Background: Bacterial colonization in the pharynx is one of the most important risk factors for ventilator-associated pneumonia. The aim of this study was to determine and compare the anti-bacterial effects of different mouthwashes in mechanically ventilated patients.

Materials and Methods: In this double-blind randomized clinical trial, 80 patients were selected from the intensive care units (ICUs) of Imam Khomeini Hospital in Sari City, Iran, during 2010-2011, and were divided into four groups of 20 cases. The first intervention group was administered with chlorhexidine gluconate (CHX) 0.2% mouthwash, the second group Persica herbal 10% mouthwash, the third group was administered with Matrica 10% and finally in the fourth group, normal saline was used. In order to culture Staphylococcus aureus and Streptococcus pneumoniae, oropharynx samples were obtained without any stimulation prior and 6 min following oral rinsing.

Results: Bacterial colonies were decreased significantly after the intervention in all four groups (P<0.001). Chlorhexidine gluconate, Persica and Matrica mouthwashes caused to decrease the Staphylococcus aureus (P<0.001, P<0.008 and P=0.01, respectively) and Streptococcus pneumoniae (P<0.001) positive cultures after the intervention.

Conclusion: Herbal oral mouthwashes including Persica and Matrica are effective in decreasing Staphylococcus aureus and Streptococcus pneumoniae colonized in the oropharynx of mechanically ventilated patients. Therefore, after further investigations, they can serve as suitable alternatives for CHX in ICU settings.