Which organism is involved in the acute exacerbation of chronic bronchitis?

• A. Haemophilus influenzae
• B. Mycoplasma
• C. Pneumococcal
• D. Legionella

Answer: (A)

Acute exacerbations of chronic bronchitis are usually triggered by bacterial infections that capitalize on the already inflamed, mucus-laden airways. Haemophilus influenzae is a classic culprit because it commonly colonizes the chronically irritated bronchial passages and can proliferate during flare-ups, leading to increased cough, sputum production, and shortness of breath.

Mycoplasma tends to cause atypical pneumonia with subtler symptoms and less the typical COPD-exacerbation pattern. Pneumococcal bacteria can cause pneumonia and bronchitis and do contribute, but Haemophilus influenzae is most commonly linked with these COPD flare-ups in this context. Legionella is more associated with severe pneumonia with high fevers, GI symptoms, and hyponatremia, often in outbreaks or specific environmental exposures, rather than the standard COPD exacerbation picture.

So the organism most consistently implicated in the acute worsening of chronic bronchitis is Haemophilus influenzae.