Enterococcus faecalis and pathogenic streptococciinactivate daptomycin by releasing phospholipids
SummaryDaptomycin is a lipopeptide antibiotic with activity against Gram-positive bacteria. We have shown previously thatStaphylococcus aureuscan survive daptomycin exposure by releasing membrane phospholipids that inactivate the antibiotic. To determine whether other pathogens possess this defence mechanism, phospholipid release and daptomycin activity were measured after incubation ofStaphylococcus epidermidis, Group A or B streptococci,Streptococcus gordoniiorEnterococcus faecaliswith the antibiotic. All bacteria released phospholipid in response to daptomycin, which resulted in at least partial inactivation of the antibiotic. However,E. faecalisshowed the highest levels of lipid release and daptomycin inactivation. As shown previously forS. aureus, phospholipid release byE. faecaliswas inhibited by the lipid biosynthesis inhibitor platensimycin. In conclusion, several pathogenic Gram-positive bacteria, includingE. faecalis, inactivate daptomycin by releasing phospholipids, which may contribute to the failure of daptomycin to resolve infections caused by these pathogens.