A novel cell-associated protection assay demonstrates the ability of certain antibiotics to protect ocular surface cell lines from subsequent clinical Staphylococcus aureus challenge.

In vivo effectiveness of topical antibiotics may depend on their ability to associate with epithelial cells to provide continued protection, but this contribution is not measured by standard antibiotic susceptibility tests. We report a new in vitro method that measures the ability of test antibiotics azithromycin (AZM), erythromycin (ERY), tetracycline (TET), and bacitracin (BAC) to associate with mammalian cells and to protect these cells from destruction by bacteria. Mammalian cell lines were grown to confluence using antibiotic-free medium and then incubated in medium containing a single antibiotic (0 to 512 µg/ml). After incubation, the cells were challenged with Staphylococcus aureus ocular isolates, without antibiotics added to the culture medium. Epithelial cell layer integrity was assessed by gentian violet staining, and the minimum cell layer protective concentration (MCPC) of an antibiotic sufficient to protect the mammalian cells from S. aureus was determined. Staining was also quantified and analyzed. Bacterial viability was determined by culture turbidity and growth on agar plates. Preincubation of Chang and human corneal limbal epithelial cells with AZM, ERY, and TET at ≥64 µg/ml provided protection against AZM-susceptible S. aureus strains, with increasing protection at higher concentrations. TET toxicity was demonstrated at >64 µg/ml, whereas AZM displayed toxicity to one cell line at 512 µg/ml. BAC failed to show consistent protection at any dose, despite bacterial susceptibility to BAC as determined by traditional antibiotic susceptibility testing. A range of antibiotic effectiveness was displayed in this cell association assay, providing data that may be considered in addition to traditional testing when determining therapeutic dosing regimens.

The disinfection of contact lenses contaminated with adenovirus.

PURPOSE: We compared the efficacy of different contact lens disinfection systems to eliminate adenovirus. METHODS: Laboratory study evaluating the elimination of adenoviral ocular isolates by contact lens disinfection systems. Hard (gas permeable) and soft contact lenses were contaminated with adenovirus serotypes 8 and 19, and then they were disinfected with chemical, hydrogen peroxide, and heat sterilization systems. The survival of the adenovirus was determined by the shell vial technique. RESULTS: Adenovirus survived chemical and hydrogen peroxide disinfection but not heat sterilization. CONCLUSION: Because heat sterilization is not readily available to sterilize adenovirus contaminated contact lenses, it may be prudent for patients with adenoviral keratoconjunctivitis to dispose of unclean contact lenses.

An in vitro resistance study of levofloxacin, ciprofloxacin, and ofloxacin using keratitis isolates of Staphylococcus aureus and Pseudomonas aeruginosa.

PURPOSE: We compared levofloxacin with ciprofloxacin and ofloxacin using the in vitro susceptibilities of Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) keratitis isolates. DESIGN: Retrospective, clinical laboratory study of antibiotic susceptibility among keratitis isolates. PARTICIPANTS: Keratitis isolates from 200 patients with either SA or PA keratitis. METHODS: Minimum inhibitory concentrations (MICs) were determined for levofloxacin, ofloxacin, and ciprofloxacin for 93 SA keratitis isolates (68 fluoroquinolone-resistant and 25 susceptible, as determined by disk diffusion) and 107 PA keratitis isolates (13 fluoroquinolone-resistant and 94 susceptible). National Committee for Clinical Laboratory Standards susceptibilities were determined and analyzed statistically. Time kill studies were determined for fluoroquinolone-susceptible and -resistant isolates to all antibiotics at 8 microg/ml. The killing rates were determined by regression, and the colony count decreases were analyzed. MAIN OUTCOME MEASURES: The susceptibilities and potencies of levofloxacin, ciprofloxacin, and ofloxacin to SA and PA were determined from the MICs. Time kill studies determined the killing rates and decreases in colony counts. RESULTS: The fluoroquinolone-resistant SA susceptibilities to levofloxacin, ofloxacin, and ciprofloxacin were only 22%, 10%, and 3%, respectively. The fluoroquinolone-susceptible SA were 100% susceptible to all antibiotics, with levofloxacin demonstrating the best potency. The fluoroquinolone-resistant PA were resistant to all antibiotics. The fluoroquinolone-susceptible PA isolates were highly susceptible to levofloxacin, ofloxacin, and ciprofloxacin, with ciprofloxacin demonstrating the highest potency. For fluoroquinolone-susceptible SA and PA, the time kill studies determined that the killing rates and decreases in colony counts were equivalent for all three antibiotics tested. The time kill studies demonstrated no colony count decreases for the fluoroquinolone-resistant SA and PA. CONCLUSIONS: Taken together, our susceptibility and time kill data failed to demonstrate convincing differences in the susceptibility of SA and PA keratitis isolates to levofloxacin, ciprofloxacin, and ofloxacin. In general, bacterial isolates that were resistant to ciprofloxacin and ofloxacin were also resistant to levofloxacin.

