Exploring the expression of Pseudomonas aeruginosa genes directly from sputa of cystic fibrosis patients

Acquisition of Pseudomonas aeruginosa is known as a negative prognostic factor in patients with cystic fibrosis. We started a pilot study to evaluate Ps. aeruginosa gene expression directly from the sputum of infected patients. Total RNA was purified from 15 sputum samples collected from 10 patients, and the expression levels of five genes from Ps. aeruginosa were measured by RT-qPCR. Expression of algD, algR, antB, lasB and pqsA genes was determined in sputa that contained Ps. aeruginosa cells. The resultant data provided an overview of the expression of these genes in CF patients. Except for the correlation between algD expression and the mucoid phenotype, the gene expression profile could not be associated with the clinical status of patients. However, beyond the heterogeneity of the Ps. aeruginosa phenotype in sputum, we observed a correlation between the expression of antB and pqsA and a low level of lasB transcripts.