Abstract: OBJECTIVE: To compare the efficacy of honey mouthwash 12.5% and chlorhexidine solution 0.2%to reduce the rate of oropharyngeal bacterial colonization in mechanically-ventilated patients.METHODS: This study was a randomized, single blind, phase Ⅲ controlled clinical trial. Sixty patients newly admitted to internal and trauma Intensive Care Units of the two educational hospitals of Sanandaj city affiliated with Kurdistan University of Medical Sciences were selected by convenience sampling and allocated to two groups of 30 patients using random blocks design. In each group,the mouthwash was applied twice a day for four consecutive days. Swab samples were taken from the mouth and throat of all patients three times a day(pre-intervention, two days, and four days after the intervention) and then the samples were transferred onto the blood agar and eosin methylene blue(EMB) culture plates and investigated for bacterial growth and colonization after 24-48 h.RESULTS: The findings showed that oropharyngeal colonization was not significantly different between the two groups, pre-intervention, two days,and four days after the intervention(P > 0.05). Rinsing with honey mouthwash 12.5% led to the inhibition of Staphylococcus aureus and Pseudomonas aeruginosa on the fourth day of the intervention in all samples.CONCLUSION: None of the studied solutions contributed to the reduction of oropharyngeal bacterial colonization. It seems that the growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa by the honey 12.5% mouthwash in mechanically-ventilated patients need further investigation.

Key words: Mouthwashes, Honey, Chlorhexidine, Ventilators,mechanical, Oropharyngeal colonization, Intensive Care Unit, Randomized controlled trial