Journal: NPJ Biofilms and Microbiomes
Article Title: Intermittent antibiotic exposure of Escherichia coli biofilms drives resistance in catheter-associated infection models
doi: 10.1038/s41522-025-00906-4
Figure Lengend Snippet: a Experimental protocol: Four cycles of 8-h intermittent amikacin lock therapy (ALT AMK ) at 500-fold MIC were performed on biofilms formed by the bioluminescent 55989 strain in TIVAPs, with a control group receiving PBS (ALT PBS ). Medical-grade 5 Fr TIVAPs were implanted in rats after a 1-week acclimatization. On day 4, the bioluminescent strain was inoculated into the TIVAP port. Biofilm formation was established over 3 days with daily TPN on days 5–8. The 8-h intermittent ALT and 16-h recovery phases were conducted from days 8–12, followed by a biofilm recovery phase with TPN on days 12–15. TIVAPs were collected from euthanized rats on day 15 for analysis. b Bioluminescence time course: Examples of bioluminescent imaging of biofilms treated with ALT AMK versus ALT PBS are presented (ALT PBS rat 3 and ALT AMK rat 4). c Endpoint TIVAP bioluminescence images: Extracted TIVAP images illustrating biofilm presence in each treatment group are shown. d Endpoint biofilm CFU: CFUs for biofilm samples were measured at the endpoint. e Growth frequencies on amikacin plates: Growth frequencies of biofilm cell samples on amikacin plates at 1 time the MIC are reported. f Amikacin MIC determination: The amikacin MIC values for biofilm cell samples grown on LB and MH media were assessed. g Whole-population genome sequencing (WGS)-based mutational analysis: Heatmaps showcasing mutations from endpoint biofilm populations, identified through WGS, are presented, with mutations at frequencies of ≥10% highlighted in orange (see Supplementary Data ). Biofilms were not recovered from the ALT AMK TIVAP 5 port and TIVAP 6 silicone and port (see Supplementary Fig. ). Si, Po, and Ca represent biofilm samples from the silicone septum, port, and catheter parts of each TIVAP, respectively. Means, individual values, and standard errors from three biological replicates (TIVAPs) are shown (Welch’s t -test, ** p < 0.001). Figure 4a was generated using BioRender.
Article Snippet: Briefly, after one week of acclimatization, TIVAP implantation surgery was performed for anesthetized 8-week male Crl:CD (SD) rats (Charles River, Wilmington, MA, USA) with isoflurane (ISO-VET, Piramal Critical Care, Bethlehem, PA, USA) on Day 0 as follows: the port part was implanted in the subcutaneous pocket on the back.
Techniques: Control, Imaging, Sequencing, Generated
