Topical treatment of Pseudomonas sp-infected corneal ulcers in horses: 70 cases (1977-1994).

OBJECTIVE

To determine which antimicrobial agents were most effective against Pseudomonas sp-infected ulcerative keratitis, and identify any trends in the various clinical conditions associated with these bacteria that might assist in effective treatment of the disease.

DESIGN

Retrospective case series.

ANIMALS

66 horses with 70 Pseudomonas sp-infected corneal ulcers.

PROCEDURE

We reviewed medical records of horses admitted to the George D. Widener Hospital for Large Animals, University of Pennsylvania between July 1977 and December 1994. Records of horses that had Pseudomonas sp isolated from a corneal ulcer scraping or deep swab were included in the study.

RESULTS

Aggressive topical medical treatment was successful in 57 ulcers and most likely would have been effective in 5 additional ulcers. Antimicrobial susceptibility testing indicated susceptibilities of 87, 85, and 93% to tobramycin, gentamicin, and amikacin, respectively. Although concurrent fungal infections were identified in only 2 of 35 ulcers examined, almost three fourths of the ulcers were treated with antifungal medications prophylactically. Clinical outcomes of the 70 affected eyes included: excellent vision with minimal leukoma, 73%; enucleation, 19%; blind phthisical eye, 4%; peripheral vision only, 3%; and euthanasia of newborn, 1%.

CLINICAL IMPLICATIONS

Aggressive topical medication with microbial agents effective against Pseudomonas sp can result in excellent vision with minimal leukoma in most horses with corneal ulcers.