TAXONOMY INFLUENCES THE EFFICACY OF PLANT EXTRACTS AGAINST ANTIBIOTIC RESISTANT BACTERIOME

Summary

Abstract
Antimicrobial resistance of the microbiome poses lately a high risk to human and animal patients and also to environment health. The missuse and lack of control in antimicrobial treatments lead to escalation of the antibiotic resistance phenomenon. The research aimed at investigating to which extent the taxonomy of plants intervenes in conditioning the antimicrobial resistance in both ATCC strains (Escherichia coli ATCC 25922 and Pseudomonas spp. 10145) and clinical isolates. The pathogenic bacteria were obtained from animal patients with diverse pathologies and identified for diagnostic purposes by standard microbiological technniques using rapid biochemical tests: GN 24 (Tody Laboratories, România) for Gram-negative, and GP 24 (Tody Laboratories, România) for Gram-positive strains as Escherichia coli, Pseudomonas putrefaciens¸ Pseudomonas fluorescens, and Staphylococcus sciuri, Staphylococcus aureus. The evaluation of both antibiotic susceptibility and the activity of essential oils against multiresistant bacteria were tested by the Kirby-Bauer disc diffusion method using amoxicillin/clavulanic acid, penicillin, imipenem, gentamycin, streptomycin, florfenicol, cefquinome, erythromycin, tylosin, tulathromycin, oxytetracycline, and doxycycline. The assessment included 10 essential oils derived from plants belonging to families Lauraceae (Cinnamomum zeylanicum), Myrtaceae (Melaleuca alternifolia), Geraniaceae (Pelargonium capitatum), Lamiaceae (Mentha piperita, Thymus vulgaris, Lavandula angustifolia, Ocimum basilicum, Salvia glutinosa). The extracts of Lauraceae family showed a significant antimicrobial activity against all strains, at least comparable or even superior to that of the most efficient antibiotics, regardless of their concentration. These results promote the further therapeutic experimentation of cinnamon essential oil as an efficient alternative to antibiotics in clinical trials.
Key words: plant taxonomy, essential oils, clinical isolates, ATCC strains, antibiotic resistance