TY - JOUR
T1 - Antimicrobial resistance and virulence gene profiles in multi-drug resistant enterotoxigenic Escherichia coli isolated from pigs with post-weaning diarrhoea
AU - Smith, M. G.
AU - Jordan, D.
AU - Chapman, T. A.
AU - Chin, J. J C
AU - Barton, M. D.
AU - Do, T. N.
AU - Fahy, V. A.
AU - Fairbrother, J. M.
AU - Trott, D. J.
PY - 2010/10/26
Y1 - 2010/10/26
N2 - This study aimed to characterize antimicrobial resistance and virulence genes in multi-drug resistant enterotoxigenic Escherichia coli (ETEC) isolates (n= 117) collected from porcine post-weaning diarrhoea cases in Australia (1999-2005). Isolates were serotyped, antibiogram-phenotyped for 12 antimicrobial agents and genotyped by PCR for 30 plasmid-mediated antimicrobial resistance genes (ARGs), 22 intestinal and 38 extraintestinal E. coli virulence genes (VGs). Nine serogroups were identified, the most prevalent being O149 (46.2%), O141 (11.2%) and Ont (31.6%). None of the isolates showed resistance to ceftiofur or enrofloxacin and 9.4% were resistant to florfenicol. No corresponding extended-spectrum/AmpC β-lactamase, fluoroquinolone or floR ARGs were detected. An antimicrobial resistance index (ARI) was calculated from the combined data with a weighting for each antimicrobial agent dependent upon its significance to human health. Serogroup O141 isolates had a significantly higher ARI due to an elevated prevalence of aminoglycoside ARGs and possession of more virulence genes (VGs), including ExPEC or EHEC adhesins (bmaE, sfa/focDE, fimH, ihA) in toxin-producing strains that lacked the normally associated F4 and F18 fimbriae. Few associations between ARGs and VGs were apparent, apart from tetC, sfa/focDE and ompT which, for a sub-set of O141 isolates, suggest possible plasmid acquisition from ExPEC. The multi-drug resistant ETEC ARG/VG profiles indicate a high probability of considerable strain and plasmid diversity, reflecting various selection pressures at the individual farm level rather than emergence and lateral spread of MDR resistant/virulent clones.
AB - This study aimed to characterize antimicrobial resistance and virulence genes in multi-drug resistant enterotoxigenic Escherichia coli (ETEC) isolates (n= 117) collected from porcine post-weaning diarrhoea cases in Australia (1999-2005). Isolates were serotyped, antibiogram-phenotyped for 12 antimicrobial agents and genotyped by PCR for 30 plasmid-mediated antimicrobial resistance genes (ARGs), 22 intestinal and 38 extraintestinal E. coli virulence genes (VGs). Nine serogroups were identified, the most prevalent being O149 (46.2%), O141 (11.2%) and Ont (31.6%). None of the isolates showed resistance to ceftiofur or enrofloxacin and 9.4% were resistant to florfenicol. No corresponding extended-spectrum/AmpC β-lactamase, fluoroquinolone or floR ARGs were detected. An antimicrobial resistance index (ARI) was calculated from the combined data with a weighting for each antimicrobial agent dependent upon its significance to human health. Serogroup O141 isolates had a significantly higher ARI due to an elevated prevalence of aminoglycoside ARGs and possession of more virulence genes (VGs), including ExPEC or EHEC adhesins (bmaE, sfa/focDE, fimH, ihA) in toxin-producing strains that lacked the normally associated F4 and F18 fimbriae. Few associations between ARGs and VGs were apparent, apart from tetC, sfa/focDE and ompT which, for a sub-set of O141 isolates, suggest possible plasmid acquisition from ExPEC. The multi-drug resistant ETEC ARG/VG profiles indicate a high probability of considerable strain and plasmid diversity, reflecting various selection pressures at the individual farm level rather than emergence and lateral spread of MDR resistant/virulent clones.
KW - Antimicrobial
KW - Diarrhoea
KW - Multi-drug resistance
KW - Post-weaning
KW - Virulence
UR - http://www.scopus.com/inward/record.url?scp=77957273967&partnerID=8YFLogxK
U2 - 10.1016/j.vetmic.2010.04.004
DO - 10.1016/j.vetmic.2010.04.004
M3 - Article
C2 - 20688440
AN - SCOPUS:77957273967
SN - 0378-1135
VL - 145
SP - 299
EP - 307
JO - Veterinary Microbiology
JF - Veterinary Microbiology
IS - 3-4
ER -