Strains of <i>E. coli</i> and plasmids used in this study.

as065 and s066 of SXT correspond to orf68 and orf69 of R391, respectively, according to the annotation of both elements [28],[29]. ApR, ampicillin resistant; CmR, chloramphenicol resistant; KnR, kanamycin resistant; RfR, rifampicin resistant; SuR, sulfamethoxazole resistant; SmR, streptomycin resistant; SpR, spectinomycin resistant; TcR, tetracycline resistant; TmR, trimethoprim resistant; Ts, thermosensitive.