In Vitro Efficacy of Essential Oils from Melaleuca Alternifolia and Rosmarinus Officinalis, Manuka Honey-based Gel, and Propolis as Antibacterial Agents Against Canine Staphylococcus Pseudintermedius Strains.

Gabriele Meroni,Joel Fernando Soares Filipe,Piera Anna Martino,Valentina Rafaela Herrera Millar,Charlotte Rendina,Elena Cardin

doi:10.3390/antibiotics9060344

Gabriele Meroni, Joel Fernando Soares Filipe + Show 4 more

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https://doi.org/10.3390/antibiotics9060344

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Journal: Antibiotics	Publication Date: Jun 19, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: University of Milan

Abstract

Essential oils (EOs) and honeybee products (e.g., honey and propolis) are natural mixtures of different volatile compounds that are frequently used in traditional medicine and for pathogen eradication. The aim of this study was to evaluate the antibacterial properties of tea tree (Melaleuca alternifolia) EO (TTEO), Rosmarinus officinalis EO (ROEO), manuka-based gel, and propolis against 23 strains of Staphylococcus pseudintermedius (SP) isolated from canine pyoderma. Antimicrobial resistance screening was assessed using a panel of nine antimicrobial agents coupled with a PCR approach. An aromatogram was done for both EOs, using the disk diffusion method. The minimum inhibitory concentration (MIC) was determined for all the compounds. Among the 23 SP strains, 14 (60.9%) were multidrug-resistant (MDR), 11 strains (47.8%) were methicillin-resistant (MRSP), and 9 (39.1%) were non-MDR. The mean diameter of the inhibition zone for Melaleuca and Rosmarinus were 24.5 ± 8.8 mm and 15.2 ± 8.9 mm, respectively, resulting as statistically different (p = 0.0006). MIC values of TTEO and ROEO were similar (7.6 ± 3.2% and 8.9 ± 2.1%, respectively) and no statistical significances were found. Honeybee products showed lower MIC compared to those of EOs, 0.22 ± 0.1% for Manuka and 0.8 ± 0.5% for propolis. These findings reveal a significant antibacterial effect for all the tested products.

Highlights

Staphylococcus pseudintermedius (SP) is a Gram-positive bacterium that can act both as a skin commensal or a pathogen and is nowadays considered one of the main causative agents of canine pyoderma [1,2]
MRSP strains are often resistant to more than three classes of antibiotics (multidrug-resistant (MDR)). This antibiotic resistance applies to all classes of antimicrobials, and is mainly mediated by resistance genes carried by mobile genetic elements (MGE) [13,17]
This study aimed to evaluate the antibacterial effects of the following natural products: tea tree and rosemary essential oils, manuka honey-gel, and propolis against strains of Staphylococcus pseudintermedius isolated from canine pyoderma

Summary

Introduction

Staphylococcus pseudintermedius (SP) is a Gram-positive bacterium that can act both as a skin commensal or a pathogen and is nowadays considered one of the main causative agents of canine pyoderma [1,2]. From the first documented identification of this pathogen [6], SP was considered to be exclusive to animals until [7] described the first case of human infection. As it belongs to the Staphylococcus genus, SP can exchange genomic material [8,9], and in this context, the spread of antibiotic resistance genes (ARG) is a huge challenge for both human and animal health [10,11,12,13]. MRSP strains are often resistant to more than three classes of antibiotics (multidrug-resistant (MDR)). This antibiotic resistance applies to all classes of antimicrobials, and is mainly mediated by resistance genes carried by mobile genetic elements (MGE) [13,17]

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