Patterns of Bacterial Infection and Antibiotic Resistance in Canine Corneal Ulcers: A Retrospective Analysis (Berlin,...

To investigate the bacterial spectrum and antimicrobial susceptibility patterns of isolates obtained from canine corneal ulcers, assessing possible associations with breed, season, and multidrug resistance.

A retrospective review was conducted on corneal ulcers from 112 dogs between May 2021 and June 2024 at a specialized veterinary ophthalmology clinic in Berlin, Germany. Bacteriological cultures and antimicrobial susceptibility tests (ASTs) were analyzed according to the Clinical and Laboratory Standards Institute (CLSI).

Brachycephalic breeds represented 79.5% of affected dogs. Positive bacterial growth was obtained in 79.5% (89/112) of samples, yielding 107 isolates. Gram-positive organisms predominated (72.2%), mainly Staphylococcus pseudintermedius (27.8%) and β-hemolytic Streptococcus (19.4%). Among 100 isolates tested, 59% were resistant to penicillins, while 71% were susceptible to aminoglycosides and fluoroquinolones, 73% to amoxicillin-clavulanate, and 78% to tetracyclines. Multidrug resistance (MDR) occurred in 27% of isolates.

Staphylococcus pseudintermedius and β-hemolytic Streptococcus were the main bacterial agents associated with infected canine corneal ulcers. The relatively high frequency of MDR isolates emphasizes the need for culture-based therapy and ongoing regional surveillance to guide empirical antibiotic use.