Definitions

Empirical therapy was considered as treatment (monotherapy or combination therapy) that was initiated when the VAP was suspected and before reception of AST.Appropriate empirical antimicrobial therapy was defined if empirical therapy included at least one antibiotic active against the isolated strain. Isolates with intermediate levels of susceptibility were classified as resistant.Combination therapy consisted of the combination of a β-lactam and an aminoglycoside or a fluoroquinolone or an association of a fluoroquinolone and an aminoglycoside.Definitive antibiotic therapy was defined as antibiotic regimen after the clinicians had adapted it according to the AST results.Definitive monotherapy was defined as only one active antimicrobial (a β-lactam, fluoroquinolone, or colistin), and considered as appropriate antibiotic therapy, administered all along duration of treatmentDefinitive combination therapy included a β-lactam and an aminoglycoside or a fluoroquinolone or an association of fluoroquinolone and an aminoglycoside, and considered as appropriate antibiotic therapy and administered all along duration of treatment.