Comparison of four methods for the detection of fecal streptococci in water

The objective of this study was to select an effective and fast method for the detection of socalled fecal streptococci in water by comparing a method acoording to the German drinking water standard, a membrane filtration met hod according to the ISO-draft standard 7899/2, the Chromocult(R) Enterococ cus Broth (Merck)(1) and the Enterolert(R)-System (IDESX)(2). The study was based on a collective of 297 water samples derived from different stages o f water treatment and distribution, as well as from individual water suppli es. The sensitivity, reliability, and selectivity of the single methods in relation to their practicability was evaluated. Concerning false positive a nd false negative results, the tests were proved by metabolic characterizat ion of the isolated strains. The advantages and disadvantages of the method s resulting from the investigated criteria are discussed. The work is part of a comparative study within the scope of the DIN ad-hoc-committee "fecal streptococci".