Impact on clinical outcome of follow-up blood cultures and risk factors for persistent bacteraemia in patients with gram-negative bloodstream infections: a systematic review with meta-analysis

Background: The clinical usefulness of follow-up blood cultures (FUBCs) in gram-negative bloodstream infections (GN-BSIs) represents a debated issue.Objective: To assess the impact on the clinical outcome of FUBCs in patients with GN-BSI and to predict risk factors for persistent bacteraemia. Data sources: PubMed-MEDLINE, Scopus, and the Cochrane Library Database were independently searched until 24 June, 2022. Study eligibility criteria: Randomized controlled trials, prospective, or retrospective observational studies, including patients affected by GN-BSIs. Primary endpoints were in-hospital mortality rate, and persistent blood stream infections were defined as FUBC-positive for the same pathogen isolated from index blood cultures (BCs).Participants: Hospitalized patients with documented GN-BSIs. Intervention: Performance of FUBCs (defined as subsequent BCs collected at least 24 hours after index BCs). Assessment of risk of bias: Quality of included studies was independently assessed according to the Cochrane Risk of Bias Tool and the Risk Of Bias In Non-randomized Studies of Interventions. Methods of data synthesis: Meta-analysis was performed by pooling odds ratio (OR) retrieved from studies providing adjustment for confounders using random-effect model with the inverse variance method. Risk factors for persistent blood stream infections were also assessed. Results: A total of 3747 articles were screened, and 11 observational studies (6 assessing impact on outcome (N = 4631), and 5 investigating risk factors for persistent GN-BSI (N = 2566)), conducted between 2002 and 2020 were included. The execution of FUBCs was associated with a significantly lower risk of mortality (OR, 0.58; 95% CI, 0.49-0.70; I2 = 0.0%). The presence of end-stage renal disease (OR, 2.99; 95% CI, 1.77-5.05), central venous catheter (OR, 3.30; 95% CI, 1.82-5.95), infections due to extended-spectrum b-lactamase-producing strains (OR, 2.25; 95% CI, 1.18-4.28), resistance to empirical treatment (OR, 2.70; 95% CI, 1.65-4.41), and unfavourable response at 48 hours (OR, 2.99; 95% CI, 1.44 -6.24) emerged as independent risk factors for persistent bacteraemia.Conclusions: The execution of FUBCs is associated with a significantly low risk of mortality in patients with GN-BSIs. Our analysis could be useful to stratify patients at a high risk of persistent bacteraemia to optimize the use of FUBCs. Milo Gatti, Clin Microbiol Infect 2023;29:1150 & COPY; 2023 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.