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Home / Equine Research Bank / Vet Ophthalmol / Using minimum inhibitory concentration values of common topi...
Veterinary ophthalmology2020; 23(5); 806-813; doi: 10.1111/vop.12801

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.

Abstract: 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. Methods: One hundred thirty-four client-owned dogs and 20 client-owned horses with bacterial ulcerative keratitis. Methods: 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. Conclusions: 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.
© 2020 American College of Veterinary Ophthalmologists.
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Publication Date: 2020-07-01 PubMed ID: 32608547DOI: 10.1111/vop.12801Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study analyzes the minimum inhibitory concentration (MIC) of common antibiotics in cases of ulcerative keratitis in dogs and horses. It reveals an increasing resistance to several antibiotics, especially in Staphylococcus infections previously treated with fluoroquinolones.

Objective and Methods

  • The main objective of this study was to determine the MIC (the lowest concentration of an antibiotic that prevents visible growth of bacteria) of 14 common topical antibiotics in cases of bacterial ulcerative keratitis in dogs and horses.
  • This was a retrospective study, which means it used data from previously recorded cases dating between 2013 and 2018.
  • In addition, the researchers were also interested in observing changes in MIC values over time and after treatment with topical fluoroquinolones, a class of antibiotics.

Findings

  • MIC values for Staphylococcus, Streptococcus, and Pseudomonas bacterial species were obtained. These bacteria were found to be the most commonly isolated genera, accounting for a majority of both canine and equine cases.
  • Overall, equine bacterial isolates and Pseudomonas isolates from both dogs and horses tended to be more susceptible to antibiotics (i.e., had lower MIC values) compared to other bacterial genera, especially the Staphylococcus species.
  • However, it was discovered that certain antibiotics’ effectiveness, such as erythromycin and trimethoprim sulfa for Staphylococcus spp., and moxifloxacin for Pseudomonas, has significantly decreased over time. This means these bacteria are essentially becoming more resistant.
  • A significant increase in MIC values was associated with previous or current use of topical fluoroquinolones, indicating a growing resistance against this class of antibiotics.

Conclusion

  • The study concludes that in cases of Staphylococcus infections previously or currently treated with topical fluoroquinolones, different antibiotics, or additional classes of antibiotics may be required to combat the infection effectively.
  • The authors also recommend MIC susceptibility testing alongside bacterial culturing if a Staphylococcal infection is suspected, to determine the most effective antibiotic treatment regimen.

Cite This Article

APA
Jinks MR, Miller EJ, Diaz-Campos D, Mollenkopf DF, Newbold G, Gemensky-Metzler A, Chandler HL. (2020). 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. Vet Ophthalmol, 23(5), 806-813. https://doi.org/10.1111/vop.12801

Publication

Veterinary ophthalmology
ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 23
Issue: 5
Pages: 806-813

Researcher Affiliations

Jinks, Maggie R
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, USA.
Miller, Eric J
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, USA.
Diaz-Campos, Dubraska
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, USA.
Mollenkopf, Dixie F
  • Department of Veterinary Preventative Medicine, The Ohio State University, Columbus, OH, USA.
Newbold, Georgina
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, USA.
Gemensky-Metzler, Anne
  • Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, USA.
Chandler, Heather L
  • College of Optometry, The Ohio State University, Columbus, OH, USA.

MeSH Terms

  • Animals
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / pharmacology
  • Corneal Ulcer / drug therapy
  • Corneal Ulcer / microbiology
  • Corneal Ulcer / veterinary
  • Dog Diseases / drug therapy
  • Dogs
  • Drug Resistance, Bacterial
  • Female
  • Horse Diseases / drug therapy
  • Horses
  • Male
  • Microbial Sensitivity Tests
  • Ophthalmic Solutions / administration & dosage
  • Ophthalmic Solutions / pharmacology
  • Pseudomonas / drug effects
  • Retrospective Studies
  • Staphylococcus / drug effects
  • Streptococcus / drug effects

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This article includes 28 references
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Citations

This article has been cited 12 times.
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