The effects of nutrients on the survival of Escherichia coli in lake water

Abstract

Escherichia coli was shown to survive without decline in viable counts for at least 12 d in filtered-autoclaved lake water. In unfiltered lake water there was a rapid decline in the viable count of E. coli. The addition of synthetic sewage to filtered-autoclaved lake water led to an increase in the viable count of E. coli at 15 degrees C and 37 degrees C and to an increase in the survival time of the E. coli in unfiltered water. The addition of phosphate and carbon sources (glucose, glycerol, succinate, acetate and lactose) did not significantly increase the survival time of E. coli in unfiltered water over the controls. The addition of ammonium sulphate and some amino acids (as nitrogen sources) to the unfiltered lake water did lead to an increase in the survival times for E. coli and this increase was proportional to the concentration of the added nitrogen source.

Alkaline phosphatase activity of Escherichia coli starved in sterile lake water microcosms

“…Alkaline phosphatase activity is expressed as pmol I-' pNP released ml-' h-' amendments as there was no increase in viable count over the starvation/incubation period. Even at higher temperatures there was no increase in viable count when these amino acids were used as amendments although there was an increase in the survival time of the cells compared to those in an unamended control (Lim and Flint 1989). This, however, was seen over an extended starvation period and not over the relatively short time period used here.…”

“…Again there was a more rapid decline in viable count at the higher temperatures although in contrast to the lake water microcosms the viable count declined at all the incubation temperatures (Table 2). Escherichia coli grown in low PO4 minimal medium was inoculated into FALW amended with amino acids, some of which had been shown previously to have some effect on the survival of E. coli in lake water (Lim and Flint 1989). The inoculated microcosm was incubated at 15°C and the AP activity was monitored over a period of 18 d. Glycine and glutamate increased the AP activity over that of the control (Fig.…”

“…derepression had occurred, in cells which had been grown in a high phosphate medium prior to the addition of the FALW. No or little increase in activity occurred with the addition of (NHJ2S0., to the medium although this has been shown to increase the survival time of E. coli in lake water (Lim and Flint 1989). Although derepression has been shown previously in liquid growth media it has always been accompanied by growth of the bacteria.…”

Bio-indicator bacteria & environmental variables of the coastal zones: The example of the Güllük Bay, Aegean Sea, Turkey

“…This situation showed that increasing nutrient levels is inducing the level of bacterial pollution. Similarly, it was reported that nutrient starvation as a factor influencing the maintenance of bacteria in water (Mitchell, 1968;Munro et al, 1987;Lim and Flint, 1989;Rippey and Cabelli, 1990;Bogosian et al, 1996).…”

Holding-time and method comparisons for the analysis of fecal-indicator bacteria in groundwater

“…Bordner and Winter (1978) recommend shorter holding times for surface water samples, especially organically rich waters, which are particularly susceptible to rapid decreases of bacteria. Higher temperatures and nutrient levels in surface water may allow for the growth of background bacterial populations which could interfere with analyses (Lim and Flint 1989). Additionally, substances that are toxic to bacteria, such as heavy metals, are more likely to be found in surface water (USEPA 2007).…”