Improved cultural detection of Burkholderia cepacia from sputum in patients with cystic fibrosis

Aims-To evaluate the sensitivity and specificity of two selective media for the isolation of Burkholderia cepacia from sputum specimens in patients wi th cystic fibrosis (CF). Methods-In total, 149 expectorated sputum specimens from 113 patients with CF (32 cepacia colonised patients and 81 non-cepacia colonised patients) at tending three CF centres were examined for the presence of B cepacia on two selective media: (1) MAST selective agar, a commercially available selecti ve medium widely used in the UK and (2) BCSA (B cepacia selective agar), a new medium recently described, which is used predominantly in North America . Results-Burkholderia cepacia was isolated from 53 of 149 (35.6%) specimens examined, representing 32 of 113 (28.3%) patients, using both the MAST and BCSA media. Growth was most rapid on BCSA with all (53 of 53) isolates dete ctable after 48 hours, compared with 50 of the 53 isolates on MAST agar, wi th the remaining three isolates detectable at five days. Twenty eight conta minants were identified on MAST agar and 13 on BCSA agar; mainly Alcaligene s xylosoxidans and yeast on MAST agar and Flavobacterium indologenes on BCS A medium. BCSA was equivalent to MAST agar in its ability to isolate B cepa cia from patients with CF with a history of B cepacia infection. Conclusions-The increased selectivity and reduced time to detection of BCSA makes it an attractive alternative to MAST. However, its present limited c ommercial availability in the UK may delay its use in routine diagnostic la boratories because of complications with media preparation and quality cont rol.