Antiviral prophylaxis with twice daily topical cidofovir protects against challenge in the adenovirus type 5/New Zealand rabbit ocular model.

Adenoviral ocular infections are the most common external ocular infections world wide and there is no approved treatment. Topical cidofovir has been shown to be effective in vitro, in animal models and in case studies for the treatment of adenoviral ocular infections. Prophylaxis to prevent transmission within households and to reduce community epidemics remains an important public health goal. The current study examined whether antiviral prophylaxis with cidofovir, twice daily dosing, would restrict viral replication following a large challenge inoculum of adenovirus type 5 (Ad5) in the New Zealand white rabbit ocular model. The results showed that antiviral prophylaxis with 1 and 0.5% cidofovir significantly reduced mean daily Ad5 ocular titers (days 0-5), the number of Ad5 positive cultures/total (days 1-14), serial Ad5 positive cultures/total (days 1, 2, 3, 4, 5, 7), and the number of eyes with Ad5 replication beyond day 0 (1% cidofovir only). Antiviral prophylaxis appears to be an effective strategy to reduce and restrict adenovirus replication experimentally.

Valacyclovir inhibition of recovery of ocular herpes simplex virus type 1 after experimental reactivation by laser in situ keratomileusis.

PURPOSE: To determine whether the systemic administration of valacyclovir (Valtrex) reduces ocular shedding of herpes simplex virus type 1 (HSV-1) after laser in situ keratomileusis (LASIK) in the New Zealand White (NZW) rabbit latency model. SETTING: Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA. METHODS: New Zealand White rabbits latently infected with HSV-1 W strain were divided into 3 groups. The first received 100 mg/kg/day of valacyclovir; the second, 200 mg/kg/day of valacyclovir; and the third (control), saline. One half the total dose of valacyclovir was delivered via intraperitoneal injections twice daily for 7 days beginning with 1 dose before LASIK. The HSV-1 ocular shedding was determined from eye cultures for 7 days after LASIK. RESULTS: The administration of both 100 mg/kg/day and 200 mg/kg/day of valacyclovir significantly reduced the number of eyes (1/16 in both groups) and the total number of HSV-1 shedding days (1/122 and 2/122, respectively) from which HSV-1 was recovered compared to the control group (7/16 [P =.0396] and 14/129 [P <.007], respectively). CONCLUSIONS: Systemic administration of valacyclovir significantly reduced HSV-1 ocular shedding after LASIK in the NZW rabbit latency model. The clinical implications of this study suggest that patients with a history of recurrent ocular herpes may be able to safely have LASIK with less risk of a recurrent herpetic episode while on valacyclovir antiviral prophylaxis.

Short-term treatment With a potent topical corticosteroid of an acute ocular adenoviral infection in the New Zealand white rabbit.

PURPOSE: To determine the effect of short-term topical therapy with 1% prednisolone acetate (PA) on normal immune adenoviral clearance in the rabbit ocular model. METHODS: Thirty rabbits were topically inoculated in both eyes with adenovirus type 5 (Ad5). On day 1, the rabbits were divided into three topical treatment groups: 1% PA four times daily for 3 days, 1% PA four times daily for 5 days, control (artificial tears) four times daily for 5 days. Eyes were cultured for virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. RESULTS: Compared with the control group, treatment with 1% PA for 3 or 5 days significantly increased the total and daily number of Ad5-positive cultures from days 7 to 14, prolonged the duration of Ad5 shedding, and increased the mean combined Ad5 titer from days 1 to 5. In addition, treatment with 1% PA for 5 days increased the mean combined Ad5 titer from days 7 to 14. CONCLUSION: Treatment of an ocular adenoviral infection with 1% PA for as little as four times daily for 3 days significantly enhanced adenoviral replication compared with the control group. Short-term corticosteroid treatment of acute adenoviral ocular infections with 1% PA should be used judiciously.

