Table 1—

Bacterial pathogens implicated in acute and chronic infections in chronic obstructive pulmonary disease

MicrobeRole in exacerbationsRole in stable disease
Bacteria
 Haemophilus influenzae20–30% of exacerbationsMajor pathogen
 Streptococcus pneumoniae10–15% of exacerbationsMinor role
 Moraxella catarrhalis10–15% of exacerbationsMinor role
 Pseudomonas aeruginosa5–10% of exacerbations, prevalent in advanced diseaseLikely important in advanced disease
 EnterobacteriaceaeIsolated in advanced disease, pathogenic significance undefinedUndefined
 Haemophilus haemolyticusIsolated frequently, unlikely causeUnlikely
 Haemophilus parainfluenzaeIsolated frequently, unlikely causeUnlikely
 Staphylococcus aureusIsolated infrequently, unlikely causeUnlikely
Atypical bacteria
 Chlamydophila pneumoniae3–5% of exacerbationsCommonly detected, pathogenic significance undefined
 Mycoplasma pneumoniae1–2% of exacerbationsUnlikely