[Studies of bacterial indicators for water pollution--growth of Escherichia coli and enterococci in limited nutrient conditions].
Bacteria, that would be an ideal indicator for fecal contamination in environmental water, should not proliferate but at the same time should survive a little longer than enteropathogenic bacteria in the environmental water. While conventional methods have recommended Escherichia coli as an indicator, enterococci is recommended as a preferable indicator for the estimation of fecal contamination based on the following observation. The relationship between the specific growth rate of organism and the concentration of peptone was determined and the value of Ks, a parameter analogous to Michaelis-Menten constant, was estimated. Ks of Escherichia coli, Enterococcus faecalis and Enterococcus faecium were 3.8, 11.1 and 12.5 mg/ml respectively, indicating that Escherichia coli will grow at lower concentration of peptone than enterococci. Escherichia coli also grew in human fecal suspension and in filtrated (0.22 microns) river water, and while in those conditions enterococci did not grow or survive longer than Escherichia coli, survival time was longer than for Salmonella typhi and Shigella sonnei. It appears that enterococci reflect more accurately actual fecal contamination.
Koujima
I
I
Shujitsu Junior College.
D013293:Enterococcus faecalis / Q000254:growth & development*; D016984:Enterococcus faecium / Q000254:growth & development*; D004926:Escherichia coli / Q000254:growth & development*; D005243:Feces; D014871:Water Microbiology; D014876:Water Pollution