Fig. 5.
Fitness cost associated with TetM overexpression and increased Tn916 copy number. Competitive fitness assays were performed between BTR strains with a deletion in the 5′-UTR of tetM and the ancestral S613 strain in the absence of antibiotic. Error bars show the 95% confidence interval between at least four replicate assays. The fitness cost of the S10R53Q-Δ54-57ATHK allele alone (BTR0) is indistinguishable from zero, whereas a fitness cost of BTR strains with deletions upstream of tetM was readily detected and was as high as 44% in BTR87a.