A randomized controlled field trial of a novel trimethoprim-sulfadiazine oral suspension for treatment of Streptococcus equi subsp zooepidemicus infection of the lower respiratory tract in horses.
Abstract: To evaluate the effectiveness of a novel trimethoprim-sulfadiazine oral suspension for the treatment of naturally acquired Streptococcus equi subsp zooepidemicus infection in horses. Methods: Randomized, controlled field trial. Methods: 180 horses with S equi subsp zooepidemicus infection. Methods: Horses with lower respiratory tract infections caused by S equi subsp zooepidemicus were treated with a new formulation of combined trimethoprim-sulfadiazine oral suspension at a dosage of 24 mg/kg (10.9 mg/lb) twice daily for 10 days (treatment group) or with an equivalent volume of saline (0.9% NaCl) solution (placebo group). Response to treatment, including clinical signs and fecal consistency scores, was assessed twice daily. Any adverse effects were recorded. The primary outcome variable was clinical response; the secondary outcome variable was eradication of S equi subsp zooepidemicus on study day 17 as determined by bacteriologic culture of repeated transtracheal-wash specimens. Results: Of the 119 horses allocated to the treatment group, 69 (58%) had a positive clinical response. A significantly smaller proportion of horses in the placebo group (9/61 [15%]) had a positive clinical response. By day 5, 25 of 61 (41%) placebo horses had been withdrawn from the study because of negative clinical response, compared with only 10 of 119 (8.4%) treated horses. By day 10, 28 of 61 (46%) placebo horses had been withdrawn because of negative clinical response, compared with only 13 of 119 (11%) treated horses. There were few adverse events associated with the trimethoprim-sulfadiazine suspension. There were no significant differences in fecal consistency scores between treatment and placebo groups. Conclusions: The new oral suspension administered at 24 mg/kg twice daily effectively treated the clinical signs of S equi subsp zooepidemicus lower respiratory infection in horses and eliminated the organism from the respiratory tract. Adverse effects were minimal.
Publication Date: 2015-06-05 PubMed ID: 26043133DOI: 10.2460/javma.246.12.1345Google Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
- Research Support
- Non-U.S. Gov't
Summary
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The research article investigates the efficacy of a new oral suspension of trimethoprim-sulfadiazine in treating horses infected with Streptococcus equi subsp zooepidemicus, a bacterium causing respiratory tract infections.
Research Objectives and Methods
- The goal was to assess the effectiveness of a novel trimethoprim-sulfadiazine oral suspension in treating horses naturally infected with S. equi subsp zooepidemicus.
- This was done through a randomized, controlled field trial involving 180 horses.
- The animals diagnosed with lower respiratory tract infections due to S. equi subsp zooepidemicus were treated either with the new medication or with an equivalent volume of saline.
- The treatment dosage for infected horses was 24 mg/kg twice daily for ten days. Clinical response to the treatment, adverse effects, and changes in fecal consistency were monitored.
- The primary outcome was clinical response and the secondary outcome was eradication of the bacteria on the 17th day of the study, confirmed through a bacteriologic culture of repeated transtracheal-wash specimens.
Research Findings
- Among the 119 horses in the treatment group, 69 (about 58%) showed a positive clinical response. Only 15% of horses in the placebo group exhibited a similar response.
- On day 5, 41% of placebo horses were withdrawn due to negative clinical response, compared to just 8.4% of treated horses.
- By day 10, the number of withdrawn placebo horses had increased to 46%, while only 11% of treated horses were withdrawn.
- The occurrence of adverse events was relatively low with the trimethoprim-sulfadiazine suspension.
- No significant differences in fecal consistency scores were observed between the treatment and placebo groups.
Research Conclusions
- The new oral suspension of trimethoprim-sulfadiazine at 24 mg/kg twice daily was effective in treating the clinical signs of S. equi subsp zooepidemicus respiratory infection in horses and in eliminating the bacteria from the horses’ respiratory tract.
- The new formulation also showed minimal adverse effects on treated horses.
Cite This Article
APA
McClure SR, Koenig R, Hawkins PA.
(2015).
A randomized controlled field trial of a novel trimethoprim-sulfadiazine oral suspension for treatment of Streptococcus equi subsp zooepidemicus infection of the lower respiratory tract in horses.
J Am Vet Med Assoc, 246(12), 1345-1353.
https://doi.org/10.2460/javma.246.12.1345 Publication
Researcher Affiliations
MeSH Terms
- Administration, Oral
- Animals
- Drug Combinations
- Female
- Horse Diseases / drug therapy
- Horse Diseases / microbiology
- Horses
- Male
- Respiratory Tract Infections / drug therapy
- Respiratory Tract Infections / microbiology
- Respiratory Tract Infections / veterinary
- Streptococcal Infections / drug therapy
- Streptococcal Infections / microbiology
- Streptococcal Infections / veterinary
- Streptococcus equi
- Sulfadiazine / administration & dosage
- Sulfadiazine / therapeutic use
- Suspensions
- Trimethoprim / administration & dosage
- Trimethoprim / therapeutic use
Citations
This article has been cited 4 times.- Kittang BR, Pettersen VK, Oppegaard O, Skutlaberg DH, Dale H, Wiker HG, Skrede S. Zoonotic necrotizing myositis caused by Streptococcus equi subsp. zooepidemicus in a farmer. BMC Infect Dis 2017 Feb 15;17(1):147.
- Cheng G, Xu Y, Zhu X, Xie S, Wang L, Huang L, Hao H, Liu Z, Pan Y, Chen D, Wang Y, Yuan Z. The antibacterial activities of aditoprim and its efficacy in the treatment of swine streptococcosis. Sci Rep 2017 Feb 1;7:41370.
- Sadaka C, Kanellos T, Guardabassi L, Boucher J, Watts JL. Evaluation of Veterinary-Specific Interpretive Criteria for Susceptibility Testing of Streptococcus equi Subspecies with Trimethoprim-Sulfamethoxazole and Trimethoprim-Sulfadiazine. J Clin Microbiol 2017 Jan;55(1):326-330.
- Alessiani A, Baffoni M, Averaimo D, Cantelmi MC, Coccaro A, Rulli M, Piersanti V, Pompilii C, Cito F, Chiaverini A, Petrini A. Antimicrobial Resistance and Genetic Characterization of Streptococcus equi subsp. zooepidemicus in Equines from Central Italy: Insights from a One Health Perspective. Animals (Basel) 2025 Sep 16;15(18).
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