Microbial biofilm on the endotracheal tube surface is a reservoir for the pathogens and prevent the microorganisms from the action of antibiotics [35] . Adair and colleagues [127] proposed that high concentrations of antibiotic on the endotracheal luminal surface, achieved either by nebuliser or endotracheal surface modification, would be expected to prevent biofilm formation on the endotracheal tube and may have a role in reducing the incidence of VAP, also minimising patient exposure to systemic antibiotics.