Objectives: This study aimed to sequence, assemble, and annotate three plasmids (two IncN and one IncI1) carrying the blaCTX-M-1 gene and assess their transferability rates between homologous and heterologous serovars and/or species of bacteria. Methods: First, the plasmids were sequenced, assembled, and annotated. They were then transferred from three donor strains (Escherichia coli/IncN, S. Heidelberg/IncN, and S. Heidelberg/IncI1) into nine recipient strains (S. Enteritidis, S. Heidelberg, S. Saintpaul, S. Cero, S. Infantis, S. Braenderup, E. coli 50, and E. coli 2010). The blaCTX-M-1 gene polymerase chain reaction (PCR), plasmid isolation, and antimicrobial susceptibility testing were used on the transconjugants to confirm the successful transfer of extended-spectrum beta lactamase (EBSL) plasmids into the recipient strains. Results: Both IncN plasmids were 42,407 bp in size and showed >99.4% similarity to the S. Bredeney pET1.2-IncN (GenBank accession CP043224.1), whereas the IncI1 plasmid was 107,635 bp in size and demonstrated >99.9% similarity to the E. coli pCOV33 plasmid (GenBank accession MG649046.1). Successful plasmid transfer was observed between donor E. coli (IncN) and all recipient strains except for E. coli 50 and between donor S. Heidelberg (IncN) and all recipient strains. Successful plasmid transfer was also observed between S. Heidelberg (IncI1) and E. coli 50. Conclusion: Transfer of the bla CTX-M-1 encoding IncN and IncI1 plasmids via conjugation is possible and yet occurs at different frequencies depending on the donor strain of bacteria, with S. Heidelberg (IncN) having the highest donor-dependent transfer frequency, followed by E. coli 9079 (IncN) and S. Heidelberg (IncI1).
Bibliographical noteFunding Information:
This study was funded by the University of Florida College of Veterinary Medicine and by faculty start-up funds through Dr. Thomas Denagamage.
This study was funded by the University of Florida College of Veterinary Medicine and by faculty start-up funds through Dr. Thomas Denagamage. None declared. No animals were used in this project; therefore, it did not require approval from the Institute of Animal Care and Use Committee (IACUC). Potentially pathogenic ESC-resistant bacteria were used; thus, this work followed the standards and procedures required under Biosafety Level 2 (BSL-2). We would like to acknowledge the Florida Veterinary Scholars Program at the University of Florida College of Veterinary Medicine and the Boehringer Ingelheim Veterinary Scholars Program for their contributions to this study. We would also like to thank Escarlett Cardenas for her assistance with this study.
© 2022 The Authors
- Escherichia coli
- Plasmid transferability
- Salmonella enterica
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't