P3-162 In Vitro Evaluation of Essential Oils and Plant Extracts as an Alternative to Antibiotic Used in Pork Meat Production

Wednesday, July 12, 2017
Exhibit Hall (Tampa Convention Center)
Carmen M. S. Ambrosio , Universidade de São Paulo , Piracicaba - SP , Brazil
Natalia Y. Ykeda , Universidade de São Paulo , Piracicaba - SP , Brazil
Severino M. Alencar , Universidade de São Paulo , Piracicaba - SP , Brazil
Carmen J. C. Castillo , Universidade de São Paulo , Piracicaba - SP , Brazil
Andrea M. Moreno , Universidade de Sao Paulo , Sao Paulo , Brazil
Eduardo M. da Gloria , Universidade de Sao Paulo , Piracicaba - SP , Brazil
Introduction: The overuse of antibiotics in animal production is a reason for the emergence of bacterial resistance to antibiotics and the possibility of resistant bacteria or resistance genes transfer to the human food chain by pork products has been considered an indirect risk to public health. There is great concern about the emergence of plasmid-mediated colistin resistance (mcr-1) in Escherichia coli, a mechanism of resistance to polymyxins (colistin).

Purpose: This study evaluated the antibacterial activity of some essential oils (EOs) and plant extracts on four Escherichia coli isolates, which were isolated from pig gut.

Methods: Initial screening of antibacterial activity of eight citrus EOs (by-products of orange juice production), two propolis EOs, and extracts (ethanolic, hexanic, and isopropilic) from jalapeño (Capsicum annum) and bacupari (Garcinia gardneriana) was performed by disk diffusion method. Colistin was used as positive control.

Results: Three citrus EOs exhibited antibacterial activity (Brazilian orange terpens (BOT), Orange oil phase essence, and Tahiti lime oil phase) on E. coli isolates; analysis of variance (ANOVA) showed a significant difference for the antibacterial activity among them. Tukey’s test (p ≤ 0.05) and Principal Component Analysis (PCA) showed that BOT demonstrateded the largest antibacterial activity; showing superior action compared to colistin. Moreover, the results showed a significantly different sensitivity of isolates to citrus EOs, with isolate E. coli U21 (K88 LT/STb/F18/STa) being the most resistant. BOT was tested to determine its MIC using survival curves, resazurin test by microdilution method, and MBC (by plaiting) with E. coli U21. The MIC and MBC of BOT were 3.7 mg/mL. The CG/MS analysis of BOT showed that Limone, cis-limonene oxide, and myrcene were the major compounds.

Significance: EOs that are by-products of orange juice production could be an alternative control for E. coli. However, its use as alternative to synthetic antibiotics should be better verified by in vivo evaluations.