Background:Burkholderia cepacia remains
a significant pathogen in persons with cystic fibrosis (CF). The
medical and psychosocial consequences of pulmonary colonization with
this bacterium are enormous. However, B cepacia may be
frequently misidentified from CF sputum culture.
objectives: To determine the rate of misidentification of
B cepacia recently recovered from CF sputum culture of
persons receiving care in US treatment centers.
Design: Bacterial isolates cultured from CF sputum and
putatively identified as B cepacia or other
related nonlactose-fermenting Gram-negative species were referred
from participating treatment centers. Isolates underwent polyphasic
analyses employing phenotypic (selective media and biochemical testing)
and genotypic (polymerase chain reaction) assays to determine species
identification. Taxonomic evaluations were performed by using sodium
dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell
proteins and amplified-fragment length polymorphism analysis.
Measurements and results: A total of 1,051 isolates
recovered from 608 patients were received from 115 treatment centers in
91 US cities. Among the isolates identified as B cepacia
by referring laboratories, 11% could not be confirmed as B
cepacia by polyphasic analyses. In addition, 36% of isolates
not specifically identified by the referring laboratory or identified
as a species other than B cepacia were, in fact, found
to be members of the B cepacia complex.
Conclusions: Rates of misidentification of B
cepacia remain unacceptably high among US treatment centers.
These data suggest the need for increased awareness of this problem
among CF centers and their affiliated laboratories, better adherence to
recommended protocols for evaluation of CF sputum, and greater use of
reference laboratories equipped to provide advanced