Decontamination of the sputum of cystic fibrosis patients during mycobacteriological explorations: Supercolonization with non-specific bacterial flora is more frequent in patients colonized with Burkholderia cenocepacia than with Pseudomonas aeruginosa
Abstract
Patients presenting cystic fibrosis are a risk group in danger of airways colonization with non-tuberculous mycobacteria. This is why sputum samples of these patients have to be regularly investigated for the presence of mycobacteria.
Chronic colonization of the airways by gramnegative bacteria capable of resisting decontamination somewhat complicate the detection of mycobacteria. In a retrospective analysis we assessed both the efficacy of decontamination with 2.7 % sodium laurysulfate and 0.9 % sodium hydroxide and the proportion of sputum sampies with bacterial supercolonization.
We evaluated 162 sputum samples from 42 patients (25 women), mean age 24.2 (19.9-41.9) years. In 13 instances there was chronic colonization with Pseudomonas aeruginosa, in 29 instances with Burkholderia cenocepacia.
Supercolonization with non-specific bacterial flora was seen in 23 out of 51 patients (45.1 %) colonized with Pseudomonas aeruginosa and in 71 out of 111 patients (64.0 %) colonized with Burkholderia ceRocepacia (p < 0.05). No sample was microscopically positive, only one sample was positive upon culture (Mycobacterium auium in a woman patient colonized with Pseudomonas aeruginosa).
All the remaining samples had negative cultures. In 14 the investigated patients (33.3 %) we found only contaminated culture media.
Our investigation demonstrated an inadequante efficacy of the decontamination method used and a more frequent non-specific contamination of culture media in airways colonization with Burkholderia cenocepacia than in colonization with Pseudomonas aeruginosa.