@article{mbs:/content/journal/jmm/10.1099/jmm.0.000271, author = "Freire Martín, Irene and Thomas, Christopher M. and Laing, Emma and AbuOun, Manal and La Ragione, Roberto M. and Woodward, Martin J.", title = "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= "Journal of Medical Microbiology", year = "2016", volume = "65", number = "7", pages = "611-618", doi = "https://doi.org/10.1099/jmm.0.000271", url = "https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.000271", publisher = "Microbiology Society", issn = "1473-5644", type = "Journal Article", keywords = "Enterobacteriaceae", keywords = "ESBL", keywords = "IncI1 curing vector", keywords = "Veterinary microbiology", abstract = "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 Klebsiella 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 vector. The IncI1 CTX-M-1 plasmid was reintroduced by conjugation into the cured K. pneumoniae strain and also a naturally IncI1 plasmid free S. enterica serotype 4,5,12:i:-, S348/11. Original, cured and complemented strains were tested for metabolic competence using Biolog 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 and l-proline as 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.", }