Ascorbic Acid-Mediated Modulation of Antibiotic Susceptibility of Major Bovine Mastitis Pathogens

Abstract

This study aimed to investigate the effects of ascorbic acid on antibiotic susceptibility of major bovine mastitis pathogens, including Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus agalactiae, and Escherichia coli. Minimum inhibitory concentrations (MICs) were determined by E-test method. The presence of 10 mM ascorbic acid decreased the MICs of penicillin and ampicillin while increased the MICs of erythromycin, kanamycin, streptomycin, and ciprofloxacin for all tested strains. Besides, ascorbic acid specifically reduced the MICs of tetracycline for gram-positive bacteria and chloramphenicol for gram-negative bacteria. This study highlights that ascorbic acid is a potential modulator of antibiotic activity against the major bovine mastitis pathogens.

Keywords:

• ascorbic acid
• antibiotic susceptibility
• bovine mastitis
• pathogens

Ethics Approval and Consent to Participate

Compliance with ethical standards: This study was approved by Ethics Committee of Lanzhou Institute of Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences (SYXK-2019-0012) and was conducted in compliance with ethical, legal, and regulatory norms. The animal owners were informed about the purpose of the study, and consent of each animal owner was obtained before the physical examination of cows for clinical mastitis and the collection of milk samples.

Acknowledgments

This study was supported by the Key Research and Development Program of Gansu Province (No. 21YF5NA141) and the National Natural Science Foundation of China (No. 31860724).

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.