DECAPAGE PROJECT: HYDROCARBON DEGRADATION IN COASTAL SEDIMENTS* Integron diversity in marine environments Justine Abella 1 & Ana Bielen 2,3 & Lionel Huang 1,4 & Tom O. Delmont 1,5 & Dušica Vujaklija 2 & Robert Duran 1 & Christine Cagnon 1 Received: 2 February 2015 /Accepted: 16 July 2015 # Springer-Verlag Berlin Heidelberg 2015 Abstract Integrons are bacterial genetic elements known to be active vectors of antibiotic resistance among clinical bac- teria. They are also found in bacterial communities from nat- ural environments. Although integrons have become especial- ly efficient for bacterial adaptation in the particular context of antibiotic usage, their role in natural environments in other contexts is still unknown. Indeed, most studies have focused on integrons and the spread of antibiotic resistance in fresh- water or soil impacted by anthropogenic activities, with only few on marine environments. Notably, integrons show a wider diversity of both gene cassettes and integrase gene in natural environments than in clinical environments, suggesting a gen- eral role of integrons in bacterial adaptation. This article re- views the current knowledge on integrons in marine environ- ments. We also present conclusions of our studies on polluted and nonpolluted backgrounds. Keywords Integron integrase . Gene cassettes . Contaminants . Adaptation . Bacterial communities Introduction Bacterial communities are able to adapt rapidly to changing conditions which help them to cope with disturbance in their environment, such as chemical contaminations. Bacterial ad- aptation is in part due to acquisition of new DNA sequences by horizontal gene transfer, involving genetic elements such as plasmids, phages, transposons, and integrons (Ochman et al. 2000; Smalla and Sobecky 2002). Integrons were the most recently discovered elements and, although their role in spreading antibiotic resistances is well known and well stud- ied (Hall and Collis 1995; Ploy et al. 2000; Cambray et al. 2010; Stalder et al. 2012), their role in other contamination contexts is still in question. Most studies on nonclinical environments have fo- cused on Bantibiotic resistance integrons^ spreading, espe- cially in freshwater and soil impacted by anthropogenic activ- ities (Henriques et al. 2006; Moura et al. 2007; Laroche et al. 2009; Byrne-Bailey et al. 2011; Gaze et al. 2011; Stalder et al. 2014). Indeed Bantibiotic resistance integrons^ present a very low diversity in comparison to the variety of integrons found in natural environments (Boucher et al. 2007) suggesting that other types of integrons might be involved in bacterial adaptation in response to the large variety of possible pollutants. Few investigations tried to characterize nonclinical integrons in various natural environments: soil, sediment or water, from terrestrial, estuarine, or marine areas (e.g., Rodriguez-Minguela et al. 2009; Stokes et al. 2001). Marine environments are subjected to a variety of pollut- ants from both sides: from the land, principally through agri- cultural practices, urban wastewaters and industrial activities Responsible editor: Philippe Garrigues * Christine Cagnon christine.cagnon@univ-pau.fr 1 Equipe Environnement et Microbiologie, MELODY Group, Université de Pau et des Pays de l’Adour, IPREM UMR CNRS 5254, BP 1155, 64013 Pau, Cedex, France 2 Laboratory for Molecular Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia 3 Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, 10000 Zagreb, Croatia 4 Present address: Euro Engineering, Technopole Hélioparc Bât Newton, 4 rue Jules Ferry, CS N 99207, 64053 Pau, Cedex 09, France 5 Present address: Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biology Laboratory, Woods Hole, MA, USA Environ Sci Pollut Res DOI 10.1007/s11356-015-5085-3