Exploitation of nitric oxide donors to control bacterial adhesion on ready-to-eat vegetables and dispersal of pathogenic biofilm from polypropylene

Background. Nitric oxide (NO) donors have been used to control biofilm formation. NO can be delivered in situ using organic carriers and act as a signaling molecule. Cells exposed to NO shift from biofilm to the planktonic state and are better exposed to the action of disinfectants. In this study, we investigate the capability of the NO donors molsidomine, MAHAMA NONOate, NO-aspirin and diethylamine NONOate to act as anti-adhesion agents on ready-to-eat vegetables, as well as dispersants to a number of pathogenic biofilms on plastic. Results. Our results showed that 10pM molsidomine reduced the attachment of Salmonella enterica sv Typhimurium 14028 to pea shoots and coriander leaves of about 0.5 Log(CFU/leaf) when compared with untreated control. The association of 10 pM molsidomine with 0.006% H2O2 showed a synergistic effect, obtaining a significant reduction in cell collection on the surface of the vegetable of about 1 Log(CFU/leaf). Similar results were obtained for MAHMA NONOate. We also showed that the association of diethylamine NONOate at 10mM and 10pM with the quaternary ammonium compound diquat bromide improves the effectiveness of biofilm dispersal by 50% when compared with the donor alone. Conclusions. Our findings reveal the dual role of NO compounds in biofilm control. Molsidomine, MAHMA NONOate and diethylamine NONOate are good candidates in either preventing biofilm formation or dispersing biofilm, especially when used in conjunction with disinfectants. NO compounds have the potential to be developed into tool-kit for pro-active practices for GAPs, HACCP and Cleaning-in-place (CIP) protocols in industrial settings where washing is routinely applied.