The antiviral resistance and replication of cidofovir-resistant adenovirus variants in the New Zealand White rabbit ocular model.

PURPOSE: To determine the antiviral resistance of three cidofovir (CDV)-resistant variants of adenovirus type 5 (Ad5) and their ability to replicate in the New Zealand White rabbit ocular model. METHODS: Rabbits were inoculated topically in both eyes with the CDV-resistant variants R1, R2, and R3, and the Ad5 parental strain. On day 1, rabbits from each virus inoculation were divided into two topical treatment groups: 0.5% CDV and PBS control. Treatment was administered twice daily in both eyes for 7 days. All eyes were cultured for virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. Using viral outcome parameters, CDV resistance was determined for each virus by comparing each CDV-treated virus group to its respective PBS control, and altered pathogenesis was assessed by comparing viral replication in the PBS control groups of the Ad5 parent and the three resistant variants. RESULTS: Topical 0.5% CDV treatment demonstrated significant antiviral inhibitory activity in the Ad5 parental group (e.g., reduced total Ad5-positive cultures, reduced daily Ad5-positive cultures on days 5, 9, 11, and 14, and duration of ocular shedding), but had no effect on the three CDV-resistant variants. There were no significant differences in pathogenicity between the Ad5 parent and the CDV-resistant variants. CONCLUSIONS: The Ad5 variants R1, R2, and R3 were resistant to topical treatment with 0.5% cidofovir in the rabbit ocular model. However, the acquisition of CDV resistance did not alter the replication of the three Ad5 CDV variants on the rabbit eye.

Lomefloxacin is an effective treatment of experimental bacterial keratitis.

PURPOSE: Lomefloxacin was evaluated as a potential topical therapy for bacterial keratitis. METHODS: Lomefloxacin was compared with ciprofloxacin in different rabbit keratitis models. A total of 216 corneas were infected with Staphylococcus aureus (ciprofloxacin-susceptible and -resistant), Streptococcus viridans, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Serratia marcescens and were treated with lomefloxacin (0.3%), ciprofloxacin (0.3% Ciloxan), and the control phosphate-buffered saline (PBS), respectively. The data were analyzed statistically comparing the decrease in the number of recovered viable bacteria. RESULTS: Compared with PBS-treated control corneas, the colony counts for all bacterial isolates were significantly reduced (p < 0.05) after topical treatment with either lomefloxacin or ciprofloxacin. For gram-positive bacteria, lomefloxacin and ciprofloxacin were equally effective. For gram-negative bacteria, lomefloxacin, while effective, was less so than ciprofloxacin under experimental conditions (p < 0.05). CONCLUSION: Our data, using multiple bacterial keratitis models, suggest that lomefloxacin is promising for therapy of bacterial keratitis. Further clinical studies are needed to expand its use for keratitis therapy.

Experimental laser-assisted in situ keratomileusis induces the reactivation of latent herpes simplex virus.

PURPOSE: We determined whether laser-assisted in situ keratomileusis acts as a trigger for the reactivation and ocular shedding of herpes simplex virus type-1 in a rabbit latency model. METHODS: Herpes simplex virus type-1 latently infected rabbits were divided into three treatment groups: Group I received surface excimer laser ablation in both eyes (positive control), Group II received laser-assisted in situ keratomileusis in both eyes, and Group III received no treatment (negative control). Eyes were cultured daily for 10 days to determine herpes simplex virus type-1 reactivation. RESULTS: The number of herpes simplex virus type-1 positive eye cultures and total herpes simplex virus type-1 shedding days were significantly greater after surface excimer laser ablation and laser-assisted in situ keratomileusis compared with the untreated control group (P < 0.002 and P < 0.000001, respectively). CONCLUSION: Laser-assisted in situ keratomileusis as well as surface excimer laser ablation act as a trigger for the reactivation of herpes simplex virus type-1 in the rabbit latency model.

Effects of diclofenac or ketorolac on the inhibitory activity of cidofovir in the Ad5/NZW rabbit model.

