“-” means that deletion of the gene decreases fitness (> 2-fold change). “+” means deletion of the gene increases fitness (> 2-fold change). Parentheses indicate that the P-value was not significant. An empty cell means that no significant effect of deletion was observed. “Ec TOB:” column summarizing results from Escherichia coli growth curves in sub-MIC TOB (Fig. 4), “N/A” means that the corresponding mutant was not tested in E. coli.