The clinical relevance of in-vitro resistance to penicillin, ampicillin, amoxycillin and alternative agents, for the treatment of community-acquired pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis.

The documentation of antimicrobial resistance in respiratory pathogens, contained within the Alexander Project, does not necessarily translate into clinical resistance in the treatment of primary community-acquired pneumonia. There is, in particular, little evidence that penicillin resistance in pneumococci is clinically relevant for the treatment of pneumonia, and there is further evidence that the production of beta-lactamase by Haemophilus influenzae may not always be clinically relevant within this setting. beta-Lactamase producing H. influenzae and Moraxella catarrhalis should probably be treated with alternative agents when they cause exacerbations of chronic bronchitis. More studies are required to define the clinical breakpoints of macrolide and co-trimoxazole resistance in the treatment of pneumonia.