The growth of an aroA mutant of Salmonella typhimurium (SL3261) in minimal
medium containing 0.5 M NaCl resulted in the intracellular accumulation of
2.2 mu mol trehalose/mg total protein. The vacuum drying of these bacteria
in the presence of trehalose allowed the recovery of 35% of the viable cell
s that were present before drying. In contrast, bacteria cultured in contro
l medium accumulated 0.4 mu mol trehalose/mg total protein and only 5% of t
he viable cells were recovered after vacuum drying with trehalose. Similar
results were obtained when S. typhimurium SL3261, expressing the vaccine an
tigen (F1-antigen) of Yersinia pestis, was cultured in minimal medium with
or without 0.5 M NaCl and dried in the presence of trehalose. Although thes
e results indicate the potential for trehalose stabilisation of vaccine str
ains of S. typhimiurium, growth in minimal medium containing 0.5 M NaCl res
ulted in the loss of invasion competence of the bacteria. (C) 2000 Elsevier
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