Genetic mechanisms behind the spread of reduced susceptibility to azithromycin in Shigella isolated from men who have sex with men, in Québec, Canada

We analysed 254 Shigella spp., isolates collected in Québec, Canada, during 2013-2014. Overall, 23.6% of isolates showed reduced susceptibility to azithromycin (RSA) encoded by mphA (11.6%), ermB (1.7%) or by both genes (86.7%). Shigella strains with RSA were mostly isolated from men who have sex with men (68.8% or higher) from the Montreal region. Complete sequence analysis of six selected plasmids from Shigella sonnei and different serotypes of Shigella flexneri emphasized the role of IS26 in RSA dissemination.