Summary

The Enteric Reference Laboratory (ERL) typed 112 Shigella isolates in 2023, an increase of 57 from 2022. This includes 2 Shigella dysenteriae and four Shigella boydii in 2023, species that were not observed in 2022. The two S. dysenteriae isolates were from one case who had travelled to Pakistan and another who had contact with a traveller to Fiji. All of the identified S. boydii isolates were found in cases with a history of travel to India Additionally, there were 45 S. flexneri and 61 S. sonnei typed at ERL. These were predominantly associated with overseas travel. Given the rise of antimicrobial resistance seen overseas with respect to the use of frontline drug treatments Azithromycin, Ceftriaxone, Ciprofloxacin, and Co-trimoxazole; a flagging system was implemented to identify potential multi-drug resistant (MDR, resistant to three of four frontline drugs) and extensively drug resistant (XDR, resistant to all frontline drugs) isolates typed by whole genome sequencing (WGS). Out of 61 S. sonnei typed by WGS, three were flagged as MDR and eight as XDR. The XDR isolates included cases who had travelled to the United States, Portugal, Australia, Nepal, and India; but also one MDR and four XDR isolates were identified in cases without documented foreign travel. Out of 41 S. flexneri typed by whole genome sequencing, there were four MDR isolates identified (two with overseas travel). No S. flexneri isolates were identified as XDR. These AMR predictions were not confirmed phenotypically, but a review of the susceptibility testing done at the diagnostic labs showed agreement with the WGS predictions for relevant drugs tested.