Use of whole-genome sequencing for the public health surveillance of Shigella sonnei in England and Wales, 2015

Shigella spp., including Shigella dysenteriae, Shigella boydii, Shigella flexneri and Shigella sonnei, are the most common cause of bacterial dysentery (bloody diarrhoea) worldwide (Kotloff et al., 1999). Although all species of Shigella contribute to the high burden of diarrhoeal disease in lowincome regions, S. sonnei is the most commonly reported species in middleand high-income countries (Thompson et al., 2015). In England and Wales, foodborne outbreaks of S. sonnei are rare with transmission most commonly associated with person-to-person spread (McDonnell et al., 2013; Morgan et al., 2006; Simms et al., 2015). Historically, schools and nurseries were regarded as the epidemic centres of domestically acquired S. sonnei infection (Evans & Maguire, 1996). More recently, outbreaks of S. sonnei amongst men who have sex with men (MSM) have been described, and the increasing incidence of S. sonnei infection in this community is a challenging public health problem (Morgan et al., 2006; Simms et al., 2015).