TABLE 1.

Characteristics of the AmpC-carrying plasmids analyzed in this study

AmpC derivativeStrain(s)Yr of isolationSpeciesSourceOriginExtra resistance in plasmidcSelf transferdReplicon typing
DHA-1A2-VLA1996S. enterica serovar SenftenbergHumanUnited KingdomCHL, SUL, TETYesFII(2), FIAe
A3-VLA1999S. enterica serovar SenftenbergHumanUnited KingdomCHL, GEN, NET, SUL, TET, TMPNoFII(2)
CMY-2EC30-VLA2003E. coliCattleUnited KingdomSULYesI1
EC44-VLA2003E. coliCattleUnited KingdomSULYesI1
A4-VLA1999S. enterica serovar 4,5,12:I:-HumanGambiaNoneYesI1
A5-VLA2001S. enterica serovar AjioboHumanUnited KingdomNoneYesI1
E108141-HPA1995E. coliHumanUnited KingdomCHL, GEN, KAN, SUL, TET, TMPNoA/C
E127226-HPA1997E. coliHumanUnited KingdomSUL, TETNoA/C
A10-VLA2003S. enterica serovar AnatumHumanUnited StatesCHL, SUL, TETYesA/C
CEF9-VLA1999S. enterica serovar BredeneyTurkeyCanadaSUL, TETNoA/C
A7-VLA2002S. enterica serovar HeidelbergHumanGreeceCHL, GEN, SUL, TETNoA/C
UCM267-VLA2002S. enterica serovar InfantisHumanHondurasAMK, CHL, GEN, SUL, TMPNoA/C
C1-VLAa2000S. enterica serovar OhioHumanUnited KingdomAMK, GEN, SUL, TMPYesA/C
A12-VLAUnknownS. enterica serovar TyphimuriumHorseIrelandCHL, GEN, NET, SUL, TET, TMPYesA/C
A11-VLA2003S. enterica serovar WorthingtonHumanIraqCHL, SUL, TETNoA/C
E108137-HPA1995E. coliHumanUnited KingdomKAN, GEN, SUL, TETNoFIA, FIBe
A9-VLA2003S. enterica serovar TyphimuriumHumanMexicoNoneNoNegative
E128986-HPA1997E. coliHumanUnited KingdomNoneNoNegative
CMY-4A6-VLA2001S. enterica serovar SenftenbergHumanUnited KingdomNoneNoA/C
CMY-7E127346-HPA1997E. coliHumanUnited KingdomNoneNoI1
E132587-HPA1998E. coliHumanUnited KingdomNoneNoI1
E133554-HPA*b1998E. coliHumanUnited KingdomNoneNoI1
E133761-HPA*1998E. coliHumanUnited KingdomNoneNoI1
E133003-HPA1998E. coliHumanUnited KingdomNoneNoI1
E146836-HPA1999E. coliHumanUnited KingdomNoneNoI1
E162599-HPA2001E. coliHumanUnited KingdomNoneNoI1
E154371-HPA**2000E. coliHumanPakistanTMPYesI1
E159045-HPA**2001E. coliHumanUnited KingdomNoneNoI1
E134708-HPA**1998E. coliHumanUnited KingdomTMPYesI1, Nf
E115837-HPA1996E. coliHumanUnited KingdomKAN, NET, SUL, TETYesI1, A/Cf
CMY-21E111726-HPA1996E. coliHumanUnited KingdomNoneNoI1
  • a This strain carries the blaCMY-2 gene and an additional blaCTX-M-15 gene.

  • b Two clusters of strains (indicated with single and double asterisks) showed a genetic similarity index of 90% by PFGE (10).

  • c Antimicrobial drugs used were the following: amikacin (AMK), chloramphenicol (CHL), gentamicin (GEN), kanamycin (KAN), netilmicin (NET), sulphonamides (SUL), tetracycline (TET), and trimethoprim (TMP).

  • d For the strains where transfer was not achieved by conjugation, transformation experiments were conducted in ElectroMAX streptomycin-resistant DH10B cells (Invitrogen, Paisley, United Kingdom) selecting on cefoxitin (4 μg/ml) MacConkey agar plates.

  • e Multireplicon plasmid; each single replicon was used as a probe in Southern blot hybridization experiments performed on purified plasmids, demonstrating their colocalization on the same plasmid.

  • f Two different plasmids simultaneously detected in the same strain.