Plasmid evolution in carbapenemase-producing Enterobacteriaceae: a review

Carbapenem-resistant Enterobacteriaceae (CRE) have been listed by the WHO as high-priority pathogens owing to their high association with mortalities and morbidities. Resistance to multiple beta-lactams complicates effective clinical management of CRE infections. Using plasmid typing methods, a wide distribution of plasmid replicon groups has been reported in CREs around the world, including IncF, N, X, A/C, L/M, R, P, H, I, and W. We performed a literature search for English research papers, published between 2013 and 2018, reporting on plasmid-mediated carbapenem resistance. A rise in both carbapenemase types and associated plasmid replicon groups was seen, with China, Canada, and the United States recording a higher increase than other countries. bla(KPC) was the most prevalent, except in Angola and the Czech Republic, where OXA-181 (n = 50, 88%) and OXA-48-like (n = 24, 44%) carbapenemases were most prevalent, respectively; bla(KPC-2/3) accounted for 70% (n = 956) of all reported carbapenemases. IncF plasmids were found to be responsible for disseminating different antibiotic resistance genes worldwide, accounting for almost 40% (n = 254) of plasmid-borne carbapenemases. bla(CTX-M), bla(TEM), bla(SHV), bla(OXA-1/9), qnr, and aac-(6 ')-lb were mostly detected concurrently with carbapenemases. Most reported plasmids were conjugative but not present in multiple countries or species, suggesting limited interspecies and interboundary transmission of a common plasmid. A major limitation to effective characterization of plasmid evolution was the use of PCR-based instead of whole-plasmid sequencing-based plasmid typing.