Comparative effects of oral administration of trimethoprim/sulphadiazine or oxytetracycline on the faecal flora of horses.

This research article compares the impacts of two drugs, oxytetracycline and a combination of trimethoprim/sulphadiazine, on the gut bacteria of horses. It finds that oxytetracycline leads to significant changes in the bacterial composition that could potentially cause colitis, while trimethoprim/sulphadiazine did not show these effects.

Study Overview

This scientific study was designed to assess and compare the impacts of two common antibacterial drugs, oxytetracycline and a combination of trimethoprim and sulphadiazine, on the bacterial flora found in horse faeces before and after oral administration of the drugs.

Methods Used

• The researchers orally administered either oxytetracycline or a combination of trimethoprim and sulphadiazine to the horses involved in the study.
• After the administration of the drugs, changes in the horses’ bacteriological faecal flora were closely monitored and observed over a period of time.

Results and Findings

When analyzing the bacterial composition in the horses’ faeces after administering the drugs, the researchers found:

• The administration of oxytetracycline led to a rapid rise in counts of several types of bacteria including coliforms, Bacteroides and Streptococcus species.
• Additionally, it caused the disappearance of Veillonella species and led to the appearance of Clostridium perfringens type A in large numbers.
• A significant physical change was also observed with the accumulation of watery fluid in the rectal contents of the horses treated with oxytetracycline.
• Contrarily, none of these changes were reported following the administration of the combination of trimethoprim and sulphadiazine.

Conclusion

Based on the results of the study, it was concluded that the oral treatment of horses with trimethoprim-sulphadiazine is preferable as it doesn’t induce significant changes in the gut bacteria as observed with oxytetracycline. The researchers inferred that this combination drug is unlikely to present the risk of colitis, an inflammation of the colon, which may potentially be caused by the alterations in the gut bacteria due to administration of oxytetracycline.