Chronic obstructive pulmonary disease: role of bacteria and updated guide to antibacterial selection in the older patient.

Chronic obstructive pulmonary disease (COPD) remains a major cause of morbidity and mortality worldwide. COPD is especially prevalent in the elderly, affecting 25% of those aged>or=75 years. The course of the disease in the elderly is often complicated by co-morbid conditions, and its management is complicated by drug-drug interactions. Exacerbations of COPD increase rates of hospitalization and mortality and decrease quality of life. Exacerbations are marked by an increase from baseline in dyspnoea, sputum volume and sputum purulence. Approximately 50% of acute exacerbations of symptoms in COPD are caused by non-typeable Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae and Pseudomonas aeruginosa. Stratification of exacerbations based on severity of symptoms and signs, and severity of underlying COPD, is useful in selecting patients likely to benefit from antibacterial therapy. Patients who are hospitalized with exacerbations, those who have all three symptoms (increased dyspnoea, sputum volume and sputum purulence), and those with severe underlying COPD and exacerbations benefit most from antibacterials. Antibacterial susceptibility patterns among the bacterial pathogens are evolving, and knowledge of local susceptibility patterns is useful in antibacterial selection. Penicillin, amoxicillin, cotrimoxazole (trimethoprim/sulfamethoxazole) and doxycycline should not be used as an initial antibacterial because of resistance patterns. We recommend second-/third-generation cephalosporins, amoxicillin/clavulanic acid, azithromycin and respiratory fluoroquinolones as initial choices. In patients at risk of colonization by, and infection as a result of, P. aeruginosa, ciprofloxacin, levofloxacin or an advanced penicillin/penicillinase combination effective against this species should be used. Drug-drug interactions should be considered in antibacterial choice. The goals of antibacterial therapy for exacerbations of COPD are the prevention of complications such as respiratory failure and death, and the reduction of treatment failures. The role of pathogenic bacteria in progression of stable COPD and the use of prophylactic antibacterials in stable COPD are under investigation. Currently available evidence does not support routine clinical use of prophylactic antibacterials in stable COPD. In conclusion, pathogenic bacteria cause a significant proportion of acute exacerbations of COPD. Use of antibacterials, based on current susceptibility patterns, is beneficial in patients with severe COPD experiencing exacerbations and in patients with severe exacerbations.