View Abstract

A5498 - Bacterial Contamination of Nebulizers After a Single In-Hospital Use
Author Block: J. Dewald1, Q. He2, K. Wyckoff2, J. Ferris1, S. Elder1, R. Dhand1; 1Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, United States, 2Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN, United States.
Rationale: Nebulizers produce aerosols with a fine particle size. Patients inhale medications through the mouthpiece of the nebulizer for several minutes with the potential to contaminate the device and produce a persistent exchange of aerosolized bacteria with the distal parts of the lung. The frequency and rapidity with which bacterial contamination of nebulizers occurs is unknown. The primary aim of this study was to determine the frequency of bacterial contamination of nebulizers after a single use by hospital patients suffering from chronic respiratory illnesses other than cystic fibrosis (CF). Secondary aims were to compare the efficacy of conventional swabbing vs. vortexing, to detect bacterial contaminants and to evaluate which parts of the nebulizer assembly were contaminated.
Methods: Disposable nebulizer assemblies (n = 16) were collected after the first in-hospital use by patients with chronic respiratory illnesses other than CF. We separately tested each individual part of the nebulizer assembly (cup, lid, T-piece, corrugated tubing, and mouthpiece) for contamination by swabbing or vortexing methods. We employed three solutions (0.9% sodium chloride, 1x phosphate buffer solution (PBS) and 10x PBS) to determine their efficacy in recovering bacteria. Recovered bacteria were cultivated on tryptic soy agar or heterotrophic plate count agar media. Suction catheters (n = 2) used by patients were collected and tested for contamination to serve as positive controls, whereas unused nebulizer assemblies served as negative controls.
Results: We recovered bacteria from 77% of nebulizer assemblies by vortexing, compared to only 10% of devices by swabbing. In a separate experiment, we recovered bacteria from two devices by vortexing that were initially negative for contamination by swabbing. The types of recovery solution and cultivation media did not influence the detection of bacterial contamination on the nebulizers. The mouthpiece, T-spacer and corrugated tubing of the nebulizer assembly frequently showed bacterial contamination. The nebulizer cup was tested only by swabbing and did not reveal bacterial contamination.
Conclusions: A majority of patients with chronic respiratory illnesses, other than CF, contaminate their nebulizers after a single use in the hospital. This study reveals that vortexing is a more effective method to recover bacteria from contaminated nebulizer assemblies compared to the conventional swabbing technique. Contamination of nebulizers has the potential to aerosolize bacteria to the distal parts of the lung and our findings emphasize the need to clean nebulizers after each use in the hospital.