains. DuraSite® inhibited biofilm formation at concentrations between 10% and 2.5% in all studied strains (P < 0.05), without affecting bacterial growth. BAK inhibited bacterial growth and biofilm formation in all strains between concentrations of 0.042 and 0.375 mg/mL (P < 0.05). CONCLUSIONS: AzaSite®, AZM, or BAK prevented biofilm formation by inhibiting growth of AZM-susceptible strains. AzaSite®, AZM, and DuraSite® also reduced biofilm formation at subinhibitory concentrations for growth. Our data indicate that AZM has a moderate inhibitory effect on biofilm formation, whereas DuraSite® appears to play a greater role in the inhibition of staphylococcal biofilm formation by AzaSite®.

The in vitro and in vivo evaluation of ddC as a topical antiviral for ocular adenovirus infections.

PURPOSE: To evaluate the antiviral activity of 2', 3'-dideoxycytidine (ddC) in vitro against a panel of ocular adenovirus serotypes and in vivo in the ocular Ad5/NZW rabbit replication model. METHODS: In vitro, the 50% inhibitory concentrations (IC(50)) of ddC and cidofovir were determined using standard plaque-reduction assays. In vivo, 40 rabbits were topically inoculated in both eyes with Ad5 after corneal scarification. On day 1, the rabbits were equally divided into four topical treatment groups: 3% ddC; 2% ddC; 0.5% cidofovir; and saline. ddC and saline eyes were treated four times daily for 7 days, and cidofovir-treated eyes were treated twice daily for 7 days. Eyes were cultured for virus a multiple times over 2 weeks. RESULTS: The in vitro IC(50) for ddC ranged from 0.18 to 1.85 microg/mL, whereas those for cidofovir ranged from 0.018 to 5.47 microg/mL. ddC was more potent than cidofovir for seven of nine serotypes. In vivo, 3% ddC, 2% ddC, and 0.5% cidofovir significantly reduced the number of Ad5-positive cultures per total (days 1-14), mean Ad5 ocular titer (days 1-5), and duration of shedding (among other outcome measures) compared with the saline control. The 3% and 2% ddC treatments were significantly more efficacious than the 0.5% cidofovir treatment in the parameters listed above. CONCLUSIONS: ddC demonstrated potent antiadenovirus activity in vitro and in vivo. Systemic safety studies after topical ocular administration are needed to evaluate ddC as a topical antiviral treatment for adenoviral ocular infections in the target population.

CAP37-derived antimicrobial peptides have in vitro antiviral activity against adenovirus and herpes simplex virus type 1.

PURPOSE: The antiviral activity of an established antibacterial CAP37 domain and its extracellular mechanism of action were investigated. METHODS: CAP37-derived peptides modified to assess the importance of disulfide bonds were evaluated in cytotoxicity and antiviral assays (direct time kill, dose dependency, and TOTO-1) for adenovirus (Ad) and herpes simplex virus type 1 (HSV-1). RESULTS: Variable virus, adenovirus serotype-dependent, and dose-dependent inhibition were demonstrated without cytotoxicity. For peptide A (CAP37(20-44)), TOTO-1 dye uptake was demonstrated for Ad5 and HSV-1. CONCLUSIONS: Unlike the antibacterial activity of this CAP37 domain, its antiviral activity is not fully dependent upon disulfide bond formation. Viral inhibition appears to result, in part, from disruption of the envelope and/or capsid.

Validation of real-time PCR for laboratory diagnosis of Acanthamoeba keratitis.

