Efficacy of a 2-dose regimen of a sustained release ceftiofur suspension in horses with Streptococcus equi subsp. zooepidemicus bronchopneumonia.

The research study examines the effectiveness and safety of a two-dose treatment of ceftiofur, a type of antibiotic, for horses with a specific type of pneumonia caused by the Streptococcus equi subsp. zooepidemicus bacterium. The study found the treatment to be effective in a majority of cases, significantly more so than a placebo.

Study Design and Participants

• The study was designed as a multicenter, placebo-controlled, double-blinded, randomized clinical trial to evaluate the effectiveness of ceftiofur. In this study design, neither the researchers nor the participants knew which treatment was being administered, reducing bias.
• The participant pool included 373 horses suffering from pneumonia, a lung condition in this case caused by the Streptococcus equi subsp. zooepidemicus bacterium. The horses were divided into two groups: 278 horses were treated with the ceftiofur drug, and the remaining 95 horses received a placebo treatment.

Inclusion Criteria and Success Metrics

• Horses were included in the study if they tested positive for the presence of the bacteria causing pneumonia. The test required to positively confirm infection was a recovery of ≥10(4) CFU/mL of the bacteria on the primary isolation plate.
• Therapeutic success was defined by several metrics, including improvement of lower respiratory tract infection at 4 and 9 days after the initial dose, resolution of all symptoms by 15 days, and no recurrence of symptoms by 25 days.

Results and Findings

• The research findings indicated that the ceftiofur treatment was notably effective. Among the horses treated with ceftiofur, 85.9% successfully completed the 25-day study period without needing additional therapy. In contrast, just 53.6% of the placebo-treated horses managed to do the same.
• When looking at confirmed cases of pneumonia caused by Streptococcus equi subsp. zooepidemicus, clinical cure was achieved in 66.9% of the treated horses, compared to only 32.1% in the placebo group, a statistically significant difference (P = 0.0286).
• The study thus concluded that the two-dose ceftiofur treatment was more effective and safer than the placebo treatment for combating the specific type of pneumonia in horses under field conditions.