Curing vector for IncI1 plasmids and its use to provide evidence for a metabolic burden of IncI1 CTX-M-1 plasmid pIFM3791 on Klebsiella pneumoniae

Freire-Martin, I., Thomas, C. M., Laing, E., AboOun, M., La Ragione, R. M. and Woodward, M. J. (2016) Curing vector for IncI1 plasmids and its use to provide evidence for a metabolic burden of IncI1 CTX-M-1 plasmid pIFM3791 on Klebsiella pneumoniae. Journal of Medical Microbiology, 65 (7). pp. 611-618. ISSN 1473-5644 doi: 10.1099/jmm.0.000271

Abstract/Summary

Using a sequence based approach we previously identified an IncI1 CTX-M-1 plasmid,pIFM3791, on a single pig farm in the UK that was harboured by K. pneumoniae,Escherichia coli and Salmonella enterica serotype 4,5,12,i:-. To test the hypothesis that the plasmid had spread rapidly into these differing host bacteria we wished to assess whether the plasmid conferred a fitness advantage. To do this an IncI1 curing vector was constructed and used to displace the IncI1 CTX-M-1 plasmids from K. pneumoniae strain B3791 and several other unrelated IncI1 harbouring strains indicating the potential wider application of the curing plasmid. The IncI1 CTX-M-1 plasmid was re-introduced by conjugation into the cured K. pneumoniae strain and also a naturally IncI1 plasmid free S. enterica serotype 4,5,12,i:-, S348/1. Original, cured and complemented strains were tested for metabolic competence using BiologTM technology and in competitive growth, association to mammalian cells and biofilm formation experiments. The plasmid-cured K. pneumoniae strain grew more rapidly than either the original plasmid-carrying strain or plasmid-complemented strains in competition experiments. Additionally, the plasmid-cured strain was significantly better at respiring with L-sorbose as a carbon source and putrescine, γ-amino-n-butyric acid,L-alanine, L-proline as a nitrogen sources. By contrast, no differences in phenotype were found when comparing plasmid harbouring and plasmid free S. enterica S348/11. In conclusion, the IncI1 curing vector successfully displaced multiple IncI plasmids. The IncI1 CTX-M1 plasmid conferred a growth disadvantage upon K. pneumoniae, possibly by imposing a metabolic burden the mechanism of which remains to be determined.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/66251
Identification Number/DOI	10.1099/jmm.0.000271
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences > Food Microbial Sciences Research Group
Publisher	Microbiology Society
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