Confirmation of Acanthamoeba keratitis by laboratory diagnosis is the first step in the treatment of this vision-threatening disease. Two real-time PCR TaqMan protocols (the Rivière and Qvarnstrom assays) were developed for the detection of genus-specific Acanthamoeba DNA but lacked clinical validation. We have adapted these assays for the Cepheid SmartCycler II system (i) by determining their real-time PCR limits of detection and amplification efficiencies, (ii) by determining their ability to detect trophozoites and cysts, and (iii) by testing a battery of positive and negative samples. We also examined the inhibitory effects of a number of commonly used topical ophthalmic drugs on real-time PCR. The results of the real-time PCR limit of detection and amplification efficiency of the Rivière and Qvarnstrom assays were 11.3 DNA copies/10 microl and 94% and 43.8 DNA copies/10 microl and 92%, respectively. Our extraction protocol enabled us to detect 0.7 Acanthamoeba cysts/10 microl and 2.3 Acanthamoeba trophozoites/10 microl by both real-time PCR assays. The overall agreement between the assays was 97.0%. The clinical sensitivity and specificity of both real-time PCR assays based on culture were 100% (7 of 7) and 100% (37 of 37), respectively. Polyhexamethylene biguanide was the only topical drug that demonstrated PCR inhibition, with a minimal inhibitory dilution of 1/640 and an amplification efficiency of 72.7%. Four clinical samples were Acanthamoeba culture negative and real-time PCR positive. Our results indicate that both real-time PCR assays could be used to diagnose Acanthamoeba keratitis. Polyhexamethylene biguanide can inhibit PCR, and we suggest that specimen collection occur prior to topical treatment to avoid possible false-negative results.

Simvastatin vs therapeutic lifestyle changes and supplements: randomized primary prevention trial.

OBJECTIVE: To compare the lipid-lowering effects of an alternative regimen (lifestyle changes, red yeast rice, and fish oil) with a standard dose of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin). PATIENTS AND METHODS: This randomized trial enrolled 74 patients with hypercholesterolemia who met Adult Treatment Panel III criteria for primary prevention using statin therapy. All participants were randomized to an alternative treatment group (AG) or to receive simvastatin (40 mg/d) in this open-label trial conducted between April 1, 2006, and June 30, 2006. The alternative treatment included therapeutic lifestyle changes, ingestion of red yeast rice, and fish oil supplements for 12 weeks. The simvastatin group received medication and traditional counseling. The primary outcome measure was the percentage change in low-density lipoprotein cholesterol (LDL-C). Secondary measures were changes in other lipoproteins and weight loss. RESULTS: There was a statistically significant reduction in LDL-C levels in both the AG (-42.4%+/-15%) (P<.001) and the simvastatin group (-39.6%+/-20%) (P<.001). No significant differences were noted between groups. The AG also demonstrated significant reductions in triglycerides (-29% vs -9.3%; 95% confidence interval, -61 to -11.7; P=.003) and weight (-5.5% vs -0.4%; 95% confidence interval, -5.5 to -3.4; P<.001) compared with the simvastatin group. CONCLUSION: Lifestyle changes combined with ingestion of red yeast rice and fish oil reduced LDL-C in proportions similar to standard therapy with simvastatin. Pending confirmation in larger trials, this multifactorial, alternative approach to lipid lowering has promise for a subset of patients unwilling or unable to take statins.

Benzalkonium chloride enhances the antibacterial efficacy of gatifloxacin in an experimental rabbit model of intrastromal keratitis.

PURPOSE: The aim of this study was to determine whether a preservative (0.005% benzalkonium chloride [BAK]) enhances the antibacterial efficacy of an antibiotic (0.3% gatifloxacin, [GAT]) in vivo. METHODS: Rabbits were inoculated intrastromally with GAT-resistant, methicillin-resistant Staphylococcus aureus or Staphylococcus epidermidis and then divided into four treatment groups: 0.3% GAT + 0.005% BAK; 0.3% GAT without BAK; vehicle including 0.005% BAK; and saline control. At 4 h postinoculation, topical treatment was initiated in both eyes every 15 min for 5 h. One (1) h after therapy, corneal colony counts were determined. RESULTS: For S. aureus, duplicate experiments demonstrated that GAT + BAK and GAT without BAK significantly reduced colony counts, compared with BAK or saline (P < 0.05). Further, GAT + BAK significantly reduced colony counts, compared with GAT without BAK. BAK alone was equivalent to the saline control. For S. epidermidis, duplicate experiments demonstrated that GAT + BAK and GAT without BAK significantly reduced colony counts, compared with BAK or saline (P < 0.05). There were no differences between GAT + BAK and GAT without BAK for S. epidermidis. CONCLUSIONS: For the first time, we demonstrated that a preservative (0.005% BAK) significantly enhanced the antibacterial efficacy of an antibiotic (0.3% GAT) in an experimental rabbit model of intrastromal keratitis.

