Increased 30-day all-cause mortality associated with Gram-negative bloodstream infections in England during the COVID-19 pandemic

Background: Our aim was to assess the impact of COVID-19 pandemic on mortality in patients hospitalised with Gram-negative bloodstream infections (GNBSIs). Methods: A retrospective cohort study including cases of Escherichia coli, Klebsiella species and Pseudomonas aeruginosa in England (January 2015–December 2021) reported to UKHSA's Second Generation Surveillance System. The outcome was 30-day all-cause mortality. Multivariable logistic regression models were built, and adjusted Odds Ratios (ORs) with 95% confidence intervals were reported. Results: Total E. coli, Klebsiella spp. and P. aeruginosa infections were 206,030, 53,819 and 21,129, respectively. Compared to the pre-pandemic period, odds of death during the pandemic (March 2020 onwards) in E. coli, Klebsiella spp. and P. aeruginosa infections with no COVID-19 infection within 28-days of onset were 1.13 (1.08–1.18), 1.15 (1.07–1.25) and 1.09 (0.97–1.22), while odds in GNBSIs with an associated COVID-19 infection were 2.45 (2.26–2.66), 2.96 (2.62–3.34) and 3.15 (2.61–3.80), respectively. Asian patients with an associated COVID-19 infection were more likely to die during the pandemic compared to White patients (E. coli: OR 1.28 (0.95–1.71); Klebsiella spp. OR 1.59 (1.20–2.11); P. aeruginosa: OR 2.02 (1.23–3.31)). Conclusions: Patients suffering from a GNBSI had increased risk of death during the pandemic, with the risk higher in patients with an associated COVID-19 infection.