Table 2.
Bacterial Yield in the Study Population and the Contribution of Different Methods to the Determination of Etiology with Respect to Their Different Specificity
| Pathogen | No. (%) of patients with positive findings (n = 184) | Blood culture (n = 179) | Pleural fluid culture (n = 13) | Urine antigen assaya | BAL and/or protected specimen brush culture (n = 12) | Culture and/or PCR from sputum sample for L. pneumophila (n = 138) | Culture and PCR from respiratory sample for M. tuberculosis (n = 18) | Sputum culture (n = 128) | RQ-PCR from sputum sample (n = 126) | Nasopharyngeal secretion culture (n = 158) | PCR from nasopharyngeal secretion sampleb | Serology (n = 131) |
| Streptococcus pneumoniae | 70 (38) | 27 | … | 16 | … | … | … | 10 | 10 | 7 | … | … |
| Mycoplasma pneumoniae | 15 (8) | … | … | … | … | … | … | … | … | … | 8 | 7 |
| Haemophilus influenzae | 9 (5) | … | … | … | … | … | … | 4 | 5 | … | … | … |
| Moraxella catarrhalis | 7 (4) | … | … | … | … | … | … | 7 | … | … | … | … |
| Staphylococcus aureus | 4 (2) | 2 | 1 | … | … | … | … | 1 | … | … | … | … |
| Legionella pneumophila | 3 (1) | … | … | 2 | … | 1 | … | … | … | … | … | … |
| Streptococcus pyogenes | 2 (1) | 1 | … | … | 1 | … | … | … | … | … | … | … |
| Streptococcus milleri | 1 (0.5) | … | 1 | … | … | … | … | … | … | … | … | … |
| Nocardia cyriacigeorgica | 1 (0.5) | … | … | … | … | 1 | … | … | … | … | … | … |
| Fusobacterium necrophorum | 1 (0.5) | 1 | … | … | … | … | … | … | … | … | … | … |
| Mycobacterium tuberculosis | 2 (1) | … | … | … | … | … | 2 | … | … | … | … | … |
| Total | 115 | 31 | 2 | 18 | 1 | 2 | 2 | 22 | 15 | 7 | 8 | 7 |
NOTE. Date are no. of patients who received a diagnosis by use of a particular method, unless otherwise indicated. Additional patients received a diagnosis by use of different methods; for example, an additional 16 cases of S. pneumoniae infection were diagnosed by a urinary antigen test that were not diagnosed by blood culture, and another 10 cases were diagnosed by sputum culture that were not diagnosed by blood culture or a urinary antigen test. BAL, bronchoalveolar lavage; RQ-PCR, real-time quantitative polymerase chain reaction.
There were 168 patients who tested positive for L. pneumophila and 169 patients who tested positive for S. pneumoniae.
The were 99 patients who tested positive for Chlamydophila pneumoniae and 101 patients who tested positive for Mycoplasma pneumoniae.