Topical 0.5% moxifloxacin prevents endophthalmitis in an intravitreal injection rabbit model.

INTRODUCTION: Intravitreal injections for the treatment of retinal disease have increased the risk of endophthalmitis. We developed a rabbit model to investigate whether topical 0.5% moxifloxacin could prevent endophthalmitis after an intravitreal injection. METHODS: A rabbit model of intravitreal injection to produce endophthalmitis was developed by injecting triamcinolone into the vitreous through a depot of subconjunctival Staphylococcus aureus (10(7) cfu). Endophthalmitis was evaluated clinically and confirmed by culture. The model was tested with a commercially available brand of topical 0.5% moxifloxacin (N = 10) and saline (N = 10). In brief, after bacterial subconjunctival challenge, a topical treatment was administered every 15 min for 1 h. Immediately thereafter, triamcinolone was injected into the vitreous through the treated bacterial depot. Topical 0.5% moxifloxacin and saline were administered QID over the next 72 h. All rabbits were examined daily, euthanized, and tested for viable bacteria when clinical signs of endophthalmitis were observed. RESULTS: Anti-infective treatment with topical 0.5% moxifloxacin prevented the development of endophthalmitis (0/9 rabbits), compared to topical saline (6/10 rabbits; P = 0.01; power = 0.99). CONCLUSIONS: Topical 0.5% moxifloxacin provided effective prophylaxis to prevent endophthalmitis after an intravitreal injection of triamcinolone. This unique model may prove valuable to demonstrate prophylaxis for other anti-infectives at an intravitreal injection site.

Efficacy of topical immunoglobulins against experimental adenoviral ocular infection.

PURPOSE: Presently, there is no U.S. Federal Drug Administration (FDA)-approved antiviral therapy for the treatment of adenoviral (Ad) ocular infections. The goal of the present study was to determine the antiviral efficacy of human immunoglobulin (Ig), a preparation of highly purified and concentrated immunoglobulin (IgG) antibodies isolated from a large pool of human plasma donors, in vitro and on acute Ad replication in the Ad5 New Zealand White (NZW) rabbit ocular model. METHODS: The antiviral activity of human Ig against multiple wild-type and human ocular isolates of adenovirus serotypes was investigated in vitro by using neutralizing assays in different human epithelial cell lines. In vivo bilateral topical ocular toxicity and antiviral efficacy were evaluated with established Ad5/NZW rabbit ocular models. In vivo Ig antiviral results were compared with those obtained with topical 0.5% cidofovir and saline. RESULTS: In three different epithelial cell lines,

Zymar (Gatifloxacin 0.3%) shows excellent Gram-negative activity against Serratia marcescens and Pseudomonas aeruginosa in a New Zealand White rabbit keratitis model.

PURPOSE: Whereas gatifloxacin, a newer fluoroquinolone, was engineered to increase its Gram-positive potency, we assessed whether it still retained significant Gram-negative activity in vivo. Specifically, we compared the efficacy of Zymar (gatifloxacin 0.3%), Ciloxan (ciprofloxacin 0.3%), and fortified tobramycin (14 mg/mL) in the treatment of experimental Gram-negative bacterial infections of Serratia marcescens (SM) and Pseudomonas aeruginosa (PA) in the New Zealand White (NZW) rabbit keratitis model. METHODS: A total of 30 NZW rabbits each were intrastromally inoculated in both eyes with approximately 1000 CFU of SM and PA. By E-test, the minimum inhibitory concentrations (MICs; microg/mL) for SM were gatifloxacin (0.125), ciprofloxacin (0.047), and tobramycin (1.5), and for PA were gatifloxacin (0.125), ciprofloxacin (0.19), and tobramycin (0.5). After 16 hours, the rabbits were divided into 4 treatment groups: (1) Zymar, (2) Ciloxan, (3) fortified tobramycin, and (4) saline control. One drop was instilled in both eyes every 15 minutes for 5 doses and then every 30 minutes for 14 doses. One hour after the final treatment, the animals were euthanized, and bacterial colony counts from the corneas were determined. RESULTS: For SM, Zymar and Ciloxan significantly reduced (P < 0.001, ANOVA) the colony counts compared with tobramycin and saline control. Zymar was more effective than Ciloxan (P < 0.001, ANOVA). For PA, all antibiotics reduced equivalently the colony counts compared with the saline control (P = 0.005, ANOVA). CONCLUSIONS: The enhanced Gram-positive activity of gatifloxacin is not associated with any decreased Gram-negative activity in vivo. Zymar may prove useful for SM and PA keratitis.

