Metersky et al1concluded in their recently published study that the initial treatment of patients with bacteremic community-acquired pneumonia (CAP) with a macrolide was associated with lower mortality compared to treatment without coverage for atypical microorganisms. Macrolide combination therapy was associated with lower mortality in several other cohort studies2–3 of bacteremic CAP patients. However, we believe that there are a few issues that should be taken into account regarding the findings of the study by Metersky et al.1 First, as shown in Table 3,1 patients who received antibiotics covering atypical pathogens were more likely (p < 0.001) to have received concordant antibiotic therapy within the first 24 h from hospital admission, which is thought to be associated with lower mortality4; concordant antibiotic therapy was defined as therapy including antibiotics to which the infecting organism was susceptible based on the in vitro susceptibility testing. Second, they were more likely to have received antibiotic therapy within 8 h from hospital admission (p < 0.001), which was also thought to be associated with lower mortality.,4 Third, they were less likely to have been admitted to the hospital from a nursing facility (p < 0.001), which may suggest that their general health status was better. Moreover, the two groups of patients had similar pneumonia severity index (PSI) scores I-IV, while PSI score V patients were fewer in the group of patients who received therapy with atypical pathogen coverage (p = 0.003); PSI score V patients are those with the highest mortality. Although the authors do state that severity of illness and concordant antibiotic therapy were predictors of outcome, they may comment further on the fact that patients receiving atypical pathogen coverage had an advantage on several issues. Thus, the authors may want to discuss the potential effect of various confounding factors.