Is there a role for antibiotics in the treatment of asthma? Involvement ofatypical organisms

Emerging evidence suggests an association between some asthma and pulmonary infection by the atypical organisms Chlamydia pneumoniae and Mycoplasma pn eumoniae, but a causal role for infection remains unproven and controversia l. Most acute exacerbations of asthma are triggered by acute infections tha t are due to viral respiratory pathogens, not to bacteria or atypical organ isms. Administration of antibiotics for acute exacerbations of asthma has b een shown to be ineffective. Most evidence linking atypical infections to a sthma is consistent with a promoting role for chronic infection in producin g persistent asthma symptoms. Preliminary studies suggest that prolonged (g reater than or equal to6 weeks) administration of doxycycline or macrolides may eradicate C. pneumoniae from respiratory secretions and improve long t erm, not acute, asthma symptoms. Randomised, controlled trials are currentl y under way to investigate the effectiveness of these prolonged courses of macrolides and azalides (roxithromycin, clarithromycin and azithromycin) in adults with stable persistent asthma, Traditional courses (7 to 10 days) o f any antibiotic are incapable of eradicating chronic C. pneumoniae or M. p neumoniae infection; furthermore, beta -lactam and sulphonamide-based antib iotics that are commonly prescribed in acute respiratory syndromes are inef fective against these atypical organisms, unless the goal is to treat docum ented sinusitis associated with asthma, it is inappropriate to prescribe tr aditional courses of any anti biotic for acute asthma exacerbations; whethe r longer courses of antibiotics should be prescribed to eradicate chronic a typical infections and decrease persistent asthma severity remains to be es tablished.