Equine ulcerative keratitis in the Netherlands (2012–2021): Bacterial and fungal isolates and antibiotic susceptibility

• Published in: Equine veterinary journal 2025-01, Vol.57 (1), p.38-46
• Main Authors: Verdenius, Clara Y., Slenter, Inge J. M., Hermans, Hanneke, Broens, Els M., Djajadiningrat‐Laanen, Sylvia C.
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; antibiotic resistance; Antibiotics; Aspergillus; Bacteria - drug effects; Bacteria - isolation & purification; cell biology; Cellular biology; cornea; Corneal Ulcer - drug therapy; Corneal Ulcer - epidemiology; Corneal Ulcer - microbiology; Corneal Ulcer - veterinary; cytology; descriptive statistics; Drug resistance; Drug Resistance, Bacterial; Drug Resistance, Fungal; Eye Infections, Bacterial - drug therapy; Eye Infections, Bacterial - epidemiology; Eye Infections, Bacterial - microbiology; Eye Infections, Bacterial - veterinary; Eye Infections, Fungal - drug therapy; Eye Infections, Fungal - epidemiology; Eye Infections, Fungal - microbiology; Eye Infections, Fungal - veterinary; Female; fungi; Fungi - drug effects; Fungi - isolation & purification; gentamicin; horse; Horse Diseases - drug therapy; Horse Diseases - epidemiology; Horse Diseases - microbiology; Horses; keratitis; Male; microbial culture; Microbial Sensitivity Tests - veterinary; Netherlands; Netherlands - epidemiology; Retrospective Studies; species; Staphylococcus; Streptococcus
• ISSN: 0425-1644; 2042-3306; 2042-3306
• DOI: 10.1111/evj.14059

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, χ2 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