Figure 2. Pathogen Detection among U.S. Adults with Community-Acquired Pneumonia Requiring Hospitalization, 2010–2012.

Panel A shows the numbers (above the bars) and percentages of all adults in whom a specific pathogen was detected. A total of 966 pathogens were detected in 853 of 2259 hospitalized adults with radiographic evidence of pneumonia who had tests available for the detection of both bacterial and viral pathogens. The proportions of viral, viral–viral, bacterial–viral, bacterial, and fungal or mycobacterial pathogens detected and no pathogen detected are shown in the pie chart. Percentages may not sum as expected owing to rounding. A total of 76 pathogens other than those listed here were detected in 74 patients, including Haemophilus influenzae (in 12 patients), Chlamydophila pneumoniae (in 9), Mycobacterium tuberculosis (in 8), pseudomonas (in 8), Streptococcus pyogenes (in 7), viridans streptococci (in 7), other streptococcus species (in 7), nontuberculous mycobacterial species (in 4), fusobacterium (in 3), Pneumocystis jirovecii (in 3), and bacteroides, coccidioides, histoplasma, pasteurella, both H. influenzae and Neisseria meningitidis, and both viridans streptococci and other streptococcus species (in 1 each). Panel B shows, according to month and year, the number of hospitalized adults who had pneumonia from any cause; patients in whom human rhinovirus, influenza virus, human metapneumovirus, and respiratory syncytial virus were detected; and patients in whom S. pneumoniae and Staphylococcus aureus were detected. Note the difference in scale of the y axis for each line graph.