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Objectives: Escherichia coli bloodstream infections have shown a sustained increase in England, for reasons that are unknown. Furthermore, the contribution of MDR lineages such as ST131 to overall E. coli disease burden and outcome is undetermined., Methods: We genome-sequenced E. coli blood isolates from all patients with E. coli bacteraemia in north-west London from July 2015 to August 2016 and assigned MLST genotypes, virulence factors and AMR genes to all isolates. Isolate STs were then linked to phenotypic antimicrobial susceptibility, patient demographics and clinical outcome data to explore relationships between the E. coli STs, patient factors and outcomes., Results: A total of 551 E. coli genomes were analysed. Four STs (ST131, 21.2%; ST73, 14.5%; ST69, 9.3%; and ST95, 8.2%) accounted for over half of cases. E. coli genotype ST131-C2 was associated with phenotypic non-susceptibility to quinolones, third-generation cephalosporins, amoxicillin, amoxicillin/clavulanic acid, gentamicin and trimethoprim. Among 300 patients from whom outcome was known, an association between the ST131-C2 lineage and longer length of stay was detected, although multivariable regression modelling did not demonstrate an association between E. coli ST and mortality. Several unexpected associations were identified between gentamicin non-susceptibility, ethnicity, sex and adverse outcomes, requiring further research., Conclusions: Although E. coli ST was associated with defined antimicrobial non-susceptibility patterns and prolonged length of stay, E. coli ST was not associated with increased mortality. ST131 has outcompeted other lineages in north-west London. Where ST131 is prevalent, caution is required when devising empiric regimens for suspected Gram-negative sepsis, in particular the pairing of β-lactam agents with gentamicin., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

Background: Escherichia coli are Gram-negative bacteria associated with an increasing burden of antimicrobial resistance (AMR) in England., Objectives: To create a comprehensive epidemiological picture of E. coli bacteraemia resistance trends and risk factors in England by linking national microbiology data sources and performing a longitudinal analysis of rates., Methods: A retrospective observational study was conducted on all national records for antimicrobial susceptibility testing on E. coli bacteraemia in England from 1 January 2013 to 31 December 2018 from the UK Health Security Agency (UKHSA) and the BSAC Resistance Surveillance Programme (BSAC-RSP). Trends in AMR and MDR were estimated using iterative sequential regression. Logistic regression analyses were performed on UKHSA data to estimate the relationship between risk factors and AMR or MDR in E. coli bacteraemia isolates., Results: An increase in resistance rates was observed in community- and hospital-onset bacteraemia for third-generation cephalosporins, co-amoxiclav, gentamicin and ciprofloxacin. Among community-acquired cases, and after adjustment for other factors, patients aged >65 years were more likely to be infected by E. coli isolates resistant to at least one of 11 antibiotics than those aged 18-64 years (OR: 1.21, 95% CI: 1.18-1.25; P < 0.05). In hospital-onset cases, E. coli isolates from those aged 1-17 years were more likely to be resistant than those aged 18-64 years (OR: 1.33, 95% CI: 1.02-1.73; P < 0.05)., Conclusions: Antibiotic resistance rates in E. coli-causing bacteraemia increased between 2013 and 2018 in England for key antimicrobial agents. Findings of this study have implications for guiding future policies on a prescribing of antimicrobial agents, for specific patient populations in particular., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Antimicrobial resistance is a major global health concern, driven by overuse of antibiotics. We aimed to assess the effectiveness of a national antimicrobial stewardship intervention, the National Health Service (NHS) England Quality Premium implemented in 2015-16, on broad-spectrum antibiotic prescribing and Escherichia coli bacteraemia resistance to broad-spectrum antibiotics in England., Methods: In this quasi-experimental, ecological, data linkage study, we used longitudinal data on bacteraemia for patients registered with a general practitioner in the English National Health Service and patients with E coli bacteraemia notified to the national mandatory surveillance programme between Jan 1, 2013, and Dec 31, 2018. We linked these data to data on antimicrobial susceptibility testing of E coli from Public Health England's Second-Generation Surveillance System. We did an ecological analysis using interrupted time-series analyses and generalised estimating equations to estimate the change in broad-spectrum antibiotics prescribing over time and the change in the proportion of E coli bacteraemia cases for which the causative bacteria were resistant to each antibiotic individually or to at least one of five broad-spectrum antibiotics (co-amoxiclav, ciprofloxacin, levofloxacin, moxifloxacin, ofloxacin), after implementation of the NHS England Quality Premium intervention in April, 2015., Findings: Before implementation of the Quality Premium, the rate of antibiotic prescribing for all five broad-spectrum antibiotics was increasing at rate of 0·2% per month (incidence rate ratio [IRR] 1·002 [95% CI 1·000-1·004], p=0·046). After implementation of the Quality Premium, an immediate reduction in total broad-spectrum antibiotic prescribing rate was observed (IRR 0·867 [95% CI 0·837-0·898], p<0·0001). This effect was sustained until the end of the study period; a 57% reduction in rate of antibiotic prescribing was observed compared with the counterfactual situation (ie, had the Quality Premium not been implemented). In the same period, the rate of resistance to at least one broad-spectrum antibiotic increased at rate of 0·1% per month (IRR 1·001 [95% CI 0·999-1·003], p=0·346). On implementation of the Quality Premium, an immediate reduction in resistance rate to at least one broad-spectrum antibiotic was observed (IRR 0·947 [95% CI 0·918-0·977], p=0·0007). Although this effect was also sustained until the end of the study period, with a 12·03% reduction in resistance rate compared with the counterfactual situation, the overall trend remained on an upward trajectory. On examination of the long-term effect following implementation of the Quality Premium, there was an increase in the number of isolates resistant to at least one of the five broad-spectrum antibiotics tested (IRR 1·002 [1·000-1·003]; p=0·047)., Interpretation: Although interventions targeting antibiotic use can result in changes in resistance over a short period, they might be insufficient alone to curtail antimicrobial resistance., Funding: National Institute for Health Research, Economic and Social Research Council, Rosetrees Trust, and The Stoneygate Trust., Competing Interests: Declaration of interests APRW was a member of the drug safety monitoring board for Roche and has given lectures at Merck Sharpe Dohme. All other authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Objective: The increase in Escherichia coli bloodstream infections mandates better characterisation of the relationship between commensal and invasive isolates. This study adopted a simple approach to characterize E. coli in the gut reservoir from patients with either E. coli or other Gram-negative bacteraemia, or those without bacteraemia, establishing strain collections suitable for genomic investigation. Enteric samples from patients in the three groups were cultured on selective chromogenic agar. Genetic diversity of prevailing E. coli strains in gut microbiota was estimated by RAPD-PCR., Results: Enteric samples from E. coli bacteraemia patients yielded a median of one E. coli RAPD pattern (range 1-4) compared with two (range 1-5) from groups without E. coli bacteraemia. Of relevance to large-scale clinical studies, observed diversity of E. coli among hospitalised patients was not altered by sample type (rectal swab or stool), nor by increasing the colonies tested from 10 to 20. Hospitalised patients demonstrated an apparently limited diversity of E. coli in the enteric microbiota and this was further reduced in those with E. coli bacteraemia. The reduced diversity of E. coli within the gut during E. coli bacteraemia raises the possibility that dominant strains may outcompete other lineages in patients with bloodstream infection.