Assessment of Urtica dioica extracts on mex A Gene in Pseudomonas Aeruginosa by Real-Time PCR in order to replace healthy preservatives to control food contamination

Pseudomonas aeruginosa is a gram-negative opportunistic human ،animals and plants pathogen associated with nosocomial infections and is a common human and fish bacterial species that causes bacteremia with bleeding in fish. It is also one of the most important pathogenic factors in chicken and poultry. So antimicrobial resistance among clinical strains of Pseudomonas aeruginosa is a major challenge with respect to treatment especially among patients suffering from nosocomial infection. On the other hand, discovering new antibacterial agents is difficult and costly. For this reason, native materials such as herbal extracts are publicized in recent years. We aimed to assess the anti-efflux properties of Urtica dioica extract, on multidrug resistant P. aeruginosa. The extract was prepared using the maceration method. All clinical isolates were identified via biochemical and molecular tests and Minimum Inhibitory Concentration (MIC) of the antibiotics was performed for all of them. Then, the presence of mexA gene was evaluated by PCR. Real-time PCR was run for measuring mexA gene expression in Urtica dioica extract treated and un-treated MDR strains. The rpsl gene was used for each reaction as the house keeping control gene. The results showed that the expression of MexA gene was down regulated under treatment with Urtica dioica extract compared with the reference rpsl gene (0.3 fold for MexA and 1 fold for rpsl). Inhibition of efflux pump activity may be a strategic procedure for overcoming multidrug resistance in bacteria and using native compounds could be considered as preservative in food industry in the future.

Keywords:

Pseudomonas aeroginosa , Efflux pump , Nettle , preservative