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Home / Equine Research Bank / Equine Vet J / Equine ulcerative keratitis in the Netherlands (2012-2021): ...
Equine veterinary journal2024; 57(1); 38-46; doi: 10.1111/evj.14059

Equine ulcerative keratitis in the Netherlands (2012-2021): Bacterial and fungal isolates and antibiotic susceptibility.

Abstract: Ulcerative keratitis is a common ophthalmic disease in horses which can be complicated by microbial infection and requires immediate, accurate treatment to prevent loss of visual function or the eye. Objective: To report the results of microbial cultures, antibiotic susceptibility tests and corneal cytology in horses with ulcerative keratitis presented to a referral clinic, to assess agreement between cytology and culture results, to investigate whether previous topical treatment affected microbial culture results and whether the incidence of antimicrobial resistance changed during the study period. Methods: Retrospective analysis. Methods: Case characteristics and results of cytology and microbial cultures were retrieved. Statistical analyses included descriptive statistics, χ2 or Fisher's exact test and McNemar test. Results: Samples for bacterial culturing (n = 187), fungal culturing (n = 153) and cytology (n = 153) were collected from 178 horses. Bacterial and fungal cultures were positive in 36% (n = 67) and 20% (n = 30), respectively. Staphylococcus (n = 35/67; 48%), Streptococcus (n = 12/67; 16%) and Aspergillus species (n = 22/30; 81%) were most frequently found. Microorganisms were observed in 14% of cytology samples (n = 22/153). Acquired antibiotic resistance was commonly observed amongst Streptococcus and Staphylococcus species. Acquired antibiotic resistance to gentamicin was more common in cases previously treated with gentamicin (p < 0.001). The incidence of acquired antibiotic resistance did not increase significantly between Cohort 2012-2017 and Cohort 2018-2021. Neither bacterial nor fungal culturing results were in agreement with cytology findings (p < 0.001 and p = 0.02, respectively). In 6 of 104 samples that were negative on fungal culturing, cytology revealed fungal elements. Conclusions: Due to the retrospective nature of this study, some case characteristics and test results were unavailable. Conclusions: Acquired resistance was commonly observed amongst Streptococcus and Staphylococcus species, and in bacteria previously exposed to topical gentamicin. The incidence of acquired antibiotic resistance did not increase over time. When fungal cultures prove negative, cytology may have some added benefit in identifying keratomycosis.
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Publication Date: 2024-01-14 PubMed ID: 38220439DOI: 10.1111/evj.14059Google Scholar: Lookup
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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 research article analyzes cases of ulcerative keratitis, a common ophthalmic disease in horses, to report microbiological culture results and antibiotic susceptibility tests. It also examines whether previous treatments affected culture results or if there were significant changes in antimicrobial resistance over a nine-year period.

Research Methodology

  • The study is a retrospective analysis where the researchers used past records to study the disease patterns.
  • Details about the cases, cytology results, and microbial culture results were collated from the referral clinic’s files.
  • Statistical analyses were performed to derive significant conclusions.
  • The researchers collected 187 samples for bacterial culturing, 153 for fungal culturing, and 153 for cytology from 178 horses.

Study Findings

  • Of the samples collected, bacterial cultures were positive in 36% of the cases and fungal cultures were positive in 20% cases.
  • The most common bacteria found were Staphylococcus (48%) and Streptococcus (16%) species while Aspergillus species (81%) topped the list in fungal cultures.
  • In 14% of the cytology samples, microorganisms were seen.
  • The study found that acquired antibiotic resistance, especially against gentamicin, was common in Streptococcus and Staphylococcus species.
  • Bacteria previously exposed to topical gentamicin also showed high antibiotic resistance.
  • Interestingly, the incidence of acquired antibiotic resistance did not show a significant increase over the studied time period (2012-2021).
  • The bacterial and fungal culture results were not in agreement with the cytology results – in 6 of 104 samples where fungal cultures were negative, cytology revealed fungal elements.

