Coevolution of Plasmids in Bacteria Evolved in Biofilm and Chemostat Cultures

Presenter/Author/Student Information

Brandon J. Cornwell, University of IdahoFollow
Thibault Stalder (Mentor), University of IdahoFollow
Bethel Kohler, University of IdahoFollow
Celeste Brown, University of IdahoFollow
Hirokazu Yano, University of IdahoFollow
Larry J. Forney, University of IdahoFollow
Eva M. Top, University of IdahoFollow

Abstract

Broad-host range (BHR) plasmids are one of the main vectors of the spread of antibiotic resistance across bacteria, a major health concern today. In well-mixed cultures, BHR plasmids can become more persistent in bacterial populations after a short period of co-evolution under plasmid selection. However, these experimental conditions do not mimic those found in 80% of bacterial infections, wherein bacteria grow in biofilms. Biofilms are known to retain genetic diversity within the bacterial population. We hypothesized that when plasmid-host pairs are coevolved in a biofilm, they will exhibit a broader range of persistence level than when coevolved in a well-mixed culture. A BHR plasmid was coevolved in the host Shewanella oneidensis MR1 for 28 days in biofilm and well-mixed culture environments. The persistence of the coevolved plasmid in their host was assessed for 3 clones isolated from each condition. Preliminary data suggests that when coevolved in a biofilm, the plasmid became more persistent than when coevolved in well-mixed environment. In order to confirm this result, more clones from several independent replicate assays are currently under investigation.