NDM-35-Producing ST167 Escherichia coli Highly Resistant to β-Lactams Including Cefiderocol.

A multidrug-resistant (carbapenems, aztreonam + avibactam, and cefiderocol) ST167 Escherichia coli clinical isolate recovered from a patient hospitalized in Switzerland produced NDM-35 showing ca. 10-fold increased hydrolytic activity toward cefiderocol compared to NDM-1. The isolate co-produced a CMY-type β-lactamase, exhibited a four amino-acid insertion in PBP3, and possessed a truncated iron transporter CirA protein. Our study identified an association of unrelated resistance mechanisms leading to resistance to virtually all β-lactams in a high-risk E. coli clone.