The in vitro impact of moxifloxacin and gatifloxacin concentration (0.5% vs 0.3%) and the addition of benzalkonium chloride on antibacterial efficacy.

PURPOSE: Varied concentrations of moxifloxacin (MOX) and gatifloxacin (GAT) and the addition of 0.005% benzalkonium chloride (BAK) were evaluated for eliminating Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA), and coagulase-negative Staphylococcus (CNS). DESIGN: In vitro laboratory investigation. METHODS: The time-kill survival of SA, PA, and CNS were tested at one, two, three, six, eight, and 24 hours to: (1) Mueller-Hinton broth, (2) BAK, (3) 0.5% MOX, (4) 0.5% GAT, (5) 0.3% MOX, (6) 0.3% GAT, (7) 0.3% GAT plus BAK, (8) 0.5% MOX plus BAK, (9) 8 microg/ml GAT, and (10) 8 mug/ml MOX. Antibiotic interactions (GAT and BAK) were determined by checkerboard testing. The outcome measures were (1) time-to-kill, (2) killing-rates, and (3) fractional inhibitory concentration (FIC) indices. RESULTS: MOX and GAT at either 0.5% or 0.3% had equivalent antibacterial effects. BAK alone or the addition of BAK to either antibiotic eliminated SA and CNS within one hour, whereas 0.3% GAT plus BAK eliminated bacteria faster than 0.5% MOX (P = .016). For PA, BAK alone had no antibacterial effect. The kill rates of MOX and GAT were equivalent. FIC indices indicated that GAT and BAK were indifferent against SA and CNS, but antagonistic to PA. CONCLUSION: As a preservative, MOX and GAT have equivalent antibacterial activity with similar killing rates. BAK appears to independently complement GAT for eliminating SA and CNS, but has no effect on PA. The in vitro predictive clinical effect due to varied antibiotic concentration and the addition of BAK requires confirmatory clinical studies for validation.

Evaluation of the SmartCycler II system for real-time detection of viruses and Chlamydia from ocular specimens.

OBJECTIVE: To compare the SmartCycler II system (Cepheid, Sunnyvale, Calif) results with those of standard cell culture, to compare the SmartCycler II system results with those of a dedicated polymerase chain reaction facility, and to establish the SmartCycler II system as a polymerase chain reaction method for detecting viral and chlamydial DNA from ocular specimens. METHODS: True-positive samples (test-positive specimens based on standard testing) and true-negative samples (test-negative specimens based on standard testing) were processed for polymerase chain reaction using the SmartCycler II system for adenovirus, herpes simplex virus type 1, varicella-zoster virus, and Chlamydia trachomatis. Sensitivity, specificity, positive predictive value, negative predictive value, and efficiency were based on the testing of true-positive and true-negative specimens. RESULTS: The descriptive statistics for adenovirus, herpes simplex virus type 1, varicella-zoster virus, and C trachomatis were, respectively, as follows: sensitivity, 85%, 98%, 100%, and 94%; specificity, 98%, 100%, 100%, and 100%; positive predictive value, 98%, 100%, 100%, and 100%; negative predictive value, 85%, 91%, 100%, and 98%; and efficiency, 92%, 95%, 100%, and 99%. Test sensitivity for the SmartCycler II system was equivalent to that from a central molecular laboratory. CONCLUSION: The descriptive statistics of the SmartCycler II system obtained in a small laboratory were comparable to those of a central molecular laboratory for detecting viruses and Chlamydia species. Clinical Relevance Polymerase chain reaction has great potential in the routine diagnosis of ocular infections in any conventional laboratory.

