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SESSION 6: FUTURE CHALLENGE FOR EUROPE AND WORLWIDE
Uneven and surprising colonization of water pipes of
hospitals and non-hospital sites by Fusarium
oxysporum and F. dimerum
C. Steinberg 1 , J. Laurent 1 , V. Edel-Hermann 1 , M. Barbezant 2 , N. Sixt 3 , F.
Dalle 4,5 , S. Aho 6 , A. Bonnin 4,5 , P. Hartemann 2 , M. Sautour 4,5
1 INRA, UMR1347 Agroécologie 17 rue Sully, BP 86510, F-21000 Dijon, France; 2 Department
Environment and Public Health Nancy University, Hospital Hygiene Unit, 9 Avenue de la Forêt de
Haye, BP154, 54505 Vandoeuvre-Nancy Cedex, 11 France; 3 Environmental Microbiology, Plateau
Technique de Biologie du CHU, 2 rue Angélique Ducoudray, BP 37013, 21070 Dijon Cedex, France;
4 Parasitology and Mycology laboratory, Plateau Technique de Biologie du CHU, 2 rue Angélique
Ducoudray, BP 37013, 21070 Dijon Cedex, France; 5 Université de Bourgogne, UMR1347
Agroécologie 17 rue Sully, BP 86510, F-21000 Dijon, France; 6 Hospital Hygiene and Epidemiology
unit, Hôpital du Bocage, BP 77908, 21079 Dijon Cedex, France
E-mail: christian.steinberg@dijon.inra.fr
Fusarium oxysporum and F. dimerum are ubiquitous soil-borne fungi found in
terrestrial ecosystems worldwide, but they were recently detected in the water
distribution systems of hospital buildings. A survey that included various hospital
buildings at different locations, various non-hospital complexes and a set of
private houses was conducted over 2 years in two French cities. The fungi were
present only in public hospital buildings and were not detected in the other water
distribution systems or in the water inlets, wherever they were. This surprising
distribution can be explained by a combination of three mains factors: i) the
complexity of the water distribution system of a set of regularly renovated
buildings; this complexity includes the diversity of materials used for the pipes and
the existence of loops in which water may stagnate; ii) the application of a
sanitizing process that creates ecological voids and makes resources of interest
available for opportunistic invasive fungi; iii) the real potential of strains of F.
oxysporum and F. dimerum to adapt in order to exploit and to tolerate urban
aquatic environments. The very low diversity among the various isolates of F.
oxysporum and of F. dimerum suggests the existence of a well-adapted
population (special form) of each of the two soil-borne species specialized in the
colonization and exploitation of the spatial and trophic resources provided by the
urbanized water supply system of public hospital buildings. The risk of fusariosis
caused by such special invasive and opportunistic forms needs to be taken
seriously to prevent any contamination of immunocompromised patients.
Keywords: Soil-borne fungi, aquatic niche, adaptation, disease risk assessment
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