Conclusions

  • Due to the retrospective nature of the study, there were some limitations in terms of availability of case characteristics and test results.
  • Streptococcus and Staphylococcus species, and bacteria previously treated with gentamicin showed a trend of acquired resistance, however, the incidence of such resistance did not show a significant increase during the study period.
  • The study indicates that in cases where fungal cultures are negative, cytology could provide additional insights to identify keratomycosis (fungal infection of the cornea in horses).

Cite This Article

APA
Verdenius CY, Slenter IJM, Hermans H, Broens EM, Djajadiningrat-Laanen SC. (2024). Equine ulcerative keratitis in the Netherlands (2012-2021): Bacterial and fungal isolates and antibiotic susceptibility. Equine Vet J, 57(1), 38-46. https://doi.org/10.1111/evj.14059

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 57
Issue: 1
Pages: 38-46

Researcher Affiliations

Verdenius, Clara Y
  • Department of Clinical Sciences, Surgery of Companion Animals, Ophthalmology Section, Utrecht University, Faculty of Veterinary Medicine, Utrecht, The Netherlands.
Slenter, Inge J M
  • Department of Clinical Sciences, Surgery of Companion Animals, Ophthalmology Section, Utrecht University, Faculty of Veterinary Medicine, Utrecht, The Netherlands.
Hermans, Hanneke
  • Equine Eye Care, Utrecht, The Netherlands.
Broens, Els M
  • Department of Biomolecular Health Sciences, Infectious Diseases & Immunology, Utrecht University, Faculty of Veterinary Medicine, Utrecht, The Netherlands.
Djajadiningrat-Laanen, Sylvia C
  • Department of Clinical Sciences, Surgery of Companion Animals, Ophthalmology Section, Utrecht University, Faculty of Veterinary Medicine, Utrecht, The Netherlands.

MeSH Terms

  • Animals
  • Horses
  • Horse Diseases / microbiology
  • Horse Diseases / epidemiology
  • Horse Diseases / drug therapy
  • Corneal Ulcer / veterinary
  • Corneal Ulcer / microbiology
  • Corneal Ulcer / drug therapy
  • Corneal Ulcer / epidemiology
  • Retrospective Studies
  • Netherlands / epidemiology
  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use
  • Male
  • Female
  • Bacteria / drug effects
  • Bacteria / isolation & purification
  • Fungi / drug effects
  • Fungi / isolation & purification
  • Eye Infections, Fungal / veterinary
  • Eye Infections, Fungal / microbiology
  • Eye Infections, Fungal / epidemiology
  • Eye Infections, Fungal / drug therapy
  • Drug Resistance, Bacterial
  • Drug Resistance, Fungal
  • Microbial Sensitivity Tests / veterinary
  • Eye Infections, Bacterial / veterinary
  • Eye Infections, Bacterial / microbiology
  • Eye Infections, Bacterial / epidemiology
  • Eye Infections, Bacterial / drug therapy