PURPOSE: The goal of this study was to determine the effects of concurrent therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) on the antiviral activity of cidofovir on adenovirus replication and the formation of subepithelial infiltrates in the Ad5/New Zealand White rabbit ocular model. METHODS: According to two protocols, 20 rabbits were inoculated in both eyes with Ad5 topically to study adenovirus replication, and 20 rabbits were inoculated in both eyes topically and intrastromally to study the formation of subepithelial infiltrates. Animals were randomized to four masked treatment groups: group I, 0.5% cidofovir + artificial tears; group II, 0.5% cidofovir + 0.5% ketorolac tromethamine; group III, 0.5% cidofovir + 0.1% diclofenac sodium; and group IV, control + artificial tears. Cidofovir and control were administered to both eyes twice daily for 7 days, and artificial tears, ketorolac, and diclofenac four times daily for 14 days. Eyes were cultured on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. RESULTS: Compared with the control group, all cidofovir-treated groups demonstrated significant antiviral effects on adenovirus replication. There were no differences in adenovirus replication among the cidofovir-treated groups (I, II, and III), nor were there any differences among all groups (I-IV) in the formation of subepithelial infiltrates. CONCLUSIONS: Concurrent treatment of ketorolac or diclofenac with cidofovir did not diminish its antiviral inhibitory activity on adenovirus replication, nor did it prevent the formation of subepithelial infiltrates in the rabbit model.

Efficacy of topical cidofovir on multiple adenoviral serotypes in the New Zealand rabbit ocular model.

PURPOSE: The goal of the present study was to determine the efficacy of topical 0.5% cidofovir twice daily for 7 days on the replication of multiple adenovirus (Ad) serotypes of subgroup C (Ad1, Ad5, Ad6) in the New Zealand rabbit ocular model. METHODS: In duplicate experiments for each serotype, a total of 20 rabbits (Ad5) or 16 rabbits each (Ad1 and Ad6) were inoculated topically in both eyes, with 1.5 X 10(6) pfu/eye of the appropriate virus. Twenty-four hours later, the rabbits in each serotype group were randomly divided into two topical treatment groups: I, 0.5% cidofovir; II, control vehicle. Treatment was twice daily for 7 days. All eyes were cultured for virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. RESULTS: Compared to the control, treatment with 0.5% cidofovir reduced the following: mean Ad titer (days 1 to 7) for Ad1 (6.3 +/- 20 x 10(1) versus 2.5 +/- 3.9 X 102 pfu/ml; P < 0.0003), Ad5 (3.4 +/-5.8 x 102 versus 1.6 +/- 2.0 x 10(3) pfu/ml; P < 0.000001), and Ad6 (1.2 +/- 5.1 x 10(2) versus 5.5 +/-14 x 10(2) pfu/ml; P = 0.015); reduced Ad-positive eyes/total for Adl [45/128 (35%) versus 84/128 (66%); P = 0.000002], Ad5 [84/160 (53%) versus 131/152 (86%); P < 0.000001], and Ad6 [36/128 (28%) versus 82/128 (64%); P < 0.000001]: and reduced the duration of Ad shedding forAdl (4.9 +/-1.9 versus 9.3 +/- 3.3 days; P < 0.00007), Ad5 (6.4 +/- 2.8 versus 11.5 +/- 2.3 days; P < 0.0001), and Ad6 (4.4 +/- 2.1 versus 8.4 +/- 2.5 days; P < 0.00004). CONCLUSIONS: Topical 0.5% cidofovir twice daily for 7 days demonstrated significant antiviral activity against multiple adenoviral serotypes (Ad1, Ad5, and Ad6) in the New Zealand rabbit ocular model. These in vivo data expand in vitro studies indicating the efficacy of cidofovir against different adenovirus serotypes and support its use in clinical trials.

Valacyclovir inhibits recovery of ocular HSV-1 after experimental reactivation by excimer laser keratectomy.

