Fig. 4: Cell length heterogeneity under nalidixic acid and tetracycline combination.

Representative differential interface contrast (DIC) combined with fluorescence microscopy images of DAPI-stained (blue) A. baumannii AYE, E. coli MG1655, and E. coli RPTU54 cells growing in the absence of antibiotics (control cells) or in the presence of DNA synthesis inhibitors (nalidixic acid), translation inhibitor (tetracycline), or in a combination of both. Cell length displays the highest variability in the presence of DNA synthesis inhibitor but not in the presence of the translation inhibitor. All antibiotic concentrations were used at 0.75× MIC. Scale bar represents 10 µm. Morphometric analysis of cell length shown as bean plots. Major solid lines represent the medians, dotted lines represent 1/4^th and 3/4^th quartile. Minimum 500 cells were analyzed in each group. P < 0.001 for all three groups, one-way ANOVA followed by the Kruskal–Wallis post test was applied.