TY - JOUR
T1 - The Prevalence of the OqxAB Multidrug Efflux Pump amongst Olaquindox-Resistant Escherichia coli in Pigs
AU - Hansen, Lars Hestbjerg
AU - Sørensen, Søren Johannes
AU - Jørgensen, Helle S.
AU - Jensen, Lars B.
PY - 2005
Y1 - 2005
N2 - The quinoxaline olaquindox has been used extensively as a growth promoter for pigs. Recently, we isolated a plasmid (pOLA52) conferring resistance to olaquindox from swine manure. On this plasmid, the oqxA and oqxB genes encode an RND-family multidrug efflux pump, OqxAB. It facilitates resistance to olaquindox as well as resistance to other antimicrobials like chloramphenicol. In this study, 10 of the 556 (1.8%) previously isolated Escherichia coli strains were shown to have an MIC = 64 µg/ml olaquindox. In nine of the ten strains, the oqxA gene was detected. Sequencing of an internal fragment of oqxA from the oqxA-positive strains showed no variation, indicating highly conserved oqxA genes. All of the oqxA-positive strains contain plasmids with replicons similar to that of pOLA52. It was verified by Southern hybridization that the oqxAB operon was situated on plasmids in most, if not all, resistant strains. Furthermore, horizontal transfer of olaquindox resistance from three olaquindox-resistant isolates was achieved using an olaquindox-sensitive E. coli as recipient.
AB - The quinoxaline olaquindox has been used extensively as a growth promoter for pigs. Recently, we isolated a plasmid (pOLA52) conferring resistance to olaquindox from swine manure. On this plasmid, the oqxA and oqxB genes encode an RND-family multidrug efflux pump, OqxAB. It facilitates resistance to olaquindox as well as resistance to other antimicrobials like chloramphenicol. In this study, 10 of the 556 (1.8%) previously isolated Escherichia coli strains were shown to have an MIC = 64 µg/ml olaquindox. In nine of the ten strains, the oqxA gene was detected. Sequencing of an internal fragment of oqxA from the oqxA-positive strains showed no variation, indicating highly conserved oqxA genes. All of the oqxA-positive strains contain plasmids with replicons similar to that of pOLA52. It was verified by Southern hybridization that the oqxAB operon was situated on plasmids in most, if not all, resistant strains. Furthermore, horizontal transfer of olaquindox resistance from three olaquindox-resistant isolates was achieved using an olaquindox-sensitive E. coli as recipient.
U2 - 10.1089/mdr.2005.11.378
DO - 10.1089/mdr.2005.11.378
M3 - Journal article
C2 - 16359198
SN - 1076-6294
VL - 11
SP - 378
EP - 382
JO - Microbial Drug Resistance
JF - Microbial Drug Resistance
IS - 4
ER -