Genetic characterization of extensively drug-resistant blaCTX-M-27Shigella sonnei clusters among men who have sex with men in a region of northern Spain.

OBJECTIVE

The convergence of globalization with increased sexual risk behaviours has significantly facilitated the dissemination of multidrug-resistant and extensively drug-resistant clusters of Shigella spp. among men who have sex with men, particularly Shigella sonnei and Shigella flexneri. A cluster of S. sonnei carrying blaCTX-M-27 caused a European outbreak in 2020-2021, with more than 30 cases in Spain, including two in our institution. In this study, we conducted a retrospective study from October 2022 to December 2023 that included five additional patients with shigellosis caused by a CTX-M-27-producing S. sonnei.

METHODS

Genetic characterization was assessed by whole-genome sequencing using the MinION Mk1C device (Oxford Nanopore Technologies, Oxford, UK).

RESULTS

All the isolates presented IncB/O/K/Z or IncFII plasmids, which carried genes conferring resistance to second- and third-generation cephalosporins, cotrimoxazole, azithromycin and quinolones. SNP analysis revealed that neither the strains within this study nor the UK cluster were related to each other.

CONCLUSIONS

Different community clusters of extensively drug-resistant S. sonnei strains harbouring blaCTX-M-27 are spreading in our area, mainly associated with sexual transmission among men who have sex with men.