Fig. 3: Inhibition of β-lactamase activity leads to a compensatory increase in blaSHV-5 copy number.
a PAP of Enterobacter RS strains plated on cefiderocol. Genotypes are ΔblaSHV-5, ΔblaSHV-5::blaSHV-5 (referred to as blaSHV-5 (WT)), and ΔblaSHV-5::blaSHV-5 M69I (blaSHV-5 M69I). Shown are the means and standard deviation of three independent experiments with 3 biological replicates each. b blaSHV-5 and blaSHV-5 M69I amplification from surviving colonies on 4 µg/mL cefiderocol in (a), each point indicates a replicate from three independent experiments, total n = 10 for blaSHV-5 (WT) and n = 15 for blaSHV-5 M69I. Data are log10 transformed, one-way ANOVA with Sidak’s correction for multiple comparisons, F (3, 46) = 6.471. c, d RS strain blaSHV-5 and blaSHV-5 M69I were plated on MHA containing cefiderocol (lightest and bottom-most line in c and d), colonies collected from 4 µg/mL cefiderocol, and grown in broth containing 4 µg/mL cefiderocol. The cultures were plated on MHA plus cefiderocol (next darker line), collected from and grown in 8 µg/mL cefiderocol, and plated on MHA plus cefiderocol (next darker line). Colonies were collected from and grown in 16 µg/mL cefiderocol, plated on MHA plus cefiderocol (darkest line), and DNA was extracted. eblaSHV-5 and blaSHV-5 M69I gene abundance quantified by qPCR and log10 transformed following growth in 16 µg/mL cefiderocol from c and d, with mean above each group. c–e show data of blaSHV-5 from 17 replicates across 4 experiments and blaSHV-5 M69I from 14 replicates across 4 experiments. c, d show the mean and standard deviation, while (e) shows each replicate as a dot. For (e), two-tailed unpaired t-test (t = 5.423, df = 29). Source data are provided as a Source Data file.
