Journal Club

Follow-Up Blood Cultures in Gram-Negative Bloodstream Infections

By Daniel Mendoza, MD

The clinical utility of follow-up blood cultures (FUBCs) in gram-negative bloodstream infections (GN-BSIs) is not clear. Gatti et al. performed a meta-analysis to assess the impact on clinical outcomes of FUBCs in patients with GN-BSI and to identify risk factors for persistent bacteremia. Their findings are reported in Clinical Microbiology and Infection.

The authors searched PubMed-MEDLINE, Scopus, and the Cochrane Library Database. They screened randomized controlled trials or observational studies that included hospitalized patients with GN-BSI. Primary endpoints were in-hospital mortality rate and persistent BSI defined as FUBC-positive for the same pathogen isolated from index BCs. FUBCs were defined as subsequent BCs collected at least 24 hours after index BCs. The authors performed the analysis by pooling odds ratios (ORs) retrieved from studies providing adjustment for confounders using the random-effects model with the inverse variance method. They also assessed risk factors for persistent BSI.

The authors screened 3,747 articles, and they included 11 observational studies (6 assessing impact on outcome [N = 4,631], and 5 investigating risk factors for persistent GN-BSI [N = 2,566]), which were conducted between 2002 and 2020. Execution of FUBCs was associated with lower risk of mortality (OR, 0.58; 95% confidence interval [CI], 0.49-0.70; I2 = 0.0%). 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 ESBL-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 unfavorable response at 48 hours (OR, 2.99; 95% CI, 1.44-6.24) were identified as independent risk factors for persistent bacteremia.

Performing FUBCs was associated with a lower risk of mortality in patients with GN-BSI. FUBCs done in patients with risk factors for persistent bacteremia could identify those who need further source control. 

(Gatti et al. Clin Microbiol Infect. 2023;S1198-743X(23)00114-3.)