Comparison of antimicrobial resistance patterns in dogs with bacterial keratitis presented to a veterinary teaching hospital over two multi‐year time periods (1993–2003 and 2013–2019) in the Southeastern United States

Abstract

Objective To report clinical characteristics of dogs with bacterial keratitis, identify the most common bacterial isolates within this population, characterize the bacterial isolates’ antimicrobial resistance patterns, and compare those resistance patterns to previously reported resistance patterns. Animal studied Dogs diagnosed with bacterial keratitis between 2013 and 2019. Procedures Data pertaining to breed; Schirmer tear test I results; use of cyclosporine, tacrolimus, or corticosteroids at time of ulcer diagnosis; bacterial genus or species isolated; and resistance to selected antimicrobials as measured by Kirby‐Bauer disk diffusion were collected. Resistance patterns were compared to those reported by Tolar et al. (2006). Results One hundred seventy bacterial isolates were cultured from 138 eyes from 130 dogs. Of these dogs, 45% were brachycephalic, 62% had STT <15 mm/min, and 28% were receiving a corticosteroid at the time of examination. The most common isolates were Staphylococcus pseudintermedius (31%), β‐hemolytic Streptococcus spp. (28%), and Pseudomonas aeruginosa (18%). Compared to the 1993–2003 study period, there were significant increases in resistance to cephalothin and polymyxin B among S. pseudintermedius isolates. β‐hemolytic Streptococcus spp. and P. aeruginosa isolates had no significant changes in resistance to the tested antimicrobials. Conclusion Isolates of S. pseudintermedius, β‐hemolytic Streptococcus spp., and P. aeruginosa had minimal changes in resistance between the two study periods. In this population, monotherapy with ciprofloxacin or combination therapy of tobramycin and a first‐generation cephalosporin continue to be appropriate for use in cases of suspected bacterial keratitis while awaiting results of susceptibility testing.

Impact of multi-drug resistance on clinical outcomes of dogs with corneal ulcers infected with Staphylococcus pseudintermedius

“…The present study was limited to cases where Staphylococcus pseudintermedius was determined to be the only primary pathogen identified to reduce variability and better focus on the variable of interest (i.e., MDR status). However, results of this work cannot be extrapolated to canine patients with polymicrobial infections (up to 21% of cases) ( 3 , 43 ) or dogs with infectious keratitis from Streptococcus spp., Pseudomonas spp., or other common bacterial pathogens reported for this condition. A recent study by Tsvetanova et al ( 40 ) showed that melting corneal ulcers associated with Pseudomonas spp.…”

Letter to the Editor: McKeever et al. 2021

“…McKeever, Ward, and Hendrix for their recent report on canine bacterial keratitis and evaluation of antimicrobial resistance (10.1111/vop.12897). 1 This is an important area that warrants closer examination given the importance of antimicrobial stewardship across species; however, there are several key errors with the interpretation of the antimicrobial resistance data that should be addressed. Because these errors are increasingly common in the veterinary literature, we are writing this letter to make the authors and readers aware of these issues to help improve analysis and reporting methods in the future.…”

“…The authors declare no conflicts of interest. Amanda J. Kreuder 1 Rachel A. Allbaugh 1 Lionel Sebbag…”

Antibiotic Recommendations for Treatment of Canine Stromal Corneal Ulcers

“…The first step in treating corneal bacterial infections is empiric therapy based on epidemiological data and use of suggested antimicrobials [ 4 ]. While large epidemiological and corneal pathogen surveillance studies have been reported in humans, similar datasets are relatively sparsely reported in veterinary medicine, so the initial selection of the antibiotic treatment is frequently chosen based on personal preference and in-hospital ophthalmic drug availability [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ].…”

“…A number of studies have evaluated a microbial community in canine corneal ulcers [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. The most frequent bacterial groups identified are Gram-positive staphylococci and streptococci in addition to Gram-negative Pseudomonas aeruginosa [ 3 , 5 , 7 , 8 , 9 , 11 , 12 , 13 , 14 , 16 , 17 ].…”