MDR Shigella sonnei in Spain: an ever-evolving emerging threat?

Area of Science:

• Microbiology
• Genomics
• Epidemiology

Background:

• Seven CTX-M-27-producing Shigella sonnei strains were isolated from patients with acute diarrhea at a Seville hospital in late 2021.
• These isolates were associated with men who have sex with men (MSM) transmission.

Purpose of the Study:

• To conduct a comprehensive microbiological and molecular epidemiological analysis of seven CTX-M-27-producing Shigella sonnei isolates.
• To compare these isolates with previously documented CTX-M-27-producing Shigella sonnei strains linked to MSM transmission.

Main Methods:

• Isolates were identified using biochemical and serological typing.
• Whole-genome sequencing was performed using MinION Mk1C, followed by genomic and molecular analyses.
• Comparative genomic analysis utilized the cgMLST (HierCC) scheme v1 from EnteroBase.

Main Results:

• All isolates exhibited resistance to multiple antibiotics, including penicillins, cephalosporins, fluoroquinolones, cotrimoxazole, and azithromycin.
• Key resistance determinants identified included blaCTX-M-27, ermB, mph(A), and qnrB19, along with QRDR mutations.
• Genomic analysis revealed close relatedness to other CTX-M-27-producing Shigella sonnei strains from Spain, Australia, and the UK associated with MSM transmission, despite variations in plasmid composition and genetic context of blaCTX-M-27.

Conclusions:

• The study confirms the emergence of CTX-M-27-producing Shigella sonnei (ST152) linked to MSM transmission in Spain.
• These findings add to the growing list of European outbreaks caused by this pathogen.
• Active surveillance and control measures are crucial for managing this high-risk clone.