Visceral muscle spasms helps to evict opportunistic bacteria.

(A) Measurement of the length or (B) phalloidin staining (red, 20X objective) of midguts from flies 2 h post-intoxication with sucrose (Ctrl), 108 CFU of Btk, sucrose + loperamide or 108 CFU of Btk + loperamide. (C) Monitoring of Btk persistence in the midgut of flies fed with 108 CFU of Btk (grey bars) or 108 CFU of Btk + loperamide (blue bars). Note that after 30 min of feeding, the same amount of Btk is recovered in the midgut (about 2.105 CFU compared to the 108 CFU/fly deposited on the medium). (D) Labelling of HOCl in anterior midgut by the R19-S fluorescent probe (Orange). Flies were fed with 108 CFU of Btk or 108 CFU of Btk + loperamide. 20X objective. The proportion of R19-S-positive (orange bars) intestines are presented in the graph below the pictures.