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Objective: To evaluate bacterial isolates from corneal stromal ulcerations in dogs and cats in the Netherlands, review their antibiotic susceptibility, determine whether recent topical treatment affected bacterial culture results, and investigate whether (multi‐drug) resistance patterns changed over time. Animals studied: Client‐owned dogs and cats were diagnosed with corneal stromal ulceration at the Utrecht University Clinic for Companion Animals between 2012 and 2019. Procedures: Retrospective analysis. Results: In total, 163 samples were collected from 122 dogs (130 samples) and 33 cats. Positive cultures were obtained from 76 canine and 13 feline samples (59% and 39%, respectively) and included Staphylococcus (42 in dogs, 8 in cats), Streptococcus (22 in dogs, 2 in cats), and Pseudomonas (9 in dogs, 1 in cats) species. Significantly fewer positive cultures were found in dogs and cats previously treated with topical antibiotics (χ2 = 6.52, p =.011 and χ2 = 4.27, p =.039, respectively). Bacterial resistance to chloramphenicol was more common in dogs previously treated with chloramphenicol (χ2 = 5.24, p =.022). The incidence of acquired antibiotic resistance did not increase significantly over time. In dogs, the incidence of multi‐drug‐resistant isolates increased significantly between 2012–2015 and 2016–2019 (9.4% vs. 38.6%, p =.0032). Conclusions: Staphylococcus, Streptococcus, and Pseudomonas species were the most common bacteria associated with canine and feline corneal stromal ulcerations. Previous treatment with antibiotics affected bacterial culture results and antibiotic sensitivity. Although the overall incidence of acquired antibiotic resistance did not change over time, the incidence of multi‐drug‐resistant isolates in dogs increased over an 8‐year period. [ABSTRACT FROM AUTHOR]

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Summary: Background: Topical dexamethasone and prednisolone are currently the mainstay treatment for equine ophthalmic inflammatory diseases, such as equine recurrent uveitis. Comparative pharmacokinetic studies in horses are lacking and current guidelines are mainly based on empirical data and extrapolation from other species. Objectives: To investigate the penetration and local concentrations of topically applied dexamethasone and prednisolone in normal equine ocular fluids and serum. Study design: Prospective randomised experimental pharmacokinetic study. Methods: Twenty‐one Shetland ponies without ophthalmic disease were treated bilaterally topically every 2 hours during 24 hours to obtain steady state drug concentrations. One eye was treated with 0.15 mg of dexamethasone disodium phosphate (0.1%), and the other eye was simultaneously treated with 1.5 mg of prednisolone acetate (1%). Serum samples were taken prior to the induction of general anaesthesia. Aqueous and vitreous humour samples were taken during euthanasia at time points after administration of the last dose (t = 5 min, t = 15 min, t = 30 min, t = 60 min, t = 90 min, t = 120 min, t = 180 min). Each pony was randomly assigned to one time point, and three ponies were sampled per time point. Dexamethasone and prednisolone concentrations were measured by liquid chromatography‐mass spectrometry. Results: The mean dexamethasone concentration in aqueous humour was 32.4 ng/mL (standard deviation [SD] 10.9) and the mean prednisolone concentration was 321.6 ng/mL (SD 96.0). In the vitreous and in serum samples concentrations of both corticosteroids were below the limit of detection (LOD 2.5 ng/mL). Main limitations: The study group was limited to subjects without evidence of current ophthalmic disease. A limited number of time points were measured. Conclusions: Potentially effective dexamethasone and prednisolone concentrations were measured in the anterior chamber, but vitreal concentrations were negligible. Systemic uptake was low. Therefore, treatment with only topically administered corticosteroids is deemed insufficient in horses in cases of posterior uveitis. Further studies evaluating other routes of administration are warranted. [ABSTRACT FROM AUTHOR]

