In vitro antimicrobial activity of non-traditional therapies for infectious endometritis in mares

Background

Endometritis is the leading cause of subfertility in horses, and it is a clinical problem where historically antibiotics have not always been used with prudent justification. Because of this, alternative therapies to treat endometritis are necessary for the rational use of antibiotics.

Objectives

To assess the in vitro antimicrobial activity of non-traditional therapies commonly used in clinical practice against microorganisms causing infectious endometritis in mares.

Study design

In vitro experiments.

Methods

A microdilution technique was performed to determine the minimum inhibitory concentrations (MIC) of 50%, 90% and 100% of microorganisms and the percentage of inhibition (PI) of each therapy against each microorganism (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Candida sp.). The MIC 50% and 90% were determined using non-linear regression, while MIC 100% was assessed using the resazurin dye technique. The serial PI was evaluated for each therapy using a spectrophotometer.

Results

All the therapies demonstrated a PI higher than positive controls for all microorganisms (p < 0.05); however, the only therapies that presented MIC 100 values were hydrogen peroxide and platelet-rich and -poor plasma.

Main limitations

In vivo, safety and treatment efficacy were not tested.

Conclusion

Hydrogen peroxide and platelet-rich and -poor plasma might be alternatives to traditional therapies for endometritis to support a reduction in antibiotic use.