Limited similarity between plasmids encoding CTX-M-1 beta-lactamase in Escherichia coli from humans, pigs, cattle, organic poultry layers and horses in Denmark

作者：Jakobsen Lotte^*; Bortolaia Valeria; Bielak Eliza; Moodley Arshnee; Olsen Stefan S; Hansen Dennis S; Frimodt Moller Niels; Guardabassi Luca; Hasman Henrik

来源：Journal of Global Antimicrobial Resistance, 2015, 3(2): 132-136.

DOI：10.1016/j.jgar.2015.03.009

• Escherichia coli
• CTX-M-1
• IncI1
• IncN
• Plasmid sequencing
• Humans and animals

CTX-M-1 is a common extended-spectrum beta-lactamase (ESBL) in Escherichia coli from animals and is often detected among human clinical isolates. The objective of this study was to investigate the epidemiological relationship between CTX-M-1-producing E. coli isolated from patients and animals in Denmark between 2006 and 2010. In total, 65 CTX-M-1-producing isolates from patients (n = 22), pigs (n = 21), cattle (n = 4), organic poultry layers (n = 3) and horses (n = 15) were typed by pulsed-field gel electrophoresis (PFGE). Plasmids harbouring bla(CTX-M-1) were characterised by S1 PFGE, PCR-based replicon typing, plasmid multilocus sequence typing, restriction fragment length polymorphism, and sequencing. Human and animal strains were unrelated based on PFGE. IncI1 was more common in human isolates (13/22) than in animal isolates (7/43), whereas the opposite trend was observed for IncN (5/22 human isolates and 24/43 animal isolates). Full characterisation of the plasmids harbouring bla(CTX-M-1) revealed host-specific patterns in the distribution of plasmid types, with specific Incl1, IncN and IncH1 plasmid subtypes being predominant in humans, livestock and horses, respectively. Three indistinguishable human, bovine and porcine Incl1/ST49 plasmids had high nucleotide sequence homology and differed by the presence of IS66 elements in the bovine plasmid and the absence of one gene within the microcin-encoding operon in the human plasmid. In conclusion, this work suggests a minor contribution by animals to the occurrence of CTX-M-1 in human E. coli infections in Denmark during the study period.

• 出版日期2015-6