Influence of hydrological conditions on the Escherichia coli population structure in the water of a creek on a rural watershed. - Inserm - Institut national de la santé et de la recherche médicale Accéder directement au contenu
Article Dans Une Revue BMC Microbiology Année : 2010

Influence of hydrological conditions on the Escherichia coli population structure in the water of a creek on a rural watershed.

Résumé

BACKGROUND: Escherichia coli is a commensal bacterium of the gastro-intestinal tract of human and vertebrate animals, although the aquatic environment could be a secondary habitat. The aim of this study was to investigate the effect of hydrological conditions on the structure of the E. coli population in the water of a creek on a small rural watershed in France composed of pasture and with human occupation. RESULTS: It became apparent, after studying the distribution in the four main E. coli phylo-groups (A, B1, B2, D), the presence of the hly (hemolysin) gene and the antibiotic resistance pattern, that the E. coli population structure was modified not only by the hydrological conditions (dry versus wet periods, rainfall events), but also by how the watershed was used (presence or absence of cattle). Isolates of the B1 phylo-group devoid of hly and sensitive to antibiotics were particularly abundant during the dry period. During the wet period and the rainfall events, contamination from human sources was predominantly characterized by strains of the A phylo-group, whereas contamination by cattle mainly involved B1 phylo-group strains resistant to antibiotics and exhibiting hly. As E. coli B1 was the main phylo-group isolated in water, the diversity of 112 E. coli B1 isolates was further investigated by studying uidA alleles (beta-D-glucuronidase), the presence of hly, the O-type, and antibiotic resistance. Among the forty epidemiolgical types (ETs) identified, five E. coli B1 ETs were more abundant in slightly contaminated water. CONCLUSIONS: The structure of an E. coli population in water is not stable, but depends on the hydrological conditions and on current use of the land on the watershed. In our study it was the ratio of A to B1 phylo-groups that changed. However, a set of B1 phylo-group isolates seems to be persistent in water, strengthening the hypothesis that they may correspond to specifically adapted strains.
Fichier principal
Vignette du fichier
1471-2180-10-222.pdf (352.51 Ko) Télécharger le fichier
1471-2180-10-222-S1.DOC (38.5 Ko) Télécharger le fichier
1471-2180-10-222.xml (109.4 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Format : Autre
Format : Autre
Loading...

Dates et versions

inserm-00663723 , version 1 (27-01-2012)

Identifiants

Citer

M. Ratajczak, E. Laroche, Thierry Berthe, O. Clermont, B. Pawlak, et al.. Influence of hydrological conditions on the Escherichia coli population structure in the water of a creek on a rural watershed.. BMC Microbiology, 2010, 10 (1), pp.222. ⟨10.1186/1471-2180-10-222⟩. ⟨inserm-00663723⟩
361 Consultations
309 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More