Emergence of co-resistance to imipenem/relebactam and ceftazidime/avibactam in clinical Klebsiella pneumoniae ST11 clone due to KPC-2 N132S and CTX-M-65 S130G/P167S substitutions.

Two episodes of imipenem/relebactam and ceftazidime/avibactam co-resistant Klebsiella pneumoniae infections were identified in a Chinese hospital with an 8-month interval. All strains belonged to the ST11-KL64 clone, with pairwise SNP distances ranging from 1 to 9, indicating clonal spread. Plasmid-borne blaKPC-157 (KPC-2 N132S substitution) and blaCTX-M-249 (CTX-M-65 S130G/P167S substitutions) conferred resistance to imipenem/relebactam and ceftazidime/avibactam, respectively. The emergence of these novel resistance determinants in the high-risk clone underscores the need for enhanced surveillance.