CEFTAZIDIME/avibactam, a key antimicrobial against multidrug-resistant Gram-negative pathogens, has seen increasing use across NHS Trusts in England since its 2017 launch, prompting new baseline data to inform resistance monitoring under the UK’s antibiotic subscription model.
To assess resistance trends and usage patterns before implementation of the subscription pilot in December 2020, researchers analysed routine surveillance and reference laboratory data from 2016 to 2020. Resistance categorisation was extracted from national surveillance records, while minimum inhibitory concentrations (MICs) and carbapenemase gene profiles were evaluated in referred isolates. Ceftazidime/avibactam usage across hospitals was measured using defined daily doses (DDDs).
Among 66,914 tested Gram-negative surveillance isolates, 6.3% (95% CI: 6.1–6.4%) were resistant to ceftazidime/avibactam. Resistance rates varied by species, with data from April 2019 to March 2020 showing resistance in 1.3% of Escherichia coli (288/22,736), 12.6% of Pseudomonas aeruginosa (690/5,495), and 6.1% of Klebsiella pneumoniae (314/5,179). MIC testing in 8,437 referred Enterobacterales isolates revealed 11.5% resistance (968/8,437), of which 89.3% (864/968) carried metallo-β-lactamase (MBL) genes, strongly associated with ceftazidime/avibactam resistance. Among 908 MBL-negative isolates harbouring non-metallo-carbapenemase genes, only 2.1% (19/908) showed resistance. Hospital use of the drug rose from 21 to 744 DDDs per month between March 2017 and March 2020, with uptake in 69.5% (105/151) of NHS Trusts during this period.
These findings highlight the importance of molecular diagnostics to guide effective therapy and support early identification of resistance patterns. Continued genomic surveillance and antimicrobial stewardship will be essential as ceftazidime/avibactam becomes further embedded in treatment strategies.
Reference
Guy RL et al. The importance of monitoring a new antibiotic: ceftazidime/avibactam usage and resistance experience from England, 2016 to 2020. Euro Surveill. 2025;30(14):2400399.
