Indications for amoxicillin and tetracyclines are certainly appropriate for COPD severity stages I and II where the local resistance patterns of H. influenzae and S. pneumoniae allow empiric treatment with these antibiotics. The combination of trimethoprim and sulfamethoxazole was never a good choice for the treatment of purulent AECB since the optimal ratio of the two parts of this combination (1:5) is never established in the bronchial mucosa. The ratio of both parts in the bronchial mucosa is usually 1:1 and therefore only TMP concentrations are therapeutically effective.