Advances in the Bacteriology of the Coliform Group: Their Suitability as Markers of Microbial Water Safety

Abstract

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.

Expression of cellulose and curli fimbriae by Escherichia coli isolated from the gastrointestinal tract

“…It is one of the first colonizers of the gastrointestinal tract of newborns, being either transferred from the mother during delivery or acquired by environmental sources (Bettelheim et al, 1974). After establishment of a stable microbial population, E. coli is, with 1 % of the total bacterial biomass, a minor component of the commensal flora; however, with up to 10 8 cells ml À1 it reaches significantly high concentrations (Hartl & Dykhuizen, 1984;Leclerc et al, 2001). These high absolute numbers make the gastrointestinal tract a major source for the spread of potentially pathogenic E. coli to susceptible sites via the faecal route (Brauner et al, 1991;Johnson et al, 1998).…”

Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture

“…According to the microbiological guidelines for safe use of wastewater in agriculture developed by the World Health Organization (WHO) and more recently revisited by Carr et al (2004), less than 0.1 intestinal nematode eggs must be detected in 1 litre, while up to 1,000 faecal coliform bacteria per 100 ml can be tolerated for unrestricted irrigation. In the United States, much stricter wastewater quality standards for irrigation are recommended by the Environmental Protection Agency (Anon 1973) but, lacking federal standards for the quality of reclaimed water, individual states have developed guidelines mainly based on the daily monitoring of faecal coliform bacteria on a single, 100-ml sample, assuming a predictive relationship between indicator microorganisms and pathogen presence (Carr et al 2004); however, new strategies in monitoring reclaimed water are required, because of the imperfect relationship between coliform bacteria and pathogens (Leclerc et al 2001; derive from the persistence in treated wastewater of Escherichia coli carrying conjugative R plasmids and integrons.…”

Correlation of Quantitative PCR for a Poultry-Specific Brevibacterium Marker Gene with Bacterial and Chemical Indicators of Water Pollution in a Watershed Impacted by Land Application of Poultry Litter

“…Knowledge of contamination source is necessary for remediation of polluted waters and in order to carry out accurate risk assessment, since certain types of animal fecal contamination, including that from poultry, are considered high risk due to the pathogens that are commonly found in the feces (58). The use of culture-independent microbial measurements, such as quantitative PCR (qPCR) of general and host-specific DNA markers, allows more rapid and potentially more accurate assessments of water quality, which can better protect public health (64) and circumvents many of the drawbacks associated with culturing indicator bacteria (2,9,24,60,63).…”