OREGANO ESSENTIAL OIL ANTIBACTERIAL EFFICACY AGAINST BACTERIA SPECIES ASSOCIATED WITH BOVINE MASTITIS

SUMMARY

This trial was conducted to determine the antibacterial efficacy of natural oregano essential oil (OEO) against Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, Streptococcus agalactiae, and Escherichia coli, using the zone of inhibition, disk diffusion technique.  These are the predominant pathogens in herds affected with mastitis.  The results of the trial showed OEO to have antibacterial efficacy against these species of bacteria, and Orego-Stim (OS) may therefore be used to help support herds where there is a risk of mastitis.  

BACKGROUND  

Mastitis in dairy cows is an inflammatory condition of the mammary gland, which is typically caused by a bacterial infection. This condition can adversely affect milk production, milk quality, and the overall health of the affected cow.  Mastitis is a significant concern in the dairy industry as it can lead to economic losses due to decreased milk yield and increased expenses for treatment. Five species of bacteria (Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, Streptococcus agalactiae, and Escherichia coli) are responsible for the majority of mastitis cases (Cheng et al., 2010).  Antibiotics have been widely used in dairy herds to control pathogens which cause mastitis, however increased use has led to the rapid spread of antimicrobial resistance (AMR). This trial was conducted as part of Anpario’s 4 R’s approach to antibiotic usage.  

TRIAL DESIGN

This trial was conducted in collaboration with a UKAS accredited microbiology laboratory in the UK in 2022/23, to determine the antibacterial efficacy of OEO, included in OS, against S. aureus, S. uberis, S. dysgalactiae, S. agalactiae and E. coli, using the zone of inhibition, disk diffusion technique. A bacterial inoculum level of 1 x 107 – 1 x 108 was achieved and streaked over the surface of a dried Mueller Hinton agar plate to ensure an even distribution. Three replicates were prepared per plate and were incubated aerobically for 24 hours. All zones of inhibition were measured using digital calipers.

RESULTS

* The results of this study support that Oregano Essential Oil has antibacterial efficacy against S. aureus, S. uberis, S. dysgalactiae, S. agalactiae and E. coli (Figure 1).  

* Orego-Stim Liquid including Oregano Essential Oil can therefore be used to help support herds where there is a risk of mastitis caused by these bacteria species.