Peer-reviewed veterinary case report
Using minimum inhibitory concentration values of common topical antibiotics to investigate emerging antibiotic resistance: A retrospective study of 134 dogs and 20 horses with ulcerative keratitis.
- Journal:
- Veterinary ophthalmology
- Year:
- 2020
- Authors:
- Jinks, Maggie R et al.
- Affiliation:
- Department of Veterinary Clinical Sciences · United States
Plain-English summary
This study looked at 134 dogs and 20 horses with a serious eye condition called bacterial ulcerative keratitis, which is an infection that causes ulcers on the cornea. The researchers wanted to understand how effective common topical antibiotics were against the bacteria causing these infections and how resistance to these antibiotics might be changing over time. They found that the most common bacteria involved were from the Staphylococcus, Streptococcus, and Pseudomonas families. Notably, the effectiveness of some antibiotics decreased over time, especially for Staphylococcus infections in pets that had been treated with certain antibiotics before. As a result, if your pet has a Staphylococcus infection, your veterinarian may suggest using different antibiotics or additional treatments, and they may recommend testing to see which antibiotics will work best.
Abstract
OBJECTIVES: To identify the minimum inhibitory concentration (MIC) distribution for commonly used topical antibiotics from isolates of dogs and horses with ulcerative bacterial keratitis, and to investigate changes in MIC values over time and following treatment with topical fluoroquinolones. ANIMALS STUDIED: One hundred thirty-four client-owned dogs and 20 client-owned horses with bacterial ulcerative keratitis. PROCEDURE: Minimum inhibitory concentration values for 14 topical antibiotics were reported for canine and equine cases of bacterial ulcerative keratitis between 2013 and 2018. Changes in MIC values over time and after treatment with topical fluoroquinolones were reported. RESULTS: The three most common bacterial genera isolated were Staphylococcus, Streptococcus, and Pseudomonas. Together, these represented 79.4% of canine cases and 77.4% of equine cases. Overall, isolates from horses tended to have lower MIC values, as did Pseudomonas isolates from both dogs and horses, compared to other bacterial genera, especially Staphylococcus spp. The MIC values of erythromycin and trimethoprim sulfa for Staphylococcus spp., and the MIC value of moxifloxacin for Pseudomonas significantly increased over time. Previous topical fluoroquinolone use was associated with a significant increase in the MIC value of ofloxacin in canine and equine Staphylococcus isolates and current topical fluoroquinolone use was associated with significant increases in the MIC values of ciprofloxacin, moxifloxacin, and ofloxacin in canine Staphylococcus isolates. CONCLUSION: Patients previously or currently treated with topical fluoroquinolones, particularly in Staphylococcus infections, may require alternative antibiotics or additional antibiotic classes other than fluoroquinolones. Bacterial culture with MIC susceptibility testing should be highly recommended when a Staphylococcal infection is suspected.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/32608547/