The aim of the work reported here was to investigate the growth-inhibi
tory activity of HOCl and H2O2 toward Escherichia coli K12 during both
logarithmic and stationary phases of the growth cycle, as well as the
response of E. coli K12 to these oxidants. Stationary phase cultures
were exposed to sub-inhibitory oxidising stress, and the minimum inhib
itory concentrations (MIC) were determined during the ensuing 24 h. Th
e effect of oxidant on logarithmically growing cultures was also deter
mined. Stationary phase cultures of E. coli K12 responded to H2O2 stre
ss, both the MIC and survival following exposure to high concentration
s increasing following exposure to stress. By contrast stationary phas
e cells did not become more tolerant of high concentrations of HOCl fo
llowing HOCl stress. Logarithmically growing E. coli K12 did not displ
ay increased tolerance to either inhibitory or lethal concentrations o
f H2O2 or HOCl following the relevant oxidising stress.