Fig. 4. Cross-stress behavior plots of E. coli exposed to biocide, followed by an antibiotic.
The cross-protection percentage for each antibiotic represents the relative difference of the shaded area compared to that of the decagon with no cross-stress behavior. A cross-stress protection index (CSPI) of more than 1 denotes cross-protection of biocide-treated cells in antibiotic compared to biocide-untreated cells. CSPI less than 1 indicates cross-vulnerability of biocide-treated cells in antibiotic compared to the biocide-untreated cells. The error bars represent the standard error of mean among 3–4 biological replicates centered at their mean.