Evaluation of different cleaning methods for feline inhalation chambers after bacterial contamination

Inhalation chambers are commonly used for the delivery of aerosol drugs to cats with respiratory disease. The aim of the study was to identify successful cleaning methods for inhalation devices after standardised bacterial contamination.

Spacer devices of two different manufacturers were used: RC Chamber (Cegla Medizintechnik) and Aerokat (Trudell Medical International). The bacterial contamination was performed using Pseudomonas aeruginosa. Previously marked areas of the chamber were contaminated with 50 μl of bacterial solution, containing between 2.2 ×10⁵ and 2.1 ×10⁸ colony-forming units/ml each. After cleaning the devices as recommended by each manufacturer (RC Chamber: special microwave cleaning bag [n = 5] or boiling water with liquid dish detergent for 15 mins [n = 5]; Aerokat: rinsing in a solution of lukewarm water and liquid dish detergent for 15 mins), chambers were air-dried for 24 h and samples for bacterial culture were taken from three defined areas. Sample material was applied on Müller-Hinton agar plates and subsequently incubated for 24 h at 37°C.

Bacterial contamination was not detected in any of the examined inhalation devices using the recommended cleaning methods.

If inhalation chambers are cleaned following the manufacturers' recommendations, successful bacterial decontamination can be expected.