Community-Acquired Infection Caused by mcr-1 and bla OXA-48-Producing Escherichia coli : A Case Highlighting Limitations of Selective Susceptibility Testing

Selective antimicrobial susceptibility supports antimicrobial stewardship strategy but may have limitations in high-resistance prevalence settings. We report a community-acquired infection of necrotic metastatic inguinal lymphadenopathy caused by two mcr-producing Escherichia coli isolates, including one blaOXA-48 producer. Initial selective susceptibility testing delayed recognition of clinically relevant resistance. This case highlights the risk of silent community dissemination of high-priority resistance determinants. It underscores the need for context-adapted susceptibility reporting to balance antimicrobial stewardship and resistance surveillance.