Survival of Escherichia coli in the environment: fundamental and public health aspects

Abstract

In this review, our current understanding of the species Escherichia coli and its persistence in the open environment is examined. E. coli consists of six different subgroups, which are separable by genomic analyses. Strains within each subgroup occupy various ecological niches, and can be broadly characterized by either commensalistic or different pathogenic behaviour. In relevant cases, genomic islands can be pinpointed that underpin the behaviour. Thus, genomic islands of, on the one hand, broad environmental significance, and, on the other hand, virulence, are highlighted in the context of E. coli survival in its niches. A focus is further placed on experimental studies on the survival of the different types of E. coli in soil, manure and water. Overall, the data suggest that E. coli can persist, for varying periods of time, in such terrestrial and aquatic habitats. In particular, the considerable persistence of the pathogenic E. coli O157:H7 is of importance, as its acid tolerance may be expected to confer a fitness asset in the more acidic environments. In this context, the extent to which E. coli interacts with its human/animal host and the organism's survivability in natural environments are compared. In addition, the effect of the diversity and community structure of the indigenous microbiota on the fate of invading E. coli populations in the open environment is discussed. Such a relationship is of importance to our knowledge of both public and environmental health.

H2metabolism is widespread and diverse among human colonic microbes

“…26,36 The only quantitatively abundant [NiFe] uptake hydrogenases detected were the oxygen-tolerant respiratory uptake hydrogenases (Group 1d [NiFe]-hydrogenases); 37 such enzymes have been linked to reoxidation of fermentatively-produced H 2 and might also contribute the metabolic flexibility needed for facultative anaerobes such as E. coli to transition between host-associated and free-living states. 38 Between them, such processes would enable the majority of H 2 produced in the human colon to be reoxidised without formation of detectable endproducts. We predict that the majority of H 2 produced by fermentative processes is immediately recycled through a combination of internal reoxidation and interspecies H 2 transfer without ever entering the H 2 pool.…”

Interacciones entre Escherichia coli O157:H7 y Plantas Comestibles. ¿Se han Desarrollado Mecanismos de Internalización Bacteriana?

“…Los genes nucleares como son los genes metabólicos pueden ser transferidos y mejorar la condición de la cepa bajo ciertas condiciones ambientales. Por ejemplo, pocas cepas de E. coli tiene la capacidad de fermentar glucosa, y la adquisición de estos genes puede mejorar la adaptación a nuevos ambiente (van-Overbeek et al, 2014). Volumen 34, Número 1, 2016 where more than 6000 schoolchildren were affected (Watanabe et al, 1996).…”

“…Esta situación permite a nuevos fenotipos incrementar su persistencia en plantas y amplía el espectro de utilización de nutrientes disponibles en las plantas (van-Overbeek et al, 2014). La aparición de nuevas características encriptadas en el genoma bacteriano, le ayudan a mejorar su condición física cuando se encuentran en frutas y hortalizas.…”

“…The presence of faecal coliforms, without the identification of E. coli, suggests this indicator is not always carrying this bacterium, or not been detected due to its ability to enter in a dormant state (van Elsas et al, 2011). Strictly, vegetables not eaten raw, should not be part of this pathogen's transmission route; nevertheless, hand-to-mouth transfer during handling and food preparation is still possible.…”

“…Genes of the core genome such as the metabolic genes can be transferred and can improve fitness of the strain under certain environmental conditions. For instance, a few strains of E. coli can ferment glucose and the acquisition of these genes can improve its adaptation to a new environment (van-Overbeek et al, 2014).…”