In this study, we focused on evaluating the occurrence of extended-spectrum b-lactamase (ESBL)-producing @entity526 in fecal samples of healthy @entity4186 and environmental samples from a @entity4186 farm in South China. @entity4186 cloacal swabs and pond water samples were cultivated on MacConkey agar plates supplemented with ceftiofur. Individual colonies were examined for ESBL production. Bacteria identified as @entity526 were screened for the presence of ESBL and plasmid-borne AmpC genes. The genetic relatedness, plasmid replicon type, and genetic background were determined. Of 245 samples analyzed, 123 had @entity526 isolates with ceftiofur MICs higher than 8  g/ml (116 [50.4%] from 230 @entity4186 samples and 7 [46.7%] from 15 water samples). bla( @entity3525 -M), bla(SHV-12), bla(CMY-2), and bla( @entity4601 -1) were identified in 108, 5, 9, and 1 isolates, respectively. The most common bla( @entity3525 -M) genes were bla( @entity3525 -M-27) (n = 34), bla( @entity3525 -M-55) (n = 27), bla( @entity3525 -M-24e) (n = 22), and bla( @entity3525 -M-105) (n = 20), followed by bla( @entity3525 -M-14a), bla( @entity3525 -M-14b), bla( @entity3525 -M-24a), and bla( @entity3525 -M-24b). Although most of the @entity3525 -M producers had distinct pulsotypes, clonal transmission between @entity4186 and water isolates was observed. bla( @entity3525 -M) genes were carried by transferable IncN, IncF, and untypeable plasmids. The novel @entity3525 -M gene bla( @entity3525 -M-105) was flanked by two hypothetical protein sequences, partial ISEcp1 upstream and truncated IS903D, @entity68 , orf1, and a Tn1721-like element downstream. It is suggested that the horizontal transfer of bla( @entity3525 -M) genes mediated by mobile elements and the clonal spread of @entity3525 -M-producing @entity526 isolates contributed to the dissemination of bla( @entity3525 -M) in the @entity4186 farm. Our findings highlight the importance of @entity4186 for the dissemination of transferable antibiotic resistance genes into the environment.

Characterization of extended-spectrum b-lactamase genes found among @entity526 isolates from @entity4186 and environmental samples obtained on a XXXX farm.

@entity4186 :: ('8839', 'Species') :: ['Duck', 'ducks', 'duck'] @entity3525 :: ('CHEBI:36467', 'Chemical') :: ['CTX'] @entity68 :: ('MESH:D007501', 'Chemical') :: ['iroN'] @entity4601 :: ('CHEBI:16016', 'Chemical') :: ['DHA'] @entity526 :: ('562', 'Species') :: ['Escherichia coli', 'E. coli']
@entity4186 :: (8839,Species) :: ['duck']