N-chlorotaurine is an effective antiviral agent against adenovirus in vitro and in the Ad5/NZW rabbit ocular model.

PURPOSE: To determine whether N-chlorotaurine (NCT) demonstrates antiviral activity against adenovirus (Ad) in vitro and in the Ad5/NZW rabbit ocular model. METHODS: The in vitro activity of NCT was evaluated by incubating different Ad serotypes with several concentrations of NCT for 1 hour and determining the reduction in Ad titers. In rabbit study 1, Ad5-infected eyes were treated with 2.5%, 2.0%, and 1.0% NCT; 0.5% cidofovir; or saline. NCT and saline groups were treated 10 times for 1 day and then 5 times daily for 6 days. In rabbit study 2, Ad5-infected eyes were treated with 1.0% NCT/0.1% ammonium chloride (NH4Cl), 0.1% NCT/1.0% NH4Cl, 0.1% NCT/0.1% NH4Cl, and 0.5% cidofovir or saline. The NCT and saline groups were treated five times daily for 10 days. Cidofovir-treated eyes received the authors' standard cidofovir dose regimen: twice daily for 7 days. RESULTS: In vitro, NCT demonstrated concentration-dependent direct inactivation of all ocular Ad serotypes tested. Rabbit study 1: 2.5%, 2.0%, 1.0% NCT, and cidofovir demonstrated significantly fewer positive cultures per total cultures during days 1 to 14, compared with saline. Rabbit study 2: 1.0% NCT/0.1% NH4Cl, 0.1% NCT/1.0% NH4Cl, 0.1% NCT/0.1% NH4Cl, and cidofovir demonstrated significantly fewer positive cultures per total cultures, during days 1 to 14; shorter durations of shedding; and lower mean combined titers, during days 7 to 14, compared with saline. Cidofovir was significantly more effective than NCT in several outcome measures in both rabbit studies. CONCLUSIONS: NCT demonstrated antiviral activity against adenovirus in vitro and in vivo. Further development of NCT as a topical antimicrobial is indicated.

Role of topical fluoroquinolones on the pathogenesis of diffuse lamellar keratitis in experimental in vivo studies.

PURPOSE: To investigate the potential role of commercially available topical fluoroquinolones in diffuse lamellar keratitis (DLK) using New Zealand White rabbit models. SETTING: Campbell Ophthalmic Microbiology Laboratory at the University of Pittsburgh, Pittsburgh, Pennsylvania, USA. METHODS: In a DLK challenge model, laser in situ keratomileusis flaps were created by a microkeratome in rabbit eyes (n = 10 per group) and the stromal beds were treated with 1 drop of Ciloxan (ciprofloxacin 0.3%), Ocuflox (ofloxacin 0.3%), balanced salt solution (BSS), or Pseudomonas aeruginosa endotoxin before flap closure. After the procedure, eyes were treated with the same drugs 4 times daily. On postoperative day 1, the eyes were examined by slitlamp and graded (modified Linebarger DLK grading scale) in a masked fashion. In a DLK exacerbation model, all eyes received 1 drop of endotoxin on the stromal interface followed by flap closure. After the procedure, the rabbit eyes (10 per group) were treated 4 times daily with Ciloxan, Ocuflox, or BSS and graded for DLK on postoperative day 1 as before. RESULTS: In the challenge model, Ciloxan, Ocuflox, and endotoxin all produced higher median DLK scores than the BSS control (P = .02). Ciloxan produced significant DLK in more eyes and had higher median scores (70%, 1.0) than Ocuflox (40%, 0.5) or endotoxin (45%, 0.5) (P = .05). In the endotoxin-induced model, Ciloxan produced significantly higher DLK scores than Ocuflox or BSS (P = .05). CONCLUSIONS: Topical fluoroquinolones caused and exacerbated DLK in rabbit models. Ocuflox was associated with less DLK than Ciloxan. The clinical significance of these findings can only be assessed in clinical trials.

An ophthalmologist's guide to understanding antibiotic susceptibility and minimum inhibitory concentration data.

