Determination of in vitro antibacterial activity of plant oils containing medium-chain fatty acids against Gram-positive pathogenic and gut commensal bacteria

Abstract

Hovorková P., Laloučková K., Skřivanová E. (2018): Determination of in vitro antibacterial activity of plant oils containing medium-chain fatty acids against Gram-positive pathogenic and gut commensal bacteria. Czech J. Anim. Sci., 63, 119-125.Increasing antibiotic resistance has led to a ban on antibiotic use in feed additives in the EU. Therefore, new non-antibiotic, pathogen-inhibiting agents are urgently needed. Inhibitory effects of eight plant oils containing medium-chain fatty acids (MCFAs) were evaluated against Gram-positive pathogenic and beneficial bacteria. The oils tested were palm, red palm, palm kernel (Elaeis guineensis), coconut (Cocos nucifera), babassu (Attalea speciosa), murumuru (Astrocaryum murumuru), tucuma (Astrocaryum vulgare), and Cuphea oil (Cuphea ignea); the method used was broth microdilution, and the findings were expressed as minimum inhibitory concentration (80%). Both hydrolyzed and unhydrolyzed forms of the oils were tested. MCFA hydrolysis was catalyzed by porcine pancreas lipase. The selective effect of the hydrolyzed forms of tested oils was highly evident. While the hydrolyzed oils were active against all tested bacteria (Clostridium perfringens, Enterococcus cecorum, Listeria monocytogenes, and Staphylococcus aureus), at 0.14-4.5 mg/ml, the same oils did not show any effect on commensal bacteria (Bifidobacterium spp. and Lactobacillus spp.). Tucuma and Cuphea seed oils showed the strongest antibacterial activity. Unhydrolyzed forms of all tested oils exerted no antibacterial effect against any test bacteria. This study, thus, forms a basis for the development of selective inhibitors in animal husbandry.

Effects of replacing dietary Aureomycin with a combination of plant essential oils on production performance and gastrointestinal health of broilers

“…Enrichment or inhibition of certain bacterial members depended on the antibiotic application–shifted gut microbiota community structure ( Rad-Spice, 2015 ). Similarly, supplementation of plant oils inhibited the colonization of pathogens ( Hovorkova et al., 2018 ), and prebiotics provided more substrates for gut microbiota ( Ohimain and Ofongo, 2012 ), which led to a significant increase in total bacterial diversity ( Johnson et al., 2015 ). Moreover, prebiotics are exclusively fermented by beneficial bacteria such as Lactobacillus, Bifidobacteria, and Bacteroides ( Ohimain and Ofongo, 2012 ), which modified the microbial community structure in the gut, and partly demonstrated the increased relative numbers of these bacteria in the present study.…”

Antibacterial Free Fatty Acids and Monoglycerides: Biological Activities, Experimental Testing, and Therapeutic Applications

“…In addition, Nakatsuji et al explored the feasibility of employing LA to treat a mouse model infection caused by another Gram-positive bacterium, specifically Propionibacterium acnes [ 20 ]. Hence, multiple antimicrobial lipids have shown in vivo therapeutic potential, and there is also growing interest to investigate combinations of several antimicrobial lipids that have antibacterial potency against specific bacteria in order to achieve synergistic and broad-spectrum effects [ 85 , 86 , 87 , 88 , 89 ].…”

Use of Medium Chain Fatty Acids To Mitigate Salmonella Typhimurium (ATCC 14028) on Dry Pet Food Kibbles

“…Future research to evaluate the effectiveness of MCFAs as antimicrobial agents against other serotypes or a combination of serotypes of Salmonella commonly associated with pet foods is suggested. In one important finding, Hovorková et al (17) discovered that MCFAs were significantly bactericidal against gram-positive pathogens such as L. monocytogenes, Clostridium perfringens, and S. aureus, whereas they did not exert inhibitory effects against gut commensal bacteria. This is very important in terms of maintaining dog colonic microbial ecology when fed MCFAs-added diets.…”