PURPOSE: The goal of this was to determine whether the systemic administration of valacyclovir (Valtrex) would reduce ocular shedding of herpes simplex virus 1 (HSV-1) after excimer laser ablation in the New Zealand rabbit latency model. METHODS: The in vitro 50% inhibitory concentration (IC50) of HSV-1 W strain was determined by using a plaque-reduction assay to verify its sensitivity to acyclovir. Forty-seven NZW rabbits latently infected with HSV-1 W strain were divided into four groups: I, 50 mg/kg/day valacyclovir; II, 100 mg/kg/day valacyclovir; III, 150 mg/kg/day valacyclovir; and IV, saline control. One half of the total dose of valacyclovir was delivered via intraperitoneal injections twice daily for 7 days beginning with one dose before excimer laser keratectomy. HSV-1 ocular shedding was determined from eye cultures for 7 days after treatment. RESULTS: The IC50 for HSV-1 W was determined to be 2.9 microg/ml. The administration of both 100 mg/kg/day (group II) and 150 mg/kg/day (group III) of valacyclovir significantly reduced the number of eyes from which latent HSV-1 was recovered compared with the control group. There was no difference between the control group and group I (50 mg/kg/day valacyclovir). However, all three valacyclovir dosages significantly reduced the total number of HSV-1 shedding days compared with the control group, and 100% HSV-1 TG latency was demonstrated for all four groups. CONCLUSION: Systemic administration of valacyclovir significantly reduced HSV-1 ocular shedding in a dose-dependent manner after excimer laser keratectomy in the NZW rabbit latency model.

The survival of herpes simplex virus in multidose office ophthalmic solutions.

PURPOSE: To determine the survival of herpes simplex virus type 1 (HSV-1) in several multidose ophthalmic solutions. METHODS: In three separate trials, 10 aliquots of 5 ml each of three common multidose topical ophthalmic solutions, sodium fluorescein, proparacaine, and nonpreserved artificial tears, were inoculated with 10(5), 10(4), and 10(3) pfu per ml of HSV-1. All samples were titered on A549 cells at various time points for surviving HSV-1. RESULTS: Herpes simplex virus type 1 was not recovered from the fluorescein and proparacaine solutions at 1 hour or any time thereafter, regardless of inoculation titer. Herpes simplex virus type 1 was recovered from the artificial tears up to 7 days. CONCLUSION: Unlike adenovirus, HSV-1 does not survive in preserved fluorescein and proparacaine multidose solutions; therefore, office transmission is highly unlikely.

Evaluation of the shell vial technique for detection of ocular adenovirus. Community Ophthalmologists of Pittsburgh, Pennsylvania.

PURPOSE: The shell vial technique is a cell culture method that uses centrifugation and immunofluorescence to decrease the time required for a positive test. The authors evaluated the shell vial technique as a diagnostic test to detect adenovirus in conjunctival specimens of patients with adenoviral conjunctivitis. DESIGN: Retrospective and prospective case series. PARTICIPANTS: Forty-six patients with adenoviral culture-positive ocular infection. METHODS: The minimum time of incubation (days) that was required for testing clinical isolates with the shell vial was determined with adenovirus serotypes 5 and 8. In a masked retrospective study, 25 true-positive (frozen clinical samples) and 25 true-negative specimens were tested for the presence of adenovirus using the shell vial technique. The 25 true-negative samples included herpes simplex virus, Chlamydia trachomatis, Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus. In a prospective study, 21 patients who later tested positive in cell culture for adenovirus were concurrently tested with shell vial. MAIN OUTCOME MEASURES: The time of incubation was determined in days, and the sensitivity, specificity, positive and negative predictive values, and the efficacy of the shell vial test were determined. RESULTS: The minimal time of incubation for testing ocular samples by shell vial was 3 days. In the retrospective study, the sensitivity, specificity, positive predictive value, negative predictive value, and efficacy were 92%, 100%, 100%, 93%, and 96%, respectively. Comparably (P = 0.99), in the prospective study the sensitivity, specificity, positive predictive value, negative predictive value, and efficacy were 95%, 100%, 100%, 96%, and 97%, respectively. The shell vial (93%, 43 of 46) was equivalent (P = 0.42) to cell culture (100%, 46 of 46) for detecting adenovirus, but a positive result was obtained in significantly less time (3 days versus 9.41 +/- 6.23 days) (P = 0.00001). CONCLUSIONS: The shell vial technique was found to be a definitive method for identifying adenovirus from ocular specimens. A clear benefit for the ophthalmologist is that the test can provide a faster positive result (3 days) compared with conventional cell culture, which can take 1 to 3 weeks for adenovirus isolation.

Comparative antiviral efficacies of cidofovir, trifluridine, and acyclovir in the HSV-1 rabbit keratitis model.

PURPOSE: To determine the relative antiviral inhibitory activity of topical 1% and 0.5% cidofovir, topical trifluridine (Viroptic; Burroughs-Wellcome, Research Triangle Park, NC), and topical acyclovir (Zovirax; The Wellcome Foundation, London, UK) during a 7-day period for the treatment of herpes simplex virus type 1 (HSV-1) keratitis and HSV-1 replication in the New Zealand rabbit ocular model. METHODS: In a series of four experiments using a two-eye design, a total of 80 New Zealand rabbits were inoculated in both eyes with HSV-1 McKrae after epithelial scarification. Forty-eight hours after inoculation, the rabbits were randomly assigned to a treatment group. Five treatment groups (16 rabbits/group) were evaluated: I, 1% cidofovir, twice daily for 7 days; II, 0.5% cidofovir, twice daily for 7 days; III, 3% acyclovir ointment, five times daily for 7 days; IV, 1% trifluridine, nine times daily for 3 days, then 4 times daily for 4 days; and V, control vehicle twice daily for 7 days. HSV-1 dendritic keratitis was graded in a masked fashion by slit-lamp examination on days 2, 3, 5, 7, 9, 11, and 14. Ocular viral cultures were obtained after slit-lamp examination on days 1, 3, 5, 7, 9, 11, and 14. RESULTS: Compared with the control group, all four treatment groups demonstrated significantly lower viral titers, fewer HSV-1-positive eyes/total during the treatment period, lower keratitis scores, fewer eyes with keratitis/total, and a shorter time to resolution of keratitis. Within the treatment groups, the 1% and 0.5% cidofovir treatments were significantly more effective than acyclovir and trifluridine as measured by the previous viral and keratitis parameters. CONCLUSIONS: Topical 1% and 0.5% cidofovir both appeared to be significantly more efficacious than topical trifluridine and acyclovir, during a 7-day course, in the treatment of experimental HSV-1 ocular disease in the New Zealand rabbit keratitis model.

The survival of adenovirus in multidose bottles of topical fluorescein.

PURPOSE: To determine if common ocular adenovirus serotypes survive in vitro in multidose bottles of topical fluorescein (Fluress; Pilkington Barnes Hind, Inc, Sunnyvale, California). METHODS: Clinical isolates of adenovirus types 8 and 19 were inoculated separately into 10 bottles each of Fluress and maintained at room temperature (25 C). All bottles were titered for adenovirus on A549 cell monolayers at 0, 7, 14, 21, 28, and 49 days. RESULTS: Adenovirus was recovered from Fluress for up to 21 days for adenovirus type 19 and 28 days for adenovirus type 8. CONCLUSION: A multidose bottle of Fluress contaminated with adenovirus can be a potential source of adenoviral transmission in an ophthalmic office setting.

The effects of topical nonsteroidal anti-inflammatory drugs on adenoviral replication.

OBJECTIVE: To evaluate the antiviral activity of topical diclofenac sodium (Voltaren Ophthalmic) and ketorolac tromethamine (Acular) (2 nonsteroidal anti-inflammatory drugs [NSAIDs]) on adenoviral replication in vitro and in the adenovirus (Ad) 5 McEwen-New Zealand rabbit ocular model. METHODS: The 50% inhibitory concentration of ketorolac and diclofenac and their respective preservative components were determined for common ocular adenoviral serotypes (Ad8, Ad19, Ad1, and Ad5). In a series of experiments, Ad5 McEwen-inoculated New Zealand rabbit eyes were treated topically 4 times daily for 18 days with either ketorolac, diclofenac, prednisolone acetate (Pred Forte), or control vehicle (Comfort Tears). MAIN OUTCOME MEASURES: Outcome measures included serial ocular tear film titers and the formation of subepithelial immune corneal infiltrates. RESULTS: In vitro, neither ketorolac nor diclofenac demonstrated significant inhibitory activity against Ad1, Ad5, Ad8, or Ad19. In the rabbit model, there were no statistically significant differences among ketorolac, diclofenac, and the control vehicle with respect to viral replication or the formation of subepithelial immune infiltrates. In contrast, 1% prednisolone prolonged viral shedding and inhibited immune infiltrates (P < .001 for both). CONCLUSIONS: Our experimental study suggests that treatment of epidemic keratoconjunctivitis with topical NSAIDs may be a safer alternative than topical steroids. Only controlled clinical trials can determine whether topical NSAIDs can provide symptomatic relief and not interfere with normal viral clearance.

