| Microorganism | Total isolates n | Samples containing specific pathogen# % | |||
| Yellow sputum | Green sputum | White sputum | Rust sputum | ||
| Samples of each colour¶ n | 2319 | 1218 | 353 | 113 | |
| Haemophilus influenzae | 605 | 14.1 | 20.0 | 10.6 | 5.9 |
| Streptococcus pneumoniae | 313 | 7.4 | 9.5 | 12.4 | 2.5 |
| Moraxella catarrhalis | 319 | 7.3 | 11.2 | 2.3 | 4.4 |
| Haemophilus parainfluenzae | 262 | 5.8 | 9.2 | 2.5 | 5.3 |
| Staphylococcus aureus | 158 | 3.4 | 5.4 | 1.7 | 5.3 |
| Klebsiella pneumoniae | 133 | 3.9 | 3.1 | 0.8 | 1.8 |
| Pseudomonas aeruginosa | 105 | 2.4 | 3.1 | 2.5 | 1.8 |
| Haemophilus spp.+ | 64 | 1.4 | 2.4 | 0.3 | 0.0 |
| Negative culture§ | 2191 | 54.5 | 41.1 | 81.6 | 61.1 |
#: percentage of isolates of each species based on the total number of culture samples; ¶: one sample obtained per patient; +: Haemophilus spp. other than H. influenzae and H. parainfluenzae; §: total number of negative cultures.