The Colilert presence/absence test has been compared with membrane filtration using membrane lauryl sulphate broth for the detection of coliforms and Escherichia coli in a number of different types of water. Colilert appears to give results which are essentially the same as those obtained by membrane filtration whilst taking considerably less time to perform. The data generated in this study are in agreement with a large number of studies published in the United States and suggest that a large comparative study with drinking water samples is warranted.

No abstract

A study of the use of a recently described single membrane medium for the simultaneous enumeration of Escherichia coli and coliforms has shown similar E. coli confirmation rates (92%) for both membrane lauryl sulphate broth (MLSB) and membrane lactose glucuronide agar (mLGA). Of the presumptive E. coli examined, a higher proportion of those examined from MLSB subsequently produced acid and gas from lactose peptone water and indole from tryptophan than on mLGA. These results differ in some respects from those presented in the original paper and may therefore be of interest to those workers involved in the detection of E. coli in water. Further investigation showed that mLGA which has been stored under aerobic conditions was less efficient than freshly‐prepared medium in recovering coliforms and that the size of the colonies obtained on stored medium was sometimes much smaller than those found on freshly‐prepared medium.

The accuracy and specificity of a commercially available ELISA kit (Locate, Rhone‐Poulenc Diagnostics) were assessed when applied to enrichment cultures of naturally contaminated water and sewage. The kit showed 66/180 samples positive by both culture and ELISA. The ELISA showed six positives which could not be confirmed by culture.

Aeromonas bacteria (110 strains) from a variety of clinical, food and environmental sources, were identified using routine biochemical tests. Concurrently they were tested aerobically and anaerobically for their ability to perform synergistic haemolysis with Staphylococcus aureus (the ‘CAMP’ reaction). Results did not support a reported observation that the ‘CAMP’ reaction can he used to facilitate speciation of Aeromonas bacteria.