Multiple adenoviral serotypes demonstrate host range extension in the New Zealand rabbit ocular model.

PURPOSE: Although several human adenoviral serotypes demonstrated the genetic capability of replicating in New Zealand rabbit corneas in organ culture, only a single adenovirus (Ad) serotype, Ad5, has been reported to replicate in vivo in New Zealand rabbit eyes. The purpose of this study was to determine whether additional adenoviral serotypes could extend their host range to the New Zealand rabbit ocular model. METHODS: Six rabbits per viral isolate were inoculated in each eye after corneal scarification with 1.5 x 10(6) plaque-forming units per eye with one of the following reference or clinical adenovirus isolates: Ad1 ATCC, Ad1 Kmetz, Ad2 ATCC, Ad2 Wolf, Ad5 ATCC, Ad5 McEwen, Ad6 ATCC, Ad 19 ATCC, and Ad8 Cray (five rabbits). Eyes were cultured on days 0, 1, 3, 4, 5, 7, 9, 11, 14, 16, 18, and 21 after inoculation, and their tear film viral titers were determined on A549 cells. RESULTS: Ad19 ATCC and Ad8 Cray demonstrated no apparent viral replication. The mean duration of shedding was 1.5 and 0.3 days, respectively, and the total percentage of Ad-positive eyes was 13% and 3%, respectively. In contrast to Ad19 ATCC and Ad8 Cray, all other isolates demonstrated productive infection. The mean duration of shedding was 8 to 16 days (P < 0.0001), and the total percentage of Ad-positive eyes was 33% to 79% (P < 0.0002). The durations of shedding for Ad1 ATCC, Ad1 Kmetz, Ad2 ATCC, Ad2 Wolf, and Ad6 ATCC did not differ statistically from Ad5 McEwen, whereas Ad5 ATCC demonstrated a duration of shedding longer than all isolates (P < 0.0001). CONCLUSIONS: This was the first demonstration of host range extension by additional clinical and reference isolates of adenovirus types 1, 2, 5, and 6 in the New Zealand rabbit ocular model. These results suggested that host specificity was less stringent than previously thought.

Topical corticosteroids reverse the antiviral effect of topical cidofovir in the Ad5-inoculated New Zealand rabbit ocular model.

PURPOSE: To determine how the addition of topical corticosteroids would affect the anti-adenoviral inhibitory effect of topical cidofovir (S-HPMPC) in the Ad5 New Zealand (Ad5/NZ) rabbit ocular model. METHODS: In a series of experiments (two-eye design), Ad5-inoculated/NZ rabbits (10(6) pfu/eye) were treated with 1 of 3 treatment regimens. Group 1 was administered 1% cidofovir (CDV) twice a day for 3 days plus comfort tears four times a day for 14 days. Group 2 was administered 1% CDV twice a day for 3 days plus 1% Pred Forte four times a day for 14 days. Group 3 was administered vehicle twice a day for 3 days plus comfort tears four times a day for 14 days and served as the control. All eyes were evaluated for 21 days for serial eye titers, Ad5 positive eyes, and duration of Ad5 shedding. RESULTS: Compared to control eyes in the Ad5/NZ rabbit ocular model, CDV alone demonstrated a significant antiviral inhibitory effect: reduced mean Ad5 eye titer during the early phase of infection (days 3 to 7), fewer Ad5-positive eyes during the early and late (days 9 to 21) phases of infection, and shortened duration of shedding. However, concomitant treatment with both Pred Forte and CDV significantly reversed the antiviral inhibitory activity of CDV: increased mean Ad5 eye titer, increased Ad5-positive eyes (early and late phases) and prolonged duration of shedding. CONCLUSIONS: These experimental data further support the clinical development of cidofovoir as a topical antiviral agent, but they do not support a treatment regimen that includes a combination of topical corticosteroids and topical cidofovir as a desirable strategy for the treatment of symptomatic adenoviral ocular infection.