title: The CTX-M conundrum: dissemination of plasmids and Escherichia coli clones.
abstract: The ongoing global spread and increased prevalence of CTX-M-type extended-spectrum β-lactamases in Enterobacteriaceae is of great concern. The successful distribution of CTX-M enzymes mainly involves Escherichia coli causing systemic as well as urinary tract infections in patients worldwide. CTX-M expression is often associated with coresistance that critically reduces treatments options. The mobilization of bla(CTX-M) genes from their original chromosomal position in various Kluyvera species has been facilitated by mobile genetic elements such as ISEcp1 or ISCR1. Molecular epidemiological studies have revealed a thriving linkage of bla(CTX-M) genes to conjugative plasmids and successful bacterial clones. Multireplicon FII plasmids are shown to carry the most widely distributed bla(CTX-M-15) across continents, paving the way for bla(CTX-M-15) into different genetic lineages of E. coli. Dissemination of virulent clones ST131-O25:H4-B2 and ST405-O102:H6-D is now being described worldwide. Importantly, CTX-M-producing strains are uncovering their ability of long-term gastrointestinal colonization often associated with travel to high-prevalent areas. Thus, we are witnessing a global epidemic of bla(CTX-M)-encoding E. coli strains and plasmids, which require serious attention and efficient infection control measures.
authors.affiliation: Research Group for Host-Microbe Interactions, Department of Medical Biology, University of Tromsø, Tromsø, Norway. umaer.naseer@uit.no
authors.forename: Umaer
authors.initials: U
authors.lastname: Naseer
authors.forename: Arnfinn
authors.initials: A
authors.lastname: Sundsfjord
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D017720:Molecular Epidemiology / Q000379:methods; D010957:Plasmids / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases