Volume 29, Number 11—November 2023
Research
Genotypic Evolution of Klebsiella pneumoniae Sequence Type 512 during Ceftazidime/Avibactam, Meropenem/Vaborbactam, and Cefiderocol Treatment, Italy
Table
MICs of antimicrobial drugs for Klebsiella pneumoniae sequence type 512 strains analyzed in study of genotypic evolution of such strains during ceftazidime/avibactam, meropenem/vaborbactam, and cefiderocol treatment, Italy*
| Strain | AZT | CZA† | FDC‡ | MEM | MVB† | IMI | COL | FOS | AMK | GTM | CIP | SXT | TGC |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 6379 | >4 | >256 | 8 | 32 | 1.5 | >8 | >4 | >64 | 16 | ≤2 | >1 | >4/76 | 2 |
| 1186W | >4 | 32 | 2 | 2 | 0.25 | ≤1 | >4 | >64 | >16 | ≤2 | >1 | ≤2/38 | ≤1 |
| 1186T | >4 | 32 | 2 | 4 | 0.25 | ≤1 | >4 | >64 | >16 | ≤2 | >1 | ≤2/38 | ≤1 |
| 6099 | >4 | 16 | 1 | 16 | 0.5 | >8 | >4 | >64 | ≤8 | ≤2 | >1 | ≤2/38 | ≤1 |
| 0296 | >4 | >256 | 32 | 32 | 0.047 | >8 | >4 | >64 | ≤8 | ≤2 | >1 | >4/76 | ≤1 |
| EUCAST breakpoint | 4 | 8 | 2 | 8 | 8 | 4 | 2 | 32 | 8 | 2 | 0.5 | 4 | ND |
*MICs are mg/L. Bold indicates resistance to antimicrobial drugs according to EUCAST breakpoints. AMK, amikacin; AZT, aztreonam; CIP, ciprofloxacin; COL, colistin; CZA, ceftazidime/avibactam; EUCAST, European Committee on Antimicrobial Susceptibility Testing (https://www.eucast.org); FDC, cefiderocol; FOS, fosfomycin; GTM, gentamicin; IMI, imipenem; MEM, meropenem; MVB, meropenem/vaborbactam; ND, not done; SXT, trimethoprim/sulfamethoxazole; TGC, tigecycline. †Tested by using the gradient strip method (Liofilchem, https://www.liofilchem.com). ‡Tested by using the Compact Antimicrobial Susceptibility Panel broth microdilution method (Liofilchem).