Rapid, quantitative determination of bacteria in water

Abstract

A bioluminescent assay for ATP in water borne bacteria is made by adding nitric acid to a water sample with concentrated bacteria to rupture the bacterial cells. The sample is diluted with sterile, deionized water, then mixed with a luciferase-luciferin mixture and the resulting light output of the bioluminescent reaction is measured and correlated with bacteria present. A standard and a blank also are processed so that the light output can be correlated to bacteria in the sample and system 'noise' can be substracted from the readings. A chemiluminescent assay for iron porphyrins in water borne bacteria is made by adding luminol reagent to a water sample with concentrated bacteria and measuring the resulting light output of the chemiluminescent reaction. The light output is correlated with bacteria present. A standard and a blank are also processed so that the light output can be correlated to bacteria in the sample and system 'noise' can be subtracted from the readings. Modifications may be made in the methodology to differentiate between live and dead bacteria. An automatic system automatically performs a biolumenscent ATP assay on a concentrated bacterial sample. Reservoirs are provided for the sample, standard and blank. These are sequentially mixed with nitric acid from a reservoir by using two channels of a peristaltic pump. This acid mixture is then mixed with sterile, dionized water from another reservoir using two additional channels of a peristaltic pump and the resulting mixture is then mixed with a luciferase-luciferin mixture from an additional reservoir by employing two more channels of a peristaltic pump. The resulting solution flows through a photometer which indicates the level of the bioluminescent light reaction.