Biomedical subjects

H Guilloteau

Publications and source records attributed to H Guilloteau.

2 recordsLinked to original sources

PubMed2006

Iron uptake is essential for Escherichia coli survival in drinking water.

AIMS: The aim of this study was to elucidate if the need for iron for Escherichia coli to remain cultivable in a poorly nutritive medium such as the drinking water uses the iron transport system via the siderophores. METHODS AND RESULTS: Environmental strains of E. coli (isolated from a drinking water network), referenced strains of E. coli and mutants deficient in TonB, an essential protein for iron(III) acquisition, were incubated for 3 weeks at 25 degrees C, in sterile drinking water with and without lepidocrocite (gamma-FeOOH), an insoluble iron corrosion product. Only cells with a functional iron transport system were able to survive throughout the weeks. CONCLUSIONS: The iron transport system via protein TonB plays an essential role on the survival of E. coli in a weakly nutritive medium like drinking water. SIGNIFICANCE AND IMPACTS OF THE STUDY: Iron is a key parameter involved in coliform persistence in drinking water distribution systems.

Aerobiosis↗

PubMed2005

Coliform culturability in over- versus undersaturated drinking waters.

The culturability of Escherichia coli in undersaturated drinking water with respect to CaCO3 (corrosive water) or in oversaturated water (non-corrosive water) was tested in different reactors: glass flasks (batch, "non-reactive" wall); glass reactors (chemostat, "non-reactive" wall) versus a corroded cast iron Propella reactor (chemostat, "reactive" wall) and a 15-year-old distribution system pilot (chemostat, "reactive" wall with 1% corroded cast iron and 99% cement-lined cast iron). The E. coli in E. coli-spiked drinking water was not able to maintain its culturability and colonize the experimental systems. It appears from our results that the optimal pH for maintaining E. coli culturability was around 8.2 or higher. However, in reactors with a reactive wall (corroded cast iron), the decline in E. coli culturability was slower when the pH was adjusted to 7.9 or 7.7 (i.e. a reactor fed with corrosive water; pH pHs). We tentatively deduce that corrosion products coming from chemical reactions driven by corrosive waters on the pipe wall improve E. coli culturability.

Bioreactors↗