Burkholderia cepacia complex in cystic fibrosis in a Brazilian reference center

Abstract

The Burkholderia cepacia complex (BCC) can cause a severe decline in lung function in cystic fibrosis (CF). Our objective was to determine the BCC prevalence and to evaluate its clinical impact on CF. Clinical and laboratory variables were determined for CF patients with BCC (Group-A = 50 patients) and without BCC (Group-B = 134 patients). The microorganisms were identified by biochemical tests, the Vitek2^®Compact test, recA-PCR and recA-nested-PCR with species-specific primers and DNA sequencing. The patients were evaluated by the Shwachman-Kulczycki score (SKCS), Bhalla score (BS), spirometry and body mass index (BMI). The BCC prevalence was 22.5%. The most common species were Burkholderia multivorans (30%), Burkholderia cepacia (24%), Burkholderia cenocepacia IIIA (10%), B. cenocepacia IIIB (2%) and Burkholderia vietnamiensis (2%). There was difference between the groups in nutritional status (p = 0.02) and general activity (p = 0.026). There was difference in total BS points (p = 0.04) and the following parameters: bronchiectasis severity (p = 0.007), peribronchial thickening (p = 0.013), bronchiectasis extent (p = 0.01) and general aspects of the affected bronchial zone (p = 0.02). The respiratory disorder classifications were as follows: obstructive-4.8% (Group-A) and 23.8% (Group-B); restrictive-9.5% (Group-A and Group-B); obstructive + restrictive-19% (Group-A) and 1.6% (Group-B); and obstructive + restrictive with a decreased forced expiratory flow-47.6% (Group-A) and 30.2% (Group-B) (p = 0.02). Nutritional status was a minor contributing factor to weight, height and BMI in the Group-A (p = 0.02). The BCC prevalence, particularly the prevalence of B. multivorans, was higher in this study. The SKCS, BS, spirometry and nutritional status results showed that BCC has a negative impact on clinical status. Phenotypic methods are useful for the identification of presumptive BCC. The Vitek2^®Compact test showed accuracy in BCC identification. PCR, nested-PCR, and recA sequencing showed specificity in BCC species identification.

Keywords: Burkholderia cepacia complex; Cystic fibrosis; Molecular diagnostic; Prevalence.