New Delhi Metallo-β-Lactamase-Producing Enterobacterales Bacteria.

To the Editor: Findlay et al. () reported a high prevalence (>25%) of New Delhi metallo-β-lactamase (NDM) among carbapenemase-producing Enterobacterales (CPE) in Switzerland during 2019–2020. To provide context, we analyzed recent trends for NDM-producers in Germany.

In a whole-genome-sequencing–based surveillance study conducted in 52 hospitals in Hesse, Germany, during 2017–2019, we detected 56 NDM-producing isolates among 346 CPE. The prevalence of NDM CPE increased from 6.3% (5/79) in 2017 to 15.0% (17/113) in 2018 and 22.1% (34/154) in 2019. A total of 56 alleles—28 NDM-1, 27 NDM-5, and 1 NDM-7—were detected in 31 Klebsiella pneumoniae, 18 Escherichia coli, and 3 Citrobacter freundii isolates and 1 isolate each of C. portucalensis, Enterobacter hormaechei, K. grimontii, and K. variicola. Isolates were derived from rectal swab (30), urine (11), respiratory tract (6), and other (9) specimens. More than 82% (23/28) of NDM-1 were associated with K. pneumoniae and 59% (16/27) of NDM-5 with E. coli; 41% of the NDM-CPE harbored a 16S-rRNA-methylase gene.

Among carbapenemase-producing K. pneumoniae isolates, NDM increased from 6.4% (3/47) in 2017 to 24.5% (13/53) in 2018 and 31.9% (15/47) in 2019; ≈50% (15/31) were sequence type 147. Thus, reports for Switzerland () and Italy () indicate that sequence type 147 NDM-carrying K. pneumoniae is a CPE clone rapidly emerging in Europe.

NDM accounted for 20% (2/10) of carbapenemase-producing E. coli in 2017, 11.1% (2/18) in 2018, and 24.1% (14/58) in 2019; the increase in NDM-5–producing E. coli was primarily associated with IncF-type plasmids (). A subgroup harboring penicillin binding protein 3 modifications exhibited increased aztreonam/avibactam MICs of 2–8 μg/mL. Higher MICs (4–16 μg/mL) were associated with the presence of an additional highly conserved blaCMY-42–encoding IncIγ plasmid (). We reiterate the call by Findlay et al. to implement genome-based surveillance studies to identify emerging clonal lineages and commonly occurring plasmids among carbapenemase-producing bacteria.