FIG 5.

Imipenem treatment decreases the early pathophysiological signs within the CNS. (A to D) tdTomato-expressing R-M. abscessus (≈300 CFU) was injected in 30-hpf embryos (n = 15, average of three independent experiments). From 1 dpi, embryos were exposed to imipenem at 0.5×, 5×, or 28× MIC for 5 days. (A) Fluorescence microscopy of a typical R serpentine cord. Scale bar, 100 μm. (B) Fluorescence and DIC overlay of whole heads of 28× MIC imipenem-treated and untreated infected embryos with fluorescent R-M. abscessus showing serpentine cord (white arrow). Scale bars, 100 μm. (C) Percentage of embryos with cords in whole untreated and imipenem-treated embryos at 4 dpi. A significant reduction in the proportion of embryos with cords was observed when embryos were treated with the highest (28× MIC) imipenem concentration. (D) Average localization of cord within the infected embryos in panel C. Infected embryos treated with the intermediate (5× MIC) and high (28× MIC) imipenem doses developed significantly fewer serpentine cords within the CNS than untreated infected embryos. For panels C and D, statistics were calculated using Fisher's exact test comparing each category of imipenem-treated embryos to untreated control. All results are expressed as the averages from three independent experiments, and error bars represent the SEM.