Iseganan and povidone iodine have also been investigated for oral decontamination. Iseganan is a topical antimicrobial with activity against gram-positive and gram-negative bacteria, and yeast. However, topical oropharyngial administration failed to show any reduction in Ventilator-associated pneumonia when compared to placebo in a multicenter randomized trial. Povidone iodine has demonstrated a benefit in Ventilator-associated pneumonia rates in patients with severe head trauma, but this has yet to be investigated in other patient populations.