Objective: To describe ultrasonography as a diagnostic method of in vivo Descemet's membrane detachment (DMD) in horses. Animals studied: Seven horses (three Icelandic horses, two Dutch Warmblood horses, one Appaloosa, and one Welsh Pony), presenting with moderate‐to‐severe focal or diffuse corneal edema, in whom DMD was suspected on ultrasonographic examination and confirmed with histopathology, were studied. Procedure: A retrospective analysis of case records of horses with suspected DMD was performed. Results: Median age at presentation was 14 years (range 11‐24). Clinical signs in eyes with DMD were unilateral in all horses and included blepharospasm and epiphora (6/7), buphthalmos (5/7), moderate‐to‐severe focal or diffuse corneal edema (7/7), corneal epithelial bullae (4/7), corneal neovascularization (4/7), Haab's striae (2/7), corneal endothelial precipitates (1/7), fibrin in the anterior chamber (1/7), focal cataract (2/7), and pigment deposits on the anterior lens capsule (1/7). During transpalpebral ultrasonography, a distinct linear echogenic structure was noted in the anterior chamber, initially diverging from, and later running parallel to, the posterior lining of the cornea in all eyes studied. In all cases, the cornea was severely thickened and echogenic, consistent with edema, and DMD was suspected. In all horses, the clinical signs progressed and the affected eye was eventually enucleated. Histopathology revealed DMD (7/7), spindle cell proliferation (4/7), Descemet's membrane reformation (3/7), and inflammation of the anterior uvea (5/7). Overall incidence was 1.04%. Conclusions: Ultrasonography is an adequate tool in diagnosing DMD in horses. Descemet's membrane detachment should be included in the differential diagnosis in horses with dense focal or diffuse corneal edema. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of topical dorzolamide 2% q8h and brinzolamide 1% q8h, administered either alone (A and B, respectively) or in combination with topical timolol 0.5% q12h (C and D, respectively), on the circadian pattern of intraocular pressure (IOP), the pupil size, and heart rate in healthy cats. Methods: In this prospective, randomized, double‐blinded study, 10 healthy, adult cats were randomly assigned to one of four groups and the eye to be medicated was randomly assigned. IOP, pupil diameter, and heart rate were measured at 3‐hour intervals. A 5 days' adjustment period was followed by a 5 days' placebo (baseline) period. Then, all groups of cats received all four treatments (A‐D) according to a Latin square‐based rotating schedule. Five days' medication periods were alternated with 3 days' washout periods. Results: Mean baseline IOP was 13.6 ± 2.7 mm Hg. All treatments resulted in a statistically significant decrease in mean IOP in the treated eye: A: −2.33 mm Hg (95% CI: −2.71, −1.94), B: −1.91 mm Hg (95% CI: −2.30, −1.53), C: −2.36 mm Hg (95% CI: −2.74, −1.97), and D: −2.37 mm Hg (95% CI: −2.76, −1.98) and the nontreated eye: A: −0.19 mm Hg (95% CI: −0.28, −0.11), B: −0.18 mm Hg (95% CI: −0.27, −0.10), C −0.31 mm Hg (95% CI: −0.40, −0.23), and D: −0.24 mm Hg (95% CI: −0.32, −0.15). Timolol resulted in an additional, significant decrease in IOP of 4% and 5%, respectively, compared to A and B, and in mild bradycardia and miosis. Conclusions: Topical administration of dorzolamide 2% and brinzolamide 1% q8h significantly decreased IOP in healthy cats. Supplemental timolol 0.5% eye drops q12h resulted in an additional, statistically significant reduction of IOP. [ABSTRACT FROM AUTHOR]

