Journal: iScience

Article Title: Nitroxoline as an antimicrobial synergist reverses colistin resistance in multidrug-resistant Escherichia coli

doi: 10.1016/j.isci.2025.114003

Figure Lengend Snippet: NTX enhances the activity of colistin and delays the emergence of resistance (A) Results of the checkerboard dilution assay, which assessed the synergistic effect of NTX in conjunction with a variety of antibiotics against MDR E. coli B2. The dark blue areas represent high bacterial density, with the data corresponding to the average OD 600 values of two biological replicates. (B) E. coli B2 time-kill curves with NTX (4 μg/mL,1/4 MIC) and COL (2 μg/mL,1/4 MIC), either individually or in combination. Data are presented as mean ± standard deviation (SD) of three biological replicates. (C and D) The combined effect of NTX and COL on both colistin-resistant and colistin-sensitive Gram-negative bacteria is illustrated by the checkerboard dilution assay. Data are presented as mean ± SD of three biological replicates. (E) Assessment of resistance development during continuous passaging, with COL alone or in combination with NTX. (F) Change in the MPC of COL against E. coli B2 with increasing NTX concentrations.

Article Snippet: E. coli BL21 and E. coli DH5α strains were obtained from Sangon Biotech (Shanghai, China).

Techniques: Activity Assay, Dilution Assay, Standard Deviation, Bacteria, Passaging

Journal: iScience

Article Title: Nitroxoline as an antimicrobial synergist reverses colistin resistance in multidrug-resistant Escherichia coli

doi: 10.1016/j.isci.2025.114003

Figure Lengend Snippet: NTX enhances the disruptive effect of colistin on the bacterial cell membrane (A) SEM images of E. coli B2 treated with NTX (4 μg/mL), COL (2 μg/mL), or their combination. Scale bars, 2 μm. (B–G) Effects of varying concentrations of NTX, COL alone, or the combination of NTX (4 μg/mL) and COL on E. coli B2, including cell membrane permeability (B and C), membrane fluidity (D and E), and biofilm formation (F and G). All data are representative of three independent experiments and are presented as the mean ± SD. p values were calculated between two groups using unpaired t tests or between several groups using one-way analysis of variance (ANOVA) (ns, not significant; ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001).

Article Snippet: E. coli BL21 and E. coli DH5α strains were obtained from Sangon Biotech (Shanghai, China).

Techniques: Membrane, Permeability

Journal: iScience

Article Title: Nitroxoline as an antimicrobial synergist reverses colistin resistance in multidrug-resistant Escherichia coli

doi: 10.1016/j.isci.2025.114003

Figure Lengend Snippet: NTX binds to the catalytic center of MCR-1, thereby affecting the resistance effect it mediates (A) The expression of the mcr-1 gene in E. coli B2 after NTX treatment was examined using RT-qPCR. Data are presented as mean ± SD of three biological replicates. (B and C) SPR analysis of NTX and MCR-1. (D) Relative RMSD of all atoms in the MCR-1-NTX complex over time. (E) RMSF variations in the free MCR-1 and MCR-1-NTX complex during the 100 ns molecular dynamics simulation. (F) The anticipated binding mode of NTX within the MCR-1 binding pocket at the 70 ns time point of the MD simulation. (G) The decomposed binding energy for each residue in the MCR-1-NTX complex was calculated from MD simulations. (H) FICI for NTX and colistin in MCR-1-negative E. coli BL21(DE3) (pET28a), MCR-1-positive E. coli BL21(DE3) (pET28a-MCR-1), and their MCR-1 mutant strains. Data are presented as mean ± SD of three biological replicates.

Article Snippet: E. coli BL21 and E. coli DH5α strains were obtained from Sangon Biotech (Shanghai, China).

Techniques: Expressing, Quantitative RT-PCR, Binding Assay, Residue, Mutagenesis

Journal: iScience

Article Title: Nitroxoline as an antimicrobial synergist reverses colistin resistance in multidrug-resistant Escherichia coli

doi: 10.1016/j.isci.2025.114003

Figure Lengend Snippet: Transcriptomic analysis of E. coli B2 treated with colistin and NTX (A) Volcano plot of DEGs in E. coli B2 that were exposed to colistin (2 μg/mL) alone or in combination with NTX (4 μg/mL) for 6 h. The y axis denotes the statistical significance of the alterations, and the x axis represents the fold change in gene expression. (B) KEGG enrichment analysis of DEGs. (C) Selected DEGs involved in processes related to ribosome biosynthesis, two-component systems, the TCA cycle, TMAO respiration, and oxidative phosphorylation. COL represents colistin alone, and COL+NTX represents colistin in combination with NTX. Data are presented as the mean of three biological replicates.

Article Snippet: E. coli BL21 and E. coli DH5α strains were obtained from Sangon Biotech (Shanghai, China).

Techniques: Gene Expression, Phospho-proteomics

Journal: iScience

Article Title: Nitroxoline as an antimicrobial synergist reverses colistin resistance in multidrug-resistant Escherichia coli

doi: 10.1016/j.isci.2025.114003

Figure Lengend Snippet: NTX enhances the in vivo efficacy of colistin (A) Survival rates of G. mellonella larvae ( n = 12) over 120 h following infection with E. coli B2 (1 × 10 6 CFU). Larvae were administered 1 h post-infection with either phosphate-buffered saline (PBS) as a control, NTX (5 mg/kg), COL (2 mg/kg), or a combination of both. (B) Five-day survival rates of KM mice ( n = 10) after infection with E. coli B2 (2.5 × 10 8 CFU). At 1 and 12 h post-infection, mice had intraperitoneal injections of COL (2 mg/kg), NTX (5 mg/kg), a combination of COL and NTX (2 + 5 mg/kg), or PBS. p values in (A) and (B) were determined using the log rank (Mantel-Cox) test ( ∗∗p < 0.01). (C) Bacterial burden in the right thigh muscles of neutropenic KM mice ( n = 6) 48 h after intramuscular injection with E. coli B2 (1 × 10 6 CFU) and subsequent treatments. (D–F) Bacterial loads in peritoneal organs of KM mice ( n = 6) infected with E. coli B2 (1.5 × 10 8 CFU). Data in (C–F) are presented as mean ± SD. p values were determined using the Mann-Whitney U test ( ∗p < 0.05, ∗∗p < 0.01).

Article Snippet: E. coli BL21 and E. coli DH5α strains were obtained from Sangon Biotech (Shanghai, China).

Techniques: In Vivo, Infection, Saline, Control, Muscles, Injection, MANN-WHITNEY