The General Stress Response Is Conserved in Long-Term Soil-Persistent Strains of Escherichia coli

What is it about?

Escherichia coli has been, and continues to be, used as an important indicator species reflecting potential faecal contamination events in the environment. However recent studies question the validity of this since E. coli has been found to be capable of long-term colonisation of soils. This study investigated whether long term soil-persistent E. coli strains have evolved altered stress resistance characteristics. In particular, the study investigated whether the main regulator of genes involved in stress protection, the sigma factor RpoS, has been altered in the soil-persistent strains. The results show that RpoS-stress protection is fully conserved in soil-persistent strains of E. coli. They also show that loss of the rpoS gene dramatically reduces the ability of this organism to survive in a soil environment. Overall the results indicate that soil represents a stressful environment for E. coli, and their survival in it requires that they deploy a full stress protection response.

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Why is it important?

The evidence that E. coli can persist in the environment has implications for the use of E. coli as an indicator of faecal contamination in the environment.