Fig. 1.

Results of biofilm formation assay. X-axis: 30 planktonic isolates P101–P310 (P samples), 30 antibiotic-free biofilm effluent isolates B101–B310 (B samples), 30 ciprofloxacin-exposed biofilm effluent isolates C101–C310 (BC samples), and 30 tetracycline-exposed biofilm effluent isolates T101–T310 (BT samples). Each sample type includes 10 isolates from each biological replicate 1 (blue bars), biological replicate 2 (orange bars), and biological replicate 3 (gray bars). The Y-axis represents corresponding absorbance values of 5-fold diluted crystal violet extracts at 590 nm (A₅₉₀). Error bars represent standard deviations between 24 technical replicates. The average value for each sample type is indicated by red dashed lines. P values denote differences between sample pairs based on nested mixed-factor ANOVA test followed by Turkey’s HSD post hoc test. P values showing statistically significant (p < 0.05) differences are presented in bold