Association of plasmid-mediated quinolone resistance with extended-spectrum beta-lactamase VEB-1

Abstract

Association of the plasmid-mediated quinolone resistance determinant QnrA and the bla(VEB-1) gene was identified in a single Enterobacter cloacae isolate from K.-Bicêtre, France, and in 11 out of 23 bla(VEB-1)-positive enterobacterial isolates from Bangkok, Thailand. This result may explain in part the association between quinolone and extended-spectrum beta-lactam resistance.

FIG. 1.

Plasmid DNAs from clinical isolates and transconjugants (A) and Southern hybridizations with the bla_VEB-1 (B) and the qnrA-like (C) probe. Lanes: 1, E. coli J53/pQR1 (used as a control); 2, E. coli J53/pMG252 (used as a control); 3, E. coli TcE1; 4, E. coli E2; 5, E. coli TcE3; 6, E. coli TcE4; 7, E. coli TcE5; 8, E. coli TcE7; 9, E. coli TcE8; 10, E. coli E10; 11, E. sakazakii E15; 12, E. coli TcE16; 13, E. coli TcE18; 14, E. cloacae GOC; M, E. coli 50192 (used as a molecular size marker [9] and negative control).

FIG. 2.

Schematic comparison of the different sul1-type integrons that contain the qnrA gene. Shown are the structures of sul1-type integrons identified in pMG252 from K. pneumoniae (A) (29), in pQR1 from E. coli Lo (B) (9), in enterobacterial isolates from Thailand and E. cloacae isolate GOC from Bicêtre (C), and in other enterobacterial isolates from Thailand (D). The vertical rectangle indicates the right-hand boundary of the CR1 element as determined previously (9), and the vertical arrow stands for a 2-bp deletion. Question mark indicates DNA sequences that are unknown but different from those reported in panels A, B, and C. Dashed vertical lines indicate the absence of the DNA fragment between qnrA and qacEΔ1 in pMG252.