Bacterial and fungal isolates from Equidae with ulcerative keratitis.

This research paper presents the findings of a study investigating the variety of bacterial and fungal infections present in the eyes of horses suffering from ulcerative keratitis. The study further explored the effectiveness of different antibiotics on these infections.

Microbial Isolates Identified

The primary focus of the research was to identify the microbial isolates from 38 eyes of 37 horses with ulcerative keratitis. The key findings include:

• Gram-negative bacteria were identified as the most common type of microorganisms isolated from the eyes of the horses.
• The most frequently present gram-negative bacteria were Pseudomonas sp, Enterobacter group, and Acinetobacter sp.
• The research also identified fungal infections in 15 eyes, with seven different genera found. Aspergillus sp was the most common of these.
• It was interesting to note that ten out of the fifteen eyes with fungal keratitis had been previously treated with corticosteroids.
• The study also found mixed bacterial and fungal infections in eleven out of the 38 studied eyes.

Severity of Infections

Another significant area of observation in the study was the severity of the infections. Based on the clinical observations:

• The research found that the most severe cases of infection were those where Aspergillus and gram-negative bacteria existed together as a mixed infection.

Antibiotic Efficacy

The researchers then conducted susceptibility testing to assess the efficacy of different antibiotics on the identified isolates. The key findings were:

• Gentamicin was identified as highly effective, with an 88.4% efficacy rate against all bacterial isolates tested.
• Cephaloridine displayed slightly higher efficacy than gentamicin against gram-positive organisms.
• However, only 32.3% of the gram-negative isolates were found to be susceptible to the antibiotic chloramphenicol.
• Out of the relatively less number of gram-positive organisms isolated, it was observed that streptococci were more often susceptible to chloramphenicol, whereas staphylococci showed higher susceptibility to gentamicin.