Biofilm-associated Mycobacterium abscessus cells have altered antibiotic tolerance and surface glycolipids in Artificial Cystic Fibrosis Sputum Media

Abstract

Mycobacterium abscessus (Mab) is a biofilm-forming, multi-drug resistant, non-tuberculous mycobacterial (NTM) pathogen increasingly found in Cystic Fibrosis patients. Antibiotic treatment for these infections is often unsuccessful, partly due to Mabs high intrinsic antibiotic resistance. It is not clear whether antibiotic tolerance caused by biofilm formation also contributes to poor treatment outcomes. We studied the surface glycolipids and antibiotic tolerance of Mab biofilms grown in Artificial Cystic Fibrosis Sputum media in order to determine how they are affected by nutrient conditions that closely mimic infection. We found that Mab biofilms grown in ACFS display more of the virulence lipid trehalose dimycolate than biofilms grown in standard lab media. Biofilms in ACFS media also afford more protection against clinically important antibiotics than biofilms grown in lab media. These results indicate that Mab cell physiology in biofilms depends on environmental factors, and that nutrient conditions found within Cystic Fibrosis infections could contribute to both increased virulence and antibiotic tolerance.