Aminoglycoside accumulation by membrane vesicles of Escherichia coli and Streptococcus faecalis

Transport of nine aminoglycosides was studied in right side out as well as inside out membrane vesicles derived from aerobically or anaerobically grown E. coli and S. faecalis. Right side out membrane vesicles prepared from aerobically grown E. coli and inside out membrane vesicles prepared from aerobically grown S. faecalis as well as inside out vesicles prepared from anaerobically grown E. coli took up all the aminoglycosides tested whereas right side out vesicles prepared from anaerobically grown E. coli did not exhibit an aminoglycoside transport. Addition of DCCD to vesicles having accumulated aminoglycosides caused an efflux of the substrates from the vesicles. Monitoring of ATP levels in E. coli transporting aminoglycosides revealed that ATP synthesis and aminoglycoside transport were closely interrelated. Based on these data it seems likely that aminoglycoside transport may be closely linked to the direction of proton fluxes catalysed by the ATP'ase.