Importance of Nebulizer Drying for Patients With Cystic Fibrosis

Abstract

BACKGROUND: Nebulizer therapy is an important treatment component for patients with cystic fibrosis (CF). Nebulizer manufacturers' guidelines advocate thorough nebulizer drying after washing. The aim of this study, therefore, was to examine the microbiology associated with nebulizer drying, particularly related to Pseudomonas control, and to examine microbiologically non-adherence to the recommended drying procedures. METHODS: Four aspects of nebulizer drying were examined in 3 common nebulizers, including examination of the drying profile, improvement to the drying profile of assembled nebulizers, survival of Pseudomonas aeruginosa in tap water and in tap water plus 0.5% (v/v) dishwashing detergent, and the effect of drying of P. aeruginosa in tap water and tap water plus residual sputum (1%v/v, 10%v/v). Microbiologic examination was performed by using P. aeruginosa (5 clinical CF strains plus 1 National Collection of Type Cultures Reference strain). RESULTS: There were differences in the time to complete dryness between disassembled and fully assembled nebulizers. Vigorous repeated shaking was unable to drive off all residual water on assembled nebulizers. P. aeruginosa counts did not decrease significantly in either tap water or in tap water plus detergent after 24 h storage at ambient temperature. In contrast, all Pseudomonas organisms were killed when nebulizers were dried for 24 h, even when contaminated with 1% and 10% sputum. Dishwashing detergent did not demonstrate any antibacterial activity. CONCLUSIONS: This study demonstrated that nebulizer drying, if applied properly, had the ability to reduce counts of P. aeruginosa to non-detectable levels. Equally, this study showed that, if the device was not dried thoroughly and moisture remained, then the device was able to support the survival of P. aeruginosa at high numbers, which constituted an infection risk to the patient with CF. This information may help educate and inform the patient with CF about the importance of proper nebulizer drying for Pseudomonas control to improve patient awareness and safety.

Enhanced clinical microbiology methods in outbreak management

“…In all cases, the outbreak strains persisted in all milieux for at least one week. Persistence behaviour of these outbreak strains are very much different from recently described P. aeruginosa clinical isolates from the sputum of patients with CF, which were unable to survive 24 h, under similar desiccation conditions (Moore et al, 2020). The relative persistence of the outbreak strains in this neonatal outbreak may therefore be considered an important aspect of their biology and a virulence factor, in prolonging strain survival in the environment and potentially outbreak duration.…”

Successful disinfection of trumpet mouthpieces using domestic steam disinfection

“…This scenario would simulate the maximum numbers of organisms contaminating the mouthpiece and therefore the greatest challenge to disinfector efficiency. Given that the outside of the mouthpiece is never in contact with secretions from the player, this was not emulated in this experiment and therefore we focussed solely on emulating wet surfaces on the inner bore of the mouthpiece, as drying has been recently shown to kill Pseudomonas aeruginosa on surfaces (Moore et al 2020). These Gram-positive and Gram-negative organisms were selected, as important clinical organisms, as well as surrogates for other opportunistic pathogens that may be found in players' saliva, as part of the normal flora of the mouth, upper respiratory tract and upper gastrointestinal tract.…”

Nebuliser hygiene in cystic fibrosis: evidence-based recommendations

“…A recent study by M oore et al [ 71 ] examined the effect of drying on P. aeruginosa and showed that there were marked differences in time to complete dryness between disassembled and fully assembled nebulisers. Vigorous repeated shaking was unable to drive off all residual water on assembled nebulisers.…”

“…Equally, this study showed that if the device is not dried thoroughly and moisture remains, then the device is able to support the survival of P. aeruginosa at high numbers, constituting an infection risk to the CF patient. These data may help educate and inform the CF patient about the importance of proper nebuliser drying for Pseudomonas control, in order to improve patient awareness and safety [ 71 ]. More recently, there have been two reports demonstrating that members of the NTM, Mycobacterium abscessus complex and S. aureus (methicillin-sensitive and -resistant) can survive for at least 24 h on plastic surfaces during air drying [ 72 , 73 ].…”