References

This article includes 32 references
  1. Plummer CE. Corneal response to injury and infection in the horse. Vet Clin North Am Equine Pract 2017;33(3):439–463.
  2. Plummer CE. Equine ophthalmology. In: Gelatt KN, editor. Veterinary ophthalmology. 6th ed. Hoboken, NJ: Wiley‐Blackwell; 2020. p. 1841–1982.
  3. Brooks DE, Matthews A, Clode AB. Diseases of the cornea. In: Gilger BC, editor. Equine ophthalmology. 3rd ed. Ames, IA: John Wiley & Sons Inc.; 2017. p. 252–368.
  4. Andrew SE, Nguyen A, Jones GL, Brooks DE. Seasonal effects on the aerobic bacterial and fungal conjunctival flora of normal thoroughbred brood mares in Florida. Vet Ophthalmol 2003;6(1):45–50.
  5. Johns IC, Baxter K, Booler H, Hicks C, Menzies‐Gow N. Conjunctival bacterial and fungal flora in healthy horses in the UK. Vet Ophthalmol 2011;14(3):195–199.
  6. Hampson ECGM, Gibson JS, Barot M, Shapter FM, Greer RM. Identification of bacteria and fungi sampled from the conjunctival surface of normal horses in South‐East Queensland, Australia. Vet Ophthalmol 2019;22(3):265–275.
  7. Mustikka MP, Grönthal TSC, Pietilä EM. Equine infectious keratitis in Finland: associated microbial isolates and susceptibility profiles. Vet Ophthalmol 2020;23(1):148–159.
  8. Andrew SE, Brooks DE, Smith PJ, Gelatt KN, Chmielewski NT, Whittaker CJG. Equine ulcerative keratomycosis: visual outcome and ocular survival in 39 cases (1987–1996). Equine Vet J 1998;30(2):109–116.
  9. Voelter‐Ratson K, Pot SA, Florin M, Spiess BM. Equine keratomycosis in Switzerland: a retrospective evaluation of 35 horses (January 2000–August 2011). Equine Vet J 2013;45(5):608–612.
  10. Reed Z, Thomasy SM, Good KL, Maggs DJ, Magdesian KG, Pusterla N. Equine keratomycoses in California from 1987 to 2010 (47 cases). Equine Vet J 2013;45(3):361–366.
  11. Moore CPC. Bacterial and fungal isolates from equidae with ulcerative keratitis. J Am Vet Med Assoc 1983;182(6):600–603.
  12. Sauer P, Andrew SE, Lassaline M, Gelatt KN, Denis HM. Changes in antibiotic resistance in equine bacterial ulcerative keratitis (1991‐2000): 65 horses. Vet Ophthalmol 2003;6(4):309–313.
  13. Jinks MR, Miller EJ, Diaz‐Campos D, Mollenkopf DF, Newbold G, Gemensky‐Metzler A. 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 2020;23(5):806–813.
  14. Keller RL, Hendrix DV. Bacterial isolates and antimicrobial susceptibilities in equine bacterial ulcerative keratitis (1993‐2004). Equine Vet J 2005;37(3):207–211.
  15. Suter A, Voelter K, Hartnack S, Spiess BM, Pot SA. Septic keratitis in dogs, cats, and horses in Switzerland: associated bacteria and antibiotic susceptibility. Vet Ophthalmol 2018;21(1):66–75.
  16. Wada S, Hobo S, Niwa H. Ulcerative keratitis in thoroughbred racehorses in Japan from 1997 to 2008. Vet Ophthalmol 2010;13(2):99–105.
  17. Utter ME, Davidson EJ, Wotman KL. Clinical features and outcomes of severe ulcerative keratitis with medical and surgical management in 41 horses (2000–2006). Equine Vet Educ 2009;21(6):321–327.
  18. Sandmeyer LS, Bauer BS, Mohaghegh Poor SM, Feng CX, Chirino‐Trejo M. Alterations in conjunctival bacteria and antimicrobial susceptibility during topical administration of ofloxacin after cataract surgery in dogs. Am J Vet Res 2017;78(2):207–214.
  19. Hewitt JS, Allbaugh RA, Kenne DE, Sebbag L. Prevalence and antibiotic susceptibility of bacterial isolates from dogs with ulcerative keratitis in Midwestern United States. Front Vet Sci 2020;7:583965.
  20. Asbell PA, Sanfilippo CM, Sahm DF, DeCory HH. Trends in antibiotic resistance among ocular microorganisms in the United States from 2009 to 2018. JAMA Ophthalmol 2020;138(5):439–450.
