the present invention is antibiotic compositions , ventilator - based systems and methods relating to ventilator - associated pneumonia and ventilator - associated tracheal bronchitis . antibiotic combinations of fosfomycin and an aminoglycoside , preferably amikacin , are administered via an inline nebulizer within the airway of the ventilator . humidified conditions create an improved aerosol mist to treat vap and vat .