Background: Ulcerative keratitis is a common ophthalmic disease in horses which can be complicated by microbial infection and requires immediate, accurate treatment to prevent loss of visual function or the eye., Objectives: To report the results of microbial cultures, antibiotic susceptibility tests and corneal cytology in horses with ulcerative keratitis presented to a referral clinic, to assess agreement between cytology and culture results, to investigate whether previous topical treatment affected microbial culture results and whether the incidence of antimicrobial resistance changed during the study period., Study Design: Retrospective analysis., Methods: Case characteristics and results of cytology and microbial cultures were retrieved. Statistical analyses included descriptive statistics, χ 2 or Fisher's exact test and McNemar test., Results: Samples for bacterial culturing (n = 187), fungal culturing (n = 153) and cytology (n = 153) were collected from 178 horses. Bacterial and fungal cultures were positive in 36% (n = 67) and 20% (n = 30), respectively. Staphylococcus (n = 35/67; 48%), Streptococcus (n = 12/67; 16%) and Aspergillus species (n = 22/30; 81%) were most frequently found. Microorganisms were observed in 14% of cytology samples (n = 22/153). Acquired antibiotic resistance was commonly observed amongst Streptococcus and Staphylococcus species. Acquired antibiotic resistance to gentamicin was more common in cases previously treated with gentamicin (p < 0.001). The incidence of acquired antibiotic resistance did not increase significantly between Cohort 2012-2017 and Cohort 2018-2021. Neither bacterial nor fungal culturing results were in agreement with cytology findings (p < 0.001 and p = 0.02, respectively). In 6 of 104 samples that were negative on fungal culturing, cytology revealed fungal elements., Main Limitations: Due to the retrospective nature of this study, some case characteristics and test results were unavailable., Conclusions: Acquired resistance was commonly observed amongst Streptococcus and Staphylococcus species, and in bacteria previously exposed to topical gentamicin. The incidence of acquired antibiotic resistance did not increase over time. When fungal cultures prove negative, cytology may have some added benefit in identifying keratomycosis., (© 2024 EVJ Ltd.)

Objectives: To describe the signalment, ophthalmic examination findings, and follow-up of dogs affected with a previously unreported retrocorneal pigmentary lesion., Materials and Methods: Retrospective record evaluation spanning 2009-2019., Results: Retrocorneal pigmentary lesions were described in 34 patients (46 eyes). German Shepherds (n = 7), Jack Russel terriers (n = 5), and terrier crosses (n = 4) made up 16/34 (47.1%) of the cases. The mean age was 13.5 years (range 1.4-14.2 years), and 16/30 (53.3%) dogs were female. Most dogs were affected unilaterally (22/34 (64.7%)), the others bilaterally, and 5/34 (14.7%) were referred for it while the others were incidentally diagnosed. The lesions affected the ventral, peripheral, inner cornea and had a round/undulated leading edge. The number of corneal clock hours affected was known for 41/46 (89.1%) eyes and involved 1-3 clock hours in 32/41 (78.1%) eyes, 4-6 in 6/41 (14.6%), 7-9 in 2/41 (4.9%), and 10 in 1/41 (2.4%). The central cornea was affected in 9/46 (19.6%) eyes, and in 5/9 (55.6%), the median corneal clarity score was G2 (scale: G0-G4). The commonest additional findings included free-floating uveal cysts (11/34 dogs, 32.4%), cataracts (6/34 dogs, 17.6%), and primary glaucoma (5/34 dogs, 14.7%). Gonioscopy was available in 16/34 (47.1%) dogs and was normal except in primary glaucoma cases. Follow-up was documented in 13/34 (38.2%) dogs with a mean follow-up of 17 months (range: 5-26 months). Lesion progression was documented in 6/13 (46.2%) dogs., Conclusions: Retrocorneal pigmentation occurs as a slowly progressive lesion of older dogs that could impact vision. Histological studies of affected eyes are warranted., (© 2020 American College of Veterinary Ophthalmologists.)

We describe two dogs with persistent visual impairment after initially mild intoxication signs following ingestion of Ornithogalum arabicum plant material. Additionally, a 12-year analysis of the Dutch Poisons Information Centre database additionally reveals that ingestion of Ornithogalum plant material can be potentially life-threatening to companion animals. Further studies are necessary to confirm the involvement of cardiac glycoside-like toxins present in Ornithogalum arabicum and the toxicity of these substances to the retina., (© 2019 The Author(s).)