PURPOSE: To address the need to establish appropriate evaluation criteria for analyzing in vitro antibiotic susceptibility based on original data. DESIGN: In vitro laboratory investigation. PARTICIPANTS: Bacterial isolates from patients with conjunctivitis. MAIN OUTCOME MEASURES: Minimum inhibitory concentrations (MICs), descriptive statistics, antibiotic susceptibility, potency, and statistical analysis. METHODS: Minimum inhibitory concentrations were determined for 80 bacterial conjunctivitis isolates to moxifloxacin, gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Using the MIC values, descriptive statistics (median, MIC50, MIC90, mode, range), antibiotic susceptibility, and potency of each antibiotic were calculated for each bacterial group. The data were analyzed statistically using appropriate randomization and nonparametric tests. RESULTS: The descriptive statistics of gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumoniae) followed a consistent trend where the median, MIC50, MIC90, and mode demonstrated the lowest values, in all instances, for moxifloxacin, gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. The descriptive statistics for Haemophilus species (the predominant gram-negative bacteria implicated in conjunctivitis) did not describe any consistent trend. In contrast, antibiotic susceptibility testing did not demonstrate any advantage among the 5 fluorquinolones tested, except for moxifloxacin in the S. aureus fluoroquinolone-resistant group. Potency studies indicated that moxifloxacin and gatifloxacin were the most potent for gram-positive bacteria, whereas gatifloxacin and ciprofloxacin were the most potent for Haemophilus species. CONCLUSION: In the absence of human clinical trial data to guide care, in vitro susceptibility data should be analyzed with a set of descriptive statistics along with a nonparametric statistical analysis. No single parameter or test should be relied upon in all instances to demonstrate the in vitro superiority of one antibiotic over another. In this study, fourth-generation fluoroquinolones did have some potency advantages over second-generation fluoroquinolones against gram-positive conjunctival bacterial isolates, but not for Haemophilus isolates.

Adenovirus-directed ocular innate immunity: the role of conjunctival defensin-like chemokines (IP-10, I-TAC) and phagocytic human defensin-alpha.

PURPOSE: Adenovirus (Ad), a major cause of viral conjunctivitis worldwide, is controlled initially by the innate immune response on the ocular surface. In the present study, cultured human conjunctival epithelial cells were used to identify host genes responsive to infection by a clinical isolate of Ad5, and the antiviral activity of some of their peptide products was investigated. METHODS: Primary human conjunctival epithelial cells in culture were infected with Ad5 at high (1.0), low (0.1), or zero (0.0) multiplicities of infection (MOI) and harvested at different times after infection (1.5, 6, and 16 hours). Host gene expression was profiled with oligonucleotide microarrays (GeneChips; Affymetrix, Santa Clara, CA). Peptide products of interest were tested for antiviral activity in direct inhibition assays against respiratory serotypes (Ad3, Ad5), ocular serotypes (Ad8, Ad19), and HSV-1. RESULTS: At high MOI, viral infection suppressed the interferon (IFN)-mediated host antiviral response seen at low MOI. At 16 hours after infection, 63 unique characterized transcripts were identified that were robustly and significantly suppressed by high MOI, (i.e., MOI [0.1]/MOI [0.1] > or = 2, P < 0.006). Of these, 29 (46%) transcripts are involved in IFN signaling or are IFN or virus induced. This subset included CXCL10 and CXCL11, encoding IP-10 and I-TAC, respectively. These defensin-like chemokines and human alpha-defensin-1 directly inhibited Ad3 and Ad5 but not Ad8 or Ad19. CONCLUSIONS: In response to low-level Ad5 infection, conjunctival epithelial cells showed upregulation of IFN-associated genes. The peptide products of two of these, IP-10 and I-TAC, are directly active against Ad3, and IP-10 is active against Ad5. The ocular tropism of Ad8 and Ad19 may be due in part to their resistance to these defensin-like chemokines.

Intracameral Vigamox (moxifloxacin 0.5%) is non-toxic and effective in preventing endophthalmitis in a rabbit model.

