Fig. 1.

MBL sorting in OMVs from E. coli, P. aeruginosa and A. baumannii. a NDM-1, VIM-2, and SPM-1 levels (fused to a C-terminal Strep-tag sequence, -ST) by immunoblotting, using anti-Strep-tag antibodies, in whole cells (WC, top panel) and in OMVs purified from the corresponding cell culture supernatants (OMVs, bottom panel) from E. coli DH5α [Ec], P. aeruginosa PAO1 [Pa] and A. baumannii ATCC 17978 [Ab] strains expressing each MBL, after induction with 20 µM IPTG. Gel lanes were loaded with equal amounts of total protein. Red arrows indicate the precursor forms in whole cells from E. coli-expressing VIM-2 or SPM-1 and from A. baumannii-expressing SPM-1. The presence of cytoplasmic contaminants in vesicle preparations was assessed by immunoblot of GroEL. b Immunoblot of spheroplasts from E. coli-expressing VIM-2 or SPM-1 treated with ( + K) or without (-K) Proteinase K to asses accessibility of precursor forms. Panels a and b are representative of two independent experiments. c Imipenem hydrolysis rate by OMVs purified from E. coli, P. aeruginosa, and A. baumannii cells expressing NDM-1, VIM-2, and SPM-1. Data correspond to three independent experiments and are shown as the mean value. Error bars represent standard deviations (s.d). Source data are provided as a Source Data file