| Summary: | Colibacillosis, caused by <i>E. coli</i>, is responsible for economic losses in the poultry industry due to mortality, decreased production, and the cost of antibiotic treatments. Prevention of colibacillosis is based on improved biosecurity measures and the use of the vaccine performed with O78 <i>E. coli</i> strains, which is responsible for most cases of colibacillosis. Recently, there has been increased interest in other infection control methods, such as the use of natural compounds. The aim of this study was to evaluate the antimicrobial efficacy of cinnamon essential oil (CEO) against <i>E. coli</i> strains isolated from poultry. The MIC<sub>50</sub> and MIC<sub>90</sub> of CEO were determined by testing 117 strains belonging to serogroups O78, O2, O128, O139, isolated from laying hens (91 strains), broilers (10 strains), and turkeys (16 strains). The bacterial strains were tested at cell densities of 10<sup>8</sup> and 10<sup>6</sup> CFU/mL. At the cell density of 10<sup>8</sup> CFU/mL, MIC<sub>50</sub> and MIC<sub>90</sub> were 0.4 and 0.5 µL/mL for most of the tested strains, while they corresponded to 0.5 µL/mL for all strains isolated from broilers and for strains belonging to serogroup O139. At the cell density of 10<sup>6</sup> CFU/mL, MIC<sub>50</sub> and MIC<sub>90</sub> were 0.3 and 0.4 µL/mL, regardless of bird species of origin and for strains belonging to serogroups O78 and O2. In addition, a concentration of 0.04 µL/mL of CEO corresponded both to MIC<sub>50</sub> and MIC<sub>90</sub> for strains belonging to serogroups O139 and O128. Based on these results, cinnamon essential oil showed an effective antibacterial activity against <i>E. coli</i> strains from poultry and could find field application for the prevention of colibacillosis.
|
|---|