The following is a summary of “Effect of follow-up blood cultures on mortality and antibiotic use in gram-negative bloodstream infections,” published in the August 2023 issue of Infectious Disease by Yildiz et al.

Gram-negative bloodstream infections (GN-BSIs) are a severe infection. The usefulness of follow-up blood cultures (FUBCs) in GN-BSIs and their effect on mortality and antibiotic use is controversial. Researchers conducted a retrospective study to evaluate the effect of FUBCs on mortality and antibiotic consumption in patients with GN-BSIs.

They involve patients >18 with GN-BSIs. FUBC, conducted 2-7 days after the initial culture, was compared between FUBC and no FUBC groups. A 1:1 match analysis was done based on the SOFA score. The matched subgroup was analyzed for mortality risk factors using logistic regression models. The two groups were compared regarding effective antibiotic therapy duration and total antibiotic consumption (DOT/1000 PD).

The results showed FUBC in 69.4% (564 out of 812) of patients. Rates of persistent, positive, and negative FUBC were 7.9%, 14%, and 78%. In patients receiving appropriate antibiotic therapy, the frequency of persistent GN-BSI was 3.9%. Independent risk factors for mortality included SOFA score (OR: 1.33; 95% CI, 1.23–1.44), Charlson comorbidity index score (OR: 1.18; 95% CI, 1.08–1.28), hospital-acquired infections (OR: 1.93; 95% CI, 1.08–3.46), and carbapenem-resistant GN-BSI (OR: 2.92; 95% CI, 1.72–4.96). There was no significant association between FUBC and mortality (P> 0.05). The FUBC group did exhibit a longer duration of effective antibiotic therapy (10(4–16) vs. 15(9–20), P<0.001) and higher DOT/1000 PD (1609 (1000–2178) vs. 2000 (1294–2769), P<0.001).

They concluded routine FUBC was not recommended due to the low prevalence of persistent infections and increased antibiotic use.

Source: bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-023-08500-9