Secondary Plant Compounds as an Alternative?
In animal production antibiotics are used for therapeutic and metaphylactic treatment of individual animals and whole flocks. As a natural reaction of the bacteria to these substances, resistances against several antibiotics can occur. The most common resistant bacteria are MRSA (methicillin-resistant Staphylococcus aureus)-strains and ESBL (Extended-spectrum-β-lactamase – an enzyme inactivating antibiotics) producing enterobacteria. Furthermore, as described in our Newsletter “Antibiotic Resistance”, bacteria are able to extend their spectrum of resistance in different ways and to create multiresistances. In the public there is intensive discussion about distribution and transmission of resistant pathogens from livestock animals to humans. Infections due to these antibiotic and multiresistant bacteria and their treatment are a global problem. For this purpose knowledge out of livestock and pet husbandry as well as human sector (hospital, rest homes, purification plants etc.) should be considered. Secondary Plant Compounds For a long time secondary plant compounds have been well known for their antimicrobial activity and therefore are used in traditional and alternative human medicine. For some time there has been research concerning the use of these substances in animal husbandry. In vitro and in
vivo trials documented antimicrobial effects of numerous secondary plant compounds. For example cinnamon oil or to be more precise, the contained cinnamon aldehyde, showed bacteriostatic effects against Salmonella, E. coli,
Pseudomonas aeruginosa, Klebsiella pneumoniae, enteroand Staphylococcus. Cinnamon aldehyde besides other compounds can inhibit the production of amino acid decarboxylases and therefore decrease cellular growth and reproduction of these pathogens. What about Antibiotic Resistant Pathogens? There is evidence that secondary plant compound also possess antimicrobial characteristics against antibiotic resistant pathogens. In-vitro trials with cinnamon oil also showed antimicrobial effects against methicillin resistant Staphylococcus aureus, as well as against multiresistant E.
coli, Klebsiella pneumoniae and Candida albicans. Further trials with MRSA pathogens revealed, that the antimicrobial effect of cinnamon oil is higher in combination with citric acid. The components eugenol and cinnamon aldehyde contained in cinnamon oil increase permeability of the plasma membrane and disturb in this way essential cellular functions of the pathogen. Until now no bacterial resistances against plant extracts are described. Literature: BAIJU, N., MODAK, S.M. (2007): Broad-spectrum disinfectant composition containing a synergistic combination of cinnamon oil and citric acid. International Journal of Essential Oil Therapeutics (2007) 1, pp. 117-121 KHAN, R., ISLAM, B., AKRAM, M., SHAKIL, S., AHMAD, A., MANAZIR ALI, S., SID-DIQUI, M., KHAN, A.U. (2009): Antimicrobial activity of five herbal extracts against multi drug resistant (MDR) strains of bacteria and fungus of clinical origin. Molecules (2009) 14, pp. 586-597 www.mdpi. com/journal/molecules YOSSA, N. PATEL, J., MACARISIN, D., MILLNER, P., MURPH, C. (2012): Antibacterial activity of Cinnamaldehyde and Sporan against Escherichia Coli O157:H7 and Salmonella. University of Nebraska, Publications from USDA-ARS/UNL Faculty. Paper 1136