  21. Lin L, Duan F, Yang Y, Lou B, Liang L, Lin X. Nine‐year analysis of isolated pathogens and antibiotic susceptibilities of microbial keratitis from a large referral eye center in southern China. Infect Drug Resist 2019;12:1295–1302.
  22. Blomquist PH. Methicillin‐resistant Staphylococcus aureus infections of the eye and orbit (an American Ophthalmological Society thesis). Trans Am Ophthalmol Soc 2006;104:322–345.
  23. Proietto L, Beatty SS, Plummer CE. Comparison of 3 corneal cytology collection methods for evaluating equine ulcerative keratitis: cytobrush, kimura platinum spatula, and handle edge of scalpel blade. Vet Ophthalmol 2019;22(2):153–160.
  24. Clinical & Laboratory Standards Institute. Available from: http://www.clsi.org
  25. Francois P, Pittet D, Bento M, Pepey B, Vaudaux P, Lew D. Rapid detection of methicillin‐resistant Staphylococcus aureus directly from sterile or nonsterile clinical samples by a new molecular assay. J Clin Microbiol 2003;41(1):254–260.
  26. Magiorakos AP, Srinivasan A, Carey RB, Carmeli Y, Falagas ME, Giske CG. Multidrug‐resistant, extensively drug‐resistant and pandrug‐resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect 2012;18(3):268–281.
  27. Chalder RH, Knott T, Rushton JO, Nikolic‐Pollard D. Changes in antimicrobial resistance patterns of ocular surface bacteria isolated from horses in the UK: an eight‐year surveillance study (2012‐2019). Vet Ophthalmol 2020;23(6):950–956.
  28. Verdenius CY, Broens EM, Slenter IJM, Djajadiningrat‐Laanen SC. Corneal stromal ulcerations in a referral population of dogs and cats in The Netherlands (2012‐2019): bacterial isolates and antibiotic resistance. Vet Ophthalmol 2023:1–10.
    doi: 10.1111/vop.13080google scholar: lookup
  29. Romanowski EG, Mah FS, Yates KA, Kowalski RP, Gordon YJ. The successful treatment of gatifloxacin‐resistant Staphylococcus aureus keratitis with Zymar® (gatifloxacin 0.3%) in a NZW rabbit model. Am J Ophthalmol 2005;139(5):867–877.
  30. Kowalski RP, Yates KA, Romanowski EG, Karenchak LM, Mah FS, Gordon YJ. An ophthalmologist's guide to understanding antibiotic susceptibility and minimum inhibitory concentration data. Ophthalmology 2005;112(11):1987.e1–1987.e6.
  31. Petroutsos G, Guimaraes R, Giraud JP, Pouliquen Y. Corticosteroids and corneal epithelial wound healing. Br J Ophthalmol 1982;66(11):705–708.
  32. O'Day DM, Ray WA, Head WS, Robinson RD, Williams TE. Influence of corticosteroid on experimentally induced keratomycosis. Arch Ophthalmol 1991;109(11):1601–1604.

Citations

This article has been cited 3 times.
  1. Stolle LM, Oltmanns H, Meißner J, Heun F, Schieder AK, Wolff HT, Ohnesorge B, Busse C. Polyhexanide, Povidone-Iodine, and Hypochlorous Acid Show High In Vitro Antimicrobial Efficacy Against Pathogens Commonly Associated With Equine Infectious Keratitis. Vet Ophthalmol 2026 Jan;29(1):e70141.
    doi: 10.1111/vop.70141pubmed: 41552904google scholar: lookup
  2. de Jong JE, Heuvelink AE, Dieste Pérez L, Holstege MMC. Aspergillus spp., aspergillosis and azole usage in animal species in Europe: Results from a multisectoral survey and review of recent literature. Med Mycol 2025 Jan 25;63(2).
    doi: 10.1093/mmy/myaf009pubmed: 39890594google scholar: lookup
  3. Roberts D, Thomas J, Salmon J, Cubeta MA, Stapelmann K, Gilger BC. Cold atmospheric plasma inactivates Aspergillus flavus and Fusarium keratoplasticum biofilms and conidia in vitro. J Med Microbiol 2024 Jul;73(7).
    doi: 10.1099/jmm.0.001858pubmed: 38985505google scholar: lookup
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