Genetic Mechanisms behind the Spread of Reduced Susceptibility to Azithromycin in Shigella Strains Isolated from Men Who Have Sex with Men in Québec, Canada

: We analyzed 254 Shigella species isolates collected in Quebec, Canada, during 2013 and 2014. Overall, 23.6% of isolates showed reduced susceptibility to azithromycin (RSA) encoded by mphA (11.6%), ermB (1.7%), or 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. A complete sequence analysis of six selected plasmids from Shigella sonnei and different serotypes of Shigella flexneri emphasized the role of IS26 in the dissemination of RSA.