Seminar Title: Burkholderia cenocepacia antimicrobial resistance and physiology at acidic pH in the cystic fibrosis nutritional environment 

Abstract: Burkholderia cenocepacia is an opportunistic pathogen correlated with increased disease severity and mortality in cystic fibrosis (CF) patients. It is resistant to a wide range of disinfectants and antibiotics, and no standard treatment is available. Previous analysis of CF sputum samples showed elevated levels of zinc and iron ions and lower pH (2.9-6.5), compared to healthy individuals. B. cenocepacia grows at acidic pH (~3.5) and persists for 24 h in intracellular acid compartments of amoebas and macrophages. I aim to understand the impact of acidic pH and increased zinc and iron concentrations on B. cenocepacia physiology and antibiotic resistance using a modified a synthetic cystic fibrosis sputum media (SCFM-FeZn). We found that acidic pH in the sputum environment modulates B. cenocepacia antimicrobial susceptibility and triggers molecular mechanisms associated with pathogenicity and virulence. Understanding B. cenocepacia physiology and antimicrobial susceptibility in the CF nutritional environment could help improve susceptibility testing in the clinical environment, and pave the way to design new antimicrobial therapies against B. cenocepacia infections.