Increased treatment requirements of patients with cystic fibrosis who harbour a highly transmissible strain of Pseudomonas aeruginosa

Abstract

Background: A group of patients who harbour the same highly transmissible strain of Pseudomonas aeruginosa were identified at a cystic fibrosis (CF) centre. Isolates of this strain display a number of unusual phenotypic features including resistance to most typical antipseudomonal antibiotics. A study was undertaken to see if there was a difference in treatment requirements between CF patients with chronic infection with their own unique P aeruginosa strains (group 1) and those who harbour a highly transmissible strain (group 2).

Methods: Data on treatment requirements for the year 2000 were collected from the case records of CF patients with chronic P aeruginosa infection who had received inpatient treatment. Patients co-infected with Burkholderia cepacia or other highly transmissible strains of P aeruginosa were excluded.

Results: There were 2/56 and 3/22 deaths in groups 1 and 2, respectively; these patients were excluded from the analysis. No difference was found between the two groups for mean age, % predicted forced expiratory volume in 1 second (FEV₁), % predicted forced vital capacity (FVC), and body mass index. Patients in group 2 had a greater median (range) number of intravenous antibiotic days (60 (17–216) v 33 (4–237) days; p=0.01), inpatient days (39 (7–183) v 16 (1–172) days; p<0.01), and inpatient episodes (3 (1–9) v 2 (1–6); p<0.01), and more respiratory exacerbations (mean (SD) 8.2 (3.4) v 6.1 (3.2); p=0.01).

Conclusions: Patients who harbour the highly transmissible P aeruginosa strain have a greater treatment burden than patients with CF who harbour their own unique strains. These findings support the need for microbiological surveillance for highly transmissible P aeruginosa and the implementation of infection control measures to prevent cross infection.