title: Global dissemination patterns of common gene cassette arrays in class 1 integrons.
abstract: Integrons are genetic elements that contain a site-specific recombination system able to capture, express and exchange gene cassettes. Mobile integrons are widespread and often confer resistance to multiple antibiotics, due to the expression of the arrays of gene cassettes they carry. Although >300 cassette arrays have been described, < 10 array compositions prevail in the reports related to class 1 integrons. These common arrays are found in a broad variety of hosts and environments, highlighting the high level of horizontal dissemination of these elements amongst bacterial populations and species. Clonal expansion also contributes to the current prevalence and inter-regional spread of integron-carrying bacterial species. Here, we review the dissemination pattern of common cassette arrays with a focus on the bacterial species, the geographical dispersal pattern and the environments in which they reside. Conserved arrays of gene cassettes are found in at least 74 countries and 72 species present in different environments. The factors governing the further spread and population dynamics of these cassette arrays remain to be determined.
authors.affiliation: 1​ Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal 2​ Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: Sara
authors.initials: S
authors.lastname: Domingues
authors.affiliation: 1​ Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal 2​ Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: Gabriela Jorge
authors.initials: GJ
authors.lastname: da Silva
authors.affiliation: 4​ GenØk-Centre for Biosafety, The Science Park, Tromsø, Norway 3​ Department of Life Sciences and Health, Faculty of Health Sciences, Oslo and Akershus University College, Oslo, Norway.
authors.forename: Kaare Magne
authors.initials: KM
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000235:genetics*; D001424:Bacterial Infections / Q000382:microbiology*; D018562:Disease Transmission, Infectious; D024881:Drug Resistance, Bacterial; D004783:Environmental Microbiology; D022761:Gene Transfer, Horizontal; D014943:Global Health; D006801:Humans; D032023:Integrons; D020071:Interspersed Repetitive Sequences
chemical_list: D000900:Anti-Bacterial Agents