Development of a computer identification system for coliform strains

Advances in the bacteriology of the coliform group: their suitability as markers of microbial water safety

Advances in the elaboration of novel genomic types of beta-galactosidase-positive Enterobacteriaceae and comprehensive studies of their habitats have resulted in an innovative approach to the assessment of the merits and shortcomings of the thermotrophic and fecal species Escherichia coli and all other coliforms as markers of the microbiological safety of water. As one of the consequences, it is recommended to abolish the "technical" designation fecal coliforms because their current method of detection will result in the isolation of thermotrophic organisms that have been demonstrated, beyond a doubt, to be of environmental, rather than uniquely enteric origin. Additional population studies have demonstrated that none of the coliforms can function as reliable markers for all enteric pathogens (index organisms sensu Ingram), nor be of use in validating adequate processing for safety of raw water, which represents the indicator function of markers, as defined by Ingram. Future studies along these lines will have to provide the data required to assess the suitability of additional markers for the reliable monitoring of drinking water for microbiological safety.

Assessment of the marker value of various components of the coli-aerogenes group of Enterobacteriaceae and of a selection of Enterococcus spp. for the official monitoring of drinking water supplies

The traditional indicators Escherichia coli (in practice currently, though ecologically inaccurately, represented by 'thermotolerant coliforms' at 44 degrees C) and Enterococcus spp. proved to be suitable for the diagnosis of heavy and frequent faecal pollution observed in potentially dangerous waters, especially those originating from karstic aquifers. On the other hand, natural and treated waters, slightly and inconsistently contaminated, occasionally showed a variable Gram-negative flora, difficult to classify by routine tests. In that case, complete identification of isolates may be necessary to ensure a valid decision on the potability of the supply. At any rate some of the Enterobacteriaceae contained in the 'faecal coliform' group and many other 'coliforms', distinct from E. coli, lack sanitary significance although their presence at certain levels may indicate inadequate disinfection, hiatuses in the integrity of the distribution system or both.