Activity of Patchouli and Tea Tree Essential Oils against Staphylococci Isolated from Pyoderma in Dogs and Their Synergistic Potential with Gentamicin and Enrofloxacin

Abstract

In this paper, we show the effect of some essential oils (EOs) on staphylococci, including multidrug-resistant strains isolated from pyoderma in dogs. A total of 13 Staphylococcus pseudintermedius and 8 Staphylococcus aureus strains were studied. To assess the sensitivity of each strain to the antimicrobial agents, two commercial EOs from patchouli (Pogostemon cablin; PcEO) and tea tree (Melaleuca alternifolia; MaEO) as well as two antibiotics (gentamicin and enrofloxacin) were used. The minimum inhibitory concentration (MIC) followed by checkerboards in the combination of EO-antibiotic were performed. Finally, fractional inhibitory concentrations were calculated to determine possible interactions between these antimicrobial agents. PcEO MIC ranged from 0.125 to 0.5 % v/v (1.2–4.8 mg/mL), whereas MaEO MIC was tenfold higher (0.625–5% v/v or 5.6–44.8 mg/mL). Gentamicin appeared to be highly prone to interacting with EOs. Dual synergy (38.1% of cases) and PcEO additive/MaEO synergism (53.4%) were predominantly observed. On the contrary, usually, no interactions between enrofloxacin and EOs were observed (57.1%). Both commercial EOs were characterized by natural composition without artificial adulteration. Patchouli and tea tree oils can be good alternatives for treating severe cases of pyoderma in dogs, especially when dealing with multidrug-resistant strains.

Evaluation of the Antibacterial Activity of Gentamicin in Combination with Essential Oils Isolated from Different Cultivars and Morphological Parts of Lavender (Lavandula angustifolia Mill.) against Selected Bacterial Strains

“…For this purpose, the biological activity of other major and minor components of lavender essential oils should be tested in analogous conditions to identify the remaining active compounds. Some authors have shown synergistic effects with gentamicin for other essential oils against Gram-positive and Gram-negative bacteria [1,44,[49][50][51]. This was confirmed in our previous study on commercial lavender essential oil [7] and the currently studied oils isolated from different cultivars and morphological parts of lavender, whose combinations with gentamicin have not yet been examined.…”

“…The overall concept of antimicrobial synergy is based on the principle that the combination of two or more antimicrobial agents (even in lower amounts) may enhance their efficacy. This is manifested, for example, due to their hydrophobicity, by reaction with lipids present in the bacterial cell membrane (e.g., destroying cell structures or increasing the permeability of the main component), a reduction in the required dose of the active substance or reduced antimicrobial resistance [44]. The biosynthesis of secondary metabolites and their proportion in essential oils vary due to environmental factors, such as seasonal variation, light availability, vegetation stage, presence of additional commensal microorganisms as well as nature of soil (e.g., pH) [42].…”

Antibacterial Potential of Essential Oils and Silver Nanoparticles against Multidrug-Resistant Staphylococcus pseudintermedius Isolates

“…Further researches are necessary to comprehensively comprehend the mechanisms of EOs and their suitable use in clinical settings [ 18 , 19 ]. In recent years, various in vivo and in vitro investigations have been conducted focusing on the efficiency of several EOs against the etiological agents of pyoderma in dogs [ 15 , 20 , 21 , 22 ]. Many EOs may be used to treat various skin disorders; however, due to their bioactive chemical components, some are particularly efficient against Gram-positive and Gram-negative bacteria [ 23 ], in particular those with significant percentages of thymol and carvacrol have extraordinary membrane-damaging action in bacteria [ 24 , 25 , 26 ].…”

The Potent Antimicrobial Spectrum of Patchouli: Systematic Review of Its Antifungal, Antibacterial, and Antiviral Properties

“…The discovery of antibiotics was a medical advancement, but bacterial resistance accelerated by genetic mutations resulted in rapid resistance. Meanwhile, a new class of antibiotics had not been developed for over three decades [1]. Research on antimicrobial substances using natural resources has become a serious discussion by researchers [2][3][4][5][6][7][8][9][10][11][12].…”

“…It has been shown that EOs from dissimilar plants and plant parts are quite different in chemical compounds and antimicrobial characteristics [16,17]. Interest in EOs and their use is steadily increasing, especially in the medical, cosmetic, and culinary industries [1]. Steam distillation can obtain EOs from different plant materials (leaves, buds, fruits, flowers, herbs, branches, bark, wood, roots, and seeds).…”