A patient presented with an infection caused by New Delhi metallo-beta-lactamase (NDM-1)-producing Escherichia coli. This carbapenem-resistant Enterobacterales (CRE) strain exhibited susceptibility to aztreonam, an unusual finding for NDM-1 producers. The diagnosis was confirmed through microbiological testing, identifying the specific NDM-1 enzyme. The infection was successfully managed with aztreonam monotherapy, demonstrating its potential utility in cases where NDM-1 producing organisms retain susceptibility. This case highlights the importance of comprehensive susceptibility testing, as it can reveal unexpected treatment options for highly resistant pathogens. Teaching point: Aztreonam can be an effective treatment for NDM-1-producing E. coli if susceptibility is confirmed, despite typical resistance patterns.