Infection in acute exacerbations of chronic bronchitis: a clinical perspective

Acute exacerbations of chronic bronchitis (AECB) is an important cause of d eath and morbidity in developed countries and also has significant economic impact. The disease is characterized by increased dyspnoea, sputum volume and sputum purulence; the most commonly associated pathogens are Haemophilu s influenzae, Streptococcus pneumoniae and Moraxella catarrhalis. H. influe nzae and S. pneumoniae express virulence determinants that directly and ind irectly impair mucociliary clearance and incite other consequences that are permissive to microbial persistence. Regarding the use of antibiotics, there is currently a lack of large-scale clinical trials that are sufficiently powerful to provide good evidence-bas ed information. Nonetheless, antimicrobial chemotherapy has repeatedly been shown to confer benefit in patients with moderately severe features of AEC B. Simple clinical criteria can be used to identify patients in whom there is a higher likelihood of treatment failure or mortality during AECB. These include significant cardiopulmonary co-morbidity, frequent exacerbations, advanced decline in lung function, malnutrition or other generalized debili ty, advanced age (> 70 years) and concurrent treatment with corticosteroids . In such patients, an aggressive antimicrobial approach to AECB may be war ranted in order to prevent clinical failure or representation. From a clini cal perspective, appropriate drugs include those that are stable to B-lacta mases, are bactericidal against causative pathogens, penetrate diseased lun g tissue in high concentrations and have a good safety profile. (C) 1999 HA RCOURT PUBLISHERS LTD.