Evaluating clinical outcomes of respiratory infection

Evaluation of clinical outcomes of respiratory infection is essential to the audit of efficacy and safety of management practices. In order to examine the appropriateness of clinical outcome measurements in treated chronic respiratory infections, it is necessary to study a defined homogeneous population of treated patients. There is a fundamental difference between acute and chronic infection which governs the mode of antibiotic therapy. Understanding of the pathogenesis of chronic respiratory infection also allows more logical use of antimicrobial agents and more logical assessment of their efficacy, taking into account the tissue-damaging inflammation which might be controlled by anti-inflammatory combined with antibiotic therapy. This contrasts with acute infection in the immunocompetent host, in whom virulent bacteria overwhelm the host's immune defences temporarily so that a brief period of antibiotic therapy may reduce bacterial counts and host immune defences achieve killing of bacteria.