Elborn et al 1 have attempted to address the important question of whether it is better to treat patients with cystic fibrosis (CF) who have chronicPseudomonas aeruginosa infection with intravenous antibiotics on the basis of symptoms or to treat them electively, and found no significant difference between their groups. They chose a particularly unwell subgroup of the CF population to study, and one might expect a policy of increasing from three symptomatic to four elective courses of intravenous antibiotics to make the least difference in such patients. We believe that patients who require 2–4 courses of intravenous antibiotics per year anyway are not those for whom this question of treatment is most pressing to answer. The benefit of elective treatment needs to be investigated in patients who have only recently acquired Pseudomonas aeruginosa, as per the Danish model.2 It is this group of patients for whom a recommendation of four intravenous treatments per year would be the greatest departure from current practice in most centres, and for whom strong evidence of benefit, including replication of the Danish results, is needed.

Of great concern in the study by Elborn et al is the finding of an excess of deaths at five years in the group treated electively. This is not well accounted for by the authors. It is possible that the patients treated electively adopted a “sick role” with concomitant reduction in physical activity contributing to deterioration. In addition, patients admitted to hospital have increased opportunity for exposure to more virulent bacteria. In the study by Elborn et al the organisms were identified by their resistance patterns and were similar between the groups. However, research currently underway at our institution indicates that infection with certain genotypes ofP aeruginosa gives a worse prognosis than others, and sharing of such organisms among those frequently admitted may account for the difference in outcome at five years. We would suggest that it is important to study P aeruginosa genotypes to identify more accurately the possibility of cross infection being responsible for the worse outcome of the group treated electively.