Identification of Shigella flexneri isolates carrying the Shiga toxin 1-producing gene in Quebec, Canada, linked to travel to Haiti

Shiga toxins (Stx1 and Stx2, also called verocytotoxins) are commonly associated with Shiga toxin-producing Escherichia coli (STEC) and Shigella dysenteriae type 1 (Tesh and O’Brien 1991). Recent studies have documented cases of stx carriage in other Shigella species, including S. sonnei linked to travel to Morocco (Nyholm et al. 2015) and S. flexneri with travel history to Caribbean (Gray et al. 2014, 2015). In the province of Quebec, more than 40% of Shigellosis cases are travel-related (Trepanier et al. 2014). Therefore, a retrospective laboratory study was performed by the Laboratoire de sante publique du Quebec to assess the presence of stx gene among the 210 strains of Shigella isolated between 2013 and 2014. The collection included 131 S. sonnei ,7 5S. flexneri ,3 S. boydii, and 1 S. dysenteriae type 12. Polymerase chain reaction targeting genes stx1 and stx2 was performed according to the methods of Paton and Paton (1998). Three isolates of S. flexneri isolated from stool were positive for the stx1 gene and belonged to serotype 2a (n = 2) and serotype y (n = 1). The amplified fragments were sequenced and identity was confirmed. Cases of shigellosis are systematically investigated as provincial regulations of notifiable diseases permits. The first case was a 62-year-old man of Haitian origin living in Montreal (isolate ID 123699). He was admitted to a hospital for bloody diarrhea, fever, and abdominal pain. Empirical antimicrobial treatment with ciprofloxacin was prescribed and the patient was discharged 2 days after admission. The second case was a 55-year-old man of Haitian origin living in Montreal (isolate ID 132104). Ciprofloxacin was prescribed in an outpatient clinic, where he consulted for bloody diarrhea, fever, and abdominal