Table 1

Characteristics of S. enterica and E. coli strains carrying blaCTX-M or blaCMY-2 isolated from chickens

Strain IDSpecies or Salmonella serotypeYrResistance pattern ofa:β-Lactamasebla-bearing plasmid size (kb)bReplicon type(s)Structurec
Wild typeTransformant or transconjugant
AD09-S19S. Enteritidis2009AMP-APR-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15190FIIB
AD09-S23S. Enteritidis2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETNDCTX-M-15200FIIB
AD09-S25S. Enteritidis2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15120FIIB
AD09-S26S. Enteritidis2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15120FIIB
AD09-S29S. Enteritidis2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETNDCTX-M-15200FIIB
AD09-S31S. Senftenberg2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETNDCTX-M-15200FIIB
AD09-S33S. Enteritidis2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15200FIIB
AD09-SKYH2S. Enteritidis2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETNDCTX-M-15200FIIB
AD10-S11S. Enteritidis2010AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-NEO-STR-SUL-TETCTX-M-15120FIIB
AD10-S15S. Enteritidis2010AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-NEO-STR-SUL-TETCTX-M-15120FIIB
AD10-S2S. Enteritidis2010AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15140FIIB
AD10-S22S. Enteritidis2010AMP-XNL-CEF-FEP-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-STR-SUL-TETCTX-M-15170FIIB
AD10-S23S. Enteritidis2010AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15120FIIB
AD10-S24S. Enteritidis2010AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15170FIIB
AD10-S26S. Enteritidis2010AMP-XNL-CEF-FEP-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-NEO-STR-SUL-TETCTX-M-15170FIIB
AD10-S7S. Enteritidis2010AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-NEO-STR-SUL-TETCTX-M-15120FIIB
AD10-S9S. Enteritidis2010AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15120FIIB
AD09-EC2dE. coli2009AMP-XNL-CEF-NAL-STR-SUL-TETAMP-XNL-CEF-STR-SUL-TETCTX-M-15190PB
AD09-EC3E. coli2009AMC-AMP-CEF-CHL-FFN-FOX-GEN-STR-SUL-TETAMC-AMP-CEF-CHL-FFN-FOX-GEN-STR-SUL-TETCMY-2160A/CC
AD09-EC6E. coli2009AMC-AMP-CEF-FOX-NALAMC-AMP-CEF-FOX-STRCMY-2100I1-IγE
AD09-EC7dE. coli2009AMC-AMP-CEF-CIP-ENO-FOX-NAL-STR-TETAMC-AMP-CEF-FOX-STRCMY-2100I1-IγE
AD09-EC17dE. coli2009AMP-XNL-CEF-CIP-ENO-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15190PB
AD09-EC25E. coli2009AMP-XNL-CEF-CHL-FFN-NAL-STR-SUL-TETAMP-XNL-CEF-STR-SUL-TETCTX-M-15160NegativeB
AD09-EC36dE. coli2009AMP-XNL-CEF-GEN-NAL-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15180NegativeB
AD09-EC38E. coli2009AMP-XNL-CEF-GEN-NAL-NEO-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15180NegativeB
AD09-EC44dE. coli2009AMP-XNL-CEF-CIP-ENO-GEN-NAL-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-1585FB
AD10-EC11E. coli2009AMC-AMP-CEF-FOX-NAL-SUL-SXT-TETAMC-AMP-CEF-FOXCMY-2100KF
DDC10-15E. coli2010AMP-XNL-CEF-GEN-NAL-STR-SUL-TETAMP-XNL-CEF-GEN-STR-SUL-TETCTX-M-15160FIVB
DDC10-30E. coli2010AMC-AMP-CEF-FOX-NAL-NEO-SXT-TETAMC-AMP-CEF-FOXCMY-2100I1-IγE
DDC10-52dE. coli2010AMP-XNL-CEF-CHL-CIP-ENO-FFN-GEN-NAL-NEO-STR-SUL-SXT-TETAMP-XNL-CEF-CHL-FFN-GEN-NEO-STR-SUL-SXT-TETCTX-M-15160FIVB
EC02384dE. coli2002AMC-AMP-CEF-CIP-ENO-FOX-NAL-STR-SUL-SXT-TETAMC-AMP-CEF-FOX-STRCMY-295I1-Iγ, PC
EC02502dE. coli2002AMC-AMP-CEF-CHL-FFN-FOX-GEN-NEO-STR-SUL-SXT-TETAMC-AMP-CEF-CHL-FFN-FOX-NEO-STR-SUL-SXT-TETCMY-2160I1-Iγ, PD
EC06036L1E. coli2006AMC-AMP-CEF-CIP-ENO-FOX-GEN-NAL-STR-SUL-TETAMC-AMP-CEF-FOX-STRCMY-295I1-IγG
EC06D097E. coli2006AMP-APR-XNL-CEF-CIP-ENO-GEN-NAL-NEO-STR-SUL-SXT-TETAMP-XNL-CEF-STRCTX-M-14100I1-IγA
EC07Q066L2dE. coli2007AMC-AMP-CEF-CIP-ENO-FOX-GEN-NAL-STR-TETAMC-AMP-CEF-FOX-STRCMY-2100I1-IγE
  • a Resistance patterns were determined by the Kirby-Bauer disk diffusion assay on Mueller-Hinton agar for 18 antimicrobials, including ampicillin (AMP), amoxicillin-clavulanic acid (AMC), apramycin (APR), cefepime (FEP), cefoxitin (FOX), ceftiofur (XNL), cephalothin (CEF), chloramphenicol (CHL), ciprofloxacin (CIP), enrofloxacin (ENO), florfenicol (FFN), gentamicin (GEN), nalidixic acid (NAL), neomycin (NEO), streptomycin (STR), sulfisoxazole (SUL), tetracycline (TET), and trimethoprim-sulfamethoxazole (SXT). ND, not determined.

  • b Each DH10B transformant or J53 transconjugant carried only one large plasmid, ranging in size from approximately 85 to 200 kb. Plasmid sizes were estimated by comparison with a supercoiled DNA ladder containing DNA bands of 8 to 165 kb (BAC-Tracker supercoiled DNA ladder; Epicentre, Madison, WI).

  • c Structures indicate the genetic context of blaCMY-2 regions as shown in Fig. 4.

  • d Nine strains also had blaTEM-1, which was harbored by bla-bearing large plasmids in five of the strains (AD09-EC2, AD09-EC17, AD09-EC44, DDC10-52, and EC02384).