Conjugative multiple-antibiotic resistance plasmids in Escherichia coli isolated from environmental waters contaminated by human faecal wastes.
OBJECTIVE
To better understand the involvement of faecal contamination in the dissemination of antibiotic resistance genes, we investigated the genetic supports of resistances in nine multi-resistant Escherichia coli strains originating from human faecal contamination, and isolated from three different aquatic environments used for producing drinking water.


RESULTS
Seven strains harboured at least one large plasmid that we have characterized (size, antibiotic resistance patterns, incompatibility group, capacity of autotransfer, presence of integron). Most of these plasmids were conjugative and carried numerous resistances. One of the plasmids studied, belonging to the IncP incompatibility group, was able to transfer by conjugation to Pseudomonas fluorescens and Aeromonas sp. Only two of the plasmids we studied carried class 1 and/or 2 integron(s).


CONCLUSIONS
Conjugative plasmids isolated from multi-resistant E. coli strains explained most of the resistances of their host strains and probably contribute to the spread of antibiotic resistance genes coming from human faecal contamination.


CONCLUSIONS
These results highlight the key role played by plasmids in the multi-resistance phenotype of faecal bacteria and the diversity of these genetic structures. Contaminated water, especially accidentally contaminated drinking water, could be a path back to humans for these plasmids.
Agri'Terr Laboratory, ESITPA, Mont Saint Aignan, France.
E
E
Laroche-Ajzenberg
A
A
Flores Ribeiro
J
J
Bodilis
W
W
Riah
S
S
Buquet
N
N
Chaftar
B
B
Pawlak
D000333:Aeromonas / Q000235:genetics; D003227:Conjugation, Genetic; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D006801:Humans; D032023:Integrons; D010957:Plasmids / Q000235:genetics* / Q000302:isolation & purification; D011551:Pseudomonas fluorescens / Q000235:genetics; D014169:Transformation, Bacterial; D014871:Water Microbiology
antibiotic resistance; environmental water; faecal bacteria; horizontal transfer; plasmids