The effects of antibacterial mouthwash on the oral microbiome: potential consequences for intensive care patients

Abstract

The role of the oral microbiome in maintaining health is becoming increasingly apparent (1). Oral nitrate-reducing commensal bacteria reduce nitrate to nitrite, which is then reduced to nitric oxide in the acidic environment of the stomach via the nitrate-nitrite-nitric oxide pathway. Nitric oxide has a key role in maintaining gastric mucosal blood flow and thickness, thereby protecting against bacterial infection. Gastric nitric oxide levels are nearly abolished in intubated and ventilated intensive care patients, which might be linked to the prevalence of ulcers and bacterial overgrowth (2). In addition, it has been reported that the nitrate content of both enteral and parenteral nutrition is minimal (3) thereby further reducing the activity of the nitrate-nitrite-nitric oxide pathway. Patients on intensive care may receive salivary suction, antibacterial mouthwash, low nitrate feeds and broad-spectrum antibiotics, all of which could affect the oral microbiome. Poor oral health and periodontal disease is associated with ventilator-associated pneumonia (4). As part of a wider study we investigated the effects of antibacterial mouthwash on oral nitrate-reducing capacity and salivary pH, glucose and lactate as well as salivary and plasma nitrate and nitrite concentrations.