Most guidelines have been proposing, for more than 15 years, a combination of a β-lactam with either a quinolone or a macrolide as empirical, first-line therapy of severe CAP requiring ICU admission [2] [3] [4] [5] [6] [7] [8] . Although a recent study demonstrated combination antibiotic therapy to be associated with a higher survival rate than monotherapy in patients with severe CAP and shock [9] , the rationale for this combination was not to increase efficacy but rather to routinely provide coverage of all common pathogens causing severe CAP and particularly, S. pneumoniae and Legionella species.