Advantage of the F2A1B- IncF Pandemic Plasmid over IncC Plasmids in In Vitro Acquisition and Evolution of bla(CTX-M )Gene-Bearing Plasmids in Escherichia coli

Anne-Claire Maherault (1, 2) , Harry Kemble (1) , Mélanie Magnan (1) , Benoit Gachet (1) , David Roche (3) , Hervé Le Nagard (1) , Olivier Tenaillon (1) , Erick Denamur (1, 4) , Catherine Branger (1) , Luce Landraud (1, 2)

1 IAME (UMR_S_1137 / U1137) - Infection, Anti-microbiens, Modélisation, Evolution
2 Hôpital Louis Mourier - AP-HP [Colombes]
3 LABGeM - Analyse Bio-Informatique pour la Génomique et le Métabolisme
4 AP-HP - Hôpital Bichat - Claude Bernard [Paris]

Despite a fitness cost imposed on bacterial hosts, large conjugative plasmids play a key role in the diffusion of resistance determinants, such as CTX-M extended-spectrum beta-lactamases. Among the large conjugative plasmids, IncF plasmids are the most predominant group, and an F2A1B- IncF-type plasmid encoding a CTX-M-15 variant was recently described as being strongly associated with the emerging worldwide Escherichia coli sequence type 131 (ST131)-O25bH4 H30Rx/C2 sublineage. In this context, we investigated the fitness cost of narrow-range F-type plasmids, including the F2A1B- IncF-type CTX-M-15 plasmid, and of broad-range C-type plasmids in the K-12-like J53-2 E. coli strain. Although all plasmids imposed a significant fitness cost to the bacterial host immediately after conjugation, we show, using an experimental-evolution approach, that a negative impact on the fitness of the host strain was maintained throughout 1,120 generations with the IncC-IncR plasmid, regardless of the presence or absence of cefotaxime, in contrast to the F2 A1B- IncF plasmid, whose cost was alleviated. Many chromosomal and plasmid rear-rangements were detected after conjugation in transconjugants carrying the IncC plasmids but not in transconjugants carrying the F2A1B- IncF plasmid, except for insertion sequence (IS) mobilization from the filM gene leading to the restoration of motility of the recipient strains. Only a few mutations occurred on the chromosome of each transconjugant throughout the experimental-evolution assay. Our findings indicate that the F2A1B- IncF CTX-M-15 plasmid is well adapted to the E. coli strain studied, contrary to the IncC-IncR CTX-M-15 plasmid, and that such plasmid-host adaptation could participate in the evolutionary success of the CTX-M-15-producing pandemic E. coli ST131-O25bH4 lineage.

Mots clés: CTX-M-15; Escherichia coli ST131; IncC plasmid; IncF plasmid; experimental evolution; extended-spectrum beta-lactamase; fitness cost

Domaines: Bibliothèque électronique [cs.DL]

Anne-Claire Maherault, Harry Kemble, Mélanie Magnan, Benoit Gachet, David Roche, et al.. Advantage of the F2A1B- IncF Pandemic Plasmid over IncC Plasmids in In Vitro Acquisition and Evolution of bla(CTX-M )Gene-Bearing Plasmids in Escherichia coli. Antimicrobial Agents and Chemotherapy, 2019, 63 (10), pp.e01130-19. ⟨10.1128/AAC.01130-19⟩. ⟨cea-02316816⟩