METABOLIC AND COMPOSITIONAL CHANGES IN ESCHERICHIA-COLI-CELLS STARVEDIN SEAWATER

Thirteen Escherichia coli strains of different biotypes isolated from urine and faeces cultures were studied for metabolic and compositional changes during starvation in seawater at different timepoints. Additi onally, the antibiotic susceptibility of the starved E. coli cells was evaluated over time on Mueller-Hinton agar (Bauer-Kirby method). All starved E. coli cells lost beta-galactosidase activity gradually with time and acquired the ability to degrade gelatine. Nine of the E. coli strains lost the ability to decarboxylate lysine and seven to acidify melibiose. C4 esterase, C8 esterase lipase, leucine arylamidase and C 14 lipase activity increased during starvation, while alkaline and aci d phosphatase and phosphoamidase activity decreased. Most of the E. co li strains underwent alterations in their electrophoretic protein patt ern. The traditional Bauer & Kirby method was shown to be inadequate f or testing antibiotic susceptibility of starved strains.