cholerae epidemic strains usually harbor Integrative Conjugative Elements (ICEs) of the SXT/R391 family [12]. SXT/R391 ICEs are self-transmissible mobile elements, ranging in size from 79 to 108 kb, able to integrate into the host bacterial chromosome and to transfer by conjugation. They are recognized for their important role in bacterial genome plasticity [13] and as vectors of antibiotic resistance and alternative metabolic pathways [12]. The name of the SXT/R391 family originates from elements SXTMO10 and R391, respectively discovered in clinical strains of Vibrio cholerae in India [14] and Providencia

rettgeri in South Africa [15]. The two elements are associated with different multi-resistance profiles: chloramphenicol, streptomycin, sulfamethoxazole, and trimethoprim for SXTMO10, and kanamycin, and mercury for R391 [12]. They share check details a highly conserved genetic backbone this website encoding their integration/excision, conjugative transfer, and regulation, but also contain variable DNA found in five insertion sites of the backbone [12]. Each ICE of the family holds specific genes scattered in the conserved sequence that code for resistance to antibiotics and heavy metals, new toxin/antitoxin systems, restriction/modification systems,

and alternative metabolic pathways [12]. To date more than 50 ICEs have been identified and grouped within the SXT/R391 family, most of them discovered in V. cholerae strains. To date, only a few SXT-related ICEs were identified in Africa, most of them through the characterization of the integrase int SXT . Only ICEVchMoz10 from Mozambique (2004) has been completely sequenced and annotated [12]. This ICE has no close relative Fossariinae in Africa except its

sibling ICEVchBan9 isolated in Bangladesh (1994), suggesting the possible spread of SXT-related ICEs between the two continents in recent times. Although the use of horizontally-transferred elements as genetic markers for strain discrimination might appear risky, we recently showed the existence of an ICE/strain association in epidemic V. cholerae strains circulating in the Indian Subcontinent [16]. The association between ICE and V. cholerae reflects the classification proposed by Chun and colleagues to describe homologous intraspecific groups of V. cholerae based on the whole genome alignment of 23 strains isolated over the past 100 years [17]. In this retrospective study, we analysed V. cholerae O1 clinical strains isolated in Luanda (Angola) in 2006. Angola is an endemic area for cholera and was subjected to two major epidemic events in the past three decades. The first see more outbreak (1987-1993) [18] was followed by a thirteen year remission phase until cholera reemerged in 2006 in one of the most severe epidemic outbreaks of the last decade, counting about 240.000 cases [19]. Here we demonstrate that the V.