Dissecting the clonality of I1 plasmids using ORF-based binarized structure network analysis of plasmids (OSNAp)

Phylogenetic relationship of 97 I1 plasmids harboring bla CTX-M genes encoding extended-spectrum beta-lactamase (ESBL) was analyzed using the ORF-based binarized structure network analysis of plasmids (OSNAp). The majority of plasmids carrying bla CTX-M-1 or bla CTX-M-8 , ESBL genes primarily associated with domestic animals, were clonal. On the other hand, plasmids carrying bla CTX-M-14 or bla CTX-M-15 , identified from both humans and domestic animals, were diverse in their contents. The findings suggest that circulation of I1 plasmids among humans and animals may contribute to their diversity.