The plasmid-borne fosfomycin resistance gene
fosA3
has been identified in
Escherichia coli
(
E. coli
)
from various animals but has rarely been reported in ducks. In this study, we investigated the
fosA3
prevalence and molecular characteristics of
fosA3
-harboring
E. coli
strains from ducks in Shandong province of China. In 416
E. coli
isolates, 91 (21.88%) were identified as
fosA3
-bearing strains, and the fosfomycin-resistant phenotype of 88 of the 91
fosA3
-harboring strains was successfully transferred to the recipient strains. Seven different genetic structures surrounding the
fosA3
gene were detected and 2 new contexts were discovered among the
fosA3
-carrying
E. coli
. Twenty
fosA3
-harboring isolates and their trans-conjugants were randomly selected for pulsed-field gel electrophoresis (
PFGE
) typing and S1-nuclease PFGE, respectively. The PFGE patterns revealed that the 20 randomly selected
fosA3
-bearing isolates were not a result of clonal dissemination. S1-PFGE showed that 15 of the 20 randomly selected trans-conjugants carried a single plasmid, and these 15 plasmids that harbored
fosA3
(55–190 kb) were distributed into the following replicon types: IncF (n = 11), IncI1 (n = 1), IncN (n = 1), untypable (n = 1), and W-FIC (n = 1). Additionally, as vectors for
fosA3
in
E. coli
, F-:A1:B6, N/ST1, IncI1/ST2, W-FIC, and one untypable plasmid had never been reported before. These observations highlighted the importance of ducks as a reservoir for multidrug-resistant
fosA3
-carrying
E. coli
.