Air ionisation and colonisation/infection with methicillin-resistant Staphylococcus aureus and Acinetobacter species in an intensive care unit

Objective: To determine effect of negative air ions on colonisation/infection with methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter species in an intensive care unit. Design: Prospective single-centre cross-over study in an adult general intensive care unit. Patients: 201 patients whose stay on the unit exceeded 48 hour's duration. Intervention:Six negative air ionisers were installed on the unit but not operational for the first 5 months of the study (control period). Devices were then operational for the following 5.5 months. Measurements and results:30 and 13 patients were colonised/infected with MRSA and Acinetobacter spp., respectively, over 10.5 months. No change in MRSA colonisation/infection was observed compared with the 5 month control period. Acinetobacter cases were reduced from 11 to 2 (p = 0.007). Conclusion:Ionisers may have a role in the prevention of Acinetobacter infections.