Global epidemiology of CTX-M β-lactamases: temporal and geographical shifts in genotype

Globally, rates of ESBL-producing Enterobacteriaceae are rising. We undertook a literature review, and present the temporal trends in bla(CTX-M) epidemiology, showing that bla(CTX-M-15) and bla(CTX-M-14) have displaced other genotypes in many parts of the world. Explanations for these changes can be attributed to: (i) horizontal gene transfer (HGT) of plasmids; (ii) successful Escherichia coli clones; (iii) ESBLs in food animals; (iv) the natural environment; and (v) human migration and access to basic sanitation. We also provide explanations for the changing epidemiology of bla(CTX-M-2) and bla(CTX-M-27). Modifiable anthropogenic factors, such as poor access to basic sanitary facilities, encourage the spread of bla(CTX-M) and other antimicrobial resistance (AMR) genes, such as bla(NDM), bla(KPC) and mcr-1. We provide further justification for novel preventative and interventional strategies to reduce transmission of these AMR genes.