Question

what cellular property of enterococcus spp. might make them more useful as an indicator species in salt water rather than E. coli ?

Answer 1

Enterococcus species are found in the gastrointestinal tracts of humans living as a commensal organism. In general, enterococci can survive very harsh environments including high salt concentrations and alkaline pH. E.coli in contrast does not tolerate high salt concentrations.

Enterococcus faecalis express cation transporters to maintain homeostasis in order to survive harsh salt concentrations. This organism expresses Na+/H+ antiporter and vacuolar type ATPase. The cationic transpoters maintain constant cation concentrations inside the cells enabling them to grow in high salt concentrations.