Topic:

Other

Abstract No.:

ISE.172

Title:

Growth response of the effects of essential oil, nisin, pH and temperature on Thermostable Direct Haemolysin production of Vibrio parahaemolyticus ATCC 43996

Author(s):

A. Misaghi¹, A. Akhondzadeh Basti², A. Khanjari³; ¹University of Tehran, Food Hygiene, Tehran, TEHRAN/IR, ²University of Tehran, Food Hygiene, Tehran/IR, ³University of Tehran, Food hygiene, Tehran/IR

Abstract:

Background: There is a constant striving to develop new antimicrobial agents. Zataria multiflora Boiss. is a plant belonging to the Laminaceae family. Vibrio parahaemolyticus is a halophilic bacterium widely distributed in coastal environments and often causes gastroenteritis due to consumption of raw or inadequately cooked seafoods.
Methods: The effects of different concentrations of Zataria multi flora Boiss. essential oil (EO: 0, 0.005, 0.015, 0.03 and 0.045%), nisin (N: 0, 0.25, and 0.75 µg ml^-1), pH values (7.5, 6.5 and 5.5) and storage temperatures (T: 35, 25 and 8 °C) on Thermostable direct haemolysin (TDH) production of Vibrio parahaemolyticus in Brain Heart Infusion broth were evaluated in a factorial design study by a reversed passive latex agglutination assay.
Results: The TDH production was significantly affected by EO, pH , T and their interactions but not by N used in this study. The inhibitory effect of EO on TDH production was significantly (P < 0.05) affected by the pH value and storage temperature e.g. The TDH titration at the combinations of EO = 0.005%, N = 0 µg ml^-1, pH = 7.5 and T = 8°C; EO = 0.005%, N = 0 µg ml^-1, pH = 5.5 and T = 35°C; and EO = 0.005%, N = 0 µg ml^-1, pH = 6.5 and T = 8°C were 1/128, 1/64 and 1/64, respectively which were 2-3 fold less than the optimum condition (combination) for the growth of the microorganism in this study (EO = 0%, N = 0 µg ml^-1, pH = 7.5 and T = 35°C). This inhibitory effect of EO was also enhanced by increasing its concentration at each pH and T combinations.
Conclusion: Targeting bacterial virulence factors is now gaining interest as an alternative strategy to develop new types of anti-infective agents. In the present study has been shown that Z. multiflora Boiss. essential oil, when used at its subinhibitory concentrations, can significantly decrease the production of TDH by the V. parahaemolyticus.