PURPOSE: To determine whether Vigamox (moxifloxacin 0.5% ophthalmic solution) can be safely injected intracamerally to prevent Staphylococcus aureus endophthalmitis in a rabbit model. DESIGN: Animal study. METHODS: The safety and bactericidal-effectiveness of Vigamox were evaluated in three stages using 189 New Zealand White rabbits. (Stage 1) The toxicity of two intravitreal doses of Vigamox (moxifloxacin 500, 250 microg) was compared with vancomycin (1 mg) and saline. (Stage 2) A reproducible rabbit model of Staphylococcus aureus endophthalmitis was established. (Stage 3) The bactericidal effect of intracameral Vigamox (moxifloxacin 500, 250, 125, 50 microg) was compared with vancomycin (1 mg) and saline. Intracameral antibiotic therapy commenced immediately after Staphylococcus aureus intravitreal challenge (5000 cfu). Toxicity was evaluated by masked clinical examination using a slit-lamp, an indirect ophthalmoscope, and corneal-ultrasound pachymetry. The clinical examination included the exterior eye, cornea, anterior chamber, vitreous, and retina. The presentations were graded on a severity scale of 0, 0.5, 1, 2, and 3. The bactericidal efficacy was determined using intracameral colony counts. RESULTS: In the toxicity studies without bacterial challenge, the clinical scores of rabbits injected intracamerally with Vigamox were statistically equivalent to rabbits given intracameral vancomycin or saline. In the efficacy studies, eyes treated intravitreally with Vigamox, at all doses, or vancomycin were negative for Staphylococcus aureus and nontreated controls remained culture-positive. CONCLUSIONS: Vigamox appears to be nontoxic for intracameral injection and effective in preventing experimental endophthalmitis in the rabbit model. Further studies will determine the clinical role of intracameral Vigamox for surgical prophylaxis and postoperative therapy.

Human cathelicidin (LL-37), a multifunctional peptide, is expressed by ocular surface epithelia and has potent antibacterial and antiviral activity.

PURPOSE: This study determined whether LL-37 (cathelicidin) is expressed by conjunctival and corneal epithelia as part of ocular host defense. The antimicrobial activity of LL-37 was also assessed in vitro against Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), herpes simplex virus type 1 (HSV-1), and adenovirus (Ad). METHODS: Expression of LL-37/hCAP 18 mRNA and LL-37 protein was determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunoblotting, respectively, in scraped human corneal epithelium and primary cultured human corneal and conjunctival epithelial cells. The EC50 values for three strains of PA and one each of SA and SE were determined for LL-37. LL-37 antiviral inhibition of HSV-1 and adenovirus was assessed by direct inactivation assays. Toxicity of LL-37 to A549 cells was evaluated by a MTT assay. RESULTS: LL-37/hCAP18 mRNA and LL-37 peptide were expressed by human corneal and conjunctival epithelial cells. Antibacterial activity for LL-37 was demonstrated (EC50 values for the three PA strains were 2.8 +/- 1.3, 1.9 +/- 0.3, and 3.6 +/- 2.1; for SA: 1.6 +/- 1.5; for SE: 1.3 +/- 1.9 microg/ml). LL-37 produced a significant reduction (p < 0.001 ANOVA) in HSV-1 and Ad19 viral titers with distinctly different time-kill curves (p < 0.001). LL-37 (up to 111 microM) produced no toxicity in A549 cells. CONCLUSIONS: Corneal and conjunctival epithelia express LL-37 as part of mucosal innate immunity to protect against bacterial and viral ocular infections.

A review of antimicrobial peptides and their therapeutic potential as anti-infective drugs.

PURPOSE: Antimicrobial peptides (AMPs) are an essential part of innate immunity that evolved in most living organisms over 2.6 billion years to combat microbial challenge. These small cationic peptides are multifunctional as effectors of innate immunity on skin and mucosal surfaces and have demonstrated direct antimicrobial activity against various bacteria, viruses, fungi, and parasites. This review summarizes their progress to date as commercial antimicrobial drugs for topical and systemic indications. METHODS: Literature review. RESULTS: Despite numerous clinical trials, no modified AMP has obtained Food & Drug Administration approval yet for any topical or systemic medical indications. CONCLUSIONS: While AMPs are recognized as essential components of natural host innate immunity against microbial challenge, their usefulness as a new class of antimicrobial drugs still remains to be proven.