Antimicrobial Activity of Essential Oils against Staphylococcus and Malassezia Strains Isolated from Canine Dermatitis

Abstract

Staphylococcus spp. bacteria are the most frequently involved agents in canine cutaneous infections. Treatment of these infections is based on antibiotic therapy, that often is not effective because of the antibiotic-resistance of the bacterial strains. Cutaneous staphylococcal infections are often complicated by Malassezia yeasts, that may be resistant to the conventional antifungal drugs. The present investigation was aimed to evaluate the in vitro antimicrobial activity of some essential oils (EOs) in view of a potential cutaneous application. In detail, EOs obtained from lemon verbena (Aloysia triphylla L’Hèr. Britton), cinnamon (Cinnamomum zeylanicum J. Presl), myrrh (Commiphora myrrha (Nees) Engl. var. molmol), lemongrass (Cymbopogon citratus (DC.) Stapf), litsea (Litsea cubeba (Lour.) Pers.), lemon balm (Melissa officinalis L.), oregano (Origanum vulgare L.), savory (Satureja montana L.), and thyme (Thymus vulgaris L.) were assayed against Staphylococcus spp. and Malassezia pachydermatis strains previously isolated from dogs with dermatitis. All EOs were tested by agar disk diffusion and minimum inhibitory concentration methods to verify the antistaphylococcal activity, and by a microdilution method to evaluate the activity against M. pachydermatis. O. vulgare, T. vulgaris, and S. montana showed the best antibacterial activity against all the selected strains, with MICs ranging from 0.29 to 0.58 mg/mL, from 0.58 to 1.16 mg/mL, and from 0.56 to 1.12 mg/mL, respectively, whereas A. triphylla (1.03 mg/mL) and S. montana (1.8 mg/mL) were the most active against M. pachydermatis. After a proper in vivo evaluation, O. vulgare, T. vulgaris, and S. montana EOs could be a promising treatment to combat canine cutaneous mixed infections.

Use of Essential Oils in Veterinary Medicine to Combat Bacterial and Fungal Infections

“…Several studies have demonstrated the anti-staphylococcal activity of O. vulgare and T. vulgaris EOs thanks to their main components carvacrol and thymol [ 36 , 47 , 48 , 49 , 50 ]. However, EOs obtained also from other botanical species were shown to be effective against staphylococci.…”

“…Ebani and coworkers [ 50 ] found that EOs from Commiphora myrrha and C. zeylanicum had low activity against some canine isolates of the species S. aureus , S. pseudointermedius , S. chromogenes , and S. hyicus , whereas no activity was observed against S. xylosus . Similarly, Adam and Selim [ 52 ] observed a slight sensitivity of S. aureus to myrrh oil.…”

“…L. cubeba was demonstrated to be an effective bacterial inhibitor and bactericide against some methicillin-resistant S. aureus strains for a destructive effect on the bacterial cell membrane [ 54 ]. EO from this plant did not always show good anti-staphylococcal activity, as demonstrated when it was tested against clinical canine isolates of different species [ 50 ].…”

“…[ 140 , 141 , 142 ], Satureja spp. [ 50 , 143 ], and O. vulgare [ 141 , 142 , 143 ]. This latter was proven to exert a synergistic action with clotrimazole also [ 139 ].…”

Organic management vs. conventional management influence the antimicrobial activity of essential oils of Origanum vulgare L

“…However, when combined with carvacrol, synergism occurred against the bacterium Bacillus cereus in in vitro test and also in rice (Ultee et al, 2000). Both oregano EO and carvacrol, present among the major compounds of all EOs used in this study, have already had their antimicrobial action proven in several previous studies (Ebani et al, 2020;Lu et al, 2018;Mayai et al, 2019;Dos Santos Rodrigues et al, 2018;dos Santos Rodrigues et al, 2017;da Silva Santos et al, 2017;Souza et al, 2016;Burt et al, 2005).…”