Emergence of lineage III of Shigella sonnei ST152 belonging to a high-risk clone harboring the blaCTX-M-15 gene in Peru

Multidrug-resistant Shigella sonnei ST152, global lineage III, is a high-risk clone, whose dissemination has limited therapeutic options for shigellosis. This study aimed to characterize two isolates of S. sonnei, which were recovered in Lima, Peru, during November 2019, exhibiting resistance to extended-spectrum cephalosporins and quinolones, and concurrently harboring bla_CTX-M-15 and qnrS1 genes, in addition to mutations in gyrA-S83L. These isolates were resistant to ceftriaxone, ciprofloxacin and trimethoprim/sulfamethoxazole. The molecular analysis showed that both isolates belonged to lineage III, sublineages IIIa and IIIb. The bla_CTX-M-15 gene was located in the same genetic platform as qnrS1, flanked upstream by ISKpn19, on a conjugative plasmid belonging to the IncI-γ group. To the best of our knowledge, this would be the first report on S. sonnei isolates carrying the bla_CTX-M-15 gene in Peru. The global dissemination of S. sonnei ST152, co-resistant to β-lactams and quinolones, could lead to a worrisome scenario in the event of potential acquisition of genetic resistance mechanisms to azithromycin.