Mecillinam activity against multidrug-resistant Shigella sonnei and Shigella flexneri

• DOI: 10.1128/spectrum.01006-24
• Publication Date: 2025-02-07T14:01:36Z
• Authors: Aleksandra Stefan...; Leah Gowland; Gordon Ritchie; Colin Lee; Sam Chorlton; Nancy Matic; Victor Leung; Michael Payne; Christopher F. Lowe; Marc G. Romney
• Keywords: Mecillinam; Shigella sonnei; Shigellosis; Agar dilution

ABSTRACT We performed phenotypic susceptibility testing and whole-genome sequencing to investigate in vitro mecillinam activity against multidrug-resistant (MDR) Shigella . Ninety-five isolates (53 [56%] sonnei 42 [44%] flexneri ) were included. The MIC 50 90 1 2 µg/mL, respectively, by agar dilution, all zone diameters ≥15 mm disc diffusion testing. No known clinically relevant resistance mutations (including cys B) detected. favorable profile absence of markers make pivmecillinam an agent worth considering for the treatment infections caused MDR Clinically feasible methods standardized interpretations spp. are needed guide therapy. IMPORTANCE Rapidly emerging species leaves few antibiotic options. World Health Organization recommends pivmecillinam, a prodrug mecillinam, infections. However, little is about North America. on our collection resistant investigated genetic mechanisms using sequencing. observed lack resistance. laboratory guidelines testing, interpreting test results challenging. propose that further studies correlate data with clinical outcomes, aim establishing breakpoints mecillinam.