Effect of topical application of 0.5% proparacaine on corneal culture results from 33 dogs, 12 cats, and 19 horses with spontaneously arising ulcerative keratitis.

This research explores the impact of using a topical anesthetic, proparacaine, on the results of bacterial and fungal cultures in animals with ulcerative keratitis, finding that proparacaine did not significantly change the culture results, but recommending further investigation for clinical significance.

Objective and Methodology

• This study aimed to understand the effects of applying proparacaine – a topical anesthetic – on the bacterial and fungal culture results in animals suffering from ulcerative keratitis. Evaluating the consistency of culture results and cytology was another objective.
• Corneal samples were collected from 64 animals (including 33 dogs, 12 cats, and 19 horses) all of which had spontaneously developed ulcerative keratitis.
• The samples for bacterial (across all animals) and fungal (only horses) cultures were collected both before and after the application of 0.5% proparacaine or saline solution.
• After applying a topical anesthetic, cytological samples were also collected from all patients.
• The research utilized statistical tests like Fisher’s exact test and McNemar’s test to analyze the data, comparing the frequency of cultivatable bacteria before and after the application of proparacaine or saline, and comparing the congruity of culture and cytology results, respectively.

Results

• The study found no significant difference in the number of animals from which bacteria were isolated before and after the application of either proparacaine or saline.
• In the case of fungal cultures in horses, no firm conclusion could be drawn due to the small sample size.
• The analysis showed bacterial presence was detected more frequently in culture (31 out of 64 animals) than in cytology (19 out of 64 animals). Cytological detection was lower due to possibly lower sensitivity.

Conclusions

• Based on the gathered data, the study concluded that the application of proparacaine did not significantly alter the results of bacterial or fungal culture in animals suffering from ulcerative keratitis.
• Even though no substantial difference was found, the importance of further investigation for clinical significance was underscored in the study.
• Given the cultures often detected bacteria more frequently than cytology, the study recommends the use of both methods simultaneously to maximize the detection of organisms in animals with ulcerative keratitis.