Summary

The Enteric Reference Laboratory (ERL) typed 165 Shigella isolates in 2025, an increase of 12 isolates from 2024. This included five Shigella boydii (sequence types 145 serotype 2, 243 serotype 8, and 243 serotype 10) and one Shigella dysenteriae (sequence type 288) compared to three S. boydii and zero S. dysenteriae in 2024. All the S. boydii isolates were associated with travel to India, similar in 2023, whereas 2024 cases had travel to India, Peru and Bangladesh. Additionally, there were 89 S. sonnei (53.9%) and 70 S. flexneri (42.4%) typed, a slight increase from 2024 numbers of 69 and 81, respectively. Of the cases with travel history recorded, 84 (50.9%) did not travel within the incubation period compared to 50 (32.7%) in 2024. There were 65 cases associated with foreign travel (39.4%) from a wide range of overseas destinations based on data from Episurv. S. boydii typed isolates comprised two sequence types, ST243 and ST145, with none of the isolates flagged as potentially multi-drug (MDR) of extensively drug resistant (XDR) based on the presence of antimicrobial resistance genes and point mutations (drug resistance predictions are not verified by phenotypic testing in all cases). The single S. dysenteriae isolate was ST288 and was not flagged as either MDR or XDR. S. flexneri isolates were much more diverse with ST145 (nine total and one MDR flag), ST245 (56 total, one XDR and four MDR flags), ST630 (one total), ST632 (one total), ST1024 (two total), ST1025 (four total one XDR flag), ST6200 (one total), ST10452 (one total) and ST17722 (one total). S. sonnei comprised two sequence type, sequence types 152 and 17383, with one isolate flagged as MDR and 48 flagged as extensively drug resistant (XDR). This is an increase of 23 XDR isolates from the previous year and an equivalent number of MDR isolates. In total, foreign travel was associated with 6 of 55 (10.9%) isolates flagged as drug resistant, whereas cases with no travel accounted for 40 (72.7%) isolates flagged as drug resistant. This is a large increase from 2024 where travel was associated with 19 of 37 (51.4%) drug resistant isolates. For at least some of the cases without travel there is epidemiological evidence of local transmission of XDR Shigella within New Zealand. In some cases, reflex culture failure may cause underreporting of Shigella.