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Limited therapeutic options are available for multidrug-resistant Acinetobacter baumannii (MDR-AB), and the development of effective treatments is urgently needed. The efficacy of four aerosolized antibiotics (gentamicin, amikacin, imipenem, and meropenem) on three different MDR-AB strains was evaluated using hypertonic saline (HS, 7 g/100 mL) as the aerosol carrier. HS aerosol effectively hindered biofilm formation by specific MDR-AB strains. It could also interrupt the swarming dynamics of MDR-AB and the production of extracellular polymeric substances, which are essential for biofilm progression. Biofilms protect the microorganisms from antibiotics. The use of HS aerosol as a carrier resulted in a decreased tolerance to gentamicin and amikacin in the biofilm-rich MDR-AB. Moreover, we tested the aerosol characteristics of antibiotics mixed with HS and saline, and results showed that HS enhanced the inhaled delivery dose with a smaller particle size distribution of the four antibiotics. Our findings demonstrate the potential of using “old” antibiotics with our “new” aerosol carrier, and potentiate an alternative therapeutic strategy to eliminate MDR-AB infections from a biofilm-disruption perspective.

BACKGROUND: Secondhand exposure to fugitive aerosols may cause airway diseases in health providers. We hypothesized that redesigning aerosol masks to be closed-featured would reduce the fugitive aerosol concentrations during nebulization. This study aimed to evaluate the influence of a mask designed for a jet nebulizer on the concentration of fugitive aerosols and delivered doses. METHODS: An adult intubation manikin was attached to a lung simulator to mimic normal and distressed adult breathing patterns. The jet nebulizer delivered salbutamol as an aerosol tracer. The nebulizer was attached to 3 aerosol face masks: an aerosol mask, a modified non-- rebreathing mask (NRM, with no vent holes), and an AerosoLess mask. An aerosol particle sizer measured aerosol concentrations at parallel distances of 0.8 m and 2.2 m and a frontal distance of 1.8 m from the manikin. The drug dose delivered distal to the manikin's airway was collected, eluted, and analyzed using a spectrophotometer at a 276 nm wavelength. RESULTS: With a normal breathing pattern, the trends of aerosol concentrations were higher with an NRM followed by an aerosol mask and AerosoLess mask (P < .001) at 0.8 m; however, the concentrations were higher with an aerosol mask followed by NRM and AerosoLess mask at 1.8 m (P < .001) and 2.2 m (P < .001). With a distressed breathing pattern, the aerosol concentrations were higher with an aerosol mask followed by an NRM and AerosoLess mask at 0.8 m, 1.8 m (P < .001), and 2.2 m (P 5 .005). The delivered drug dose was significantly higher with AerosoLess mask with a normal breathing pattern and with an aerosol mask with a distressed breathing pattern. CONCLUSIONS: Mask design influences fugitive aerosol concentrations in the environment, and a filtered mask reduces the concentration of aerosols at 3 different distances and with 2 breathing patterns. [ABSTRACT FROM AUTHOR]